IBM Personal Computer
Models
All IBM personal computers are software backwards-compatible with each other in general, but not every program will work in every machine.

IBM Personal Computer

Section Title: Models
Table Section Text: All IBM personal computers are software backwards-compatible with each other in general, but not every program will work in every machine.

Model name	Model #	Introduced	CPU	Features

PC	5150	August 1981	8088	Floppy disk or cassette system. One or two internal floppy drives were optional.

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, but also used ROM cartridges; 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	80C88	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

Sentence(s)

The "IBM Personal Computer/AT" (model 5170), announced on August 15, 1984, used a 80286 processor running at 6 MHz.

final_sentence: The "IBM Personal Computer/AT" (model 5170), announced on August 15, 1984, used a 80286 processor running at 6 MHz.