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CHAPTER ONE BASIC COMPUTER CONCEPTS 5 1. HISTORY OF COMPUTERS 6 2. HARDWARE 11 A) CPU (CENTRAL PROCESSING UNIT) 11 B) MEMORY 12 i) RAM (random-access memory) 12 ii) ROM (Read-Only Memory) 13 C) PERMANENT DATA STORAGES 13 i) Magnetic Tape 13 ii) Magnetic Disk 14 iii) Hard Disk 15 iv) Floppy Disk 16 v) CD-ROM (Compact Disc Read-Only Memory) 16 4. INPUT DEVICE 17 A) PERIPHERAL 17 B) KEYBOARD 17 C) MOUSE 18 D) SCANNER 19 5. OUTPUT DEVICE 19 A) MONITOR 19 B) PRINTER 20 6. SOFTWARE 20 A) SYSTEM SOFTWARE 21 i) Programming Language 21 B) APPLICATION PROGRAM 22 i) Word Processor 22 ii) Spreadsheet 23 iii) Database 23

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Page 1: Entrance to Computer

CHAPTER ONE

BASIC COMPUTER CONCEPTS 5

1. HISTORY OF COMPUTERS 6

2. HARDWARE 11

A) CPU (CENTRAL PROCESSING UNIT) 11

B) MEMORY 12

i) RAM (random-access memory) 12

ii) ROM (Read-Only Memory) 13

C) PERMANENT DATA STORAGES 13

i) Magnetic Tape 13

ii) Magnetic Disk 14

iii) Hard Disk 15

iv) Floppy Disk 16

v) CD-ROM (Compact Disc Read-Only Memory) 16

4. INPUT DEVICE 17

A) PERIPHERAL 17

B) KEYBOARD 17

C) MOUSE 18

D) SCANNER 19

5. OUTPUT DEVICE 19

A) MONITOR 19

B) PRINTER 20

6. SOFTWARE 20

A) SYSTEM SOFTWARE 21

i) Programming Language 21

B) APPLICATION PROGRAM 22

i) Word Processor 22

ii) Spreadsheet 23

iii) Database 23

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CHAPTER TWO

DATA COMMUNICATION AND INTERNET 25

1. INTERNET HISTORY 25

2. WHAT IS THE INTERNET? 30

A) WHAT DO PEOPLE ON THE INTERNET? 30

B) WHO RUNS THE INTERNET? 30

C) WHAT IS THE REGIONAL NET? 30

D) WHO RUNS THE REGIONAL? 31

E) WHAT ARE THE BACKBONE NETWORKS? 31

F) WHY IS THERE MORE THAN ONE BACKBONE? 31

G) WHO RUNS THE NSFNET? 31

H) WHO PROVIDES ACCESS OUTSIDE THE UNITED STATES? 32

I) IS THE INTERNET DIFFERENT FROM TELEPHONE NETWORKS? 32

3. GETTING CONNECTED 32

A) OPTICAL FIBRE 33

B) MODEM 33

i) TCP/IP Protocol 34

ii) IP Address Internet Protocol 34

iii) Hostname- Domain Name 35

4. NETWORK 36

A) NETWORK ADDRESS 36

B) WHAT IS THE STRUCTURE OF THE INTERNET? 37

i) Local Area Network 37

ii) Wide Area Networks 37

5. INTERNET PROTOCOLS 37

A) WHAT IS ELECTRONIC MAIL? 37

i) Understanding an E-mail address 38

ii) Understanding an E-mail message's parts: 38

B) TELNET 38

i) Common Uses of Telnet 39

ii) Basic Telnet commands 40

C) FTP 40

i) File Types 41

ii) Basic FTP Commands: 42

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D) POST OFFICE PROTOCOL (POP) 43

E) GOPHER 43

i) Advantages and disadvantages of Gopher 44

6. INTERNET SOFTWARE 45

A) ELECTRONIC MAIL SOFTWARES 45

i) Pine 45

ii) Outlook Express, Eudora, Netscape Messenger 45

B) BROWSER 46

i) Netscape Navigator 46

ii) Internet Explorer 47

C) FRONT PAGE, HOT DOG 48

i) What is HTML? 48

ii) Uniform Resource Locator URL 50

iii) Web Page 51

CHAPTER THREE

MAIN CONCEPTS 53

1. FOLDER 53

2. FILE 53

3. MAIN DOS (DISK OPERATING SYSTEM) COMMANDS 54

A) DIR 54

B) CD 54

C) MD 55

D) RD 55

E) DEL 55

F) UNDELETE 55

G) COPY 56

H) MOVE 56

WINDOWS 95 OPERATING SYSTEM 57

1. USER INTERFACE 57

2. GRAPHICAL USER INTERFACE 57

3. STARTING WINDOWS 95 58

4. DESKTOP MANAGER 58

5. PARTS OF A WINDOW 59

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6. LEAVING WINDOWS 95 59

7. FORMATTING FLOPPY A 3½ 60

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CHAPTER ONE

BASIC COMPUTER CONCEPTS

A computer is an electronic tool for inputting, processing, storing, manipulating, and

retrieving information. It operates by joining hardware to enable people to generate text,

automate record keeping, complete various mathematical operations, and communicate the

results of these operations to others. Computers are electronic machines that get data, process

and returns this data to information. Numbers, letters voice or photographs can be taken as

data. Processed data is considered as information. A computer does not create information; it

is a tool that helps people handle information and increases our productivity.

The basic process which computers use for data processing are:

Input

Four basic arithmetic process (addition, subtraction, multiplication, division)

Logical processes

Output

Memory

Above processes are done by computer hardware. Super computers multiply more

than 500 million number pairs in one second.

Supercomputers have many processors (which perform the actual computing) the

work together to help to solve complex problems. Mainframes are large, expensive, powerful

systems

Advantage of computers are:

Economic machines

Dependable

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Precise

Computers can be used in the following fields:

Finance

Medicine

Communication

Marketing

Libraries

Education

Commerce

And surely in game sector.

1. History of Computers

Calculation was a need from the early days when it was necessary to account to others

for individual or group actions, particularly in relation to maintaining inventories (of flocks of

sheep) or reconciling finances. Early man counted by means of matching one set of objects

with another set (stones and sheep). The operations of addition and subtraction were simply

the operations of adding or subtracting groups of objects to the sack of counting stones or

pebbles. Early counting tables, named abaci, not only formalized this counting method but

also introduced the concept of positional notation that we use today.

Somewhere around 3000 BC the first (probably) mechanical counting device was created

-- the abacus (By Babylonians).

In 1642 another mechanical device was created called the Pascaline (after Blaise Pascal, a

famous French mathematician). The Pascaline used gears and wheels ("counting-wheels")

to perform the calculations. The interesting thing to note is that the counting-wheel design

was used in calculators until the 1960s.

The next major breakthrough in computer history revolves around Charles Babbage and

his Difference Engine and Analytical Engine. The machines that Charles designed in the

early 1800s were not electronic computers as we know them now but they were general

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purpose computational devices that were designed to be driven by steam. Charles is

credited with being the "Father of Computing" due to the fact that his designs were WAY

ahead of his time. He did, however, lay the foundation for the modern computer.

1884: The American Institute for Electrical Engineering (AIEE) was founded; the first of

the organizations that would eventually merge to form the IEEE in 1963.

1890 The increasing population in the US, and the demands of the data a longer and

longer process. It was anticipated that the Congress to ask more questions in each census,

was making the processing 1890 census data would not be processed before the 1900

census was due unless something was done to improve the processing methodology.

Herman Hollerith won the competition for the delivery of data processing equipment to

assist in the processing of the data from the 1890 US Census, and went on to assist in the

census processing for many countries around the world. The company he founded,

Hollerith Tabulating Company, eventually became one of the three that composed the

Calculating-Tabulating-Recording (C-T-R) company in 1914.

Calculating-Tabulating-Recording (C-T-R) company in was renamed IBM in 1924. The

Hollerith machines were the first to appear on a magazine cover.

1937: While not using the practical technology of the era, Alan Turing developed the idea

of a "Universal Machine" capable of executing any describable algorithm, and forming the

basis for the concept of "computability".

Later that 1946 Eckert and Mauchly, in a patent dispute with the University of

Pennsylvania, left the University to establish the first computer company -- Electronic

Control Corp. with a plan to build the Universal Automatic Computer (UNIVAC). After

many crises they built the BINAC for Northrup Aviation, and were taken over by

Remington-Rand before the UNIVAC was completed.

1947: William Shockley, John Bardeen, and Walter Brattain invent the "transfer

resistance" device, later to be known as the transistor that will revolutionize the computer

and give it the reliability that could not achieved with vacuum tubes.

On June 21, 1948 their prototype machine, the "Baby" was operated for the first time; the

world truly moved from the domain of calculators to the domain of computers. Williams,

Kilburn, and Newman continued to build a full scale machine they designated the

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Manchester Mark I. The Ferranti Corporation took the design and began a line of

computers that were one of the major components of the British Computer Industry.

1949: Just a year after the Manchester Baby machine became the first operating stored

program machine in the world, then first large scale, fully functional, stored-program

electronic digital computer was developed by Maurice Wilkes and the staff of the

Mathematical Laboratory at Cambridge University. It was named EDSAC (Electronic

Delay Storage Automatic Computer); the primary storage system was a set of mercury

baths through which generated and regenerated acoustic pulses represented the bits of

data.

1950: After five years of work and several different instantiations of the first computer

company established by Eckert and Mauchly, the UNIVAC computer was delivered to the

Census Bureau, just in time to begin work on the decennial census.

