IPT HSC Summary

IPT HSC Summaries Pg. 1 Patrician Brothers College 2010

HSC

Information Processes &

Technology

Summary Sheets


Characteristics

Types & Purposes

ExamplesFlat File D B

Relational DB

Data modelling

Hypermedia

Database Management Systems

Accessing Data

Storage M edia

Displaying

Issues

Information Systems & Databases

Organisation of data into information

Analysis of information to give

knowledge

Transaction Processing SystemDecision Support Systems

Expert SystemsManagement information Systems

Office automation systems

Database Management System:

School databaseRTA database

Video Hire databaseLibrary database

Organisation Methods

Non-Computer methodComputer base method

FileRecord

FieldCharacter

KeysSingle Key

Composite KeyPrimary Key

Secondary key

SchemaEntity

AttributeTuple

Relationship1:1, 1:many, many to

manyForeign Key

TablesForms

Data DictionaryCalculated Field

Field N ameData TypeField Size

Descr iption

Schematic Diagrams:Entity-Relationship diagram

(ER D)Normal isation

Hyper textUniform Resource Locator

StoryboardHTML

Storage & Retr ieval

DBMS Tasks:organising the data via data dictionary

Shows relationshipsChecks for data entry errors

Allow changes of DB structureRestricts access if neededShows performance of DB

Sequential accessDirect access

Index

Distributed databasetwo-phase commit

Online storageOffline storage

hard diskoptical disk

removable car tridemagnetic tape

flash card

EncryptionAsymetr ic encryptionSymmetric encryption

Backup/Securi tyData secur ity

Physical secur ityFirewal l

Data EncryptionClosed Circui t TV

Restricted Levels of Access

Sorting dataAscending

Descending

QueryingQuery by ExampleRelational opertorsLogical operators

Wi ldcard charactersSQL ->

Structured Query Language

Hypermedia & Searching

Search Engines (Web)Index

DirectoriesSearch robot

Other Information Processes

Repor ting:Hardcopy, softcopy

Repor t HeaderPage Header

DetailsPage Footer

Repor t Footer

Design of Di fferent Repor t Views:Headings -> Purpose

Layout -> tabular, columnText Balanced

Consistent stylesColumns have headingsWhite space used well

Page numbers/date included

Data Source

Accuracy of D ata:Data validation via ->

range checklist check

type checkcheck dig it

Data Integr ity

Privacy

Access to Data

Data warehousingData mining

Emerging Technologies:Smart Card

New DB software / strateg ies

Calculation of Storage:Total Field size of each field X

number of records = number of bytes


Concept: Information Process - Collecting Definition: involves deciding what to collect, locating it & collecting it. Summary Points: § data formats may be numbers, images, text, forms audio, video § input devices: pointing devices, scanners keyboard digital still cameras / video cameras, microphones, optical recognition devices (OCR). § operating system is used to interface with the hard ware collection device & the user Example: Flatbed scanner may be used to digitise an image. The operating system connects to the scanner.

Concept: Information Process - Organising Definition: involves the modification of data by arranging, representing & formatting data. Summary Points: § digitising is the process of translating data into binary digits that can be stored & used by a computer. § each type of data must be represented digitally text: ASCII; images: bit-map (jpg, gif) audio: sampling § application software organises data. Paint / draw, multimedia, word processing, desktop publishing, spreadsheet, database, slide shows. Example: Powerpoint may use text, images, video & audio. Each datatype is processed differently.

Concept: Information Process - Analysing Definition: involves the interpretation of data, transforming it into information. Summary Points: § information is processed raw data, it has been ordered and given meaning to people. § searching, sorting, modelling (simulations) ‘what if’ predictions, charts allows analysing Example: Counting the total number of students who do Biology in Year 12, sorting in alphabetical order

Concept: Information Process – Storing / Retrieving Definition: involves saving data & information for use (storing) and obtaining data and information that has been previously saved (retrieving) Summary Points: § writing and reading data to hard disk § direct access: access to data like a CD

sequential access: access to data like a casessette music tape. Used in backup magnetic tapes § floppy disk, usb flash drive, optical disks, zip disks § hard disk storage is in gigabytes generally. Example: A word document can be saved to an Apple machine, it is formatted as an Apple file, saved to the hard drive. The file is accessed directly. The entire hard drive can be backedup to magnetic tape using sequential access

Concept: Information Process - processing Definition: involves the manipulation of data & information. Summary Points: § speed of the cpu determines how quickly data can be processed. Current speed 3 gigahertz (clock speed) § images take a lot longer to process as compared to text due to the amount of memory / storage an image data type takes Example: Editing of a video takes up a tremendous amount of processing power to edit as well as storage of raw video footage. The final video is compressed using less storage but needs to be unencrypted when run.

Concept: Information Process – Transmitting / Receiving Definition: involves the transfer of data & information from within & between information systems. Summary Points: § parallel transfer: like a multilane highway

serial transfer: like a single lane highway § includes the use of networks and modem. § at least always transmits to a printer to produce a hard copy. Example: When one prints: from within information system. When one sends an attachment via email: it is transmitted between information systems.


Concept: Information Process - Displaying Definition: involves the output from an information system to meet a purpose. Summary Points: § includes monitors, printers, speakers & plotters § each application software displays data Example: a. Word processing draft shown on a monitor. b. Edited music listened to on speakers.

Concept: Information System Definition: a set of information processes requiring participants, data/information, & info. technology. It is created for a purpose, operates in a particular environment. It performs the 7 info. processes. Summary Points: § info technology includes software & hardware § participants are direct users of an info. system. A person using the screen at an ATM is a direct user at the moment. § A person using a clerk within a bank would be an indirect user at the moment. Example: Use of ATM, eftpos, library cataloguing system. RTA licensing, Netmeeting, web ordering, SMS, voice mail, video mobile phone

Concept: IS Characteristics: organisation of data into information (IS = Information System) Definition: data re-arranged so that it may be useful Summary Points: § must be organised before it can be stored & analysed by the info. system. § if not organised, data could be meaningless § may require sorting, summarising, classifying. Example: Paper forms for new school enrolments have to match the database fields that the school uses.

Concept: IS Characteristics: analysis of information to give knowledge. (IS = Information System) Definition: information is processed raw data Summary Points: § tools for analysis may include: tables, queries & reports from a database or spreadsheet § people make decisions based on the information they receive from an information system Example: After doing a count of students from the school’s database, it was discovered there are 30 less students in Yr.7 than Yr.8. Decisions have to be made as to how large the Yr.7 class sizes will be (24 versus 30).

Concept: Type of IS: Transaction Processing System Definition: collects, stores, modifies & retrieves the daily transactions of an organisation Summary Points: § buying goods at a Point of Sale terminal § processing eftpos / credit card transactions § keeping track of the volume of steel produced at Bluescope Steel Example: Tracking one’s new computer system on the web from Dell computers which is assembled in Malaysia.


Concept: Type of IS: Decision Support Systems (DSS) Definition: assists people to make decisions by provid ing information, models and analysis tools. Summary Points: § used when an organisation has to react to something unexpected (911, SARS epidemic) § used when changes have to be made § accuracy depends on mathematical model. § expert systems are a type of DSS Example: A stockbroker uses software that analyses the stock-market & helps the user to make decisions about buying or selling shares.

Concept: Type of IS: Expert System Definition: provides information & solves problems that would otherwise require a person experienced in that field (an expert). Summary Points: § an expert systems asks a lot of questions and com pares the answers to a knowledge base. § useful in diagnosing, monitoring, selecting, designing, predicting and training. § the solutions from an expert system are not always correct Example: Helps doctors diagnose infectious blood diseases & prescribes antibiotics. System uses medical history, symptoms & lab tests to make a recommendation.

Concept: Type of IS: Management Information Sys. Definition: provides information for an organisation’s managers. It presents basic facts about the performance of the organisation. Summary Points: § examples: reports on sales, stock inventory, payroll, orders & budgets. § Executive Information System: designed for the needs of senior managers & provide information on strategic issues, using data from the share market, commodity prices, interest rates & other economic indicators. Example: China’s economic indicators indicate it has a demand to purchase more steel from Bluescope steel. Manage- ment adjusts its planning accordingly.

Concept: Type of IS: Office Automation Systems Definition: provides people with effective ways to complete administrative tasks in an organisation. Summary Points: § software tools: word processing, spreadsheets, databases, desktop publishing, slide shows, project management § communication technologies: web browsers, email, facsimile, paging, voice mail, mobile phones § emails, forwarding phone calls, photocopying, printing via network, uploading to internet, sending faxes, paging Principal, radioing grounds people Example: The administrative tasks carried out by the Office staff at The Illawarra Grammar School. Same may be true at parents place of work.

Concept: Database Management System DBMS Definition: software package that builds, maintains, and provides access to a database. Summary Points: § School database: MAZE § School Library catalogue system: Alice § Video Hire database § RTA database § Accountant’s database § Board of Studies database § restricts access if needed § checks for data entry errors § shows db performance § allows changes of DB structure Example: A DBMS adds records, delete records, creates database design, links tables for relationships, produces reports, does queries and only allows one person to access a record at a time.

Concept: Flat file database Definition: organises data into a single table. Summary Points: § data redundancy occurs when using more than 1

db. § file: is a block of data. Divided into related records § record: collection of facts about 1 specific entry in a database. Divided into 1 or more related fields § field: specific category in a database. Data items are made up of characters. § character: the smallest unit of data people can use § keys: fields used to sort & retrieve information § single key: a field in which each item is unique § composite key: or compound key made by joining 2 or more fields together. eg. chrimeaipt04 § primary key: a key that must have a value, it can not be empty or null. It is unique. § secondary key: a second field that contains useful data, used for sorting. eg. Smith Anne, Smith Bill


Concept: Relational Databases Definition: organises data using a series of tables which are linked using relationships between fields. Attempts to keep data redundancy to a minimum. Summary Points: § schema: an organised plan of the entire database showing how & where data is found, descriptions of the data & the data’s logical relationships. Usually, schema consists of several pages with many elements: § entity: a specific thing in a relational database about which information is collected and stored. eg. school database would have an entity for students, teachers, classes, and students and classes § attribute: a defined property of an entity in a relational database. eg: student entity would have: studentID, Firstname, Surname, Address, City, etc.

