What is a Computer ? A ‘compute’-r is a device which ‘compute’-s to compute = to calculate, to make sense
Parts of a Computer There is no such particular part known as the ‘computer’ The ‘computer’ is a collection of many parts working together The computer is divided into two categories – mainly known as ‘hardware’ and ‘software’
Hardware & Software The physical parts of a computer which you can see and touch are collectively called the ‘hardware’ E.g. keyboard, cd-rom drive The programs or instructions sent to the hardware are called the ‘software’ E.g. Microsoft Word, Internet Explorer
Functions of the hardware The computer hardware can again be divided into ‘input’ and ‘output’ devices An Input device feeds data into the computer E.g. keyboard, mouse, scanner An Output device displays or receives data from the computer E.g. monitor, printer
INPUT – process - OUTPUT Any activity on a computer is an input - process - output sequence E.g. Sugarcane >>>> Factory >>>> Sugar Question (input) add 5 + 2 ------------------------------------------process----- ----------------------------------------------Answer (output) = 7
Data & Instructions A computer requires data and instructions to work on.E.g. to print the name and address of a person,the following data has to be provided:Name of Person, Address of Personthe instruction given to the computer will be: Print name and address of PersonInput – name and address-process of reading data-Output – Printout of name and address
System Unit The system unit is the main part of a computer All other parts of the computer connect to the system unit using cables
Parts of the System UnitCPU The CPU is the Central Processing Unit of the computer It is also known as the ‘processor’ in the computer The CPU is the ‘brain’ of the computer which computes calculations and instructions received from the RAM
Central Processing Unit CPU is divided into 2 parts Control – it manages the complete processing activities Arithmetic & Logical Unit (ALU) – does all the arithmetical and logical calculations
Parts of the System UnitMemory All data or input instructions must be first stored into the memory to be processed by the CPU The types of Memory are:e) Primary (internal) Memoryf) Secondary (external) Memory
Memory is also referred as StoragePrimary (internal) StorageROM – Read Only memory Contains permanent computer information. It cannot be used for storing data. Data in ROM Memory does not get lost even if the computer is switched off.RAM – Random Access Memory Contains temporary data. The contents inside RAM get erased as soon as the computer is switched off.
Secondary (external) storage Internal Storage (ROM & RAM) is always limited. In everyday computer use, all programs or data cannot be stored permanently stored into internal memory. To store data permanently, external memory is used. E.g. tape disc, hard drive, pen drive, floppy, CD, DVD
Types of Storage Each computer has one or more Disk Drives. Disk drives – or disks - are devices which store information on a metal or plastic disk. The disk preserves the information even when your computer is turned off.
Types of StorageHard Disk The hard disk is a large capacity disk which is normally located inside the system unit. On the inside, it is a stack of platters with a magnetic surface. Because a hard disk can store huge amounts of data and information, it usually serves as your computer’s main data storage.
Types of StorageFloppy Disk Floppies or diskettes, are less popular than they used to be. They store very little information compared to CD’s or DVD’s and are easily damaged in daily use. The inside is a thin flexible material whereas the outside is hard plastic.
Types of StorageCD or DVD diskCD – Compact diskDVD – Digital Versatile DiskCDROM – Compact disk Read only Memory It’s main use is for loading new programs onto the hard disk. A CD Drive uses lasers to read information from a CD or to write information onto a CD. A DVD is similar to a CD but has larger capacity compared to the CD.
Assignments Give one example of the input-process- output activity Describe the uses of a Pen Drive. How is it different from the other disks – hard disk, floppy disk and CD ?