Unit 1B – Capabilities & limitations of ICT. Capabilities & limitation of ICT ICT vs Manual methods of data processing Case Study – the school reporting

Unit 1B – Capabilities & limitations of ICT

Capabilities & limitation of ICT

ICT vs Manual methods of data processing

Case Study – the school reporting system

Your intermediate reports used to be done by hand, the system has now been computerised.

What benefits are there of having a computerised reporting system ?




The old system was for subject teachers to transfer levels and effort grades from their mark books into a grid for pupils in each form.

Image of markbook & grid sheets in here




These levels and grades were then copied onto pupil report sheets by form teachers.

Image of report sheets in here




The grids and duplicates of the reports were then stored in a room.

Image of bundles of reports in here




The new, computerised system requires teachers to select the class they teach and then enter levels and effort grades into the class list.

Image of class list page in here




The data for each pupil is then processed and printed.

Image of final printout in here




Consider the two systems and using a table (full page of A4 with explanations) make a comparison of the two systems :

Manual Computerised

Repetitive processing

Speed of processing

Data storage capacity

Speed of searching

Accuracy & speed of data communications

Ability to produce different output formats


Factors affecting the efficiency of data processing systems

Consider the effects of :

Hardware

Software

Suitability of operating system

Communication

GIGO



Hardware :

Does the existing hardware meet minimum specifications for the software? Ideally it should meet the recommended specification.

System Requirements

Minimum System Requirements:Intel® Pentium® or AMD® Athlon® 2 GHz512 MB RAMWindows® XP or Windows 2000 (XP recommended)USB 2.0 portDirect X® compatible graphics card (ATI® Radeon® or NVIDIA® GeForce" or higher recommended)Direct X compatible sound card650 MB hard disk spaceDVD burner, mouse, CD-ROM driveHardware specifications:External Hi-Speed USB 2.0 video capture deviceComposite video input (RCA connector)S-Video input (mini-DIN connector)Stereo audio input (2 x RCA connectors)



Software : (object linking and embedding)OLE allows information to be shared between different programs

–For example, a spreadsheet created in Excel can be included in a Word document either by embedding it in the document, or by creating a link from the document.

An embedded object has no connection with its original source file.A linked object ensures that the information displayed in the document will always be displayed – via the link – directly from the source file.



Software :Linked object

–original information remains in the source file–destination file displays a representation of the linked information but stores only the location of the original data–linked information is updated automatically if you change the original data in the source file–Use if file size is a consideration

Embedded object–becomes part of destination file. –because an embedded object has no links to the source file, the object is not updated if you change the original data



Software :Consider the data processing efficiency of a piece of software in terms of :

Ease of data entrySpeed of processingCompatibilityMemory requirementsUnnecessary features




Operating systems available are :

Windows – most common PC op sys

OSX (Panther) – most common apple mac op sys

Unix/Linux – GUI similar to windows but open source

MSDOS – command line driven op sys




Operating systems deal withMemory management. Resource allocation and schedulingBacking store managementInterrupt handlingAllowing a user to communicate with the computerControlling peripheral devices

If the operating system does not run efficiently then the application software will not run efficiently.



Communication

If an application is being used on a network machine and the processing is taking place over the network (grid processing) then the efficiency & capability of the network becomes a factor when considering efficiency of processing.

GIGO – garbage in = garbage out

If the data entry method is inefficient or input data is not valid then the efficiency of processing is affected – errors will occur during the data processing stage.



Other factors affecting efficiency

Change in circumstance during software development

Software takes a long time to develop, if during this time another product comes onto the market or a new system is released (win 98 vs win XP) then the development of the software is affected.

Speed of implementation

Once an organisation has acquired software it has to implement it, this involves installing & training. This has a direct affect on processing efficiency




Compatibility

When windows XP was released, users who upgraded from win 98 suddenly found that their scanners / printers / applications would not work – oops.

Insufficient testing

Software development is a very competitive field with pressure to release products ahead of the field. As a result, software is sometimes not fully tested.




Poor communication with user

The user interface may not be very friendly (how ?)

Validation rules may not have sensible error messages, informing the user of their mistake

The instruction manual could be poor



Ability of user

If the user is clueless then the efficiency of data entry / processing is affected.

