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Introduction to Computers and Information Systems

Ass. Prof. Emin Korkut

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SYLLABLES• Fundamentals of Computers (1 week-Chapter 1)

• Introduction to Computer hardware• History of Computers (Homework)

• Operating Systems (2 weeks-Chapters 2, 3 and 4)• Dos, Windows (1 week-Chapter 2)• Unix, Boot up actions and X Window (1 week-Chapters 3 and 4)

• Internet (2 weeks-Chapters 5 and 6)• FTP, DNS, IP, Telnet, Mail, WEB, and Search Engines (1 week-Chapter 5)• Search in Search Engines (Homework)• HTML (1 week-Chapter 6)

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•Word Processing (2 weeks-Chapters 7 and 8)•Star office (Chapter 7), TeX (Chapter 8)

•Spreadsheet (1 week-Chapter 9)•Star office, MS Excel (Chapter 9)

•Database Systems (2 weeks-Chapters 10-11)•Access (Chapter 10), SQL (Chapter 11)

•Plotting (1 week-Chapter 12)•GNU Plot

•Mathematical Operations at Numerical and Symbolic Level (2 weeks-Chapters 13 and 14)

•Mathematica

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MILESTONES

Exam:1st Exam --- 6th Week --- Chapter 1-42nd Exam --- 7th Week --- Chapter 1-43rd Exam --- 8th Week --- Chapter 5-74th Exam --- 10th Week --- Chapter 8,95th Exam --- 12th Week --- Chapter 10,116th Exam --- 14th Week --- Chapter 12-14

4 best results will be assigned as mid-term grade.

Homework: Given Week Return Week1st Homework --- 3rd Week 5th Week2nd Homework --- 5th Week 7th Week

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LECTURE NOTES

http://www.be.itu.edu.tr/lisans/bil101/notlar/

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A Brief History of Computers and Knowledge Processing with a Short Introduction of the

Computer Hardware

• Some introductory information about the fundamental components of the computers• The history of computers and knowledge processing.

• Knowledge processing• Information systems • Devices for these processes (computers and their peripherals)

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Knowledge

Knowledge is a static concept for information systems. The dictionary meaning of this concept can be given in three different ways without using the word information :

1. Something learned and kept in mind, 2. Clear perception of truth, 3. Understanding gained by actual experience, This entity means that something obtained and stored.The procedures, learning, perception and understanding are not involved in the content of this concept. So it is not dynamic entity, it is static.

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Information

In contrast to the knowledge concept, information is a dynamic entity. Its dictionary meaning can be given as follows.

1. The communication or reception of knowledge or intelligence,

2. Knowledge obtained from investigation, study, or instruction

•dynamic entity without any appearable loss of generality. On the other hand, the definition for the concept of information is based on the knowledge concept. Hence, the knowledge is a required thing or a brick for the construction of the information.

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Informatics

Related to the statement Information Sciences.

Collection, classification, storage, retrieval, and disseminationof recorded knowledge treated both as a pure and as an applied science.

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Counting

Historically, the beginning of the counting in the human sociallife lies at the very early ages of the human evolution.

•It is a comparison procedure•aimed to the determination of the population of some elements in a specified collection.

For example, consider a classroom involving a specified number of seats and a group of students. •Comparison procedure here aims to determine whether the population of the students is greater than, equal to, or less than the population of the seats•The procedure produces a unique answer which decides the valid one of these possibilities. Of course, this is just a raw process

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To develop a more sophisticated precise comparison we needto use a unique and universal set.

This can be chosen as the set of positive integers. Then the comparison procedure turns out to be the determination of a positive integer subset which is ordered and contains all the integers between 1 and the number of its elements inclusive.

Number Systems: The numbers are the essential components of quantitative sciences. Since the total number of fingers in two hands of humans are 10, the decimal number system became overruling number system.

Representation of number: We first deal with the integers. According to the one of very famous theorem of the number theory,any given number can be resolved into the following linear combination

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where n is the number to be represented in the number system whose basis, b, is a positive integer. The coefficients of theabove linear combination can take values from the set {0,1,2,3,...,b-1}. These are the arabic numerals {0,1,2,3,...,9}.

If the number under consideration, say p, is not an integer then the finite linear combination turns out to be the following infinite expansion

where the coefficients of this expansion can take the values only from the set s1,s2,...,sb.

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In the practical applications the representation is more concise than the above expansion and only the coefficients are used in the representation as follows

where the parentheses and the index b are used to specify the number system more clearly. In decimal notation, or in thenotations which use the same number system without passing to some other ones, the parentheses and the index b can be considered unnecessary.

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Decimal System

•uses 10 as the base•Its digit symbols are arabic numerals 0, 1, 2, 3, 4, 5, 6, 7, 8, 9.

Binary System

Computers can only use the electronic devices like chips, microchips which can be considered as a combination of zillions of the microscopic switches such that each switch can have only two positions, open or closed.

Each switch can store two option knowledge which can be represented by either 0 or 1. That is, each switch can store a single bit. This means that computers can not use decimal system in its chips. A binary number can be composed of 0s and 1s only.

