There are many physical devices, such as the monitor, floppy disk drive, hard disk drive, keyboard, printer(s) etc. in PC. These physical devices are called hardware. The hardware does all operations in PC, such as accepting and storing data, performing calculations and displaying or printing results.
The various physical devices or the hardware in a PC cannot work on their own. To make the hardware work, you require a set of programs. A set of programs associated with the operation of a computer is called software. Different types of software (also called software programs) are used on PCs. Software can be classified into the following major categories :
1.Operating Systems, e.g. DOS, Windows 95, Windows 97, Unix, etc.
2. Programming Languages, such as Basic, Fortran, Cobol, C++etc.
3 Application programs / Packages, such as word processors, spreadsheet, Database Management System (DBMS), etc.
4 Others application programs doing a specific job, such as accounting, payrolls, billing, weather forecasting, ticket reservation, etc.
Firmware refers to the software routines (small software programs) that are stored in the read-only memory (ROM) of the computer. These software routines are used to start the com* and to perform low-level .input/output instructions (to control input/output devices).
A personal computer consists of the following units :
2. Keyboard and Mouse
3. Video Display Unit (Monitor)
4. Floppy Disk Drive (s) 5. Hard Disk Drive (s)
1. CPU Box-
The CPU Box houses the heart and brain of the computer. All electronic circuits, power supply, floppy drive (s) and hard disk drive(s) are housed in this box. The shape and size of the box may differ from computer to computer. However, they all have the same electronic circuits and parts inside. The storage unit or the memory of the computer is also in the same box. The primary memory of the PC is housed on electronic circuits boards kept in this box. These boards are not visible from the outside The CPU box also houses the floppy disk drive(s) and hard disk drive(s) that from the secondary memory.
The keyboard of a computer looks quite similar to the keyboard of a typical typewriter. A typical keyboard used with a PC. The keyboard may have 84,101 or 104 keys. The keys on the computer keyboard are arranged in the same order as on the keyboard of an ordinary typewriter. However, there are a few additional keys on the computer keyboard.
Mouse is a device that is used extensively in Windows based programs. The Mouse acts as an interface between the PC and the user. You can use the Mouse to move the cursor, select options and to execute commands, as an alternative to entering commands through the keyboard.
3. Video Display Unit (VDU)/Monitor-
When you type text through the keyboard, it is not directly printed (typed) on a sheet of paper. Instead, it is displayed on a Video Display Unit (VDU) or monitor that looks similar to an ordinary television screen. The current typing position on the screen is informed through a special character displayed on the screen. This special character is called the cursor.
4. Floppy Disk Drive(s)-
The floppy disk drive is an important input/output (I/O) device in the PC. The I/O device is used for inputting (reading) and storing (writing) information. The ‘ contains one or more floppy disk drives. The floppy disk drive a storage device. It stores information (documents) on the floppy’ diskette that is inserted in the floppy disk drive. The– floppy diskette is usually called floppy disk or just disk (disc).
The floppy disk is a flexible plastic disc that has magnetic coating on one or both side. This plastic disk is enclosed inside another square plastic jacket. Two types of floppy disks are used in PCs.
1. 5.25″ Floppy Disk (Mini Floppy Disk)
2. 3.5″ Floppy Disk (Micro Floppy Disk).
5. Hard Disk-
Unlike a floppy disk that is flexible and removable, the hard disk used in the PC is permanently fixed. The hard disk has storage capacity of 10 MB (10,000,000 bytes or characters) or higher. The hard disk used in a higher end PC can have a storage capacity up to 8 G B (Gege Bytes; 1GB = 1000 MB). Now-a-days, hard disk capacities of 540 MB, 1GB, 1.6GB, 2GB and 4GB are quite common.
The printer is an output device that is used to print documents on paper. Various kinds of printers are used with PCS. The Dot Matrix Printer (DMP) is the most commonly used printer with PCs because of its low cost and reasonably good speed.