1957: The IBM 305 RAMAC was the first disk memory system.

1960: After three years of work Backus and his colleagues delivered the first FORTRAN

program compiler for the IBM 704, and almost immediately the first error message was

encountered -- a missing comma in a computed GO TO statement. The unmarked 2000

card deck was received at Westinghouse in Pittsburgh by Herbert Bright who deduced that

it was the long expected compiler, and created the first user program -- complete with an

error. The world of programming languages had taken a large step upward, from a domain

in which only specially trained programmers could complete a project, to a domain in

which those with problems could express their own solutions.

1960: Since 1952 Grace Murray Hopper had been developing a series of programming

languages that increasingly used natural language-like phrases to express the operations of

business data processing. FLOWMATIC was the last of these. Others had also taken on

the challenge, including IBM that had produced a language named COMMERCIAL

TRANSLATOR. From these bases an industry-wide team -- Conference on Data System

Languages (CODASYL) -- led by Joe Wegstein of NBS (now NIST) developed a new

language in a very short time and created the first standardized business computer

programming language, COBOL (Common Business Oriented Language). For the next 20

years there were more programs written in COBOL than any other single language

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By 1963 the process of standardization of the elements of the industry was becoming

prevalent and among the first was a standard for a code for information interchange

(ASCII). For the first time there was a means for computers to interchange information,

but it would take almost 15 years before this would become commonplace.

In 1964 Douglas Engelbart had developed the "mouse," to be followed by the

development of two-dimensional editing, the concept of windows, cross-file editing,

uniform command syntax, remote procedure-call protocol, mixed text-graphic files,

structured document files, idea processing, and many more developments.

To many the world of computing changed radically on April 7, 1964 when IBM

announced System/360, the first IBM family of compatible machines.

In the Fall of 1964, the Dartmouth Time Sharing System became operational with BASIC

(Beginner's All-purpose Symbolic Instruction Code) as principle language for student

program development. Developed by John Kemeny (later president of Dartmouth and

chairman of the commission that investigated the Three Mile Island accident) and Tom

Kurtz, together with lots of help from undergraduates, BASIC was to become the "lingua

playpen" of the young computer community.

1966: A joint project between IBM and the SHARE user's group developed a new

programming language with the intention of combining both scientific and business data

processing as had the System/360 machines. The language was also intended to be a high

level system development language.

1969: Work on ARPAnet begins. The concept of networking was by no means new in

1969; even as early as the Romans had there been a network of roads that facilitated not

only the rapid movement of troops but also the rapid interchange of information by

messengers.

1971: The world of personal computing has its roots in 1971, with two important products

- First commercially available microprocessor and the first floppy disk. The recently

founded Intel Corporation produced the Intel 4004 for Busicom company, giving birth to a

family of "processors on a chip". Ted Hoff produced the Intel 4004 in response to the

request from a Japanese company (Busicom) to create a chip for a calculator.

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1973: While the concept of a wide area network had been effectively developed as a

part of the ARPANet project, the basis for a "local area net" was Ethernet, created at

Xerox PARC by Robert Metcalfe.

1974: The world of personal computing was growing. Intel introduced the 8080 for the

purposes of controlling traffic lights, but it was to find fame later as the processor for the

Altair.

First ATM machines appear.

1975 was also the year in which IBM produced their first "personal computer", the 5100.

1976: A year after the Altair was produced, Steve Jobs and Steve Wozniak produced the

Apple II that was assembled and complete with its own keyboard and monitor. It was an

immediate success, priced within the reach of the enthusiast and supporting some basic

software applications that showed its true usefulness. The Apple II was quickly

assimilated into schools and colleges and was the basis of many early "microprocessor"

courses. That same year the Microsoft and Apple Corporations founded.

Micropro International released Wordstar in 1979, which like Visicalc would set the

standards for word processing systems.

1980 The personal computer moved from being a microcomputer limited by its storage

capabilities to compete effectively with the power of many mainframe systems, and

certainly with the majority of minicomputers.

After waiting for the opposition to soften up the market, IBM entered the field in 1981

with the IBM "PC" and supported by the DOS operating system developed under an

agreement that gave Microsoft all the profits in exchange for the development costs

having been borne by Microsoft. That same year Commodore introduced the VIC-20, and

quickly sold 1 million units!

1982 Less than four months after IBM introduced the PC, Time Magazine named the

computer as the man of the year! Never before (or since) had an inanimate object been

chosen as the "man of the year".

1983: Software development exploded with the introduction of the PC, standard

applications including not only spreadsheets and word processors, but also graphics

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packages and communications systems. Games were also prolific. In 1983 Mitch Kapor

introduced Lotus 1-2-3, and took over the spreadsheet supremacy from Visicalc.

1984 The first portable computer 50 B.C. (Micro 2/84), Sony and Phillips announced CD-

ROM.

1985 Microsoft Windows 1.0 had been announced.

1986: Starting from the 8086 chip used in the IBM PC, Intel Corporation continually

developed new chips to support the ever increasing demand for processing power; in 1986

Intel released the 386 chip -- the intermediate stage between the 1980 8086 and the 1994

Pentium.

1987 Computer Society opens European office in Brussels

1988 Computer Society opens Asian office in Tokyo

1990 Software for Workstations (Computer Graphics 7/90)

1993 in University of Illinois NCSA Mosaic interface has been developed for Internet.

1994 Netscape browser has been developed.

1995 Windows 95 announced.

http://video.cs.vt.edu:90/history/

2. Hardware

We call all physical devices of a computer "Hardware".

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The part of a computer which controls all the other parts. Designs vary widely but, in

general, the CPU consists of the control unit, the arithmetic and logic unit (ALU) and memory

(registers, cache, RAM and ROM) as well as various temporary buffers and other logic.

The control unit fetches instructions from memory and decodes them to produce

signals which control the other part of the computer. This may cause it to transfer data

between memory and ALU or to activate peripherals to perform input or output.

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The term "processor" has to some extent replaced "CPU", though RAM and ROM

are not normally considered as part of a processor. This is particularly true of common

modern microprocessors though there have been microprocessors which include RAM and/or

ROM on the same integrated circuit.

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These days, usually used synonymously with Random Access Memory or Read-Only

Memory, but in the general sense it can be any device that can hold data in machine-readable

format.

DRAM SRAM

RAM

Random Access Memory

PROM EPROM

ROM

Read-Only Memory

Memory Cache Memory

i) RAM (random-access memory)

(Previously "direct-access memory"). A data storage device for which the order of

access to different locations does not affect the speed of access. This is in contrast to, say, a

magnetic disk, magnetic tape or a mercury delay line where it is very much quicker to access

data sequentially because accessing a non-sequential location requires physical movement of

the storage medium rather than just electronic switching.

The most common form of RAM in use today is built from semiconductor integrated

circuits, which can be either static (SRAM) or dynamic (DRAM). In the 1970s magnetic core

memory was used. RAM is still referred to as core by some old-timers.

The term "RAM" has gained the additional meaning of read-write. Most kinds of

semiconductor read-only memory (ROM) are actually "random access" in the above sense but

are never referred to as RAM. Furthermore, memory referred to as RAM can usually be read

and written equally quickly (approximately), in contrast to the various kinds of programmable

read-only memory. Finally, RAM is usually volatile though non-volatile random-access

memory is also used.

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Interestingly, some DRAM devices are not truly random access because various

kinds of "page mode" or "column mode" mean that sequential access is faster than random

access.

We use known units for memory capacity. The smallest memory unit is called BIT

(BInary digiT). 8 bits makes 1 BYTE. A character (a letter, a number or a symbol) can be

saved in a 1 byte space.

1 KB =1024 Byte 1000 Byte (thousand byte)

1 MB = 1024*1024 Byte 1.048.576 Byte 1.000.000 Byte (million byte)

1 GB =1024*1024*1024 1.073.741.800 Byte 1.000.000.000 Byte (billion byte)

ii) ROM (Read-Only Memory)

A type of data storage device which is manufactured with fixed contents. In its most

general sense, the term might be used for any storage system whose contents cannot be

altered, such as a gramophone record or a printed book; however, the term is most often

applied to semiconductor integrated circuit memories, of which there are several types, and

CD-ROM.

ROM is inherently non-volatile storage - it retains its contents even when the power is

switched off, in contrast to RAM.

ROM is often used to hold programs for embedded systems since these usually have a

fixed purpose. ROM is also used for storage of the lowest level bootstrap software (firmware)

in a computer.

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i) Magnetic Tape

A data storage medium consisting of a magnetisable oxide coating on a thin plastic

strip, commonly used for backup and archiving.

Early industry-standard magnetic tape was half an inch wide and wound on removable

reels 10.5 inches in diameter. Different lengths were available with 2400 feet and 4800 feet

being common. DECtape was a variation on this "round tape".

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Tape is read and written on a tape drive (or "deck") which winds the tape from one

reel to the other causing it to move past a read/write head. Early tape had seven parallel tracks

of data along the length of the tape allowing six bit characters plus parity written across the

tape. A typical recording density was 556 characters per inch. The tape had reflective marks

near its end which signaled beginning of tape (BOT) and end of tape (EOT) to the hardware.

Data is written to tape in blocks with inter-block gaps between them. Each block is

typically written in a single operation with the tape running continuously during the write.

The larger the block the larger the data buffer required in order to supply or receive the data

written to or read from the tape. The smaller the block the more tape is wasted as inter-block

gaps. Several logical records may be combined into one physical block to reduce wastage

("blocked records"). Finding a certain block on the tape generally involved reading

sequentially from the beginning, in contrast to magnetic disks. Tape is not suitable for random

access. The exception to this is that some systems allow tape marks to be written which can

be detected while winding the tape forwards or rewinding it at high speed. These are typically

used to separate logical files on a tape.

ii) Magnetic Disk

A flat rotating disc covered on one or both sides with some magnetisable material. The

two main types are the hard disk and the floppy disk.