Concept: Relational Databases - relationships Definition: the way entities are related to each other in a relational database. Summary Points: § Can be One-to-One § Can be One-to-Many § Can be Many-to-Many

Concept: Relational Databases – One to One Relationship Definition: this occurs when only one record in a table relates only to one record in a second table § A primary class has only one teacher and that

teacher is assigned onlyone class. § Only 1 customer can purchase a new car and the

sale of each new car is related to only one customer

NOTE: read the tables left to right AND right to left

Concept: Relational Databases – One to Many Relationship Definition: when a single record in the first table can be related to one or more records in the second table, but a single record in the second table can be related to only one record in the first table. § One student can take out many books from the

library, but any one book can be taken out by one student at a time.

§ This the most common relationship that exists

Concept: Relational Databases – Many to Many Relationship Definition: a single record in the first table can be related to one or more records in the second table, and a single record in the second table can be related to one or more records in the first table § Each student studies many subjects, and each

subject is studied by many students § Must use a linking table for many-to-many relationships in a relational database

Concept: Relational DB: primary / foreign key Definition: Primary Key is field that UNIQUELY identifies that object within its table eg. StudentID. Foreign Key is a field of a table that is a primary key of another table. It is used to create a relationship between a pair of tables.

Primary Key

Foreign Key


Concept: Relational DB – Linking Many-to-Many Relationship Definition: a linking table is inserted by copying the Primary key from each table

Concept: Relational DB: Tuple, Forms Definition: Tuple: a row in a table is called a tuple of an entity or one record. Form: in a db used to view, enter and change data in a table. Summary Points: § each tuple of an entity must be uniquely identified by a key § db forms can need to be well designed Example: Access database tables and forms used in past practical examples.

Concept: Relational DB: data modelling Definition: the process of identifying entities, the relationship between those entities & the attributes of those entities. Summary Points: § used to develop a schema for the database § is critical to creating an efficient database § tools used for data modelling:

§ data dictionaries § schematic diagrams § normalisation

Concept: Data modelling: Data Dictionary Definition: a comprehensive description of each field (attribute) in a database. (field size, data type, name, field description. Summary Points: § Field name is the name of the field § Data type: the kind of data that can be stored in in the field eg. text, memo, graphic, currency, date, logical fields (Y/N) § Field size: the number of characters allowed in each field (up to 256 characters). A memo field allows over 256 characters. § Description: specifies the contents of the field. eg. Access’ data dictionary § data dictionary consists of metadata which is information about data. It provides common ground if several people are developing the same database. It reduces data redundancy. § calculated field: has a formula into which a calculation results eg. calc_field = price * units

Concept: Data modelling: schematic diagrams Definition: graphical tools that help define the data base & develop a schema. § entity-relationship diagram (ERD) is a graphical method of identifying entities & showing relationships between them. § helps to decide what data is needed or excluded

Concept: Data modelling: normalisation Definition: the process of organising data into tables so that the results of using the database clear and used as intended. Summary Points: § A refinement process that aims to reduce data redundancy § complex data is separated into more tables. § First Form Norm (1NF): moving data into separate tables of a similar type. Each table given a primary key § Domain/key normal form (DKNF): a key uniquely identifies each row in a table. This is the final level of normalisation that db designers aim to achieve. Example: Having a database that has a table for products, a table for customers and a table about each product and its price.

1 1 n n

1n

1 1n n


Concept: DB Storage & Retrieval: Sequential access Direct access Definition: Sequential access occurs when data is accessed in a sequence. Direct access occurs when data is accessed without accessing previous data items Summary Points: § sequential: like accessing a song on a music cassette tape. To get to song 4, one has to fast forward through the first 3 songs. Used in backup magnetic tape. § direct: like accessing a song on a music CD. To get to song 4, one goes directly to it.

o an index may be used in a db. It is very like an index in a book. ‘Absolute referencing’ is on page 162 of the text book. o indexing requires more processing o records are rarely physically sorted in a db

Concept: DB Storage & Retrieval: distributed db Definition: is a database located at more than one site. It acts like a single collection of data but is geographically dispersed. Summary Points: § reduces the cost of transmission § more difficult to obtain a complete view of the db § needs to be synchronised with each other. § a two-phase commit is used to maintain consistency Example: The RTA may use a distributed db system.

Concept: DB Storage & Retrieval: storage media Definition: online: storage device is directly under the users control. Offline: storage device is not directly under the users control. eg. centralised database Summary Points: § hard disk: made of metal covered with magnetic material. Direct access. Measured in gigabytes usually § optical disk: plastic disk. Data is read / written to disk using laser technology. CD, DVD § removable cartridge: hard disk encased in a cartridge and can be removed like a floppy disk. eg. zip drive, jaz disk § flash memory: data stored to flash memory eg. usb thumb drive § magnetic tape: cheap, thin plastic ribbon inside a cartridge. Sequential access. Used in backups of data bases.

Concept: DB Storage & Retrieval: Encryption / Decryption Definition: process of encoding data (encryption) and process of changing it back (decoding, decryption). Summary Points: § most effective way of achieving data security during transmission. § essential for transferring financial transactions § used extensively on the Internet § involves complex manipulations of bit patterns. § asymmetric: requires a key for encryption & a key for decryption. Public key is used to encrypt, private key is used to decrypt. § symmetric: requires the same key for both encryption and decryption. eg Data Encryption Standard

Concept: DB Storage & Retrieval: Backup Definition: backup is another copy of the data that can be used to rebuild the system. Summary Points: § when the system goes down, the backup is used in the recover procedure § son, father, grandfather backup strategies § inferential backup strategy: since last full backup only daily files changed or are new are backed up daily § differential backup strategy: since last full backup weekly new or changed files are backed up daily Example: Student directories of TIGS are backed up everyday with a full backup done on Friday evenings.

Concept: DB Storage & Retrieval: Security Definition: involves a series of safeguards to protect the data and the data’s physical storage media. Summary Points: use encryption § close circuit TV on terminals § allow restricted access to work station room via key lock, swipe card or biometrical device § use level of password control. Administrator has control over the entire db. User is restricted parts of the db and can only read the data, can’t modify the data § use a firewall if connected to the Internet (verifies & authenticates incoming data) § store backup tapes off site Example: MAZE, school’s database. Bursar has full control, secretaries have partial control (can modify records), staff has access to student records only and can only read the records.


Concept: DB Manipulations: Summary Points: § sorting: the process of arranging data in a

particular order: descending or ascending § searching: the process of examining the database to retrieve selected data. Large db’s create a query. § query: is the search of a db for records that meet a certain condition eg. Classname = IPT § query by example (QBE): in Access, a graphical user interface is used for the user to match criteria against a field. § SQL: in Access, QBE produces SQL language in the background. (structured query language) Example: Access database practical examples used in class.

Concept: DB Manipulations Summary Points: § Relational operators: indicates relationship between 2 expressions eg. Order ID = 15 § Logical operators: used to combine queries eg. AND OR NOT operators used. § wildcards: represent unknown characters. eg. ?? stands for two characters. * substitutes for any number of characters § Lastname = Ma? may produce Mat or May § Lastname = Ma* : Madrid, Martinelli, Martin, Mars

Concept: DB Manipulations Summary Points: § sql contains key words such as SELECT, FROM, WHERE and ORDER BY § must use correct syntax § QBE allow easy generation of SQL

Concept: DB Displaying Definition: presenting the output from a db to meet a given purpose. A report is the formatted & organised presentation of data. Summary Points: § Report generator quickly produces a professional looking report. § hardcopy or softcopy reports § report header § page header § details of body § page footer § report footer Example: A report generated in Access by using the Report Wizard which includes all the above summary points

Concept: DB Report Design Definition: Reports should be designed well. Summary Points: § Headings should indicate purpose § Layout: tabular, column § use of text should be balanced with white space § use of consistent styles § page numbers / dates should be included Example: A report generated in Access by using the Report Wizard which includes all the above summary points

Concept: DB Issues: Data source Definition: The source of the data is the person or organisation that developed the data Summary Points: § ethical issue: goes against the moral code of a society eg. copying music illegally § social issue: has impact upon the individual and a significant number of people of a society. (locally regionally, & nationally). ATM’s displaced workers. § informal source: conversation, meetings or observation § formal source: report, book, official document § no guarantee to source’s accuracy § shouldn’t use other people’s work without per- mission (copyright) Example: text, images gained from the Internet should at least be acknowledged in one’s work.


Concept: DB: Accuracy of Data Definition: is the extent to which data is free from errors. Data validation techniques are used to check data entry in a database form. Summary Points: § range check: restricted to a range of values eg. postcode range > 500 and < 8500 § list check: compared to a list of acceptable data. eg. lookup table for the states in Australia. Entry is slower, but more accurate § type check: checks that the data type is correct. eg. text is entered when a number is required in a db field. § check digit: a digit calculated from the digits of a code number

Concept: DB: Integrity of Data Definition: describes the reliability of data. It is accurate, current & relevant Summary Points: § Need to cross reference when researching on the Internet § An URL may be accurate at first, but 3 months later, the URL may be a dead link, hence, not current nor relevant. § data accuracy, data security & data integrity are closely related to each other. Example: A new David Jones customer may subscribe to their catalogue. If customer moves & doesn’t notify DJ’s, data has lost its integrity.

Concept: DB: Privacy Definition: is the ability of an individual to control personal data. Summary Points: § db’s allows client lists to be sold to marketeers § users of a db system have different levels of access depending on their username & password § db lists are for sale on the Internet § gov’t db’s allows for cross – referencing on individ uals to try to stop fraudulent claims. § credit card numbers are encrypted & stored in databases § Australians may check their files and go through procedures to correct errors in their files Example: Clerical staff have copied staff phone numbers & addresses & sold them to Insurance sales people who in turn contacted staff on the list to make a sale.

Concept: DB: Warehousing & Datamining Definition: data warehouse is a database that collects information from different data sources. The data is analysised to assist in decision making. Data mining is a process that looks for relationships & patterns in the data store in the data warehouse. Summary Points: § data mining discovered that the air conditioning of certain jet aircraft malfunctioned 2 or 3 weeks before that particular model crashed. Example: There may be a relationship between meat pie sales & tomato sauce sales.