It has been postulated that if a monkey randomly hit keys on a PC for 10,000 years then at some point they would type the entire works of Shakespeare !



Poor post implementation

Post implementation is the procedures / actions that are carried out after the software has been installed. These could be :

Training

Monitoring

Evaluation



Maintenance procedures

• Required for a number of reasons• Errors may appear in the software• Original requirements are modified• Hardware developments may make it desirable to change the software to take advantage• New legislation may be introduced

•Perfective maintenancesystem can be made better in some way without changing its functionality.•Adaptive maintenancechanging needs in a company may mean systems need to be adapted – e.g. a single-user system may be adapted to a multi-user system.•Corrective maintenanceinvolves correction of previously undetected errors. e.g. the millennium bug. Many major programs are released with ‘bugs’ that require maintenance releases – ‘patches’ or ‘service packs’ to fix them (most of the Microsoft products)

Types of maintenanceFactors affecting the efficiency of data processing systems

• Process triggered by: – user or management requests– Further development by manufacturer

• Cost and impact on system are assessed for feasibility

• New release has to be programmed and tested• Software packages generally have release numbers

– Minor releases are indicated by a change in number suffix e.g. 3.0 to 3.1 with Windows

– Major releases are often indicated by a change like 4.0 to 5.0 or by a change in name

Types of maintenance (cont)Factors affecting the efficiency of data processing systems

Types of maintenance (cont)•Most software developers would prefer to be working on exciting new projects

•Maintenance is very expensive

•Cost-effectiveness depends upon•A clearly-defined and well-documented original system

•Suitably qualified and informed analysts and programmers

•A clear and uncomplicated dialogue path between user and developer

•A transparent structure that allows analysts and programmers to assess fully the impact of any changes

•Limiting the amount of change at any one time


CostCost can be considered in terms of money, time and human resources.

If a system has a high financial cost and takes a long time to be implemented or process data then it would be considered inefficient.


Hardware(refer previous notes)

The hardware that is needed to run software efficiently is a factor to be considered :

Is the hardware powerful enough to run the software ?

Is the hardware reliable enough ?

Is new hardware needed to run the software ?

Is the hardware compatible (mac vs PC)


SupportWhen you purchase software you often receive a form of support.

This may be in the form of :

-Help files

-Online (internet) help

-Technical advice over the phone

-Engineer callouts

-Updates


Nature & Capabilities of Software

• What is software?• Types of software• Generic software• Drivers, protocols and standards for interfacing with

peripherals and storage devices• Object linking and embedding• Functionality of internet software• Compatibility and portability• Features of software & evaluation/comparison• Upgrading - technical and human implications• Reliability - how do we make software reliable?

What is software?• Hardware is the physical

components that make up a computer system.

• Software is the programs and data that make the hardware do something useful.

• Software is NOT the CD or floppy disc that the program comes on - usually you are just buying the licence to use the software, and not the software itself.


Firmware

• You may also come across the term Firmware - this is software that is stored in hardware (i.e. on a chip) and is usually found in embedded systems.

• Not all computers are multi-purpose desktop or laptop PCs, mainframe or mini-computers, so are designed for a specific purpose and are built into machinery - these are called embedded systems.

• Embedded systems are mostly used for control, e.g. in washing machines.


Types of Software

• Specific purpose - e.g. Encarta, POS, etc.• Generic - e.g. spreadsheets, databases, etc.• Off the shelf - i.e. a product such as Sage Accounts• Bespoke - i.e. custom-made for the user

• Operating systems• Utility programs• Applications

There are three main categories of software:

Applications come in different types :


Operating Systems• Control and manage the computer’s resources

– memory management– resource allocation– storage– communication– interrupt handling

• Examples include Windows (NT, 2000 and XP only, not versions up to 98), Unix, Linux, CPM, Mac-OS.

• Heathcote says that they are installed on the hard disc, but this is not always the case, e.g. RISC-OS, PDAs, embedded systems and early home computers such as Spectrums and VIC-20s!


Shell

Operating Systems

Kernel

• The kernel is hardware specific and controls primary and secondary storage, input and output.

• The shell provides the user interface - this could be a command line or a Graphical User Interface.

