IBM PC

The IBM Personal Computer , the IBM PC , less known under the denominations of PC/G or IBM model 5150 , is the first Personal computer produces per million by IBM (with the difference of its three predecessors IBM 5100 and 5110 and Système 23 Datamaster ). Its open architecture made the ancestor of all of it the PC compatibles. It was launched the August 12th 1981. It comprised a Microprocesseur Intel 8088 given rhythm with 4,77 MHz and a Random access memory of 16 KB which can be increased to 256 KB. It had according to the models no, one or two disk drives of 160 KB, was equipped with an interpreter of the language BASIC Microsoft in Read-only memory and could manage an external unit of cassette.

The PC/XT

In 1983, it was followed PC/XT , or model IBM 5160 , which accepted a Hard drive of 10 Mo. An electric anomaly returned one of the sites of charts slightly parasitized, which could assign the operation of charts to fast flow. Rather than to reconcevoir the unit, IBM delivered the PC/XT out of standard with a connection card series RS232 C assembled to this place. This one was indeed not affected by the spurious frequency.

Peter Norton, which had not been informed by it, took to the presence of this catch for a message of IBM incentive the users of PC to make of it a communications tools and announced it in its book Inside the IBM PC by adding that it was there that the future of the PC would be played. The starting assumptions had beautiful being false, the conclusion appeared exact.

Note

One should not confuse the PC/G with the 3270 PC/G , which was a version of 3270 PC having a graphic screen and had a version moreover named high-resolution 3270 PC/GX .

The PC/AT

In 1984, the offer widens with PC/AT , officially rérérencé like IBM model 5170 .

Provided with a processor Intel 80286 in the place of the 8088 of the first PC, he saw his performances multiplied by approximately 2,5 compared to this one. A new bus 16 Bit S, bus AT, was designed for the circumstance. Bus AT accepted the charts designed for bus PC, but not the reverse, since the new one had more pins.

The PC/AT existed at IBM in version 6 MHz and 8 MHz, the performance profit in front of more with truth 16 bits with the increase in frequency. In its laboratory of Boca Raton, IBM devoted to a first surcadencement and was able to make it function in 19 MHz under condition of replacing the ROMANIANS of the BIOS by RAM (faster, and thus being able to manage to follow rate), and of changing its cooling system completely. This test just intended to find the limits of the technology of the time, and thus to estimate the safety margins, did not have a commercial continuation.

The machine was considered to be sufficiently powerful - according to the criteria of the time - to be prohibited with export to the Eastern European countries, then under technological embargo. IBM as refused of it during two years the sale at reduced price with the personnel, asserting as a private individual could not need such a power nor of such a capacity disc (30 Mo), which rather intended it for the Small and medium-size companies.

Frequently put question

A question frequently put about the PC IBM is the reason for which its team of design had chosen to use standard components of the market (thus not-IBM), thus breaking with all the practices of the manufacturers.

The director of its division PC, Mr. Wladawsky-Shepherd, mentioned the two reasons which had led Estridge (project manager) and IBM to this choice: it was necessary to be ready quickly (because the sales of the APPLE II progressed in an almost exponential way) and the direction of IBM very did not take the crenel of the PC to serious considering its modest price: in We dealt with big, complex computer systems, our management did not look to the PC ace something that could seriously challenge our business.

See too

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