Concept: DB: calculation of Storage Total Field size of each field X number of records = number of bytes

Concept: DB: Emerging technologies Summary Points: § smart card: accounts are debited from smart card; much personal details can be placed on it § New database software and strategies


Concept: Definition: Summary Points: News Article: Y/N § § § Example:







components

Characteristics

Examples

Communication Concepts Network Hardware

Network Software

Processing

Displaying

Messaging systems

Internet

Emerg ing Technolog ies

Protocol

Collecting

Communication Systems

Data SourceTransmitter

Transmission medium

ReceiverDestination

ProtocolsHandshaking

Speed Error Checking

Comms Settings

TeleconferencingMessaging Systems

Electronic Commerce

Transmitting & Receiving

Transmission of DataProtocols / handshaking

NetworksNetwork Topolog ies

Network AccessMethods

Network Inter face cardServers

Routers/SwitchesBridges/Gateways

HubsTransmission Media

Wireless transmission

Network AdministratorNetwork Operating system

administrationfi le management

appl icationsresource management

securi tyLogon / Logoff

IntranetExtranet

Other Information Processes

Encoding / Decodinganalogue / dig ital conversions

AttachmentsClient-server architecture

peer to peerdata conversions

TelephoneEFTPOS terminal

Web pageComputer M onitor

Television

Issues

Social contextMisinterpretation

Power relationshipsPrivacy/Confidentiality

E-junk Mai lInformation Over load

Internet Trading:Taxation

Employment ripplesNature of business

Trade bar iersCensorship

Internet BankingRadio & Video

ICQ, FTPNetiquette

spamLess Isolation in CountryWireless laptop securi ty

Working from Home:Telecommuting

Vir tual Organisation

BandwidthHacking software3G mobile phonesLAN within homesLG Refr idgerator

Internet via power cablesTyranny of Distance

New video / audio codecsNew search engines

Larger data pipesdig ital TV

WAPThin Cl ients

ConvergenceBluetooth wireless

Wireless laptops, bui ldings

Traditional Messaging:TelephoneCall waiting

Call blockingFax

Paper messagePager

New MessagingVoice Mail

EmailSMS

Mobile PhoneMob. Phone

Services: weather , news, airl ines

OSI Reference ModelLayer 7 application

Layer 6 presentationLayer 5 sessionLayer 4 transpor tLayer 3 networkLayer 2 data linkLayer 1 physical

token passed

Polling

Carrier Sense Multiple Access & Collison Detection

CSMA/CD

ATM terminalsEFTPOS terminals

Telephones - voice mailkeyboards - email

video camerasbarcode scanner

Hybr id


Concept: Communication System Definition: enables people to send & receive data and information Summary Points: § data source: produces the data to be sent § transmitter: encodes the data into a signal suitable for a transmission medium § transmission medium: is a channel, such as a cable, in which the signal is transmitted to the destination. Signal may be distorted or changed during transmission. § receiver: decodes the signal back into the original data or an approximation of the data. § destination: is the receiver of the information Example: FM commercial radio stations. eg. Wave FM

Concept: Protocols Definition: In data transmission, a set of rules that governs the transfer of data between computer devices. Summary Points: § computers must use the same protocols or data transfer will be unsuccessful § a German and a French person may agree to speak English so that communication can take place § protocols have been written to International standards Example: The computers at TIGS communicates with the file- server using the Ethernet protocol. http: means hypertext transfer protocol (web pages)

Concept: Handshaking Definition: the sending of signals to reach an agree- ment about which protocol to use to accomplish an exchange of information. Summary Points: § in a modem, those crunching sounds is handshaking in progress § when 2 devices successfully handshake, a connection is made § hardware flow control: uses a dedicated connection, such as a wire, to control the flow of data § software flow control: uses a special code sent with the data to control the flow of data: XON/X0ff Example: When the printer buffer is full, the printer sends a XOFF to pause print data until the buffer empties.

Concept: Speed of Transmission Definition: the speed of data transmission is deter- mined by the transmitting device & bandwidth. Summary Points: § bandwidth: the capacity of the transmission ium. eg. fibre-optic § bits per second: is the maximum number of bits that can be transmitted in 1 second. bps aka bit rate § baud rate: maximum number of electrical cycles that can be transmitted in one second. Example: 56,000 bits may be forced through a baud rate of 4,800.

Concept: Error Checking Definition: When data arrives at its destination, it may contain errors. Summary Points: § parity check: can be odd or even. Addition of binary numbers agreed to be odd or even. 2 errors cancels each other out indicating correct transmission § checksum: 0’s & 2’s in a block summed. Checksum is sent to receiver. Receiver carries out checksum. If agreed, OK sent. If not block resent. Errors can also cancel each other out. § CRC: binary numbers in the block are treated as 1 long binary number & divided by a number (CRC-32). The remainder of the division is retained & sent. Receiving computer does the calculation. If both agree OK is sent, if not block is re-sent. § Error correction: most common, simplest is to send a code back to retransmit the last data block.

Concept: Communication Settings Definition: parameter settings that may be altered to allow computer or peripherals to communicate. Summary Points: § bits per second: speed of transmission: 56,000 § data bits: the number of bits in each group of data which is a 7-bit ASCII or 8-bit ASCII § parity: indicates if data has parity for error detection. odd, even or None § stop/start bits: parameter is used to identify each byte. (start of a byte, end of a byte). § flow control: handshaking protocol such as XON/ XOFF Example: Computers communicate with printers using these settings as well as to other computers.


Concept: Teleconferencing Definition: the use of electronic transmission to allow a meeting to occur at the same time in different places Summary Points: § audio conference: a single phone call involving 3 or more people at different locations. § video conference: allows people in different places to see video images & audio of each other. § teleconferencing reduces costs (airfares, hotels meals) by simulating a face-to-face meeting. Example: Bluescope Steel management video conferences with a branch in another country eg. China

Concept: Messaging System Definition: used to send messages to people in different locations who can receive the message at a later time. Summary Points: § Traditional: include the telephone & fax. § telephone answering system § Fax: sends graphics over telephone lines. § computers may have a fax modem § voice mail: storing & forwarding spoken messages stored digitally . Example: Typical small business will have a telephone, answering machine and fax. Mobile phones offer voice mail. Middle management TIGS staff have voice mail.

Concept: Electronic Email Definition: mail sent electronically. Has been around long before the Internet came into being. Summary Points: § email address: consists of 2 parts § cc: carbon copy. Everyone can see to whom it was sent § bcc: blind carbon copy. Sent to other people but they can not see who else it was sent to. § subject: topic of the message. Beware of general topics, could have a virus. § reply: automatically inserts return email address § address book: contains people’s email addresses § mailing list: a group of people who may want to receive the same messages. § signature: several lines that can be appended to emails automatically.

Concept: Electronic mail continued: Issues: § spam § anti-spam legislation to prevent spam § anti-spam software, filters in email software § society impact: an additional activity (checking email) for 10 – 20 minutes daily close to a set time. § organizations (TIGS) use to to communicate internally. § beware of creating emotional replies § deleted emails can be recovered by an employer and used against an employee if sent on employers email system § spread of viruses. Plain text is the only safe method. HTML can have hidden virus coding. Don’t open attachments without scanning for viruses. § reduces the tyranny of distance world wide § spread of Internet cafes

Concept: Electronic Commerce Definition: is the buying and selling of good and services through the Internet. Summary Points: § provides 24 hour availability, global reach § security of credit card numbers are an issue § amazon.com, www.ebay.com most famous at the moment for web orders § has gone through a bust cycle. § EFTPOS connects from retailer to bank § Internet Banking: people transfer funds between accounts at home, bank employees lost jobs, banks closed Example: www.wineplanet.com.au was a famous site in Austral- ia for selling wines. Wholesalers refused to sell to them at a fair price. Eventually the company was pur- chased & the site no longer exists.

Concept: Parallel/Serial Transmission Definition: Parallel: transmission of data at the same time using separate channels. Serial: transmission of data one after the other Summary Points: § Parallel: like a multilane highway. 8 bits arrive at the same time. Is faster but easily gets out of syncro- nisation. Limited cable length: 3 metres § Serial: like a single lane highway, 8 bits arrive one after the other. Slower, but easy to detect errors and correct.

0 1 0 0 1 1 0 1

01001101


Concept: Asynchronous / Synchronous transmission Definition: Asynchronous: sending of data by identifying each byte with special start & stop bits. Synchronous: requires all data to be sent at the same time.

Concept: simplex, half-duplex, full-duplex data flow Definition: Simplex: 1 direction: eg. TV transmission

Half-duplex: both directions but only 1 way at a time. eg. Citizen’s Band radio (CB radio). or

Full-duplex: both directions at the same time. eg. telephone conversation

Concept: Some common data Transfer Protocols: § x.25: standard packet switching protocol. Used for low speed applications, such as credit card veri- fication & automatic teller machine transactions. § TCP/IP: transmission control protocol/ Internet protocol. Common set of rules for data transmission & error detection across the Internet. It works by break- ing information into smaller packets of data. § HTTP: hypertext transfer protocol. Allows access web pages that are based on hypertext. Enables user to send & receive files over the Internet § FTP: file transfer protocol. Enables user to login to a server. Oldest form of remote file access for the Internet. § POP: post office protocol. Specifies how email messages may be exchanged between a computer an ISP

Concept: Data Transfer Protocols continued: § MIME: multipurpose Internet Mail. designed to enable files to be sent across the Internet as email. § XModem: file transfer protocol developed in the late 70’s for PC’s. Data is transferred in blocks 128 bytes long. Later versions supported CRC. § YModem: an extension of XModem. Blocks increased to 1024 bytes long. Increased reliability of error checking & increased data transfer. § ZModem: rectified limitations of YModem. Uses a variable block size, supports CRC, provides for high speed packet & network communication environments.

Concept: Network Definition: is a number of computers & their periph- eral devices connected together in some way. Summary Points: § node: each device in a network § terminal: devices that send & receive data from another computer system. § PC’s classified as intelligent terminals since processing can be done at the terminal. § Local Area Network: LAN. Covers a small geo- graphical area. § WAN: can used normal phone line, leased data lines. (Wide Area Network) § packet switching: a technique that divides messages into small data packets, transmits the packets, and later re-assembles the packets to form the original message. Packets do NOT have to take the same route to destination.

Concept: Topology is the physical arrangement of the devices in a network. Definition: Bus: all the devices are attached to a direct line called the bus. Summary Points: § nodes listen if the network

is clear. If so, a node will transmit.

§ If collision occurs, CSMA/CD Carrier Sense Multiple Access and Collision Detection allows node to re-transmit at later time.

§ Ethernet Protocol is base on a bus topology.


Concept: Topology: Star Definition: has a central computer with each device connected directly to it. Summary Points: § central computer

receives messages & sends them to the destination.

§ No data collisions with this method

§ if central computer fails, entire system goes down.

§ allocates a certain amount of CPU time for each user

Concept: Topology: Ring Definition: all devices are attached so that the path is the shape of a continuous circle. Summary Points: § each device as a unique address § data flows in one

direction, moving from device to device until it arrives at destination

§ This avoids data collisions

§ A node transmits when it receives a token, hence, token ring network

Concept: Server Definition: is a computer that provides services to other computers on the network. Summary Points: § file server: stores the programs & data shared by users. Files can be retrieved by any node if it has access rights. § print server: controls 1 or more printers & stores data to be printed (print queue). § mail server: provides email facilities. Stores incoming mail for distribution & forwards outgoing mail. § web server: provides a connection to the Internet. Stores web pages that are accessed by others via the Internet through their browsers. eg. IPT web site.

