18 with so many types of computers in all price

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Unformatted text preview: rs to invest only in the hardware configuration and software of their need and value. 18. With so many types of computers in all price ranges, today we have a computer for almost any type of user- whether the user is a small child or a scientist of world-fame. Figure 1.3 summarizes the key technologies and features of the various generations of computers discussed above. We have looked at the history of computing divided into five generations, and we have seen how quickly things have changed in the last few decades. But the rate of technological progress outlined in the preceding pages is not slowing down at all. As we enter into the 21st century, future generations of computers will evolve with higher capability and user friendliness. In fact, the fastest-growth period in the history of computing may be still ahead.18 1 Foundations of Computing Generation Key hardware technologies (Period) First (1942- Vacuum tubes; electromagnetic 1955) relay memory; punched cards secondary storage Key software technologies Third 1975) Timesharing operating system; standardization of high-level programming languages; unbundling of software from hardware Machine and assembly languages; stored program concept; mostly scientific applications Second (1955- Transistors; magnetic cores Batch operating system; 1964) memory; magnetic tapes and high-level programming disks secondary storage languages; scientific and commercial applications (1964- ICs with SSI and MSI technologies; larger magnetic cores memory; larger capacity disks and magnetic tapes secondary storage; minicomputers; upward compatible family of computers Key characteristics Bulky in size; highly unre limited commercial commercial production di and costly; difficult to use Faster, smaller, more reliabl easier to program than pre generation systems; comm production was still difficu costly Faster, smaller, more re easier and cheaper to pr commercially, easier to use easier to upgrade than pre generation systems; scie commercial and interactive o applications Fourth (1975- ICs with VLSI technology; 1989) microprocessors; semiconductor memory; larger capacity hard disks as in-built secondary storage; magnetic tapes and floppy disks as portable storage media; personal computers; supercomputers based on parallel vector processing and symmetric multiprocessing technologies; spread of highspeed computer networks Operating systems for PCs; GUI; multiple windows on a single terminal screen; multiprocessin...
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This document was uploaded on 04/07/2014.

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