Small areas or "zones" on a magnetic disk are magnetised. The magnetisation is

aligned in one of two opposing orientations with respect to the recording head. Each zone of

magnetisation. The head writes data by altering the alignment and reads data by detecting

current pulses induced in a coil as zones with different magnetic alignment pass underneath it.

Data is stored on either or both surfaces of discs in concentric rings called "tracks".

Each track is divided into a whole number of "sectors". Where multiple (rigid) discs are

mounted on the same axle the set of tracks at the same radius on all their surfaces is known as

a "cylinder".

Data is read and written by a disk drive which rotates the discs and positions the

read/write "heads" over the desired track(s). The latter radial movement is known as

"seeking". There is usually one head for each surface that stores data though, for increased

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performance (from reduced rotational latency), it is possible, though expensive, to position

multiple heads at equally spaced angles around the discs.

Therefore there are two states that can be detected for each zone - a change in

alignment, or no change.

Ideally a data bit of one or zero can be recorded in each zone of magnetisation,

however, if a zero represents an absence of magnetic change, the detection of several

consecutive zeros would imply accurately measuring the length of time of the absence, i.e.,

measuring the time between two magnetic changes. However, the variability of motor speed

limits the number of consecutive zeros which can be read reliably.

The best recording methods accurately follow the characteristics of the magnetic and

rotational aspects in recording the disk, to be as dense as possible in recording bits.

a) Track

The part of a disk which passes under one read/write head while the head is stationary.

The number of tracks on a disk surface therefore corresponds to the number of different radial

positions of the head(s). The collection of all tracks on all surfaces at a given radial position is

known a cylinder and each track is divided into sectors.

b) Sector Interleave

(Or sector map) The mapping from logical to physical sector numbers on a magnetic

disk designed to optimise sequential reads and writes. Data is usually transferred to and from

the disk in blocks or sectors where one sector lies within a continuous range of rotational

angle of the disk. If logical sectors are assigned sequentially to physical sectors (0,1,2,...) then

by the time one sector has been read and processed (e.g. writen to main memory) the start of

the next logical sector will have passed the read/write head and will not be accessible until the

disk's rotation brings it back under the head.

iii) Hard Disk

(In contrast to floppy disk). One or more rigid magnetic disks rotating about a central

axle with associated read/write heads and electronics, used to store data. Most hard disks are

permanently connected to the drive (fixed disks) though there are also removable disks.

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High speed disks have an access time of 28 milliseconds or less, and low-speed

disks run 65 milliseconds or more. The higher speed disks also transfer their data faster than

the slower speed units.

Each surface of each disk is divided into a number of evenly spaced concentric

circular tracks. The set of all tracks at a given radius on all surfaces (the tracks which can be

accessed without moving the heads) are known as a cylinder. Each track is divided into

sectors.

iv) Floppy Disk

(Or "floppy", "diskette") A small, portable plastic disk coated in a magnetisable

substance used for storing computer data, readable by a computer with a floppy disk drive.

The physical size of disks has shrunk from the early 8 inch, to 5 1/4 inch ("minifloppy") to 3

1/2 inch ("microfloppy") while the data capacity has risen.

These disks are known as "floppy" disks (or diskettes) because the disk is flexible and

the read/write head is in physical contact with the surface of the disk in contrast to "hard

disks" (or winchesters) which are rigid and rely on a small fixed gap between the disk surface

and the heads. Floppies may be either single-sided or double-sided.

3.5 inch floppies are less floppy than the larger disks because they come in a stiff

plastic "envelope" or case, hence the alternative names "stiffy" or "crunchy" sometimes used

to distinguish them from the floppier kind.

The following formats are used on IBM PCs and elsewhere:

Capacity Density Width

360K double 5.25"

720K double 3.5"

1.2M high 5.25"

1.44M high 3.5"

Double denisty and high density are usually abbreviated DD and HD. HD 3.5 inch

disks have a second hole in the envelope and an overlapping "HD" logo.

v) CD-ROM (Compact Disc Read-Only Memory)

A non-volatile optical data storage medium using the same physical format as audio

compact discs, readable by a computer with a CD-ROM drive.

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CD-ROM is popular for distribution of large databases, software and especially

multimedia applications. The maximum capacity is about 600 megabytes. A CD can store

around 640 megabytes of data - about 12 billion bytes per pound weight.

CD-ROM drives are rated with a speed factor relative to music CDs (1x or 1-speed

which gives a data transfer rate of 150 kilobytes per second). 12x drives were common in

April 1997. Above 12x speed, there are problems with vibration and heat. Constant angular

velocity (CAV) drives give speeds up to 20x but due to the nature of CAV the actual

throughput increase over 12x is less than 20/12.

Most CD-ROM drives can also play audio CDs.

4. Input Device

A peripheral used to transfer data from the outside world into a computer system.

Some input devices are operated directly by the user, e.g. keyboard, mouse, touch screen,

joystick, digitising tablet, microphone; others are sensors or transducers which convert

external signals into data, e.g. using an ananlog to digital converter (this would also be true of

a microphone). Other kinds of inputs are really one half of a bidirectional link with another

computer or storage device, e.g. serial line, SCSI interface.

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(Or "peripheral device", "device") Any part of a computer other than the CPU or

working memory, i.e. disks, keyboards, monitors, mice, printers, scanners, tape drives,

microphones, speakers, cameras, to list just the less exotic ones.

High speed working memory, such as RAM, ROM or, in the old days, core would not

normally be referred to as peripherals. The more modern term "device" is also more general in

that it is used for things such as a pseudo-tty, a RAM drive or a network adaptor.

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A hardware device consisting of a number of mechanical buttons (keys) which the

user presses to input characters to a computer.

Keyboards were originally part of terminals which were separate peripheral devices

that performed both input and output and communicated with the computer via a serial line.

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Today a keyboard is more likely to be connected directly to the processor, allowing the

processor to scan it and detect which key or keys are currently pressed. Keyboards vary in the

keys they have, most have keys to generate the ASCII character set as well as various

function keys and special purpose keys, e.g. reset or volume control.

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The most commonly used computer pointing device, first introduced by Douglas

Engelbart in 1968. The mouse is a device used to manipulate an on-screen pointer that's

normally shaped like an arrow. With the mouse in hand, the computer user can select, move,

and change items on the screen.

A conventional roller-ball mouse is slid across the surface of the desk, often on a

mouse mat. As the mouse moves, a ball set in a depression on the underside of the mouse rolls

accordingly. The ball is also in contact with two small shafts set at right angles to each other

inside the mouse. The rotating ball turns the shafts, and sensors inside the mouse measure the

shafts' rotation. The distance and direction information from the sensors is then transmitted to

the computer, usually through a connecting wire - the mouse's "tail". The computer then

moves the mouse pointer on the screen to follow the movements of the mouse. This may be

done directly by the graphics adaptor, but where it involves the processor the task should be

assigned a high priority to avoid any perceptible delay.

Some mice are contoured to fit the shape of a person's right hand, and some come in

left-handed versions. Other mice are symmetrical.

Included on the mouse are usually two or three buttons that the user may press, or

click, to initiate various actions such as running programs or opening files. The left-most

button (the primary mouse button) is operated with the index finger to select and activate

objects represented on the screen. Different operating systems and graphical user interfaces

have different conventions for using the other button(s). Typical operations include calling up

a context-sensitive menu, modifying the selection, or pasting text. With fewer mouse buttons

these require combinations of mouse and keyboard actions. Between its left and right buttons,

a mouse may also have a wheel that can be used for scrolling or other special operations

defined by the software. Some systems allow the mouse button assignments to be swapped

round for left-handed users.

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Just moving the pointer across the screen with the mouse typically does nothing.

Normally, the pointer is positioned over something on the screen (an icon or a menu item),

and the user then clicks a mouse button to actually affect the screen display.

The following table defines the five most common functions performed with the

mouse and its buttons.

Point To place the pointer over an on-screen item

click To press and release a mouse button

double-click To press and release a mouse button twice in rapid succession

right-click To quickly press and release the right mouse button

drag To hold down the mouse button while moving the mouse

Most modern computers include a mouse as standard equipment. However, some

systems, especially portable laptop and notebook models, may have a trackball, touchpad or

Trackpoint on or next to the keyboard. These input devices work like the mouse, but take less

space and don't need a desk.

DD)) SSccaannnneerr

An input device that takes in an optical image and digitises it into an electronic image

represented as binary data. This can be used to create a computerised version of a photo or

illustration.

A scanner may be linked to optical character recognition software allowing printed

documents to be converted to electronic text without having to type them in at a keyboard.

5. Output Device

Electronic or electromechanical equipment connected to a computer and used to

transfer data out of the computer in the form of text, images, sounds or other media to a

display screen, printer, loudspeaker or storage device. Most modern storage devices such as

disk drives and magnetic tape drives act as both input and output devices, others such as CD-

ROM are input only.

AA)) MMoonniittoorr

A cathode-ray tube and associated electronics connected to a computer's video output.

A monitor may be either monochrome (black and white) or colour (RGB). Colour monitors

may show either digital colour (each of the red, green and blue signals may be either on or

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off, giving eight possible colours: black, white, red, green, blue, cyan, magenta and yellow)

or analog colour (red, green and blue signals are continuously variable allowing any

combination to be displayed).