Concept: Data Traveling between networks Summary Points: § router: determines where to send a data packet between networks. It determines the best route for a given data packet. § switch: directs data packets along a path within a LAN. Is a simpler device than a router. High speeds. Limits traffic to the intended node rather than being broadcast over the entire network as a hub does § hub: a central connecting device to nodes. Centralises cable connections. Smart hubs exist today. Used in slower connections (10Mb/sec.) § bridge: links two similar networks. § gateway: links two dissimilar networks.

Concept: Network Access Diagram (Worth memorising).

Concept: Web server with Order Form (Worth memorising)

Web & Merchant Server

Buyer with Browser

Catalog and Order Database

Financial Network

Internet Web & Merchant Server

Buyer with Browser

Catalog and Order Database

Financial Network

Internet


Application Web Server

Application Web Server

Encrypted Payment authorisation request and

response

Encrypted Payment authorisation request and

responsePrivate AS2805 secure network

Westpac bank

Private AS2805 secure networkPrivate AS2805 secure networkPrivate AS2805 secure network

Westpac bank

End UserEnd User

Credit Card

Processor

eSec

Credit Card

Processor

eSec

Credit Card

Processor

eSec

Concept: Credit Card Payment Solution Networks

Concept: Transmission Media Definition: data is transferred along a transmission medium Summary Points:

Concept: Transmission Media continued: Summary Points: § twisted pair: consists of copper wires twisted to form a spiral. Twisting reduces the amount of interference from other cabling. Cat 5, 6 cabling are twisted in a special manner to allow 100 kbps. It is the slowest medium § coax: like the cable running from one’s VCR to the back of the TV. Has shielding to allow for little electrical distortion. Used over a few kilometres. Haven’t seen it used in recent times. § fibre-optic: uses laser light to carry data. It is free from electromagnetic & radio interference. Can transmit at high speeds & is secure. Example: cat 5 is blue cabling at back of computer. TIGs uses a combination of Cat 5 cabling and fibre- optics to send data to the various buildings. No coax is used.

Concept: Network transmissions § baseband: uses the entire capacity of copper cabling to transmit one signal at a time. § broadband: divide the cable so that several signals can be transmitted at the same time. eg. ADSL sends the phone signal & internet signal through 1 phone line § wireless: moves data through air & space. § microwave: high-frequency radio signal sent through space in a straight line from 1 antenna to another. Weather can affect transmission rates. § satellite: specialised receiver & transmitter placed in orbit. A signal is sent from the ground to the sat- elite & back to ground. eg. TV signals from Europe to Australia. § Wireless LANs: use radio waves not cables for the LAN medium. Becoming very popular but there are security concerns. § mobile phones: transmit data to a grid of cellular stations that are linked to wire-transmission telephone network.

Concept: Network Operating System Definition: is an operating system designed to support computers connected on a LAN. It contains the rules for communication & determines how to send & receive data. Summary Points: § NOS tasks: administration-> manages users, file- management eg. home directories, applications-> handles requests to share applications & data, reroutes to specific printer, resource management, security § network administrator: person who manages the network: grants access rights to users & various directories, network security, installing new software, updating software, monitoring daily activity, enforcing licensing agreements, developing a storage system, carrying out backups. § login / password procedures: usernames have different levels of access in the network. eg. comput- ing teachers can read students files in their home directories but can’t write to them.

Concept: Intranet Definition: is a private network that uses a similar interface to the Web. Summary Points: § main purpose is to share information, resources among employees of an organisation. eg. industrial technology at TIGS-> can be seen at school but not through the Internet. § usually has links to the Internet (seamless) § users sometimes can’t tell if they are using an intranet or the Internet § Extranet: is an intranet that is accessible to customers, suppliers or others outside the ogranisation Example: TIGS has access to the intranet run by the company that carries out most of the networking support. TIGS is able to check on the status of a particular works order that TIGS has given them. If it isn’t in the system, then the order isn’t being carried out. (Saves phone calls).

• RJ-45 Connector Unshielded Twisted Pair

• BNC connector Coaxial Cable

• ST fibre-optic connector


Concept: Collecting, Processing & Displaying in communication systems. Summary Points: § collecting: generating that data to be transmitted. eg. ATM keyboard entry, EFTPOS, telephones for voice mail, keyboards for email, video cameras for surveil- lance, bar code scanner. § processing: converting the data into a form for transmission-> involves coding & decoding. § encoding: converting data from original form to another form. § decoding: convert data from form used in transmission to its original form. § computers use digital signals. The real world analogue has to be converted to digital signals. § modem: modulate, demodulate analogue. computer digital -> analogue telephone lines ->receiv- computer digital signal § email attachments are encoded for transmission

Concept: Client-server architecture Definition: describes the software relationship between the client (user) and the server. Summary Points: § the web browser is a client (user) program that requests services from a web server using agreed protocols, that being http: Example: Every time a student requests a web page through their computer, they are using a client-server architecture.

Concept: Displaying Definition: the presentation of information in the form of text, numbers, images, video or audio. Summary Points: § audio information is displayed when using a telephone. eg. retrieving voice mail § web page § EFTPOS terminal: if transaction approved, it is

displayed on the screen. A receipt is printed out through the terminal listing all the transactions.

§ computer monitor § phone menu of an organisation “press 1 if you want… “ Example: Any electronic financial transaction.

Concept: Communication Issues: Summary Points: § social context: ideas delivered by messaging systems appear less forceful & caring. § misinterpretation: statements can be misunder- stood due to a lack of reading body language or hearing the tone of the voice in personal interaction. § power relationships: email provides an easy way to communicate with the CEO of an organisation rather than going through the chain of command. § junk email: spam § information overload: refers to the enormous amount of information that people have to absorb. § small business owers eg. trades people are working a longer week courtesy of the mobile phone.

Concept: Communication Issues continued: Summary Points: § Internet trading: is increasing due to 24 hour day shopping and global market § taxation: gov’t can’t tax transactions carried out on the internet, reduces gov’t funds for gov’t projects. § Employment: physical buildings & workers may decrease but more people needed in IT industry § Offshore employment: call centres located in India § Nature of business: is changing. People are ordering via the web their green groceries, groceries, etc. due to their hectic lifestyle. Internet banking § trade barriers have become less important. eg. people using ebay to order a product from overseas. § Censorship: nations such as China have attempted to stop the use of the Internet to keep the population under control. § Censorship: the amount of offensive material, eg. pornography should be banned to protect children

Concept: Communication Issues continued: Summary Points: § Internet banking: allows transfer of monies 24 hours a day between accounts & pay using Bpay. * security: data encryption is used to secure data transfer. Monthly articles on how false web sites obtain usernames, account numbers & passwords * changing nature of work: people require more IT skills than banking skills * branch closures & job loss due to EFTPOS, ATM’s & Internet banking § radio: radio on the Internet. eg. ABC radio can be heard in North America § video: can be streamed, quality is less. Video has not taken off due to the limited bandwidth currently. * video can be downloaded & played. * film piracy eg. The Last Samurai actually went 24 hours before first illegal copy hit the Internet


Concept: Communication Issues continued: Summary Points: § telecommuting: people are able to work from home & send files back & forth. Saves the environment, flexibility of hours. eg. Graphic Design Artists. § virtual organisations: workers are able to meet via video conferencing at an agreed time. Face to face meeting minimised. § ICQ, Netmeeting: chat software. People are able to disguise themselves. Cases of people convicted of luring young children into their presence. § Netiquette: proper behaviour on the net. § Less isolation for people in the rural areas. § Wireless laptop technology is becoming much more popular but there are security concerns. Hasn’t taken off in Australia like European countries. Quite expensive. eg. hot spots located in parts of North Sydney

Concept: Emerging Technologies: Communications Summary Points: § bandwidth will continue to increase. Price is going down in Australia. eg. Telstra is making a big push. § hacking software: will continue to be developed to get at financial records or credit cards. § 3rd generation mobile video phones. § LANs within homes § LG refrigerator, internet connection, notifies technician if a problem is developing, keeps track of goods inside § Internet access via power points rather than telephone cables. § Tyranny of distance reduced § New video / audio codecs eg. wma, wmv § New search engines to challenge Google § WAP: hasn’t been a success in Australia § Convergence of digital technologies § selling of goods through ATM’s

Concept: Emerging Technologies: Communications Summary Points: § larger data pipes for multimedia § thin clients: all applications come from a server, the client is just a terminal. Good way to use obsolete computers § Bluetooth wireless: is available but is difficult for the common user to operate § use of wireless laptops inside buildings eg. library § monitoring of inventory within vending machines





batch processing

realtime

DataValidation

Collecting

Analysing

Characteristics

TPS Examples

Issues

EmergingTechnology

Transaction Processing Systems

Generates / M odifies data

Collecting/Storing Rapid response

Reliabil ityInflexibi lity

Control led Processing

Advantages:Control When to processEconomical to process

Cost per transactionResul ts stil l useful

Standardisation

Disadvantages:Wait until a set timeCan't correct er rorsSorting expensive &

time consuming

ConcurrencyAtomici ty

Transaction Moni torDifferences batch / real time

Ensure transactions are correct & proper ly stored in the database

Transaction initiationField checking: range check, list check, type check, check dig it

