Comp233 – Computer Systems Organization and Assembly LanguageLesson 1&2

LESSON 1 – Introduction to Computer Systems

Definition of Terms

Computer – is an electronics device capable of manipulating data into information at great speed, and with high accuracy.

System – a system is a group of elements that work together to complete a certain task or to achieve a specific goal.

Elements of a Computer System

  1. Hardware – input, processing and output
  2. Software – operating systems and application software
  3. Peopleware – users, literates, and professional

Classification of Hardware

  1. Input – hardware that allows the user to communicate to the computer, ex. keyboard, mouse, scanner, etc.
  2. Processing – refers to the central processing unit which performs either arithmetic/logic operations or control the system. Arithmetic operations include all mathematical computations like Addition, Subtraction, Division, Multiplication; Logic Operations include comparisons like <,>, =, or bit operations like OR, NOT, NOR, AND, XOR, XNOR, etc.
  3. Output – output hardware allows the computer to communicate provide information to the user ex, monitor and printer.

Classification of Software

  1. Operating Systems – software that are required by the system to function (i.e. boot up) are called the operating systems, ex. Windows95,Windows Vista, Windows , etc.
  2. Application Software – are programs that are used by the user ex. MS-Word, Excel, PowerPoint, Games, etc.

Classification of Peopleware

  1. User – a user is someone who uses the computer system. S/he may not have the necessary technical background or knowledge on how the machine works.
  2. Literates – are users who have the necessary know-how regarding computer.
  3. Professionals – professionals are people who have in-depth training on computer systems, ex. Programmers, Analysts, Engineers, etc.

Basic Building Blocks of a Computer System

The basic building block of a computer system includes

  1. Input
  2. Processing
  3. Output
  4. Memory

Types of Memory

  1. ROM – Read Only Memory (PROM, EPROM, EEPROM, etc.)
  2. RAM – Random Access Memory (SRAM, DRAM, etc)

Classifications of a Computer System

  1. Microcomputer – laptops, desktops, PDA’s
  2. Minicomputers – servers
  3. Supercomputers – Pentagon, NASA
  4. Mainframes – computers "housed in a metal frame"

Bus Lines

  1. Address Bus
  2. Data Bus
  3. Control Bus

  1. LESSON 2 – Information Representation

Integer Data / Short / Long
Signed / -32768 / +32767 / -2147483648 / +2147483647
Unsigned / 0 / 65535 / 0 / 4294967295

Number Systems

  1. Binary – B2 - 0,1
  2. Octal – B8 - 0,1,2,3,4,5,6,7
  3. Decimal – B10 - 0,1,2,3,4,5,6,7,8,9
  4. Hexadecimal – B16 - 0,1,2,3,4,5,6,7,8,9,A,B,C,D,E,F

Code Conversion

  1. Binary – Octal – Decimal – Hexadecimal

1a.To convert from binary to octal, group the binary digits into 3 (from the right), and use 4-2-1 to get the equivalent in octal.

4 2 1 4 2 1

Ex. 100012= 10 / 001 = 218

1b.To convert from binary to decimal, multiply each binary digit to powers of 2.

Ex. 100012

1x 20= 1

0x 21= 0

0x 22= 0

0x 23= 0

1x 24= 16

1710

1c.To convert from binary to hexadecimal, group the binary digits into 4 (from the right), and use 8-4-2-1 to get the equivalent value in hexadecimal.

84 2 1 8 4 2 1

Ex. 100012= 0001/ 0001 = 1116

  1. Octal – Binary – Decimal – Hexadecimal

2a.To convert from Octal to Binary, use 4-2-1 and convert each octal digit to 3-digit binary code.

Ex. 218

4 2 1 4 2 1

010 / 0012

2b.To convert from Octal to Decimal, multiply each Octal digit to powers of 8.

Ex. 178

7 x 80 = 7

1 x 81 = 8

1510

2c.To convert from Octal to Hexadecimal, first convert to binary by getting the 3-digit equivalent of each octal digit using the 4-2-1, then group the Binary digits into 4 and get the equivalent hexadecimal value using 8-4-2-1 code.

Ex. 518

4 2 1 4 2 1

101/ 0012

8 4 2 1 8 4 2 1

10/ 10012

2 516

  1. Hexadecimal – Binary – Octal – Decimal

3a.To convert from Hexadecimal to Binary, use 8-4-2-1 and convert each hexadecimal digit to 4-digit binary numbers.

Ex. 8A16

84 2 1 8 4 2 1

1000/ 10102

3b. To convert from Hexadecimal to octal, first, convert to Binary then group the binary digits into 3, use 4-2-1 to get the octal equivalent.

Ex. 8A16

8 4 2 1 8 4 2 1 4 2 1 4 2 1 4 2 1

1000/ 10102 10/ 001/ 0102

2 1 28

3c.To convert from Hexadecimal to Decimal, multiply each hexadecimal digit to the powers of 16.


Ex. ACE16

14 x 160 =14

12 x 161=192

10 x 162 =2560

276610

  1. Decimal – Binary – Octal - Hexadecimal

4a.To convert from Decimal to Binary, divide the number by 2, then continuously divide the remainder by 2 until remainder is 0 or 1. Record the remainder backwards.

Ex. 1010 to B2

10 / 2 = 5 remainder 0 10102

5 / 2 = 2 remainder 1

2 / 2 = 1 remainder 0

4b.To convert from Decimal to Octal, divide the number by 8, then continuously divide the remainder by 8 until the remainder is less than 8. Record the remainder backwards.

Ex. 10010 to B8

100 / 8 = 12 remainder 4 1448

12 / 8 = 1 remainder 4

4c.To convert from Decimal to Hexadecimal, divide the number by 16, then continuously divide the remainder by 16 until remainder is less than 16.

Ex. 10010 to B16

100 / 16 = 6 remainder 4 6416

Instructor: Ms. Solane DuqueCollege of Arts and Sciences

Computer Science Section