8/14/2019 lec 2.docx

1/6

LECTURE NO- 02

Parts of the Computer System:Computer systems have four parts:

Hardware. Software. Data. User.

Computer Hardware:It is any part of computer system, which you can touch. Thisincludes:

Processor.

Memory. Input and output Devices. Storage Devices.

Processor: Brains of the computer. Carries out instructions from the program. Manipulate the data. Most computers have several processors.

Central Processing Unit (CPU). Processors made of silicon and copper.

Memory: In a computer, memory is one or more sets of chips that store

data and/or program instructions, either temporarily or permanently.

Memory is a critical processing component in any computer. Personal computers use several different types of memory, but

the two most important are called Primary Memory. Senondary Memory.

8/14/2019 lec 2.docx

2/6

Primary Memory: The primary memory or the main memory is part of the main

computer system. The processor or the CPU directly stores and retrieves

information from it.

That means any location of this memory can be accessed bythe CPU to either read information from it, or storeinformation in it.

Types of Primary Memory:It has two types:

Random Access Memory (RAM).

Read Only Memory (ROM).

Random Access Memory: RAM is volatile, meaning that it loses its contents when the

computer is shut off. RAM has tremendous impact on the speed and power of a

computer. Computer memory is measured in kilobyte (KB), megabyte

(MB), Gigabyte (GB), and Terabyte (TB).

Read Only Memory: Read only memory (ROM) permanently stores its data, even

when the computer is shut off. ROM is called nonvolatile memory because it never loses its

contents. Whenever the computers power is turned on it checks ROM

for directions that help it start up, and for information about itshardware devices.

Holds the computer boot directions.

Input and Output devices: Allows the user to interact. Input devices accept data. Output devices deliver data. Some devices are input and output.

8/14/2019 lec 2.docx

3/6

Storage Devices Secondary Memory: Hold data and programs permanently. Different from RAM. Magnetic storage.

Optical storage. USB Flash Memory Storage.

Software : Software is set of programs (which are step by step

instructions) telling the computer how to process data.

Software needs to be installed on a computer, usually from aCD. Software runs on Computer Hardware. Thousands of software exists.

Categories of System Software:There are two main categories of software:

System Software. Application Software.

System Software: System software is any program that controls the computerhardware or that makes the computer runs more efficiently.

There are three basic types of system software: Operating System. Network Operating System. Utility Program.

Operating System: An operating system tells the computer how to use its own

components. Examples of operating systems include windows, the

Macintosh operating system, and Linux. When a program wants the hardware to do something, it

communicates through the operating system.

8/14/2019 lec 2.docx

4/6

Network Operating System:

A network operating system allows computers to communicateand share data across a network while controlling networkoperations and ov erseeing the networks security

Utility Programs:

A utility is program that makes the computer system easier touse or performs highly specialized functions.

Utilities are used to manage disks, troubleshoot hardware problems, and perform other tasks that the operating systemitself may not be able to do.

Application Software:

Application software tells the computer how to accomplishspecific tasks, such as word processing or drawing for the user.

Thousands of applications are available for many purposes andfor people of all ages.

Information Processing Cycle:

Using all its parts together, a computer converts data intoinformation by performing various actions on the data.

These operations are part of a process called the information processing cycle.

Information Processing Cycle is set of steps the computerfollows to:

Receive data. Process the data according to instructions from a program. display the resulting information to the user. Store the results.

Steps followed to process data: Input. Processing. Output. Storage.

8/14/2019 lec 2.docx

5/6

8/14/2019 lec 2.docx

6/6