Manual transaction systemsComputer ised transaction

systems

Components:Users

ParticipantsPeople

Real TimeReservation Motel

Reservation Ai rplanePoint of Sales Terminals

Library Loan systemEFTPOS terminal / card reader

Batch ProcessingCheque Clearance

Bil l GenerationCredit Card Sales transacitons

Offline, Centralised,Decentralised

Databases / Fi lesHierarchial DBNetwork DB

Relational D B

DB Design:Good data placement

Shor t transactionsReal time backupHigh normal isation

Archiving histor ical dataGood hardware configuration

File -> block of dataMaster file

Transaction fileRepor t fileWork file

Program file

Data warehousingDataming

ConsolidatedSubject oriented

Histor icalRead ony

Stor ing & Retr ieving

Recovery ProcessBackup / M edia

JournalCheckpoint

Recovery ManagerBackward recoveryForward recovery

Magnetic Tape MediaGrandfather- father-son

Partial backupsInferential

Differential

Updating in batchsequential acess

Updating in real timedirect access

InformationProcesses

Other

Hardware: MICR, ATM ,

Barcode readers, Forms -> paper ,

on-screen forms,web forms

Decision Support systemsDatamining

Management Information sys

Nature of WorkAutomation of jobs

People as participants (ATM s) less personal

approachNon-computer

proceduresBias

Importance of datadata securi tydata accuracydata integri ty

Control in Transaction processing

Credit Card checksWeighing Grocer ies no checkout

personBetter encryptionBetter fi rewalls

Electronic document management systems

ATMs order flowersMobile phone: pay for Dr ink

SMS Truancy

Data Integr ity:Atomici ty

ConsistencyIsolation

Durabil ity

Secur ity:Off site storageSecure on si te

(safe)Uninter ruptible Power Supply

Stor ing Data:sequential files

indexed sequential fi les

hashed files

Credit Card:Real time: lost, stolen,

cancelled, over l imtBatch: money transferred,

new balance calculation


Concept: Transaction Processing Systems (TPS) Definition: collect, store, modify and retrieve the transactions of an organisation. Summary Points: § transaction: generates or modifies data that is stored in an information system. § tps directly support business operations. TPS must be designed with the organizations procedures. § tps usually involves updating a database to reflect changes to the transaction data. § collecting & storing are the main info processes Example: selling goods using a POS system; processing credit card payments, making a motel reservation, ordering a product through a web page eg. Amazon.com

Concept: Four characteristics of a TPS Summary Points: § rapid response: the turnaround time from the input of a transaction to the production of the output must be a few seconds or less. Time is critical. § reliability: TPS failure rate must be low. Quick & accurate recovery must be possible due to well – designed backup & recovery procedures. § inflexibility: a TPS wants every transaction to be processed the same way. eg. commercial airlines ac- cept bookings from a number of travel agents. Their data must be identical from agent to agent. § controlled processing: TPS processing must support an organisation’s operations. eg. allocation of roles & responsibilities to particular employees should be enforced, maintained by the TPS.

Concept: Batch Processing Definition: collects the transaction data as a group, or batch, & processes it later. Summary Points: Advantages § Processing is spasmodic according to the timing or amount of data to be processed, more econom- cal to process, standardised process § waiting for large volume of data results in lower processing costs per transaction § System failure is less critical as there may be time to restore the system before the batch is scheduled to occur Disadvantages § Processing and output is delayed § Errors cannot be corrected during processing § sorting expensive & time consuming Example: cheque processing, wage processing, electricity bill processing, water bill processing, phone bill processing

Concept: Real-time Processing Definition: the immediate processing of data. Summary Points: § provides instant confirmation of a transaction § has to have access to an online database § terminals -> communications -> mainframe -> online database § involves a large number of users who are perform- ing transactions at the same time § concurrency: ensures that 2 users can’t change the same data at the same time. eg. flight reservation. § atomicity: ensures that all of the steps involved in transaction are completed successfully as a group. eg. withdrawal of funds from 1 account and deposit into another account must both be successful. If one of steps is unsuccessful, the entire transaction is aband- oned. (Minimises errors). § hardware, software very expensive Example: airline reservation, internet banking, POS, charging transaction to credit card via the Internet

Concept: Transaction Processing Monitor Definition: is software that allows the TPS application programs to run efficiently. Summary Points: § manages the sequence of events that are part of a transaction § provides a standard interface between the terminals, TPS programs and the Database Management System. § makes sure transactions don’t get lost or corrupted (data security) § atomic commitment protocol: ensures that if 1 part of a transaction is either carried out or aborted then all parts of the transaction are similarly handled Example:

Concept: Data Validation Definition: procedures to ensure that transactions are correct & have been accurately stored in the db. Summary Points: § transaction initiation: used to make sure that the TP monitor is ready to receive the transaction data. § Field checking on data entry o range check: restricted to a range of values eg. postcode range > 500 and < 8500 o list check: compared to a list of acceptable data. eg. lookup table for the states in Australia. Entry is slower, but more accurate o type check: checks that the data type is correct. eg. text is entered when a number is required in a db field. o check digit: a digit calculated from the digits of a code number


CreateStore

Retrieve

Modify

Process

Decision Support System

Management Info System

Transaction Processing System

Office Automation System

Typical Business Structure

Upper Management

Middle Management

Concept: Comparison of Batch Processing and § Transactions are handled as a batch, that is, a

group of transactions of the same type § Processing is spasmodic according to the timing or

amount of data to be processed § Processing and output is delayed § System failure is less critical as there may be time to restore the system before the batch is scheduled to occur § db does not need to be available all of the time § needs to access master file less often § batch processing has more errors due to lack of data entry validation § errors will halt a batch process § less computer operators required since processing is centralised. § less difficult to maintain a batch processing system

Real-time Processing § Transactions are handled individually regardless of

the type of transaction involved; unique § Processing is ongoing according to the transactions

required § Processing and output is ‘immediate’ § System failure is critical as it prevents processing

taking place § database needs to be available all of the time § needs to access master file more often § has less errors due to data entry validation by users § infrequent errors are tolerated. Not practical to shut down the system § more computer operators needed § more difficult to maintain real-time process

Concept: Components of a TPS / Examples Summary Points: § users: takes data provided by the TPS and use it in another type of information system. eg. TPS and Management Info System to make strategic decisions. § participants: the people who conduct the information processing. eg. when a person uses an ATM, they are a participant Examples of real-time: § reservation motel § reservation airline § POS terminals § library loan system § EFTPOS terminal/card reader Examples of batch: § cheque clearance § bill generation § credit card sales when offline

Concept: Credit card is both real-time & batch Summary Points: § real-time: is immediately checked if the card was reported lost, stolen or cancelled. Also checked to see if the credit card is over its limit. § batch: funds are actually transferred at a later time when the system is less busy as well as a new balance calculation. Example: When a credit / debit card is used. An Internet banking transaction usually required 12 hours minimum to confirm that the transaction took place successfully.

Concept: TPS Cycle: Storing & Retrieving may be seen as cyclical. Eg. Database storing transactions related to fees for a student excursion for 2 or more students.

Concept: TPS User Example:


New transactions

Update file

Sort file

Merge data files

Transaction file

Transaction file

Master file

Master file

Concept: Databases Definition: db is an organised collection of data. An organisation stores all accounting & operational records in a database. Summary Points: § network: organises data as a series of nodes linked by branches. § each node can have many branches. § an upper node can be referred to as a parent, the lower node a child. § each child can have more than one parent

Concept: Hierarchical Structure Summary Points: § organises data in a series of levels. § uses a top-down structure using nodes & branches. § each child is linked to only one parent

Concept: Relational Structure Summary Points: § organises data using a series of related tables § relations are built between tables to provide a flexible way of combing & manipulating data

Concept: Designing a database for real-time Summary Points: good data placement: place frequently accessed data together and groups of related data. eg. address data should be next to each other: name, address, city, state, postcode § short transactions: quickly processed records improves concurrency (less likelihood of 2 people trying to save to the same record at the same time). § real-time backup: backups need to be scheduled at times of low activity eg. after 11pm § high normalisation: redundant information is kept to a minimum to increase speed of updates & improve concurrency. § archiving historical data: data that is rarely used should be kept in separate db’s or moved out of tables that are heavily updated. This keeps the tables small which improves backup times & query performances. § good hardware config: hardware needs handle users & provide quick response times.

Concept: File Types within a TPS Definition: file is a block of data. In a db a file is divided into related records. Summary Points: § master file: stores the operational database. Transaction data is stored in the master file. § transaction file: a collection of transaction records. It is used to update the master file. It also serves as audit trails & history of the organisation. § report file: contains data that has been formatted for presentation to a user. § work file: a temporary file used during processing § program file: contains instructions for the processing of data. Written in Fortran, Visual Basic, C++, etc.

Concept: Batch Processing Update of Master File


Concept: Data warehousing Definition: is a database that collects information from different data sources. Summary Points: § analysed for patterns. § consolidated: data is organised using consistent naming conventions, measurements, attributes & sem- antics. Data in the data warehouse has to be in the same acceptable formats. § subject oriented: a data warehouse organises only the key business information from operational sources. A lot of data from the source is irrelevant § historical: data is accurate for a specific moment in time. It is a snap shot. It can’t be changed. It repre- sents historical information § read-only: can’t be changed. Only loading data & querying of data can take place. § data warehouses can be data mined for names & addresses to be sold to marketing companies.

Concept: Data mining Definition: a process that finds relationships & patterns in the data stored in a database. Summary Points: News Article: Y Example: * Found relationship between the sales of meat pies & tomato sauce * Found relationship between the crashes of a partic- lar jet aircraft & malfunctioning of air conditioning 2 weeks prior to the crashes. * Chatswood shopping centre built for professional business women based on results of data mining.

Concept: Backup procedure Definition: backup is another copy of the data that could be used to rebuild the system. Summary Points: § if the TPS system goes down, the recovery process rebuilds the system. eg. library database § backups stored off site or stored onsite in fire- proof safes. eg. fire in administration block. Example: *TIGS library loan system, TIGS students’ home folder *TIGS Maze administration software

Concept: Recovery of a TPS database involves: Summary Points: § backup: periodic backup copies are made of the entire database. § journal: maintains an audit trail of transactions & db changes. transaction log: records all the essential data: data values, time, terminal number database change log: contains before & after copies of records that have been modifies. § checkpoint: after the TPS system is synchronised, a special checkpoint record is written. A copy of the db is made with the check point. It is often possible to resume processing from the most recent check point. § recovery manager: restores the database to a correct condition & restarts the transaction processing.

Concept: Types of recovery Summary Points: § backward recovery: is used to back out or undo unwanted changes to the db. It is used to reverse the changes made by transactions that have been aborted and restoring the original values. eg. unsuccessful transfer of funds from one account into another accnt. § forward recovery: starts with a backup copy of the database. It reprocesses the transactions in the transaction journal that occurred between the time the backup was made & the present time. o forward recovery is much faster & accurate than

backward recovery o backward recovery involves the logic of reproces- ing each transaction. Very time consuming.

Concept: Backup Medium: Magnetic Tape Definition: is a very long thin strip of plastic, coated with a thin layer of magnetic material. Summary Points: § can store huge quantities of data inexpensively § has a variety of sizes & formats. § disadvantage: uses sequential access. Has to start at the beginning of the tape & reads all the data until the item is found. Example: TIGS student home folders are backed up on magnetic tape cartridges.


