01 - software

1188 110 Computer Programming : Chapter 1.3 – Software | Data | Users

Software


Hardware

Software brings the machine to life When a computer is using a particular program, it

is said to be running or executing that program. Two major categories of software

System software, i.e., Operating System Application software

SystemSoftware

ApplicationSoftware

234525543089...

Useful outputReal-world tasks


Operating Systems The operating system tells the computer how to

interact with the user and how to use devices such as the disk drives, keyboard, and monitor. The operating system is continue to run until the computer is turned off.

When a computer is turned on, it goes through steps to prepare itself to run user's application: Run system software located in ROM BIOS. Next, the computer runs the operating system in

diskette, hard disk, or other storage devices. After the computer finds and runs the operating

system, the user can issue commands to the computer.


Application software Application software is a program that help

people accomplish specific tasks. Thousands of application are available; however

some major categories that likely to be encounter are: Word processors Spreadsheets Database management software (DBMS) Multimedia, graphics and presentations Utilities Communications


Word Processors


Spreadsheets


Graphics


Presentations


Data


Transforming Data into Information Computers cannot understand anything about us.

All they can do is recognizing two distinct states produced by electricity, magnetic polarity, or reflected light.

All they can understand is whether a switch is on or off. The CPU consists of several million tiny electronic switches

called transistors. A computer assembling its individual on/off switches into

patterns that are meaningful to us. In strictest sense, data consists of the raw numbers that

computers organize to produce information. Computers turn raw, separated data into meaningful

information.


Data and Information


How Computer Represents Data To a computer,

everything is a number.

For computer, the sentence "Here are some words" is represented by:

Here

are

some

words

0100 10000110 01010111 00100110 01010010 00000110 00010111 00100110 01010010 00000111 00110110 11110110 11010110 01010010 00000111 01110110 11110111 00100110 10000111 0011


Number Bases A number base is a specific collection of symbols

on which a number system can be built. The number base familiar to us is base 10, upon

which the decimal number system is built. There are ten symbols, 0 through 9, used in decimal system.

When we need to represent a number greater than 9 we use two symbols together; as 9 + 1 = 10.

Each symbol in a number is called a digit, so 10 is a two-digits number.


Other Number Systems Binary: Base 2 Octal: Base 8 Hexadecimal: Base 16


Number Base Systems

Decimal Binary Octal Hexadecimal

0123456789101112

01101110010111011110001001101010111100

012345671011121314

0123456789ABC


(cont'd.)

Decimal Binary Octal Hexadecimal

13141516171819202122232425

11011110111110000100011001010011101001010110110101111100011001

15161720212223242526273031

DEF10111213141516171819


Numbers in a computer In a computer, all data must be reduced to

electrical switches. A switch has only two states --”ON” or “OFF” -- so it has only two numeric symbols. 0 stands for “OFF”, and 1 stands for “ON”.

Computers function in a binary number system (base 2).

When a computer needs to represent a quantity greater than 1, it uses the second digit.


Bits and Bytes When referring to computerized data, each

switch -- whether on or off -- is called bit. The term bit is a contraction of binary digit. A bit is the smallest possible unit of data.

To represent anything meaning -- that is to convey information -- the computer needs groups of bits.

The larger unit of data is the byte, which is a group of 8 bits.


(cont'd.) With one byte, the computer can represent up to

256 different values because it is possible to count from 0 to 255 with 8 binary digits (one byte).

One byte combination is an enough unit to represent all the (English) characters on the keyboard, including all letters (uppercase and lowercase), numbers, punctuation marks, and other symbols.


Character Codes The programmers need a standard code which is

group of numbers to represent or stand for letters of the alphabet, punctuation marks, and other symbols. ASCII Unicode


ASCII The American National Standard Institute (ANSI)

solution to represent the symbols with bits of data was the ASCII character set. ASCII = American Standard Code for Information

Interchange Today ASCII is the most common character set

used. ASCII is the seven bits code. The ISO (International Standard Organization)

standard expanded on the ASCII character set, to offer different sets of characters for different language group.


(cont'd.)

Dec Hex Code32333435363738394041424344454647

202122232425262728292A2B2C2D2E2F

space!“#$%&'()*+,-./

Dec Hex Code Dec Hex Code4849505152535455565758

64656667

303132333435363738393A..

40414243

0123456789:

@ABC

686970

90919293949596979899

100101

404142..

5A5B5C5D5E5F606162636465

DEF

Z[\]^_`abcde


Unicode Unicode Worldwide Character Standard

represents each symbol by two bytes --16 bits. With two bytes, a Unicode character can be any

one of more than 65,536 different characters or symbols.

Many software publishers, including Microsoft, Netscape, and Accent, encourage their developers to use Unicode in their programs.


Users Job related to computer

Computer engineers System administrators Network administrators System analysts Programmers Software testers System maintainers


(cont'd.) Many jobs use computer as a tool.

Accountants Draftsmen Animators Data entry worker Customer support specialists


Responsibility of the users Keep computer from malicious software

Virus, worm, trojan, spam, internet fraud Anti virus/spyware Update software, patches

Recognize limitations of computer systems Hardware errors ~ design error, hardware failure Software errors ~ OS, applications Applying wrong ways

Use computer for working The Computer Crime Act B.E. 2550

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