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Octal Systems

The base of octal system is 8 and the digital symbols are 0, 1, 2, 3, 4, 5, 6, 7. It is used in the informatics science because of its conciseness. As a matter of fact, a binary number can be separated into three digit groups from right to left and then each individual group can be converted into an octal number. The result is replaced with the corresponding three binary digit group.

Hexadecimal Systems

The hexadecimal system's base is 16 and the digital symbols are 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C. D, E, F. A binary number can be separated into four digit groups from right to left and then each individual group can be converted into a hexadecimal number.

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Information Units, BIT and BYTE

To deal with the knowledge in quantitative scale we need to define units for it.

Since the computer memories are designed to have switches which have only two options (open or closed) it is quite natural to use binary system for number representation. This means that the atom of the knowledge is a unit which can have only two options, 0 or 1. The binary digits are composed of 0s and 1s.

So the smallest unit of data in a computer is called BIT.

There are eight bits in a BYTE. 1 byte = 8 bits

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Hardware and Software

Hardware is touchable items like disks, disk drives, display screens, keyboards, printers, boards and chips.

Software is an untouchable thing like computer instructions or data. All electronically storable items are software.

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Computing Systems in Human History

The humankind started with the fingers for constructing a computing system although there were some signals of the existence of a twenty based numbers system used by the ancient Northwest French tribes. If they are true one may expect that they possibly used their fingers and toes together for computation.

The first device for computation is known as abacus which uses counter balls on rods.

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A mechanical calculator designed by Blaise Pascal in thesecond half of the second millennium.

The mechanical device inventions continued and resulted in the birth of famous company IBM (International Business Machines).

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Transistor

This is a semiconductor material involving device amplifying a signal or opens or closes a circuit. It is invented in 1947 at Bell labs and have become the key ingredient of the digital circuit. Today's microprocessors contain tens of millions of microscopic transistors.

Integrated Circuit

This is another name for chip. It is a small electronic device which is made out of a semiconductor material. Its first version was developed in the 1950s by Jack Kilby of Texas Instruments and Robert Noyce of Fairchild semiconductor.

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Printed Circuit Board

This is sometimes abbreviated PCB. It is a thin plate on which chips and other electronic components are placed. Computers may contain one or more than one PCBs. The varieties for these boards spreads on a spectrum containing mother board, expansion board, daughtercard, controller board, Network Interface Card (NIC), video adapter.

Chips

This is a small piece of semi conducting material which is usually silicon. An integrated circuit is embedded on this small piece. A typical chip is less than 1/4 square inches. It contains millions of electronic components like transistors.

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Cache

The term cache which is pronounced cash is a special high--speed storage mechanism. It can be a reserved section of the main memory or can be designed as an independent high--speed storage device. In personal computers there are two commonly used caching: memory caching and disk caching.

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Memory cache is sometimes called cache store orRAM cache is a portion of memory made of SRAM whichis a high--speed static random access memory. It does not use DRAM which is a slower and cheaper dynamic random access memory. Memory caching is effective because most programs access the same data or instructions over and over.

Disk caching is based on the same principle as memory caching. It does not use SRAM. Instead, it uses conventional main memory. The most recently accessed data from the disk is stored in a memory buffer. A program first checks the disk cache to see if the data is there when it needs to access a data from the disk. The accessing to the data in the adjacent sectors of the main memory is handled in the same way.

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Computer Memories

There are several different type of memory units in a computer. The hardware design and purposes are different for these units. In some of the following sections we give certain information about these items.

RAM

RAM stands for Random Access Memory. It is same as the main memory. When employed by itself RAM refers to read and write memory. That is, it is possible to read data from or to write data into this type of memory. When the electricity breaks down the content becomes unrecoverably unavailable.

DRAM, Dynamic Random Access Memory, and SRAM, Static Random Access Memory can be given as examples of RAM.

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ROM

ROM stands for Read Only Memory. It holds the instructions for starting up the computer. The content is written by the producer company during the construction of the computer. The ROM can not be written.

PROM

PROM stands for Programmable Read Only Memory. It is a memory chip on which a program can be stored. However once the PROM has been used it can not be wiped clean and can not be used to store something else. In other words, PROMs are nonvolatile like ROMs.

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EPROM

EPROM stands for the Erasable Programmable Read Only Memory. It is a special type of PROM which can be cleaned by exposing it to ultraviolet light.

EEPROM

EEPROM stands for Electrically Erasable Programmable Read Only Memory. It is a special type of PROM which can be cleaned by exposing it to electrical charge.

Floppy DiskThe term floppy disk is used for a soft magnetic disk. The commercially available first version of floppy disks had 5.25inch diameter. It has also a 3.5 inch version.

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Hard Disks (IDE, SCSI)The term hard disk is used for a magnetic disk on which computer data can be stored. •Storage capacity is very large compared to the floppies•faster than floppies in data transfer.

A single hard disk is usually composed of several platters. Each platter requires two read/write heads, one for each side.These heads can not move independently since they are attached to the same arm. Each platter has the same number of tracks. A track location cutting across all platters is called cylinder. Although you may find removable hard disks, they are less portable than floppies.