Monday

TuesdayTuesday

Wednesday

ThursdayThursday

Friday: All Files are Backed up

Concept: Backup Strategy: Grandfather-father-son Definition: refers to at least 3 generations of backup master files. Summary Points: § the most recent backup is the son, the second is the father, the oldest: grandfather § if son is corrupted, the father can be used, if father is corrupted, grandfather can be used. § may have to restore more data each generation away from the present. Example: Library Loan system (Alice) is backed up daily. If first backup tape is corrupted & the system needs to be recovered, the 2nd generation tape is used.

Concept: Inferential backup (partial) Summary: Only the files that have changed since the last full or partial backup are copied. On Monday only the files that were created or changed would be copied onto the Monday backup. On each day, only the files that were created or changed since the previous day’s backup would be copied. If a file were altered on Monday but not on any other day that week, it would only be copied into the Monday backup

Concept: Differential backup (partial) All the files that have changed since the last backup are cop-ied. On Mon-day, all the files that were created or changed are cop-ied onto the Mon-day backup. On Tuesday, all the files that were created or changed are copied onto the Tuesday backup, this INCLUDES those that have already been copied into the Monday backup. On each day, every file that has been created or changed since the last full Friday backup is copied. If a file were altered on Monday but not on any other day that week, it would still be copied into the Monday, Tuesday, Wednesday and Thursday backups.

Concept: Comparison of Incremental, Differential Partial Advantages Disadvantages Incremental

* faster backups * uses less space

the full backup plus all the daily backups have to be loaded to restore all the data.

Differential

the full backup and only the last daily backup have to be loaded to restore all the data

* slow by the end of the week * each backup needs more space

Concept: Updating in a batch Summary Points: § collects the transaction data as a group or batch & processes it later. § occurs when transactions are recorded onto paper or stored on a magnetic tape. § involves sequential access, data is stored in sequence like a music track on a cassette tape. § information technology: requires a storage medium that can store large quantities of data inexpensively. Example: magnetic tape

Concept: Updating in real-time Summary Points: § immediate processing of data, instant confirmation § increases of data transmission speeds & improve- ments in bandwidth has aided real-time processing § user involved helps with error detection eg. $50.00 is this correct? § direct access used. Acccessed without acessing previous items. o faster than sequential access o may use an index to get to specific data § information technology: requires a secondary storage medium that can store huge quantities of data. eg. magnetic hard disk storage. o software: user friendly interface o turn around time must be a few seconds or less


Enrolment systemTimetable systemCurriculum Inspection System

EnrolmentAssessment RecordsCurriculum Records

School

Payroll systemEmployee recordsBenefits systemCareer path systemPersonnel training system

Personnel reocrdsEmployee benefitsCompensationLabour relationsTraining

Human Resources

General ledgerAccounts receivable/payableBudgeting: funds management system

BudgetingGeneral LedgerBillingCost Accounting

Finance and Accounting

Material resource planning sysPurchase order control systemEngineering systemsQuality control sytems

SchedulingPurchasingShipping/ReceivingEngineering operations

Manufacturing and production

Sales order information sysMarket research systemPricing system

Sales ManagementMarket ResearchPromotionsPricing new products

Sales and MarketingApplication SystemsFunctions of SystemTPS

Enrolment systemTimetable systemCurriculum Inspection System

EnrolmentAssessment RecordsCurriculum Records

School

Payroll systemEmployee recordsBenefits systemCareer path systemPersonnel training system

Personnel reocrdsEmployee benefitsCompensationLabour relationsTraining

Human Resources

General ledgerAccounts receivable/payableBudgeting: funds management system

BudgetingGeneral LedgerBillingCost Accounting

Finance and Accounting

Material resource planning sysPurchase order control systemEngineering systemsQuality control sytems

SchedulingPurchasingShipping/ReceivingEngineering operations

Manufacturing and production

Sales order information sysMarket research systemPricing system

Sales ManagementMarket ResearchPromotionsPricing new products

Sales and MarketingApplication SystemsFunctions of SystemTPS

Concept: Indexed Sequential File An Indexed sequential file is made up of the main data file and a separate, smaller index file. The index file is loaded into memory to search employee no. 1329965 which is linked to record no. 10. The system then goes directly to record no. 10 without having to read records 1 to nine making it more efficient.

Concept: TPS collecting Definition: involves generating transaction data. In- volves the use of hardware & a variety of paper forms. Summary Points: § Magnetic ink character recognitions (MICR): used to read account numbers on cheques § Automatic Teller Machines: swipe card, enter PIN by the keyboard § Bar code readers: used to collect product information at point of sale. quick, accurate Example: * processing of cheques * use of automatic teller machines * use of bar code scanners at super market, libary

Concept: TPS collecting continued Summary Points: § form: a document used to collect data from a person. When the form is completed, it is processed in real-time or in a batch § paper form: forms printed on paper eg. payroll, new school enrolments, pension, medicare o processed paper forms as a batch. § web forms: a form on a web page requesting data from the user. Used in purchasing items over the Internet. delivery address, method of payment, item o may be processed in real-time or batch processed o responses become data in fields of a database Example: Web: purchasing of a book from Amazon.com. Web form details goes into the fields of a database. Com- munications used.

Concept: Analysing data in a TPS Definition: output from a TPS is the input into other types of information systems. Summary Points: § decision support system: data from a TPS is stored in a separate db & analysed by senior management to make strategic decisions. § data mining can be used to analyse data to find paterns between products eg. meat pies, tomato sauce § management information system: provides information for the organisation’s managers. Usually in report format. o scheduled reports: middle-level to low-level management uses these reports. o forecasting reports: help make projections about business trends. High-level management uses these. o on-demand: report generated on request & in response to a specific need. High-level management. o Exception: alerts management to unexpected events. Middle-management

Concept: TPS in action


DataSource

DataSource

DataSource

DataSource

Data Loading

DBMS

DBMS

DBMS

DBMS

Query &analysis

TerminalDisplay

Atomicity

Consistency

Isolation

Durability

Concept: Issues in TPS Definition: both positive & negative impacts arise from the use of a TPS. It can have impact upon an individual, regionally or nationally (society). Summary Points: § nature of work: essentially automates business operations. o automation of jobs: technology performs tasks once done by people. o workers required to learn new skills o fewer people required to perform same task o retraining of people should occur o ATMs -> people are participants -> results in fewer clerks needed -> physical banks close o ATMs less personal o web purchases: consumers bypassing people who provide a service at the shop front. o more opportunities in the Information Technology jobs area

Concept: TPS Issues continued: Summary Points: § non-computer procedures: when TPS goes down, paper procedures need to be in place to continue business transactions § bias: means data is unfairly skewed or gives too much weight to a particular result. It is rarely an issue for TPS collection. o data could be collected from a specific group, however, eg. asking IBM questions to Apple users. o purposeful misinterpretation of data (ethical issue) § data security: involves a series of safeguards to protect the data. o physical computer system protection: keylocks, password, biometric devices o data transmission protection: encryption, decryption o firewalls, virus protection, encryption of data on the hard drive o uninterruptible power supply

Concept: TPS Issues continued: Summary Points: § data accuracy: is the extent to which data is free from errors. o errors in entering data (use validation techniques) o errors in gathering data o mismatch of the data & the person o out-of-data: URL, person’s address, price of items § data integrity: describes the reliability of data. It involves the accuracy, currency & relevance of data. § data accuracy, data integrity & data security are related to each other. Need to be able to show the relationships in writing. § control in transaction processing: starts with collecting & includes the way the TPS manipulates data & the way error are detected. o false transaction data can be created for unethical purposes. eg. more money, promotion of career

Concept: ACID test (data integrity) Atomicity: the transaction must occur completely or it should be undone completely. Consistency: All parties must agree on the facts of the exchange. Isolation: Transactions must be independent of each other & to prevent the same data being treated twice. Durability: The effects of a completed transaction should last.

Concept: Emerging Technology Summary Points: News Article: Y § credit card checks within a TPS (evolving) § weighing groceries, no checkout person § better encryption on data transmission & on hard drive § better firewalls § electronic document management systems eg. scan all blueprints made within an organisation o managing all letters within a law firm § ATMs: ability to order flowers & other specific items.

Collect data from a wide range of sources Data cleansing… poor quality data needs to be removed or fixed Metadata might be created (Data about data… origins, transformations, summary of data, description Data warehouse hardware: huge storage & processing eg. RAID, parallel processors









Characteristics

MM edia Examples

Techology AdvancesDesign

Media

DisplayingMmedia Issues

Emerging Technologies

Multimedia

Interactivi tyimagevideoaudio

text hyper text numbersanimation

Education & trainingLeisure & Entertainment

InformationVir tual Reali ty/Simulations

Wor ld Wide WebCDROM speed

DVD

ConsistentNavigation

Simple

Characters seri fScreen Layout

Text ColourImages

animationsaudio / video

Hardware:Screens- CRT, LC D, Touch

Data projectorsspeakers

Headup displays

Software:Presentation

Word processorSpreadsheet

GraphicsAudioVideo

Project ManagementAuthor ingAnimation

Web BrowsersHTML editors

Collecting:scanners

dig ital cameravideo cameravideo capture

cardframe grabbermicrophonesound card

Organising:Storyboard

Linear layouthierarchial layoutnon- linear layout

combination

InformationProcesses

Processing:Integration of Data

Compression & Decompression

(CODEC)Hypermedia

Stor ing/Retr ievingLossy compression

Lossless compressionASCII, RTF, TIFF, BMP, JPEG, GIF, WAV, MP3,

MIDI, MPEG, QuickTime, animated Gif

audio compressionstil l image compression

video compression

Copyr ightsources l isted

Privacy use of InternetData integr ity

Merging Technologies

Storage formulas:ImageAudioVideo

Animation:cel l basedpath based

morphing, warping

People in MmediaContent providersSystem DesignerProject ManagerTechnical Staff

Creative di rectorsWritersEditors

Graphic designersAnimators

Emerging TechnologiesWWW:

Increased bandwidthfibre optic, ADSL, satelli te

linksStreaming audio, video, Flash

animationsMore effective CODEC

algori thmsPlugin software

Applets & controls embedded in web pages would removed

need for plug in softwareSoftware to identify Internet

route offering greatest bandwidth

USB peripherals: thumb drive

Formulas: calculation of storage space:image;

audio:

video:


Concept: Multimedia Characteristics – Interactivity (Multimedia will be referred to as Mmedia for short) Definition: allows the user to choose the sequence and content of the information to be displayed. Summary Points: § accepts input from a mouse, touch screen or key board and performs some action. § hypertext & hypermedia are used to navigate through a multimedia product § product may link to audio, an image, animation, video or another page Example: Clicking on hyperlinks on a web page, choosing to listen to a speech on an encyclopaedia CD. Using a CD that teaches concepts about Networking

Concept: Multimedia Characteristics – Image Definition: data in the form of a picture, such as a drawing, painting or photograph. Summary Points: § images place extra demands on a multimedia computer system in terms of processing and storage. § an image with high resolution requires more memory than a low resolution image. § an image is stored in the frame buffer, a section of memory § storage requirements are dependent on the number, size, tone & colour of each pixel. § an image on the screen is bit mapped in memory § bit depth is the number of bits per pixel § colour increases the number of bits per pixel and require more storage § colors obtained from a RGB, red green blue screen

Concept: MMedia – Image continued Formula: File size = Horizontal X Vertical X Bit depth 8 X 1024 Students expected to know formula(s) but calculators are not allowed in exam, hence, the questions will involve formula manipulation rather than actual calculations § 256 colours are used in a gif file, can have transparent back ground § millions of colours are used in a jpg file (photo realistic). § image can show a concept more clearly than text § people may learn faster using images § images can be used as navigation buttons Example: a button on a web page can be an image which hyperlinks to somewhere else on the web site. Logos have transparent background in web header.

