Models
IBM 5150 PC with IBM 5151 monitor |
| Model name | Model # | Introduced | CPU | Features |
|---|---|---|---|---|
| PC | 5150 | August 1981 | 8088 | Floppy disk or cassette system |
| XT | 5160 | March 1983 | 8088 | First IBM PC to come with an internal hard drive as standard. |
| XT/370 | 5160/588 | October 1983 | 8088 | 5160 with XT/370 Option Kit and 3277 Emulation Adapter |
| 3270 PC | 5271 | October 1983 | 8088 | With 3270 terminal emulation, 20 function key keyboard |
| PCjr | 4860 | November 1983 | 8088 | Floppy-based home computer, infrared keyboard |
| Portable | 5155 | February 1984 | 8088 | Floppy-based portable |
| AT | 5170 | August 1984 | 80286 | Faster processor, faster system bus (6 MHz, later 8 MHz, vs 4.77 MHz), jumperless configuration, real-time clock |
| AT/370 | 5170/599 | October 1984 | 80286 | 5170 with AT/370 Option Kit and 3277 Emulation Adapter |
| 3270 AT | 5281 | June 1985 | 80286 | With 3270 terminal emulation |
| Convertible | 5140 | April 1986 | 8088 | Microfloppy laptop portable |
| XT 286 | 5162 | September 1986 | 80286 | Slow hard disk, but zero wait state memory on the motherboard. This 6 MHz machine was actually faster than the 8 MHz ATs (when using planar memory) because of the zero wait states |
All IBM personal computers are software backwards-compatible with each other in general, but not every program will work in every machine. Some programs are time sensitive to a particular speed class. Older programs will not take advantage of newer higher-resolution and higher-color display standards, while some newer programs require newer display adapters. (Note that as the display adapter was an adapter card in all of these IBM models, newer display hardware could easily be, and often was, retrofitted to older models.) A few programs, typically very early ones, are written for and require a specific version of the IBM PC BIOS ROM. Most notably, BASICA which was dependent on the BIOS ROM had a sister program called GW-BASIC which supported more functions and was 100% backwards compatible and could run independent from the BIOS ROM.
Read more about this topic: IBM Personal Computer
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—Judith Viorst (20th century)