• It is possible that an operating system, e.g. Windows NT or Linux, could run on several platforms (e.g. Intel, Power PC, DEC Alpha) by having the same shell with different kernels


Memory Management

• System resources and hardware often require memory which must be allocated by the OS

• Most modern operating systems are capable of multi-tasking (running several programs at once) - each program will require its own area of memory to store data.

• Some types of OS can use multiple processors, so they must also decide where a process takes places, as well as which memory it will use!


Memory Management

• Non-volatile, usually magnetic media - stored without power

• Slower - access time of around 8ms

• Cheaper, e.g. 40Gb for £35

• Volatile - i.e. contents are lost without power

• Fast - access time of around 7ns for PC RAM

• Relatively expensive - 1Gb DDR RAM costs £140

Primary storage (e.g. RAM):

Secondary storage (e.g. hard disc):


Virtual Memory• Sometimes the operating system can use secondary

storage to supplement primary storage in a way that is transparent to the application - this is called virtual memory

• RAM overflows onto the disc - e.g. in the Windows paging/ swap-file


Disc Storage

Constant angular velocity

Constant linear velocity

Sector

• CLV discs (e.g. Compact Discs) slow down as sectors nearer the edge are read - the sectors are the same physical length so that capacity is increased


File Allocation and Fragmentation• File A is written

• File B is written

• File A is edited

• Disc is fragmented

• The disc is now defragmented - the sectors are contiguous and so quicker to read

• Location of file is stored in the File Allocation Table (FAT)

A

A A

B

B

AB

B

A

B

B


User Interface

• Manages multi-tasking – e.g. each application in a separate window

• Allocates events to the appropriate application:– Mouse movement– Mouse click/double-click– Key presses– Timers

ShellKeystrokes

Mouse movements or clicks

GUI

WIMP

Menu

Command


http://www.microsoft.com/presspass/images/gallery/hardware/MultiMedia-Keyboard.jpg

User Interface• Provides the ability to transfer information between

applications – e.g. the clipboard in Windows

• Provides a consistent appearance to applications, e.g. menus, help, printing and error messages

Application BCopy

Application A Past

e

Clipboard


Peripherals

• Peripherals can be connected to a computer either internally - e.g. video or sound cards - or externally, through USB, serial or parallel ports.

• Internal devices are serviced through interrupts - the OS polls each device in turn to see whether it requires any processing time.

• The operating system communicates with the device through a driver.

• A driver is a piece of software that translates the user’s instructions - e.g. that they want a particular piece of text to be bold - into the device-specific control codes that the particular hardware uses.


Utility Programs• A utility is a small program, usually with a technical

function - they often come with an operating system.• Examples of utilities are:

– Virus checkers– Windows Explorer/File Manager/Xtree– Printer Manager– Scandisk & Defrag– Winzip (or other compression software)– Norton Utilities/PC Tools– Compilers and interpreters– Performance monitoring– Backup and restore


Applications

• Written for a specific purpose - inflexible• Such systems may be bespoke or off-the-shelf• Bespoke systems are those written specifically for a

particular customer, usually in a language such as C++, Visual BASIC or Java, e.g.– Point of Sale (POS) systems– Insurance quotation systems– Management Information Systems (MIS)

• Off-the-shelf software is the boxed products you might see in PC World:– Sage Accounting– AutoRoute


Bespoke Software

• Purpose-designed for task - it does exactly what you want (or what you asked for, anyway!)

• Purpose-designed for hardware

• Extra features can be integrated more easily

• More likely to be bug-ridden

• Tied into one suppliers, e.g. for:– documentation (no

books!)– training– support

• Portability of data is less likely

• Much more expensive


General Purpose/Generic Software

• Some software wasn’t designed for a specific purpose - they are known as generic or content-free applications

• Examples of generic software include:– word processors and DTP applications– database management systems– spreadsheets

• Integrated packages contain several of these functions in one application - e.g. Microsoft Works or Lotus Symphony

• Software suites contain these functions in separate applications, e.g. Microsoft Office or Lotus SmartSuite


Documents

Unit 1B – Capabilities & limitations of ICT. Capabilities & limitation of ICT ICT vs Manual methods of data processing Case Study – the school reporting