The Four Generation: The Evolution Of Computers

The remarkable thing about the computer age is that so much has happened in so short time. We have leap frogged through four generations of technologies in about 40 years. The first three generation are pinned to three technological developments -the vacuum tube, transistor and integrated circuit- each of which has drastically changed the nature of computers. We define the timing of each generation according to the beginning of the hardware technology.

Through 1970s computers gained dramatically in speed, reliability and storage capacity. The fourth generation was in fact an extension of third-generation technology. The beginning of the fourth computer generation coincided with the development of the large scale integrated (LSI) circuit which

Microcomputers were integrated with other microcomputers and with main frames to form integrated packages. An interesting trend during this periods was a rapid drop in the cost of microcomputers design specifically around a visual operating system . The Apple Lisa marked the beginning of this trend, it was introduced in the early 1983 at $9995.Then came the Apple Macintosh (introduced in the early 1984 at $2495), the Commodore Amiga (introduced in mid-1984 at $1295) and the Atari 520 ST (introduced in late 1985 at $799). All of these machines used the same processor, but the latter two also have sound-generation chip that can generate three or four simultaneous audio voice. a graphic compressor that can provide superior

The AT is about for time factor than the IBM PC and is far more expendable because it can support virtual memory , it can addressed up to 1 gigabyte .The processor also are designed to be multitasking that its can support multiple user or concurrent applications. Starting in 1985, a flood of “AT Compatible” microcomputers was introduced by competitors include Compaq, Texas Instruments, Kaypro, and AT&T.

By 1985,the IBM family captured a dominate role in corporate personal computing. For example, in 1985 Dun and Bradstreet Corporation surveyed the buying plan of businesses that already have a personal computer. But in 1986 desktop publishing suddenly burst on the scene as the fastest growing segment of personal computing and business began opening it doors to Macintosh computers. In March 1987,Apple announced its Macintosh 11 computer which offered a color display, used a faster processor and provided the option of an IBM compatible microprocessor and easy conversion of files between IBM and Macintosh format. In April 1987 IBM effectively replaced the entire family system. These computers use microfloppy diskettes and hard disk, boast better display system and incorporate a new type of expansion