BB)) PPrriinntteerr

Output device which use to take copy of screen to paper. There are several kind of

printers. Dot matrix, ink jet and laser jet.

6. Software

We call all physical device of a computer is hardware, and the software is the

instructions executed by a computer, as opposed to the physical device on which they run (the

"hardware").

Software can be split into two main types - system software and application software

or application programs. System software is any software required to support the production

or execution of application programs but which is not specific to any particular application.

Examples of system software would include the operating system, compilers, editors and

sorting programs. Such as Windows 95, Linux, Unix.

Examples of application programs would include an accounts package or a CAD

program. Microsoft Office, Star Office. Other broad classes of application software include

real-time software, business software, scientific and engineering software, embedded

software, personal computer software and artificial intelligence software.

Software includes both source code written by humans and executable machine code

produced by assemblers or compilers. It does not usually include the data processed by

programs unless this is in a format such as multimedia which depends on the use of computers

for its presentation. This distinction becomes unclear in cases such as spread sheets which can

contain both instructions (formulae and macros) and data. There are also various intermediate

compiled or semi-compiled, forms of software such as library files and byte-code.

Some claim that documentation (both paper and electronic) is also software. Others go

further and define software to be programs plus documentation though this does not

correspond with common usage.

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The noun "program" describes a single, complete and more-or-less self-contained

list of instructions, often stored in a single file, whereas "code" and "software" are

uncountable nouns describing some number of instructions which may constitute one or more

programs or part thereof. Most programs, however, rely heavily on various kinds of operating

system software for their execution.

AA)) SSyysstteemm SSooffttwwaarree

Any software required to support the production or execution of application programs

but which is not specific to any particular application.

System software typically includes an operating system to control the execution of

other programs; user environment software such as a command line interpreter, window

system, desktop; development tools for building other programs such as assemblers,

compilers, linkers, libraries, interpreters, cross-reference generators, version control, make;

debugging, profiling and monitoring tools; utility programs, e.g. for sorting, printing, and

editing.

Different people would classify some or all of the above system software as part of the

operating system while others might say the operating system was just the kernel.

i) Programming Language

A formal language in which computer programs are written. The definition of a

particular language consists of both syntax (how the various symbols of the language may be

combined) and semantics (the meaning of the language constructs).

Languages are classified as low level if they are close to machine code and high level

if each language statement corresponds to many machine code instructions (though this could

also apply to a low level language with extensive use of macros, in which case it would be

debatable whether it still counted as low level). A roughly parallel classification is the

description as first generation language through to fifth generation language.

FORTRAN (1957) FORmula TRANslation

COBOL (1954) COmmon Business Oriented Language

LISP (1958) LISt Processing

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BASIC (1964) Beginner's All Purpose Symbolic Instruction Code

PASCAL (1968)

C (1970) Unix operating system has been written with C.

ADA (1980)

JAVA (1995) Java is mostly using to create Web pages. Java can be used in different

computer systems.

BB)) AApppplliiccaattiioonn PPrrooggrraamm

(Or "application", "app") A complete, self-contained program that performs a specific

function directly for the user. This is in contrast to system software such as the operating

system kernel, server processes and libraries which exists to support application programs.

Editors for various kinds of documents, spreadsheets, and text formatters are common

examples of applications. Network applications include clients such as those for FTP,

electronic mail, telnet and WWW.

The term is used fairly loosely, for instance, some might say that a client and server

together form a distributed application, others might argue that editors and compilers were not

applications but tools for building applications.

One distinction between an application program and the operating system is that

applications always run in "user mode" (or "non-privileged mode"), while operating systems

and related utilities may run in "supervisor mode" (or "privileged mode").

The term may also be used to distinguish programs which communicate via a

graphical user interface from those which are executed from the command line.

i) Word Processor

A program used to create and print (chiefly textual) documents that might otherwise

be prepared on a typewriter. The key advantage of word processor is its ability to make

changes easily, such as correcting spelling, changing margins, or adding, deleting, and

relocating entire blocks of text. Once created, the document can be printed quickly and

accurately and saved for later modifications.

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Today most popular word processors, such as Microsoft Word, offer a much greater

range of facilities than the first such programs.

ii) Spreadsheet

(Or rarely "worksheet") A type of application program which manipulates numerical

and string data in rows and columns of cells. The value in a cell can be calculated from a

formula which can involve other cells. A value is recalculated automatically whenever a value

on which it depends changes. Different cells may be displayed with different formats.

Many spreadsheets have a "What-if" feature. The user gives desired end conditions

and assigns several input cells to be automatically varied. An area of the spreadsheet is

assigned to show the result of various combinations of input values.

Spreadsheets usually incorporate a macro language, which enables third-party writing

of worksheet applications for commercial purposes.

Microsoft produced MultiPlan for the Macintosh, which was followed by Excel for

Macintosh, long before Microsoft Windows was developed.

Today, Microsoft, Lotus, Borland and many other companies offer Windows-based

spreadsheet programs. The main end-users of spreadsheets are business and science.

Spreadsheets are an example of a non-algorithmic programming language.

iii) Database

One or more large structured sets of persistent data, usually associated with software

to update and query the data. A simple database might be a single file containing many

records, each of which contains the same set of fields where each field is a certain fixed

width. A database is one component of a database management system.

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CHAPTER TWO

DATA COMMUNICATION AND INTERNET

1. Internet History

The internet's history is rather short, spanning, at most, the period from 1968 until

present. The internet's roots can be traced to the Advanced Research Projects Agency

Network (ARPANET) created by the Department of Defense in 1968. The current term,

"internet," came into being in the late 1980's to describe a series of national and international

computer networks that had a series of informal interconnections. In 1990, with the merger of

USENET, NSFNET, ARPANET, and BITNET the generic term of internet began to refer to a

specific network configuration.

Short History of the Internet:

1957 USSR launches Sputnik, first artificial earth satellite. In response, US forms the

Advanced Research Projects Agency (ARPA) within the Department of Defense

(DoD) to establish US lead in science and technology applicable to the military.

1966 First ARPANET plan

1968 PS-network presented to the Advanced Research Projects Agency (ARPA)

1969 ARPANET commissioned by DoD for research into networking

1970 ARPANET hosts start using Network Control Protocol (NCP), first host-to-host

protocol

First cross-country link installed by AT&T between UCLA and BBN at 56kbps.

1973 Bob Metcalfe's Harvard PhD Thesis outlines idea for Ethernet. The concept was

tested on Xerox PARC's Alto computers, and the first Ethernet network called the

Alto Aloha System (May).

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ARPA study shows email composing 75% of all ARPANET traffic

1974 BBN opens Telenet, the first public packet data service (a commercial version of

ARPANET)

1975 Satellite links cross two oceans (to Hawaii and UK) as the first TCP tests are run

over them by Stanford, BBN, and UCL

1976 Elizabeth II, Queen of the United Kingdom sends out an email in February from the

Royal Signals and Radar Establishment (RSRE) in Malvern

1979 Meeting between Univ of Wisconsin, DARPA, National Science Foundation (NSF),

and computer scientists from many universities to establish a Computer Science

Department research computer network (organized by Larry Landweber).

1981 BITNET, the "Because It's Time NETwork"

Started as a cooperative network at the City University of New York, with the first

connection to Yale.

Original acronym stood for 'There' instead of 'Time' in reference to the free NJE

protocols provided with the IBM systems.

Provides electronic mail and listserv servers to distribute information, as well as

file transfers

CSNET (Computer Science NETwork) built by a collaboration of computer scientists and

Univ of Delaware, Purdue Univ, Univ of Wisconsin, RAND Corporation and BBN

through seed money granted by NSF to provide networking services (especially

email) to university scientists with no access to ARPANET.

1982 DCA and ARPA establish the Transmission Control Protocol (TCP) and Internet

Protocol (IP), as the protocol suite, commonly known as TCP/IP, for ARPANET.

This leads to one of the first definitions of an "internet" as a connected set of

networks, specifically those using TCP/IP, and "Internet" as connected TCP/IP

internets.

DoD declares TCP/IP suite to be standard for DoD

EUnet (European UNIX Network) is created by EUUG to provide email and

USENET services.

original connections between the Netherlands, Denmark, Sweden, and UK

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1983 Desktop workstations come into being, many with Berkeley UNIX (4.2 BSD)

which includes IP networking software.

1984 Domain Name System (DNS) introduced

1986 NSFNET created (backbone speed of 56Kbps)

NSF establishes 5 super-computing centers to provide high-computing power for

all (JVNC@Princeton, PSC@Pittsburgh, SDSC@UCSD, NCSA@UIUC, Theory

Center@Cornell). •This allows an explosion of connections, especially from

universities.

Network News Transfer Protocol (NNTP) designed to enhance Usenet news

performance over TCP/IP.

1987 NSF signs a cooperative agreement to manage the NSFNET backbone with Merit

Network, Inc. (IBM and MCI involvement was through an agreement with Merit).

Merit, IBM, and MCI later founded ANS.

