TechMint

Consider the case of four persons, Leonardo, Chou, Ivan, Hari, who understand and speak Spanish, Chinese, Russian and Hindi, respectively. To be able to understand each other, they would require some person or persons who could translate whatever is spoken into the language each understands.

Similarly, since there are so many programs written in different computer languages, the hardware also needs a translator to convert the computer language into a form that it can understand.

The computer only understands a language of electrical signals, called machine language.

Software called the compiler converts the computer language into machine language. For example, there is a C compiler that converts programs written in the C language to machine language.

Besides the application software and compiler software, there is a third kind of software, called the operating system, which is very important for the working of the PC.

When a user wants to store any data or program, the data or program is stored at a location that is known only to the operating system. Therefore, the operating system performs the task of storage management.

Besides storage management, the operating system also performs device management. For instance, when a user wants to print information on the printer, or display information on the VDU, he or she does not have to bother about the actual transportation of the information from the internal storage to the VDU or to the printer. The operating system takes care of it.

All application software packages are written in computer languages. There are various computer languages like C, C++, FORTRAN and Pascal. Each language is best suited for a particular application.

C and C++ languages are used to develop highly complex software. FORTRAN is used for scientific applications

Each language has its own vocabulary. There are some packages like FoxPro, MS Access and Sybase that are more English-like. Thus, even non-computer professionals, like executives and managers who have never studied computer science, can learn to use these languages.

Since each language has its own vocabulary, each language differs from the other.

We have identified the need for an external storage media and made a comparison between two popular forms of storage media—the hard disk and the floppy disk. However, the microprocessor does not perform the task of writing on or reading from this media. A device specially designed to perform these functions is the disk drive.

Data is fed into the PC and written on the hard disk or the diskette by the disk drive. When the data is to be processed, it has to be read from the disk before processing actually takes place. The disk drive also performs this function of reading the data. Since the disk drive performs both the tasks of writing and reading the data, in other words, the input and output functions, it is referred to as an \nput-output device.

A simple analogy of how a disk drive works is the cassette tape recorder. It encodes music and stores it on a cassette tape as a series of signals. It also reads the stored signals on the cassette tape and converts them back to music. The cassette player records as well as plays back the music. Therefore, it performs both reading and writing. A disk drive works in much the same way, reading and writing whenever required.

The disk drive is contained within the system unit. The drive for a diskette is called a diskette drive while the drive for a hard disk is called the hard disk drive.

It is important to differentiate between the storage media and storage devices. While the diskette and the hard disk on which data is stored are the storage media, the disk drives are the devices that do the reading and writing. Going back to the analogy of the cassette tape recorder mentioned earlier, the cassette tape would be called the storage medium while the cassette player is the storage device.

Since the internal storage capacity of PCs is limited, it places a restriction on how much data can be stored at a time for processing. However, this is not the only drawback. Once the PC is switched off, or in case of a power failure, all the data stored in the internal storage is lost. This means that every time you want to work on the PC, you would have to input the data required for processing.

For permanent storage of data, external storage media can be used with a PC system. External storage is also referred to as secondary storage.

There are two kinds of external storage media used with a PC, they are:

• Floppy Disk
• Hard Disk

Another media for external storage is the cartridge tape. It is particularly suitable for storage of large volumes of data. Now, CD-ROMs and Magneto-Optical (MO) disks have also become an important media to store large volumes of data.

Comparison between a Diskette and a Hard Disk

Besides the microprocessor, the system unit also contains a storage area where the data is stored before being actually processed. This storage area is called the internal storage. It is also referred to as primary storage, main memory ox Random Access Memory (RAM).

Internal storage capacities may differ in different PCs. Typically; a PC will have an internal storage capacity of 640,000 characters or more.

In computer terminology, the storage capacity of a PC is measured in terms of bytes, where one byte can store one character. Character here refers to any alphabet, number or other symbol. Therefore, to store the word COMPUTER, 8 bytes would be required. Just as there is a basic unit, gram, and another unit, kilogram to measure weight, there is also byte and kilobyte (KB) to measure storage capacity. One KB is approximately equal to 1000 bytes. Therefore, 1 KB can store approximately 1000 characters. Another common unit of measurement of storage capacity is the megabyte (MB), which is equal to approximately 1000 KB. Very large storage capacities are measured in terms of gigabytes (GB). One GB is approximately equal to 1000 MB.

The output on the VDU cannot be stored for later reference. For a permanent output, you would require a printer that is also a common output device. Using the printer, you can obtain output on paper. Printers are capable of printing at very high speeds. The printers commonly used with the PC are the dot-matrix printer, the ink jet printer and the laser printer.

Comparison between Printers