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The interfaces which are used in data transmission from/tohard disks may vary. One of most common interface is IDE which stands for either Intelligent Drive Electronicsor Integrated Drive Electronics. In IDE interface the controller is integrated into the disk or CDROM device.

The other well--known interface is called SCSI which is pronounced scuzzy. Its stands for Small Computer System Interface. It is a parallel interface standard. For this interface a special type port SCSI port is used. This enables us to attach many devices to the same port. The interface is faster than parallel and serial ports.

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RAIDRAID stands for Redundant Array of Independent Disks or Redundant Array of Inexpensive Disks}. This is a category of disk drives employing two or more drives in combination for fault tolerance and performance. They are frequently used on servers but not for personal computers generally.

Tape DriveTape drive is like a tape recorder. It reads data from and writes it onto a tape. Their well--known disadvantage is their sequential structure. There is no capability of random accessing so it may take a very long time to get a specified data from the tape.

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CPU: Central Processing Unit

CPU is Central Processing Unit. The CPU can be considered as the brain of the computer. It is sometimes referred as the processor or central processor. The CPU is the place of computer where most calculations take place. In the computing point of view CPU is the most important part of computer.

On large machines, CPU's may necessitate one or more printed circuit boards while on small workstations and personal computers, the CPU is housed in a single chip which is called microchip.

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Assembly Language, Assembler

Assembly language is a programming language which makes the machine language codes more amenable for the humans. Machine language are only composed of numbers. However, assembly language can use names or words which are more meaningful for humans although its instruction structure is same with the machine language.

• An assembly language designed for a specific processor does not run for a different CPU as the machine language does the same thing.

Assembler means a program which translates programs from assembly language to machine language.

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Keyboard

It’s a device like type-writer.

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Monitor

The term monitor was first used for the statement display screen. However, today it has a broader meaning since now monitor implies the entire box of the device while display screen recalls just the screen. Additionally, monitor often implies graphics capabilities. There are three group of monitors.

• Monochrome which display two colours one for background and one for foreground. These colours can be black and white or gray and white or amber and black.• Grayscale monitors is a special type of a monochrome monitor which is capable of displaying different shades of gray. • Colour monitors can display anywhere from more than 1 million to 16 million different colours.

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Mouse

Mouse is a cursor or pointer control device. It controls the location and the movement of the cursor or pointer on a display screen.

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Printers

It prints text or illustrations on paper. There are a lot of different type printers. They can be categorized into seven groups in terms of the technology they use.

• Daisy wheel composed of a ball and ribbon. These devices can not print graphics.

• Dot-matrix creates the characters by striking pins against an ink ribbon. While the each one of the pins make a single dot the combination of the dots forms the characters and illustrations.

• Ink jet sprays ink at a sheet of paper. These produce high--quality text and graphics.

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• Laser uses the same technology as copy machines.

• LCD\&LEDs are similar to the laser printers but they use either liquid crystal diode or light emitting diode to produce an image on the drum.

• Line printer contains a chain of characters or pins and can print an entire line at a single stroke. Although they are very fast the quality of the output is quite low.

• Thermal printer pushes heated pins against a heat--sensitive paper. They are used in calculators and fax machines.

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Scanners

A scanner is a peripheral device for computers. It can read text or illustrations printed on paper and translate the information into a form which can be used by computer.

Digitizing Tablets

A digitizing tablet is a peripheral device for computers such that they enable an user to enter drawings and sketches into a computer. It consists of an electronic tabler and a cursor or a pen. In the digitizing tablet each point on the tablet uniquely corresponds to a point on the screen whereas the mouse works in relative movements by referring the cursor position.

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Communication Devices

Communication devices imply the hardware facilities enabling the computer nodes to communicate through the available connections. These are ethernet cards, modems, connection hardware, etc.

Ethernet CardsThe hardware which is a special card to beused for this protocol is called ethernet card. The data transfer rate through ethernet was 10 Mbps (an acronym for mega bits per second). The later version of the ethernet which had a data transfer rate of 100Mbps was called fast ethernet. The most recent version of the ethernet supports a data transfer rate of 1Gigabit (1000 megabits) per second and is called gigabit ethernet.

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Modem (Dialup, Null)

The term modem stands for MOdulator -- DEModulator where the capitalized letters are used to form the acronym. The term {modem} is used both the hardware device and the program used for the connections. It enables a computer to transmit data over telephone lines. The information storage in a computer is at digital level whereas the information transmitted over telephone lines are analog waves. Modem makes conversions between these two forms.

Modem can also be used for the data transmission between two serially connected computers.

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Connections (Parallel, Serial)

The personal computers use both parallel and serial connections. The connections between the computer and its peripheral devices are satisfied by using the connection points which are called ports. A port is parallel if it is a connection point for a parallel connection. Otherwise it is called serial. There is at least one serial port in a personal computer. In the parallel connections the data transmission takes place in a parallel fashion, that is, more than one synchronous data transmission occur. Whereas in the serial data transfer, the data is transferred in data trains, that is, there is only one single transmission. The parallel connection is used to connect a computer to its peripheral printer. On the other hand, mouse forexample, is serially connected to its computer.