Text 10 using disks and disk drives

A disk is a data storage device consisting of a flat, circular, magnetic surface on which information can be recorded. You will receive several disks with your computer. These already contain information and programs, and are ready to use.

A disk, like a cassette tape, is reusable storage device that holds information, such as software and data, in files. As with random access memory, the amount of space on a disk is measured in bytes. Unlike information stored in random-access memory, however, information stored on a disk is not deleted when you turn off your computer. If you choose to, you can delete the information on a disk, and with proper care, you can use the disk over and over again. Your computer’s disk drives move information stored on the disks into and out of random-access memory. For example, your computer can read software instructions from a disk into random-access memory, and write your data to a disk for safekeeping.

There are two kinds of disk drives: a hard disk drive and floppy disk drive. A hard disk drive contains a non-removable disk that is built in your system. With a hard disk drive, you can store large amounts of information in one convenient place, instead of storing it on many floppy disks.

The hard disk drive can also write and read information to and from your system much faster than a floppy disk drive can write and read information to and from a disk. When your system writes or reads information to or from a disk, the indicator light on the drive goes on.

Each disk drive has a letter assigned to it so you can tell your system where to find instructions and information. For example on many systems the floppy disk drive is called the A drive, and the hard disk drive is called the C drive.

The default drive is the one which operating system uses unless you tell it to do otherwise. It is shown by the prompt that OS displays.

Text 11 what is a computer?

The term computer is used to describe a device made up of a combination of electronic and electromechanical (part electronic and part mechanical) components. Computer has no intelligence by itself and is referred to as hardware. A computer system is a combination of five elements:

- Hardware

- Software

- People

- Procedures

- Data/information

When one computer system is set up to communicate with another computer system, connectivity becomes the sixth system element. In other words, the manner in which the various individual systems are connected — for example, by phone lines, microwave transmission, or satellite — is an element of the total computer system.

Software is the term used to describe the instructions that tell the hardware how to perform a task. Without software instructions, the hardware doesn't know what to do. People, however, are the most important component of the computer system: they create the computer software instructions and respond to the procedures that those instructions present.

The basic job of the computer is the processing of information. Computers accept information in the form of instruction called a program and characters called data to perform mathematical and logical operations, and then give the results. The data is raw material while information is organized, processed, refined and useful for decision-making. Computer is used to convert data into information. Computer is also used to store information in the digital form.