Number of hosts breaks 10,000

Number of BITNET hosts breaks 1,000

1988 Internet Relay Chat (IRC) developed by Jarkko Oikarinen (:zby:)

1990 The World comes on-line (world.std.com), becoming the first commercial provider

of Internet dial-up access

1991 Wide Area Information Servers (WAIS), invented by Brewster Kahle, released by

Thinking Machines Corporation

Gopher released by Paul Lindner and Mark P. McCahill from the Univ of

Minnessota

World-Wide Web (WWW) released by CERN; Tim Berners-Lee developer

1992 World Bank comes on-line

The term "surfing the Internet" is coined by Jean Armour Polly (:jap:)

1993 InterNIC created by NSF to provide specific Internet services: (:sc1:)

US White House comes on-line (http://www.whitehouse.gov/):

United Nations (UN) comes on-line (:vgc:)

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Countries connecting to NSFNET: Bulgaria (BG), Costa Rica (CR), Egypt (EG),

Fiji (FJ), Ghana (GH), Guam (GU), Indonesia (ID), Kazakhstan (KZ), Kenya (KE),

Liechtenstein (LI), Peru (PE), Romania (RO), Russian Federation (RU), Turkey

(TR), Ukraine (UA), UAE (AE), US Virgin Islands (VI)

1994 ARPANET/Internet celebrates 25th anniversary

Shopping malls arrive on the Internet

Yes, it's true - you can now order pizza from the Hut online

1995 The new NSFNET is born as NSF establishes the very high speed Backbone

Network Service (vBNS) linking super-computing centers: NCAR, NCSA, SDSC,

CTC, PSC

Hong Kong police disconnect all but 1 of the colony's Internet providers in search of

a hacker. 10,000 people are left without Net access. (:api:)

Radio HK, the first commercial 24 hr., Internet-only radio station starts broadcasting

Registration of domain names is no longer free. Beginning 14 September, a $50

annual fee has been imposed, which up until now was subsidized by NSF. NSF

continues to pay for .edu registration, and on an interim basis for .gov

Operation Home Front connects, for the first time, soldiers in the field with their

families back home via the Internet.

1996 Malaysian Prime Minister Mahathir Mohamad, PLO Leader Yasser Arafat, and

Phillipine President Fidel Rhamos meet for ten minutes in an online interactive chat

session on 17 January.

Domain name tv.com sold to CNET for US$15,000

The WWW browser war, fought primarily between Netscape and Microsoft, has

rushed in a new age in software development, whereby new releases are made

quarterly with the help of Internet users eager to test upcoming (beta) versions.

Restrictions on Internet use around the world:

China: requires users and ISPs to register with the police

Germany: cuts off access to some newsgroups carried on Compuserve

Saudi Arabia: confines Internet access to universities and hospitals

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Singapore: requires political and religious content providers to register with the

state

New Zealand: classifies computer disks as "publications" that can be censored and

seized

source: Human Rights Watch

1997 Domain name business.com sold for US$150,000

1999 Internet access becomes available to the Saudi Arabian public in January

First Internet Bank of Indiana, the first full-service bank available only on the Net,

opens for business on 22 February

Free computers are all the rage (as long as you sign a long term contract for Net

service). Vizzy Go, Vestel.

Technologies of the Year: E-Trade, Online Banking

Internet Growth

Date Hosts Date Hosts Networks Domains

12/69 4 07/89 130,000 650 3,900

04/71 23 07/91 535,000 3,086 16,000

08/81 213 01/93 1,313,000 8,258 21,000

01/89 80,000 07/97 19,540,000 1,301,000

Hosts = a computer system with registered ip address (an A record)

Networks = registered class A/B/C addresses

Domains = registered domain name (with name server record)

Note: A more accurate survey mechanism was developed in 1/98; new and some

corrected numbers are shown below. For further info, see

WWW Growth:

Date Sites Date Sites

06/93 130 04/97 1,002,512

12/94 10,022 01/98 1,834,710

06/95 23,500 12/97 1,681,868

12/96 603,367 01/99 4,062,280

01/97 646,162 08/99 7,078,194

Sites = # of web servers (one host may have multiple sites by using different domains or

port numbers)

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2. What Is the Internet?

The internet is very difficult to define. Principally because things change on the

internet with great rapidity, definitions that are appropriate at one time have little meaning

later. However, a review of some previous explanations of the internet reveals several things

in common. The internet is:

a worldwide network of networks as Kevin Hughes defined in A Guide to

Cyberspace.

a way to communicate and share resources as described in the "What is the

Internet?" by the Internet Society.

The Internet is a system for allowing computers to communicate with each other. So

before we get the Internet we have to have computer. Therefore, I like to define the Internet is

a world-wide network of computer networks that use a common communications protocol,

TCP/IP. TCP/IP provides a common language for interoperation between that use a variety of

local protocols. (Netware, AppleTalk, DECnet and others).

AA)) WWhhaatt DDoo PPeeooppllee OOnn tthhee IInntteerrnneett??

Probably the most frequent use is e-mail. After that are file transfer and remote login

(loggin into a computer that is running some where else on the Internet). In terms of traffic,

discussion groups (netnews) and 38 percent is from the information retrieval programs gopher

and world wide web. People can search databases, download data and software, and ask

questions in discussion groups on numerous topics.

BB)) WWhhoo RRuunnss tthhee IInntteerrnneett??

The short answer is "no one". The Internet is a loose amalgamation of computer

networks run by many different organizations in over 70 countries. Most of the technological

decisions are made by small committees of volunteers who set standards for interoperability.

CC)) WWhhaatt iiss tthhee RReeggiioonnaall NNeett??

Regional networks provide connectivity between end users and the NSFNET

backbone. Most universities and large organizations are connected by leased line to a regional

provider.

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Some of the regional networks received subsidies from the NSF; many receive

subsidies from state governments. A large share of their funds are collected through

connection fees charged to organizations that attach their local networks to the mid-levels. For

example, a large university will typically pay $60.000 to $100.000 per year to connect to a

regional.

DD)) WWhhoo RRuunnss tthhee RReeggiioonnaall??

The regionals are generally run by a state agency or by a coalition of universities in a

given geographic region. They are operated as non-profit organizations.

EE)) WWhhaatt aarree tthhee BBaacckkbboonnee NNeettwwoorrkkss??

In 1994 there were four public fiber-optic backbones in the United States: NSFnet,

Altenet, PSInet and SprintLink. The NSFnet is funded by the NSF, and is the oldest, having

evolved directly out of ARPANET, the original TCP/IP network. The other backbones are

private, for profit enterprises.

FF)) WWhhyy IIss TThheerree MMoorree TThhaann OOnnee BBaacckkbboonnee??

Due to its public funding, the NSFnet has operated under an Acceptable Use Policy

that limits use to traffic in support of research and education. When the Internet began to

rapidly grow in the late 1980s, there was an increasing demand for commercial use. Since

Internet services are unregulated, entry by new providers is easy, and the market for backbone

services is becoming quite competitive.

Nowadays the commercial backbones and the NSFNet backbone interconnect so that

traffic can flow from one to the other. Given the fact that both research and commercial traffic

is now flowing on the same fiber, the NSF's Acceptable Use Policy has become pretty much

of a dead letter.

GG)) WWhhoo RRuunnss tthhee NNSSFFnneett??

Currently the NSF pays Merit Network, Inc. (Michigan Educational Research

Information triad) to run the NSFNET.

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HH)) WWhhoo PPrroovviiddeess AAcccceessss OOuuttssiiddee tthhee UUnniitteedd SSttaatteess??

There are now a large number of backbone and mid-level networks in other countries.

For example, most Western European countries have national networks that are attached to

EBone, the European Backbone. The Infrastructure is still immature, and quite inefficient in

some places. For example, the connections between other countries often are slow or of low

quality, so it is common to see traffic between two countries that is routed through the

NSFNet in United States (Braun and Claffy, 1993).

II)) IIss tthhee IInntteerrnneett DDiiffffeerreenntt ffrroomm TTeelleepphhoonnee NNeettwwoorrkkss??

Yes and no. most backbone and regional network traffic moves over leased phone

lines, so at a low level the technology is the same. However, there is a fundamental distinction

in how the lines are used by the Internet and the phone companies. The Internet provides

connectionless packet-switched services whereas telephone service is circuit-switched. The

difference may sound arcane, but it has vastly important implications for pricing and the

efficient use of network resources.

3. Getting Connected

There are basically three ways to connect to the internet, as illustrated in this chart.

Direct connection to the internet is most often chosen by medium to large sized

businesses and organizations. In this model, the organization attaches its local area network

(LAN) to the internet through a line leased from the local telephone company and a router.

The major advantage from direct connection is speed. By leasing T1 lines or OC3

connectivity, internet traffic is delivered to the LAN at the same speed it travels on the larger

internet backbone. The cost of operating a direct connection is its major disadvantage. In

addition to the router and leased line cost, staff familiar with the TCP/IP network is required

to keep things running. Directly connected routers are expected to be constantly operational.

For this class, you have access to a direct connection through the University's

computer labs. In addition, you may be able to use a direct connection where you work or at a

convenient library or school. Connections through jobs and publicly-available terminals often

come with restrictions. You may not be able to use all of the internet tools you'll learn in

class.

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AA)) OOppttiiccaall FFiibbrree

(fibre optics, FO, US "fiber", light pipe) A plastic or glass (silicon dioxide) fibre no

thicker than a human hair used to transmit information using infra-red or even visible light as

the carrier (usually a laser). The light beam is an electromagnetic signal with a frequency in

the range of 10^14 to 10^15 Hertz.

Optical fibre is less susceptible to external noise than other transmission media, and is

cheaper to make than copper wire, but it is much more difficult to connect. Optical fibres are

difficult to tamper with (to monitor or inject data in the middle of a connection), making them

appropriate for secure communications. The light beams do not escape from the medium

because the material used provides total internal reflection.

AT&T Bell Laboratories in the United States managed to send information at a rate of

420 megabits per second, over 161.5 km through an optical fibre cable. In Japan, 445.8

megabits per second was achieved over a shorter distance. At this rate, the entire text of the

Encyclopedia Britannica could be transmitted in one second. Currently, AT&T is working on

a world network to support high volume data transmission, international computer

networking, electronic mail and voice communications (a single fibre can transmit 200

million telephone conversations simultaneously).

