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Computer Hardware and Software

ByMr. Abdalla A. Shaame

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What is ComputerAn electronic device that stores, retrieves, and processes data, and can be programmed with instructions.

A computer is composed of hardware and software, and can exist in a variety of sizes and configurations.

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Computer SystemComputer system consist of four basic hardware

components: input, process, output and storage.

The term hardware refers to the physical components of your computer such as the sys tem unit, mouse, keyboard, monitor etc.

The software is the instructions that makes the computer work.

Software is held either in the computers hard disk, CD-ROM, DVD or on a diskette (floppy disk) and is loaded (i.e. copied) from the disk into the computers RAM (Random Access Memory), as and when required.

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Types of ComputersMini and Mainframe ComputersVery powerful, used by large organisations such an

banks to control the entire business operation. Very expensive!

Personal ComputersCheap and easy to use. Often used as stand-alone

computers or in a network.May be connected to large mainframe computers

within big companies.Personal computers come in a variety of forms such

as desktops, laptops and personal digital assistants (PDA)

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Hardware ComponentsInput Devices -- "How to tell it what to do“- A keyboard and mouse are the standard way

to interact with the computer. Other devices include joysticks and game pads used primarily for games.

Output Devices -- "How it shows you what it is doing"

- The monitor (the screen) is how the computer sends information back to you. A printer, speaker are example of output devices.

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Hardware ComponentsStorage Devices -- "How it saves data and

programs“- Hard disk drives are an internal, higher

capacity drive which also stores the operating system which runs when you power on the computer.

- "Floppy" disk drives allow you to save work on small disks and take the data with you.

Flush disk used as an alternative to floppy disk which is used to store data. It vary in size up to 8GB

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Identify the following hardware devices

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Characteristics of Hardware componentsSpeedCapacityCost

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Main parts of ComputerMemory -- "How the processor stores and uses

immediate data“RAM - Random Access Memory The main 'working' memory used by the computer. When the operating system loads from disk when

you first switch on the computer, it is copied into RAM.

computer will operate faster if you install more RAM. Data and programs stored in RAM are volatile (i.e.

the information is lost when you switch off the computer).

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Memory

ROM – Read Only Memory Read Only Memory (ROM) as the name

suggests is a special type of memory chip that holds software that can be read but not written to.

A good example is the ROM-BIOS chip, which contains read only software.

Often network cards and video cards also contain ROM chips.

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How Computer Memory Is MeasuredBit All computers work on a binary numbering system, i.e.

they process data in one's or zero's. This 1 or 0 level of storage is called a bit.

Byte A byte consists of eight bits.Kilobyte A kilobyte (KB) consists of 1024 bytes.Megabyte A megabyte (MB) consists of 1024 kilobytes.Gigabyte A gigabyte (GB) consists of 1024 megabytes.

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Microprocessors"The brain of the computer“- PCs primarily use microprocessors (sometimes called the

chip).The older Intel versions include the 386, 486 and now the

Pentium line.The CPU (Central Processing Unit) is normally an Intel

Pentium (or equivalent) and it is one of the most important components within your computer.

It determines how fast your computer will run and is measured by its MHz speed.

Thus a 600 MHz Pentium is much faster than say a 400 MHz Pentium CPU.

It is the CPU that performs all the calculations within the computer.

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Factors that impact the performance of Computer

CPU speed RAM size Hard disk speed and capacity

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Software ComponentsSoftware refers to any program that tells the

computer system what to do.Software are divided into:System SoftwareApplication SoftwareSystem Software: Are those software for

system uses. Eg Operating system, and utilities.

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Operating SystemIs a software which control all other parts of computer.The operating system is a special type of program that loads

automatically when you start your computer.Objectives of Operating systemTo facilitates communication between the computer system

and its users.To facilitates communications among computer system

componentsTo facilitates communication between linked computer

system.To maximize throughput To optimize the use of computer system resourcesTo keep track of all files in disk storageTo provide an envelop of security for the computer systemTo monitor all system capabilities and alert the user of

system failure or potential problems

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Relationship between the Operating System and Applications SoftwareThe operating system coordinates all software activity within a computer system.

The interaction of user to Operating system is through the Graphical User Interface (GUI)

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PC PlatformsThe most common types of operating system are:

Microsoft windowsMac OSUNIX/Linux

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Window PlatformsEarly versions of WindowsWindows 95, Windows 98, Windows ME are

old versions of Windows but still can be used in the home and in business.

These old versions of Windows are emerged from MS-DOS, a text based operating system.

Windows NT was the first operating system to divorce itself from the limitations of MS-DOS

Windows 2000 was the successor to Windows NT.

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Windows PlatformModern PC Operating systemWindow XP and its successor (ie Windows Vista and

Windows 7) is a foundation for Windows family of client operating systems. These Operating System works with Windows 2003 Server, the server side portion of the operating system (which runs on the server computer) to make client/server computing possible.

Windows XP, Windows Vista and Windows 7 comes in several versions for home, office and taplet PCs.

Popular features of modern OS are plug-and-play and home networking

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Windows PlatformWindows CE. NETThe Windows CE. NET operating system designed for hand-held, pocket PCs, and other small-footprint devices

Windows CE. NET users can share information with other Window based PCs and they can connect to the internet.

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The Macintosh/Mac OS X PlatformThe Apple family of microcomputers (including the Power Mac G4, iMac, eMac Desktop and iBook notebook) and its operating system, Mac OS X

The Apple line of microcomputers is based on the Motorola family of microprocessors.

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UNIX/ LinuxCreated in the 1970s, Unix was the one

operating system with the flexibility to be used on almost any computer.

UNIX is a multiuser operating system, become very popular in Universities and mostly used for powerful workstation.

However the UNIX movement has been slow until recently.

Linux is a free and open source software where its source code available free, free to use, to copy and distribute to others.

Currently, the Linux is become competitors to Windows system for client and server.

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UTILITY PROGRAMSA wide variety of system software utility is available to help you with the day-to-day tasks associated with personal computing.

It include disk and file maintenance, system recovery, security, backup, virus protection, and so on.

The purpose of utility is to keep the system running at peak performance.

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Application SoftwareApplication software are those software

designed for users.An application program is the type of

program that you use once the operating system has been loaded.

Application software divided into:General purpose software: Those software

for general uses. Eg, Ms word, Ms Excel, Ms Power point, etc

Special purpose software: Those software for special uses. Such as QuickBooks for accounting, Banking software, etc

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DiscussionWhy is the selection of a platform such an important decision to an organization.

Discus consequence of not performing routine disk maintenance with utility software.

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Next LessonComputer impact and applications