Concept: Mmedia Characteristics - audio Definition: sound that has been digitised. Summary Points: § use of audio can supplement text, graphics and increase one’s understanding of a concept. § formats include: wav, mp3, wma § wav formats tend to be very large & slow to load § mp3 has decreased storage requirements by re- moving sounds not heard by the human ear. § sound formats are continually being developed § sampling rate: the number of times a sample is taken from a sound wave § sample size is the number of bits per sample.

o 8-bit sound: mono channel, used for voice o 16-bit sound; stereo; used for music

Concept: Mmedia Characteristics – audio continued Sampling rates: § 11 kHz: speech & short segments of music § 22 kHz: better music playback § 32 kHz: broadcast audio standard § 44 kHz: CD-quality audio playback § 48 kHz: digital audio tape (DAT) playback Formula: File siz3=(SampleRateXSampleSizeXtime)xNo.channels § sound editors and video editors have sample rate settings for audio. Example: Sound effect when a button is pushed. Background music when a game is played. A recorded talk from a grandfather within a multimedia presentation

Concept: Mmedia Characteristics - Video Definition: a data type that combines pictures and sounds displayed over time. Summary Points: § played back at 15-30 frames per second to give the illusion of full motion. § can significantly impact the user’s experience § can reinforce text articles or bring dull subjects to life. § places extra demands on the multimedia system § formats include: mpeg, wmv, avi, quicktime


Concept: Mmedia Characteristics – video continued Calculate the file size in kilobytes of a 90 minute movie at 24 frames per second: Number of frames = Frame Rate X time in seconds = 24 x 90 x 60 = 129,600 frames File size for = Horizontal x Vertical x Bit depth each frame 8 x 1024 = 2048 x 872 x 32 8 x 1024 = 6976 kilobytes File size for = 129,600 frames X 6976 kilobytes movie = 904,089,600 Kb = 862.207 03 gigabyte Example: a 30 second digital video is recorded and edited on video editing software. The video is played as part of a multimedia presentation. Generally a hyperlink will activate the video eg. marshall arts move- ments activated by a button.

Concept: Mmedia Characteristics – text, hypertext Definition: text: a data type consisting of letters, numbers and other characters whose meaning and format are not specified. Hypertext: a system that allows documents to be cross linked in such a way that the user can move from one document to another by clicking on a link. Summary Points: § navigation technique. Can link to another document, elsewhere in the same document or to a multimedia event such as an audio recording or video. § hypertext provides the interactivity because the user chooses which link is desired in whatever order Example: Hypertext is used mainly on the Web, can be used in Help files, or interactive CD’s.

Concept: Mmedia Characteristics - numbers Definition: a data type consisting of predefined characters (usually numbers) whose meaning and format are specified. Summary Points: § calculations are often performed on this data type § can be linked to some type of chart Example: The purchase amount of items is a calculated number with a predefined dollar format.

Concept: Mmedia Characteristics - animation Definition: the movement of a graphic, as in a cartoon, accomplished by presenting a series of still images in rapid succession that gives the illusion of motion. Summary Points: § animation can display a concept more clearly than text alone. § can be a blinking button or the eruption of a volcano. § used significantly in game playing. § formats: animated GIF, QuickTime Example: The Office Assistant found in Word is an animation and when clicked, offers aid. Uses sound also. Runs poorly on older computers.

Concept: Mmedia Animation – Cell Based Definition: animation that involves drawing and displaying individual frames or cells Summary Points: § Each frame is stored separately and loaded into a graphics page of primary memory. § Considered to be the traditional method of ani- mating. Example: Each frame of an animated GIF is drawn.

Concept: Mmedia Animation – Path Based Definition: animation that involves displaying the movement of objects onto a fixed background in a particular sequence or path Summary Points: § saves memory and processing time § animation is achieved by drawing it, wiping it, & re-drawing the object in a new position § key frames are drawn & the computer creates the frames between the key frames, hence, the term tweening. Example: Creation of a Flash MX animation using keyframes. eg. rotation of an object. The software creates all the other frames to make a smooth animation.


Concept: Mmedia Animation - Morphing Definition: animation technique that involves the smooth transition between two images. Summary Points: § results in one image being merged into another § became well known in Terminator II § Free/Shareware available from the Internet Example: A photograph could be morphed into a photograph of a movie star. Many TV ads make use of the technique

Concept: Mmedia Animation - Warping Definition: animation technique that involves transforming or distorting a portion of an image. Summary Points: § The technique divides the image into objects that can be manipulated. § Free/Shareware available from the Internet Example: A sad face could be given a smile with the remainder of the face staying the same.

Concept: People in Mmedia: Content Providers Definition: are people who provide the material for the mmedia product. Summary Points: § May include text, graphics sketches, final drawings video footage and audio tracks. § Creative directors: directs the creative parts. § Writers may write the text content. § Editors may edit / oversee the text content § Graphic Designers may create the varied graphics § Cameramen may shoot the required video / vision § Animators may create any required animations § Technical staff may be responsible for saving the material to a server, give appropriate rights to personnel, making backups, maintenance of a network § system designer: plans & organises the hardware and software required for the presentation § project manager: organises the scheduling of vari-ous components of the product; overall supervision

Concept: Mmedia Examples – Education & Training Summary Points: § One may go through a multimedia application at their own pace. § Feedback may be provided in the form of sound, score or other response. § Define one’s own learning path § Investigate topics in depth § Drill and practice activities (not the all to end all in learning eg. showing relationships between Concept A and Concept B) § Multimedia applications may engage and challenge users, thus encouraging them to think creatively and independently. § allows training to be carried out at convenient times. § disabled students respond well to mmedia Students make use of HSC Assistant IPT to learn the concepts covered in the IPT course. It doesn’t teach how to write essays.

Concept: Mmedia – Computer Based Training Summary Points: § students learn by using and completing exercises with instructional software. § is popular in business, industry and schools to teach new skills. § courseware is usually available off CD-ROM, DVD-ROM or shared over a network. § CBT allow for flexible, on the spot training § Employees can update their skills without leaving the work place; Reduces cost of training. § Learners can receive instant feed back in CBT § Testing and self diagnostic features allow instructors to verify that a student has mastered curriculum objectives § CBT designed by experts in their field Example: Employees receive theoretical training by the use of CD or personal interviews. CD has the ability to login to their Internet site.

Concept: Mmedia – Leisure & Entertainment Summary Points: § games provide a high level of interactivity. § graphics and animations are complex § edutainment: games that are entertaining and educational § alternative forms of input may be used such as a joystick, glove, pistol, steering wheel, pedals etc. Example: Where in the World is Carmen San Diego is considered to be edutainment


Concept: Mmedia - Information Summary Points: § multimedia Encyclopaedia on CD § allows searching of keyword § may connect to the Internet for updated info. § displays information using coloured text, audio, video or animation § provides easy navigation techniques § Information Kiosks: allow people to use a touch screen & select information about an organisation or service. § Usually is a self-service structure equipped with hardware and software (kiosk). § All the data and information needed for the kiosk is stored directly on the computer. Example: kiosks can be used at museums, airports, shopping centres, photo enlargements at camera shops.

Concept: Mmedia – Virtual Reality / simulation Definition: the use of computer modelling & simulation to enable a person to interact with an artificial environment Summary Points: § Displays a view that appears to be a three - dimensional view of a place or object § More advance forms require one to wear head gear, body suits and gloves to enhance the experience § One’s first encounter with VR was probably something like flight simulator. § One can take a tour of the International Space Station at the NASA site using VRML on the web § Real Estate agents make use of VRML on the web § Auto sales firms make use of VRML on the web to sell niche market cars § practical applications of VR will continue to emerge Example: a dentist may provide a patient with a VR headset as work is carried out on the teeth.

Concept: Mmedia – simulations continued Summary Points: § more employers are using VR for training § simulations are cheaper than crashing actual aircraft or tanks. § driver simulator exists § flight simulators exist at airports for pilot training § commuter train drivers use simulators § 747 pilots can become fully qualified pilots without leaving the ground

Concept: Mmedia – Web Based Training (WBT) Definition: computer - based training that employs the technologies of the Internet and the World Wide Web. Summary Points: § same advantages as computer based training § content can be easily be updated at the server. No need to post out CD’s § often used for distance learning courses (distance education). § money can be saved by eliminating the costs of airfare, hotels, and meals for centralised training sessions. § students who live far from the campus or work full time, allows them to attend class from home or at any time that fits their schedules.

Concept: Mmedia Technology – World Wide Web Definition: the WWW has multimedia capabilities but is still very much text based Summary Points: § the downloading of multimedia events takes too long especially over a 56k modem. § bandwidth is quickly filled up by the sheer number of users world wide. § the WWW is interactive due to the non-linear links. § WWW is NOT a multimedia medium in the opinion of the teacher due to technical limitations § streaming radio via Internet eg. can listen to radio in other countries § some streaming TV § data transmission is considered expensive in Oz Example: Web sites may have only an introductory Flash presentation as first page. Web sites try to have advertisements that use Flash animation.

Concept: Mmedia Technology – CD-ROM speed Summary Points: § CD-ROM speed has increased significantly over the years that allows smooth playing of animations, video and audio. § A multimedia CD will keep its multimedia material stored on the CD and will not transfer the material to the hard disk of the user to save storage. § multimedia events do run better directly off the hard drive. § the speed of CD-ROM drives will continue to get faster in the future. § will probably be replaced by DVD burner / drives Example: Platypus allows the developer to keep the material on the CD when installed on a user’s machine or copy the material to the user’s hard drive.