BB)) MMooddeemm

(Modulator/demodulator) An electronic device for converting between serial data

(typically RS-232) from a computer and an audio signal suitable for transmission over

telephone lines. In one scheme the audio signal is composed of silence (no data) or one of two

frequencies representing 0 and 1.

Modems are distinguished primarily by the maximum baud rate they support. Baud

rates can range from 75 baud up to 28800 and beyond. Data to the computer is sometimes at a

lower rate than data from the computer on the assumption that the user cannot type more than

a few characters per second.

Most modern modems support a number of different protocols and two modems, when

first connected will automatically negotiate to find a common protocol. Some modem

protocols allow the two modems to renegotiate ("retrain") if the initial choice of data rate is

too high and gives too many transmission errors.

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SLIP or PPP protocol connections are probably the most used connection for an

individual. In this model, any computer with a fast modem (14.4 kilobaud or faster) can

connect to the internet. SLIP stands for Serial-Line Internet Protocol and PPP stands for Point

to Point Protocol. Both of these protocols are operated in software for your microcomputer.

Both SLIP and PPP programs are commercially available and some versions are available as

freeware or shareware on the internet. The major advantages of SLIP or PPP connections is

that they are inexpensive (modems are only about $150) and don't require your computer to

be on all the time. The major disadvantage is speed. Even the fastest modem still operates at

less than 5% of the speed of direct connection.

Host computer connection is probably the least expensive form of connection. It

requires that you have an account on a host computer which is connected to the internet. Your

microcomputer dials-in to the host computer using standard modems and asynchronous

communications protocols. You'll need software like Kermit, Crosstalk, etc. to run the

asynchronous protocols and you'll have to have an account on the host computer. The major

advantage of this connection model is that it may be free (with the costs being paid by the

organization who provides you with the computer account). The disadvantage is that the host

computer acts as your proxy on the internet. You have to learn how to give it commands and,

quite often, it doesn't offer the graphical user interface that allows the World Wide Web to

run.

i) TCP/IP Protocol

(TCP) The most common transport layer protocol used on Ethernet and the Internet. It

was developed by DARPA.

TCP is built on top of Internet Protocol (IP) and is nearly always seen in the

combination TCP/IP (TCP over IP). It adds reliable communication, flow-control,

multiplexing and connection-oriented communication. It provides full-duplex, process-to-

process connections.

ii) IP Address Internet Protocol

(IP) The network layer for the TCP/IP protocol suite widely used on Ethernet

networks, defined in STD 5, RFC 791. IP is a connectionless, best-effort packet switching

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protocol. It provides packet routing, fragmentation and re-assembly through the data link

layer.

iii) Hostname- Domain Name

(Or "sitename"). The unique name by which a computer is known on a network, used

to identify it in electronic mail, Usenet news, or other forms of electronic information

interchange.

On Internet the hostname is an ASCII string, e.g. "foldoc.doc.ic.ac.uk" which, consists

of a local part (foldoc) and a domain name (doc.ic.ac.uk). The hostname is translated into an

Internet address either via the /etc/hosts file, NIS or by the Domain Name System (DNS) or

resolver. It is possible for one computer to have several hostnames (aliases) though one is

designated as its canonical name.

It is often possible to guess a hostname for a particular institution. This is useful if you

want to know if they operate network services like anonymous FTP, World-Wide Web or

finger. First try the institution's name or obvious abbreviations thereof, with the appropriate

domain appended, e.g. "mit.edu". If this fails, prepend "ftp." or "www." as appropriate, e.g.

"www.data-io.com". You can use the ping command as a quick way to test whether a

hostname is valid.

The folklore interest of hostnames stems from the creativity and humour they often

display. Interpreting a sitename is not unlike interpreting a vanity licence plate; one has to

mentally unpack it, allowing for mono-case and length restrictions and the lack of whitespace.

Hacker tradition deprecates dull, institutional-sounding names in favour of punchy,

humorous, and clever coinages (except that it is considered appropriate for the official public

gateway machine of an organisation to bear the organisation's name or acronym).

Mythological references, cartoon characters, animal names, and allusions to SF or fantasy

literature are probably the most popular sources for sitenames (in roughly descending order).

The obligatory comment is Harris's Lament: "All the good ones are taken!"

2. Berkeley Unix command to set and get the application level name used by the host

Edu Education Com Commercial

Org Organizations Mil Military

Gov Government Net Network

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4. Network

<networking> Hardware and software data communication systems.

The OSI seven layer model attempts to provide a way of partitioning any computer

network into independent modules from the lowest (physical) layer to the highest

(application) layer. Many different specifications exist at each of these layers.

Networks are often also classified according to their geographical extent: local area

network (LAN), metropolitan area network (MAN), wide area network (WAN) and also

according to the protocols used.

AA)) NNeettwwoorrkk AAddddrreessss

The network portion of an IP address. For a class A network, the network address is

the first byte of the IP address. For a class B network, the network address is the first two

bytes of the IP address. For a class C network, the network address is the first three bytes of

the IP address. In each case, the remainder is the host address. In the Internet, assigned

network addresses are globally unique.

(Or "net address") An electronic mail address on the network. In the 1980s this might

have been a bang path but now (1997) it is nearly always a domain address. Such an address

is essential if one wants to be to be taken seriously by hackers; in particular, persons or

organisations that claim to understand, work with, sell to, or recruit from among hackers but

*don't* display net addresses are quietly presumed to be clueless poseurs and mentally

flushed.

Hackers often put their net addresses on their business cards and wear them

prominently in contexts where they expect to meet other hackers face-to-face (e.g. science-

fiction fandom). This is mostly functional, but is also a signal that one identifies with

hackerdom (like lodge pins among Masons or tie-dyed T-shirts among Grateful Dead fans).

Net addresses are often used in e-mail text as a more concise substitute for personal names;

indeed, hackers may come to know each other quite well by network names without ever

learning each others' real monikers.

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BB)) WWhhaatt IIss tthhee SSttrruuccttuurree ooff tthhee IInntteerrnneett??

The Internet is usually described as a three-level hierarchy. At the bottom are local

area networks (LANs) for example, campus networks. Usually the local networks are

connected to a regional or mid-level network. The mid-levels connect to one or more

backbones. The US backbones connect to other backbone networks around the world.

i) Local Area Network

(LAN) A data communications network which is geographically limited (typically to a

1 km radius) allowing easy interconnection of terminals, microprocessors and computers

within adjacent buildings. Ethernet and FDDI are examples of standard LANs.

Because the network is known to cover only a small area, optimizations can be made

in the network signal protocols that permit data rates up to 100 Mb/s.

ii) Wide Area Networks

(WAN) A network, usually constructed with serial lines, extending over distances

greater than one kilometer.

5. Internet Protocols

AA)) WWhhaatt iiss EElleeccttrroonniicc MMaaiill??

Electronic mail, or e-mail, is a simple tool for exchanging messages between

individuals or among a larger audience. Email messages travel very quickly and

inexpensively. The delivery of messages from one part of a country or a continent to another

may take only minutes. Once a message has been received, it can be saved, printed, edited,

forwarded to another e-mail user, or deleted. E-mail is becoming one of the most widely used

services on the Internet.

Like the phone and fax, e-mail is fast.

Like US Mail and fax, you can save messages for future reference.

Unlike the phone, fax, or US Mail, there is no charge for the messages UH students

send or receive.

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The requirement to use the electronic mail service is that you have to have an E-

mail account and know the address of the receiver.

i) Understanding an E-mail address

An Internet address has two main parts:

Username,

Domain name (reading from right to left, general to specific, and specifies a series of

encapsulated logical domains).

For example:

[email protected]

username is kidney.

edu is the domain, indicating that this is an education site.

uh specifies the name of the institution (university).

cl further specifies a campus or sometimes a department within this university.

ii) Understanding an E-mail message's parts:

A email message must have at least two parts:

Header, which contains information about the message: who it came from, where it's

going, when it was sent, and what's about.

body, which contains the actual message being sent.

Sometimes, an email message contains a third part, called the signature. It is optional,

and usually identifies or provides information about the message's sender.

BB)) TTeellnneett

Telnet is one of the Internet protocols. The telnet protocol facilitates remote login, that

is, users log on to a remote computer system from a local computer.

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Telnet is one of the first services to take advantage of the Internet connectivity.

Many years ago, before the widespread distribution of microcomputers, terminals were used

by people to communicate with their large mainframes and minicomputers. Telnet is simply a

way to offer this same kind of interaction over the network. In today's world of fancy and

flashy graphical interfaces this may seem archaic.

However, some useful services are still accessed in this fashion. Telnet allows users to

access their email systems remotely and allows guest logins to a publicly-accessible facility,

such as a library catalogue or campus-wide information system.

i) Common Uses of Telnet

Telnet is a way to remotely connect to another system with privileges to run specific

programs on that system. Common uses of Telnet include:

connecting to a system to use specific programs such as electronic mail and statistics

programs,

connecting to a library to search that library's collection,

connecting to an on-line database of information,

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connecting to a MOO or MUSH environment to interact and communicate with

other users.

ii) Basic Telnet commands

open - establishes a connection to the specified host.

close - closes an open connection and leaves you in the telnet software.

quit - closes any open telnet sessions and exits the telnet software.

