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The IBM Personal Computer XT (model 5160, often shortened to PC/XT) is the second computer in the IBM Personal Computer line, released on March 8, 1983. [1] Except for the addition of a built-in hard drive and extra expansion slots, it is very similar to the original IBM PC model 5150 from 1981.
The IBM Personal Computer, commonly known as the IBM PC, spanned multiple models in its first generation (including the PCjr, the Portable PC, the XT, the AT, the Convertible, and the /370 systems, among others), from 1981 to 1987. It eventually gave way to many splintering product lines after IBM introduced the Personal System/2 in April 1987.
The CGA and MDA support in the BIOS proper was maintained through the IBM PC XT and PC AT product lines (which did support option ROMs), so that those cards worked (with full BIOS support) in those machines. The first PC video adapter card that had an option ROM was the IBM EGA, introduced in 1984 with the IBM PC AT.
IBM PC-Compatible CGA Video Reference – includes technical details; CGA monitor calibration – Technical information on the IBM 5153 monitor's color decoding and calibration; IBM Personal Computer Hardware Library: Technical Reference (Revised edition, 1983) This article was originally based on material from the Free On-line Dictionary of ...
IBM published the entire listings of the BIOS for its original PC, PC XT, PC AT, and other contemporary PC models, in an appendix of the IBM PC Technical Reference Manual for each machine type. The effect of the publication of the BIOS listings is that anyone can see exactly what a definitive BIOS does and how it does it.
The PGC was, at the time of its release, the most advanced graphics card for the IBM XT and aimed for tasks such as CAD. [ 2 ] Introduced in 1984, [ 3 ] the Professional Graphics Controller offered a maximum resolution of 640 × 480 with 256 colors on an analog RGB monitor , at a refresh rate of 60 hertz—a higher resolution and color depth ...
The IBM PC AT came with a 192-watt switching power supply, significantly higher than the 130-watt XT power supply. According to IBM's documentation, in order to function properly, the AT power supply needed a load of at least 7.0 amperes on the +5 V line and a minimum of 2.5 amperes on its +12 V line.
In the IBM PC XT upon which the PCjr is based, DRAM refresh is performed by one channel of the 8237 DMA controller, triggered by one channel of the 8253 programmable timer, while in the PCjr the 8237 is eliminated and the timer channel is repurposed (to work around a complication of other cost-cutting in the keyboard interface). [25]