Concept: Mmedia Techology - DVD Definition: digital versatile disk. Stores 4 – 17 GB which allows it to store movies on one disk usually. Summary Points: § has made the VHS video machine obsolete § DVD-R+ or DVD=R- means a dvd can be written to on just one layer of the DVD § 2004: new dvd burners available to use all layers § 2004: manufacturers negotiating over new dvd format that allows for more storage § text, images, video & audio have to be in the same format called UDF (universal disc format) Example: Most new computers have a dvd burner to cope with home made videos. Most movies fit on 1 dvd disk.

Concept: Mmedia – Design – Screen Design Summary Points: § good design is critical to a product’s success § Alignment: Use left-alignment to provide a more natural reading flow § Balance: Avoid centring objects on the page. Place a graphic off to one side and text on the other. § Brevity: Use short, concise phrases. § Colour: Keep the number of colours to a minimum, and use light text on a dark, consistent background. § Emphasis: Emphasize key concepts by using media elements such as video, audio and graphics. § Font size: Use a font size big enough for your audience to read. § Formatting: Use appropriate formatting, such as bold formatting of keywords, to ensure your message is clear.

Concept: Screen Design - Continued Summary Points: § Navigation: Place navigation buttons at the bottom of the screen. § Number of ideas: Present only a few ideas per page. § Images & animations places extra demands on a multimedia computer system § Too many images may lose impact § Too many audio events may lose impact, use sparingly. § Titling is the placement of a caption to accompany and image or graphic element § animations should be used sparingly. Usually placed to introduce a new section Example: Student’s own multimedia end-product that was created for assessment purposes.

Concept: Mmedia – Displaying Hardware- CRT Summary Points: § Cathode Ray Tube (CRT): fires a stream of electrons onto inside of phosphorous screen. § CRT: raster scan: fires the electrons in a series of zigzag lines that starts in the upper left-hand corner & moves left to right. § refreshing: refreshes the phosphorous screen 72 times a second. May use interlacing which re- freshed every other line but this causes flickering & gives user’s headaches, hence, it isn’t used much. § when a screen is being altered only the data that is changed is transmitted. The information describes the difference between the two screens & is called delta information. § vector display: specialised CRT that displays only vector graphics. Shading is drawn as a series of lines. Example: Any cathode ray tube computer monitor.

Concept: Mmedia-Displaying Hardware - LCD Summary Points: § Liquid Crystal Display (LCD): consist of a layer of liquid crystal material. When light is passed through & current is applied, the material becomes visible. § these displays are light and take up less room, produce no glare, no heat and no radiation. § requires less power, good for laptop computers § LCD technology is almost as good as CRT techn. § LCD may fall down in game playing area. § Touch screens enter data by detecting the touch of the user’s finger. The fingers interrupt a matrix of infrared beams shining vertically & horizontally across the screen which gives the finger’s coordinates. Does not allow for fine precision, hence, large buttons are used on the screen. Example: Laptop computer, Kiosk or ATM that uses a touch screen.

Concept: Mmedia-Displaying Hardware-Data Projector Summary Points: § projects image onto wall or screen. § takes video signal directly from the computer. § quite expensive, but getting smaller & lighter Example: Data projectors used at school.


Concept: Mmedia-Displaying Hardware-Speakers Head-up displays Definition: Speaker: a device to produce sounds. Head-up display: device worn on head to display information. Summary Points: § speaker: audio signals from the computer are translated into analogue sound waves for transmission through the speakers. § head-up: technology has been miniaturised and their application has widened. § heavy helmets have been replaced with displays no larger than glasses. Information is displayed on the glasses. Example: Military use in aircraft, tanks, night goggles. Minority Report (Movie)

Concept: Mmedia –Software Applications Summary Points: a variety of software is used in creating a multimedia presentation: § presentation software: to create a professional looking presentation for a group of people. May include

o audience handouts o overhead transparencies o speaker’s notes o transistions o on-screen presentation

§ word processor: allows content text to be created § spreadsheets: number calculations, charts created § graphics software: create / edit images § audio software: create / edit audio events.

o editing length, altering speed, giving echo o mixing audio files

§ video software: creates / edits video that was captured through a digital video camera. § project management: used to efficiently plan, manage development of mmedia product.

Concept: Mmedia-Software Applications - continued Summary Points: § authoring software: combines text, graphics, animation, audio & video into a multimedia product. eg. Platypus, PowerPoint, Hyperstudio, Flash MX § animation software: takes individual frames and creates the illusion of movement. eg: Flash MX, PhotoShop Elements, Paint Shop Pro. § web browsers: can receive multimedia files that are embedded in a web page. Can be from the net or from a CD. § HTML editors: specialises in writing HTML code which is interpreted by web browsers. Used for fine detail. Word, Publisher, Dream Weaver produce web pages. One can view the source HTML code of each web page. Example Students own multimedia end product using authoring software and / or a web site using a web browser.

Concept: Mmedia Info. Process - Collecting Definition: writing text, drawing images, recording / editing audio files, recording video or gathering data from the Internet or reference books. Summary Points: § identify the source of the information § check the accuracy of collected information § Scanners: can capture images or text (OCR)

o Technology Without An Interesting Name o (TWAIN) software standard for scanners o hand-held scanner o flatbed scanner

§ Digital camera o capture & stores images in digital form o stored in memory card, transferred to hard disk for editing o easy to evaluate photo and retake

Concept: Mmedia Info. Process – Collecting continued Summary Points: § Video camera: digital and analogue

o analogue has to use a capture card which converts analogue into digital o digital: can directly be stored on computer

§ VCR: a frame grabber can capture & digitise images from a video. o VCR can use digital camera to convert a video into digital video to be stored on a computer

§ Microphone: captures sound. A sound card trans-forms the sounds from a microphone into digitised audio. o MIDI records how an instrument is played not the sound that was created.

Concept: Mmedia Info. Process - Organising Definition: 2 tools that are used to organise a multimedia product are a script and storyboard. Summary Points: § script: a printout of all the text, graphics, animation, audio & video used in the production.

o outlines the interactivity o gives directions for the construction of the multimedia product.

§ storyboard: a series of frames each representing a different action or screen image. It is based on the cartoon storyboard.

o linear layout o hierarchical layout o non-linear layout o combination layout o consists of navigation paths, images &

information


Concept: Mmedia Info. Process - Processing Definition: is the manipulation of the data. It involves the integration of data, compression of data & hypermedia Summary Points: § authoring software brings all the mmedia elements together. The elements are of different media types and in a variety of formats. § compression & decompression: Compres- sion reduces the number of bits to represent information. § compression allows the user to store more data & transfer data faster. § Compressed data must be decompressed to ex- tract the original information, hence, this is processing.

Concept: Mmedia Info. Process-Processing continued Summary Points: § GIF, JPEG are compressed file formats. § GIF: 256 colours, transparent background allowed § JPEG up to 16.7 million colours can be used. § CODECS (coder – decoder): compresses & de- compresses various types of data

§ used in sound files eg. RealAudio § used in videos eg. MPEG, AVI

§ when played these formats must be decoded or decompressed, hence, processing. § CODECS depend upon the algorithms which are continually being updated and improved. § Hypermedia: when a hyperlink is activated, processing takes place. Example Video editing software has several CODEC options to choose from in its settings.

Concept: Mmedia Info. Process-Storing / Retrieving Definition: efficient methods for storing & retrieving information for a multimedia product using different compression techniques and file formats. Summary Points: § compression ratio: a measurement of the amount a file has been compressed. § lossy compression: removes a number of data bytes from the file. The file is smaller & quality is reduced but the human eye / ear does not notice. eg MPEG, MP3 file. § lossless compression: allows the original file to be recovered in full. It replaces data that takes up less room. Used on word processing, text, spreadsheet and database files.

Concept: Mmedia Info. Process-Storing / Retrieving Continued Summary Points: File Formats § ASCII: text file, raw text without any formatting. Most applications can store data in ASCII format § RTF: rich text format: specifies the format of text documents. Allows underlining, italics, boldface and formatting of paragraphs. Developed by Microsoft. § HTML: hypertext Markup Language: special instructions indicate how parts of a web page will be displayed. § BMP: bit map: stores graphical data inefficiently with large file sizes in this raw format. § JPEG: Joint Photographic Expert Group: compresses bmp images; uses lossy compression; used best with photo quality images; used with web pages. § GIF: Graphics Interchange Format: compresses bmp images; lossless compression; 256 colours; used with line-art drawings, logos, simple graphics; trans-parent background; used with web pages

Concept: Mmedia Info. Process-Storing / Retrieving Continued Summary Points: File Formats continued § TIFF: tagged image file format: used to be widely used between Mac & Window platforms. § PICT: picture: standard graphic file format for the Macintosh platform. § EPS: encapsulated postscript: stores vector graphics. Postscript is a printer language used to print out in high resolution. Includes text & images. § WMF: windows metafile format: stores bit mapped or vector graphics; used to exchange images between Windows applications. § WAV: stores either 8-bit or 16-bit sound. Disad- vantage is that it requires large file size. § RealAudio: used for exchanging sound files over the Internet. § AIFF: audio interchange file format: stores 8-bit sound files; developed by Apple.

Concept: Mmedia Info. Process-Storing / Retrieving Continued Summary Points: File Formats continued § MIDI: musical instrument digtal interface: contain musical note information not details of the sound wave. § MP3: MPEG audio layer 3: removes high and low frequencies that are out of human hearing range. § MPEG: motion picture expert group: uses lossy compression; stores changes from one frame to another; sufficient for all TV standards & is used on DVD; found on all computers; up to MPEG 4. § Quicktime: developed by Apple for the Macs. Later versions may not play with Windows applications eg. Powerpoint. Is available for Windows. § Animated GIF: a type of GIF image that can be animated; supported by all web browsers; does not give the same level of control; rough animation


Concept: Mmedia Issues Definition: there are positive & negative impacts from the use of multimedia systems. Summary Points: § copyright: protect the original artist

§ list sources § music files § image files § animated gifs § buttons

§ privacy: video data used in CD or over the Internet § data integrity: needs to be accurate, current and relevant. Sources should be cross-checked § merging technology: radio, television and the Internet are said to be merging.

Concept: Mmedia – Emerging technologies Definition: technologies that are continually evolving or technologies that have been recently created. Summary Points: § WWW: increased bandwidth § ADSL, satellite links for increased bandwidth § More effective CODECS for streaming audio, video and Flash animations § Applets (small applications) & controls embedded in web pages would remove need for plugin software § software to identify Internet route offering great-est bandwidth § USB peripherals: thumb / flash drives § Bluetooth, super Bluetooth technology § fully burned DVD from computer § evolving DVD format