CC)) FFTTPP

FTP (File Transfer Protocol) is a method of transferring files from one computer to

another over the Internet. It has two major purposes:

to moves files (programs and data or text) from one computer to another. For example,

I created a picture on my Macintosh and I want to put it on my UNIX-based World

Wide Web server so I can show it on my home page.

to get public domain and shareware files that I can use on my computer. For example,

I've heard that there's a wonderful program for teaching mathematics called

"Geometer's Sketchpad" so I copy it from a shareware archive.

How you do ftp is different based upon your purpose. That means there are two kinds

of FTP:

Named ftp. This requires you have an account on each computer. You'll login to the

computers with your account ID and password. Any user can use named ftp between

any two computers and accounts on the internet.

Anonymous ftp. This is used when an ftp server is set up to allow general public

access to its archives. Not many internet computers allow anonymous ftp. When you login

using anonymous ftp, your username or ID is the word "anonymous" (spell it correctly and

without quotation marks) and your password should be your email address.

FTP Client: The program which initiates an FTP session is the client. It is responsible

for issuing the commands that send and receive files. Programs like UNIX ftp, Fetch (Mac),

and WS_FTP (Windows) are FTP clients.

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FTP Server: An Internet host which allows clients to connect, then request or offer

files to be transferred. Most UNIX hosts offer FTP service to valid users, and NCSA Telnet

and FTPd let your Mac become an FTP file server and so does the Windows FTTP server.

FTP Archive: An FTP server offering a collection of related files, generally for public

access with anonymous FTP.

ASCII File: A simple text file, or a file that has been converted into ASCII with a

program like uuencode or BinHex. Most files available for FTP are ASCII files.

Binary File: If a file is raw data and not converted into an ASCII file, then it is

considered binary. Graphic images are often treated as binary files, so such files are also

called "Image Files."

Download: A client sending the get command asks the FTP server to send the

indicated file.

Upload: A client giving the put command tells the FTP server that it is sending a file

to be stored with the indicated name. Not all anonymous ftp servers allow uploads.

i) File Types

Originally, the ftp process needed to know what type of file was being transfered

(ASCII or binary). So users had to specify the file type before beginnning the transfer. Some

ftp programs, like the one on the VAX, still require this file typing. Newer ftp programs, like

WS_FTP and Fetch can automatically determine the file type and adjust accordingly. If you

have to manually set file type, here's some rules of thumb for you:

HTML files should be transfered in ASCII.

text files should be transferred in ASCII. Treating them as Binary files will add

control-M to the end of every line.

programs, compressed files and images should be transfered as BINARY. Treating

them as ASCII files will insure that they won't run or decompress.

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ii) Basic FTP Commands:

cd []: Change current directory to the indicated directory

ls []: List the contents of the indicated directory

dir []: List extended information for the contents of the indicated directory

type : Set the file transfer type to the indicated type; files must be transferred

according to the type of data or they may be corrupted. Transfer type should be one of the

following: ascii, binary, or macbinary. The default of most FTP servers is ASCII.

get []: Request that the FTP server send the file with the indicated name, and save it

with the same or the second file name.

put []: Send the indicated file to the FTP server, and save it with the same or the

second file name.

mget : Related to the get command. This retrieves multiple files matching the

indicated pattern (using '*' as a wildcard character, so that "*.html" represents all HTML files

in the given directory).

mput : Related to the put command. This sends multiple files matching the indicated

pattern.

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bye: Close this FTP session.

The following illustrates how the these commands are used to retrieve a file called

readme.txt from Microsoft's site.

DD)) PPoosstt OOffffiiccee PPrroottooccooll ((PPOOPP))

A protocol designed to allow single user computers to retrieve electronic mail from a

POP server. The POP server might be a computer with a permanent Internet connection

whereas its clients might only connect to it occasionally, e.g. by modem.

There are (in 1994) three versions: POP, POP2, and POP3. Later versions are NOT

compatible with earlier ones.

EE)) GGoopphheerr

Gopher is a menu-driven information retrieval tool which provides access to

information from all over the world on the Internet in a seamless fashion. The purpose is to

allow simple and easy access to a variety of information on the Internet.

Gopher presents the user with a hierarchy of menus where each menu entry provides

access to text files, directories, other gophers, etc. and each of which can reside on any

computer on the Internet.

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Gopher was originally developed in April 1991 by the University of Minnesota's

Microcomputer Workstation Networks Center to help campus users find answers to their

computer questions. It has since grown into a full-fledged World Wide Information System

used by thousands of sites.

i) Advantages and disadvantages of Gopher

Gopher was designed to resemble a file system, therefore the user sees the network

document and sub-directories. Because of the menu-oriented nature, Gopher users do not have

to master any languages or remember any IP address information to connect to any particular

computer. Gophers became very popular about five years ago -- before the World Wide Web

was developed. Many features now commonly found on the Web had their beginnings in the

earlier Gopher technology. Gopher includes two search tools -- Veronica and Jughead, to help

locate specific information.

Most Gophers cannot display graphics. The user can only see text displayed on the

screen. A number of more powerful WWW browsers, such as Netscape Navigator and

Microsoft Internet Explorer, can read information from Gopher servers, but not vice-versa.

Thus, Gophers have been eclipsed by the enormous growth of the Web. However, there are

still many Gopher sites in use today and a wide variety of materials are still stored on Gopher

servers around the world covering a variety of subjects from Agriculture to Zoology.

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6. Internet Software

AA)) EElleeccttrroonniicc MMaaiill SSooffttwwaarreess

i) Pine

Pine -- a Program for Internet News & Email -- is a tool for reading, sending, and

managing electronic messages. Pine was designed by the Office of Computing &

Communications at the University of Washington specifically with novice computer users in

mind, but it can be tailored to accommodate the needs of "power users" as well.

Pine Information Center at the University of Washington provides detailed

information about Pine, its background, features, history, and uses.

ii)

Outlook Express, Eudora, Netscape Messenger

These are Windows based e-mail applications programmes. Outlook Express comes

with Internet Explorer 4.0 and higher. Netscape Messenger is coming together with Netscape

Navigator.

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This view is from Outlook Express.

This view is Internet Mail screen which is coming with Internet Explorer 3.0.

BB)) BBrroowwsseerr

<hypertext> A program which allows a person to read hypertext. The browser gives

some means of viewing the contents of nodes (or "pages") and of navigating from one node to

another.

Netscape Navigator, NCSA Mosaic, Lynx, and W3 are examples for browsers for the

World-Wide Web. They act as clients to remote web servers.

i) Netscape Navigator

/Mozilla/ (Often called just "Netscape") A World-Wide Web browser from Netscape

Communications Corporation. The first beta-test version was released free to the Internet on

13 October 1994. Netscape evolved from NCSA Mosaic (with which it shares at least one

author) and runs on the X Window System under various versions of Unix, on Microsoft

Windows and on the Apple Macintosh.

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It features integrated support for sending electronic mail and reading Usenet news, as

well as RSA encryption to allow secure communications for commercial applications such as

exchanging credit card numbers with net retailers. It provides multiple simultaneous

interruptible text and image loading; native inline JPEG image display; display and

interaction with documents as they load; multiple independent windows. Netscape was

designed with 14.4 kbps modem links in mind.

You can download Netscape Navigator for evaluation, or for unlimited use in

academic or not-for-profit environments. You can also pay for it.

ii) Internet Explorer

<World-Wide Web> (IE, MSIE) Microsoft's free World-Wide Web browser for

Microsoft Windows, Windows 95, Windows NT, and Macintosh. Internet Explorer is the

main rival to Netscape Navigator (which runs on many more platforms). Both support the

same core features and offer incompatible extensions.

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Microsoft combined later versions of IE with their file system browser, "Explorer" and

bundled it with Windows 95 in an attempt to use their dominance of the desktop operating

system market to force users to abandon Netscape's browser, which they perceived as a

potential threat. This, and other dubious business moves, became the subject of a US

Department of Justice antitrust trial in late 1998/early 1999.

When you see text that is colored and underlined, like the blue underlined words to the

right, it means that those words are a hypertext link to another document. You follow the link

by clicking your mouse on the text. When you finish with the linked document, you can return

to this lesson by pressing the "Back" button in the upper left hand corner of your window.

CC)) FFrroonntt PPaaggee,, HHoott DDoogg

Front Page, Hot Dog and similar programs are good and easy to create web pages.

They have easy tools to use

i) What is HTML?

The Hypertext Markup Language (HTML) is a collection of formatting tags that are

used to prepare documents for distribution on the World Wide Web. These tags define various

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areas of your document as headers, paragraphs, lists, quotations, emphasized text and so on.

HyperText Markup Language (HTML) controls what you view on every WWW page.

Using HTML is not much different to using a word processor. In a word processor,

when you highlight a heading and tell it to be a particular font and size, the text changes

appearance and the program marks the beginning and end of the formatted text. In an HTML

document, you define the heading with an HTML tag pair and the browser displays it as you

have specified.

HTML is platform independent. An HTML file written on a Mac will run on a PC, or

UNIX computer. Each browser understands how to display text and HTML.

But you can never be quite sure how your document will look. People on the WWW

have control of their own fonts and styles. Someone's standard font might be someone else's

heading font.

Links to other documents are in the form

<A HREF="http://machine.edu/subdir/file.html">foo</A>

where "A", "/A" delimit an "anchor", "HREF" introduces a hypertext reference, which

in this case is a Uniform Resource Locator (URL) (the thing in double quotes in the example

above). The text "foo" will be the label appearing on the link in the browser.

A certain place within an HTML document can be marked with a named anchor, e.g.:

<A NAME="baz">

The "fragment identifier", "baz", can be used in an HREF by appending "#baz" to the

document name.

Other common tags include <P> for a new paragraph, <B>..</B> for bold text, <UL>

for an unnumbered list, <PRE> for preformated text, <H1>, <H2> .. <H6> for headings.

