A 286 desktop, in VGA

A 286 desktop from anyone but IBM is an IBM PC/AT built by someone else. (IBM never said what AT stood for, and largely failed to trademark it.) Phoenix sold a compatible BIOS from 1984; Chips and Technologies followed in 1986 with the 82C206, one part doing the work of the TTL logic on IBM's board; and by 1988 Gartner counted 1.5 clones bought for every IBM PC. The processor had other makers too. AMD built the 286 under its second-source contract with Intel, and AMD and Harris took it to three times the clock of IBM's last AT.

VGA is the part IBM did not build into an AT. It arrived with the PS/2 in the spring of 1987, three months before the last ATs were made, and clone cards were on sale within six months. (IBM did offer a PS/2 Display Adapter for machines without it.) The original carried 256KB of video memory, which mode 12h uses as four bit planes.

80286 introduced

February 1, 1982

IBM PC/AT released

August 14, 1984

PC/AT clock

6MHz, 8MHz from April 1986

fastest 286s

25MHz, AMD and Harris

VGA introduced

April 2, 1987

286 address space

16MB

• Intel 80286 Wikipedia. The processor's date, its clock speeds, and the AMD and Harris parts.
• IBM Personal Computer AT Wikipedia. The AT's dates and clock speeds.
• Video Graphics Array Wikipedia. VGA's arrival with the PS/2, its memory, and how soon it was cloned.
• INT 10h, Set Video Mode Ralf Brown's Interrupt List. Mode 12h by number.
• IBM PC compatible Wikipedia. Phoenix's BIOS and Gartner's count.
• Chips and Technologies Wikipedia. The 82C206.
• AMD Wikipedia. The second-source contract.