HTML supports some standard SGML national characters and other non-ASCII

characters through special escape sequences, e.g. "&eacute;" for a lower case 'e' with an acute

accent. You can sometimes get away without the terminating semicolon but it's bad style.

The World-Wide Web Consortium is the standards body for HTML.

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ii) Uniform Resource Locator URL

A draft standard for specifying the location of an object on the Internet, such as a file

or a newsgroup. URLs are used extensively on the World-Wide Web. They are used in

HTML documents to specify the target of a hyperlink which is often another HTML

document (possibly stored on another computer).

Here are some example URLs:

http://www.w3.org/default.html

http://www.acme.co.uk:8080/images/map.gif

http://www.hun.edu.tr

http://www.dpt.gov.tr

ftp://ftp.metu.edu.tr

ftp://spy:[email protected]/pub/topsecret/weapon.tgz

mailto:[email protected]

news:alt.hypertext

telnet://dra.com

The part before the first colon specifies the access scheme or protocol. Commonly

implemented schemes include: ftp, http (World-Wide Web), gopher or WAIS. The "file"

scheme should only be used to refer to a file on the same host. Other less commonly used

schemes include news, telnet or mailto (e-mail).

The part after the colon is interpreted according to the access scheme. In general, two

slashes after the colon introduce a hostname (host:port is also valid, or for FTP

user:passwd@host or user@host). The port number is usually omitted and defaults to the

standard port for the scheme, e.g. port 80 for HTTP.

For an HTTP or FTP URL the next part is a pathname which is usually related to the

pathname of a file on the server. The file can contain any type of data but only certain types

are interpreted directly by most browsers. These include HTML and images in gif or jpeg

format. The file's type is given by a MIME type in the HTTP headers returned by the server,

e.g. "text/html", "image/gif", and is usually also indicated by its filename extension. A file

whose type is not recognised directly by the browser may be passed to an external "viewer"

application, e.g. a sound player.

The last (optional) part of the URL may be a query string preceded by "?" or a

"fragment identifier" preceded by "#". The later indicates a particular position within the

specified document.

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Only alphanumeric, reserved characters (:/?#"<>%+) used for their reserved

purposes and "$", "-", "_", ".", "&", "+" are safe and may be transmitted unencoded. Other

characters are encoded as a "%" followed by two hexadecimal digits. Space may also be

encoded as "+". Standard SGML "&<name>;" character entity encodings (e.g. "&eacute;")

are also accepted when URLs are embedded in HTML. The terminating semicolon may be

omitted if &<name> is followed by a non-letter character.

iii) Web Page

A block of data available on the World-Wide Web, identified by a URL. In the

simplest, most common case, a web page is a file written in HTML, stored on the server. It

may refer to images which appear as part of the page when it is displayed by a web browser.

It is also possible for the server to generate pages dynamically in response to a request, e.g.

using a CGI script.

A web page can be in any format that the browser or a helper application can display.

The format is transmitted as part of the headers of the response as a MIME type, e.g.

"text/html", "image/gif".

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An HTML web page will typically refer to other web pages and Internet resources

by including hypertext links.

A web site often has a home page (usually just the hostname, e.g.

http://www.hun.edu.tr). It may also have individual home pages for each user with an account

at the site.

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CHAPTER THREE

MAIN CONCEPTS

1. Folder

A directory in the sense of a collection of computer files. The term is more common in

systems such as the Macintosh or Windows 95 which have a graphical user interface and

provide a graphical file browser in which directories are traditionally depicted as folders (like

small briefcases).

2. File

An element of data storage in a file system. The history of computing is rich in varied

kinds of files and file systems, whether ornate (e.g., Macintosh file system for a well-known

case) or deficient (e.g., many simple pre-1980s file systems don't allow directories).

However, the prototypical file has these characteristics:

* It is a single sequence of bytes (but consider Macintosh resource forks).

* It has a finite length, unlike, e.g. a Unix device.

* It is stored in a non-volatile storage medium (but see ramdrive).

* It exists (nominally) in a directory.

* It has a name that it can be referred to by in file operations, possibly in combination

with its path.

Additionally, a file system may associate other information with a file, such as

permission bits or other file attributes; timestamps for file creation, last revision, and last

access; revision numbers (a` la VMS), and other kinds of magic.

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3. Main DOS (Disk Operating System) Commands

The low-level software which handles the interface to peripheral hardware, schedules

tasks, allocates storage, and presents a default interface to the user when no application

program is running.

The OS may be split into a kernel which is always present and various system

programs which use facilities provided by the kernel to perform higher-level house-keeping

tasks, often acting as servers in a client-server relationship.

Some would include a graphical user interface and window system as part of the OS,

others would not. The operating system loader, BIOS, or other firmware required at boot time

or when installing the operating system would generally not be considered part of the

operating system, though this distinction is unclear in the case of a rommable operating

system such as RISC OS.

The facilities an operating system provides and its general design philosophy exert an

extremely strong influence on programming style and on the technical cultures that grow up

around the machines on which it runs.

AA)) DDiirr

Dir command is used for listing files and folders.

Way of Using:

C:\> DIR we would see all files and folders in C:\

C:\> DIR /p lists files and folders page by page

C:\> DIR *.EXE

C:\> DIR A*.*

C:\> DIR ?A.*

BB)) CCDD

Use for chancing directory.

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Way of Using:

C:\> CD {dizin adı}

C:\WINDOWS>

CC)) MMDD

Use for creating new directory.

Way of Using:

C:\> MD {isim}

DD)) RRDD

Use for removing directory.

Way of Using:

C:\> RD {folder name}

Invalid Path, not directory or directory not empty

EE)) DDeell

Use for deleting files.

Way of Using:

C:\> DEL {file name}

C:\>del command.com

C:\>del mail.doc

A:\>del m*.doc

C:\MFIT>del W???.*

FF)) UUnnddeelleettee

Use for recovering files and folders.

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Way of Using:

C:\> UNDELETE

GG)) CCooppyy

Use for copying files from one folder to other or from hard disk to floppy.

Way of Using:

C:\> COPY {FORM WHERE WHICH FILE} {TO WHERE}

C:\WINDOWS>COPY MIN*.* A:

HH)) MMoovvee

Use for moving files from one folder to other or from hard disk to floppy.

Way of Using:

C:\> CD {FROM}{TO}

C:\WINDOWS>MOVE MIN*.* A:

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WINDOWS 95 OPERATING SYSTEM

Microsoft's successor to their Windows 3.11 operating system for IBM PCs. It was

known as "Chicago" during development. Its release was originally scheduled for late 1994

but eventually happened on 11 Jul 1995, followed by Service Release 1 on 1995-12-31 and

OSR2 (OEM Service Release 2) on 1996-08-24.

In contrast to earlier versions, Windows 95 is a complete operating system rather than

a graphical user interface running on top of MS-DOS.

It provides 32-bit application support, pre-emptive multitasking, threading and built-in

networking (TCP/IP, IPX, SLIP, PPP, and Windows Sockets). It includes MS-DOS 7.0, but

takes over completely after booting. The graphical user interface, while similar to previous

Windows versions, is significantly improved.

Windows 95 has also been described as "32-bit extensions and a graphical shell for a

16-bit patch to an 8-bit operating system originally coded for a 4-bit microprocessor, written

by a 2-bit company that can't stand 1-bit of competition".

1. User Interface

The aspects of a computer system or program which can be seen (or heard or

otherwise perceived) by the human user, and the commands and mechanisms the user uses to

control its operation and input data.

A graphical user interface emphasises the use of pictures for output and a pointing

device such as a mouse for input and control whereas a command line interface requires the

user to type textual commands and input at a keyboard and produces a single stream of text as

output.

2. Graphical User Interface

The use of pictures rather than just words to represent the input and output of a

program. A program with a GUI runs under some windowing system (e.g. The X Window

System, Microsoft Windows, Acorn RISC OS, NEXTSTEP). The program displays certain

icons, buttons, dialogue boxes etc. in its windows on the screen and the user controls it mainly

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by moving a pointer on the screen (typically controlled by a mouse) and selecting certain

objects by pressing buttons on the mouse while the pointer is pointing at them.

Though Apple Computer would like to claim they invented the GUI with their

Macintosh operating system, the concept originated in the early 1970s at Xerox's PARC

laboratory.

3. Starting Windows 95

Turn on your computer by pressing On/Off button. Your operating system would open

your computer after testing your system in a short while.

You will see Windows 95 license screen after that you will be asked for Windows

login and password. Press Enter button.

When you see My Computer, Recycle Bin and My Briefcase icons you may begin to

work on computer.

4. Desktop Manager

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A user interface to system services, usually icon and menu based like the Macintosh

Finder, enabling the user to run application programs and use a file system without directly

using the command language of the operating system.

5. Parts of a Window

Title Bar: Place where written window's name.

Window Border: Shows the borders of a window.

The window which is in use is called Active Window.

Maximize is used to enlarge the window, Minimize is used to minimize window size

as an icon, Close to close the window.

Scroll Bar is used to see unseen parts of window.

6. Leaving Windows 95

To turn off computer you have to go to Start button on the left bottom corner, and

must give Shut Down command. You first have to turn off Windows 95 and then press

On/Off button on computer.

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7. Formatting Floppy A 3½

1. Place the disket in Floppy A:

2. Double click on My Computer

icon.

3. Select 3½ Floppy (A:)

4. From File menu select Format.

5. To Capacity: select 1.44 MB by

mouse.

6. Format: Full and then click Start.

7. After formatting press Close button.