IBM Personal Computer XT

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IBM XT keyboard with 83 keys. With the 10 function keys on the left, from the early 1980s.

The IBM Personal Computer XT (Type 5160) or simply XT (for e X tended T echnology), introduced on March 8, 1983, is a minor further development of the IBM PC . Both devices, PC and PC XT, are often grouped under the abbreviation PC / XT and thus differentiated from the technically significantly changed successor model, the IBM PC AT .


In contrast to the original PC, it has a hard disk ( MFM ) with a capacity of 10 MB , a correspondingly larger power supply , a ST-506 compatible hard disk controllers , and more slots for memory and XT bus - expansion cards on the motherboard . It was also delivered with the newer PC-DOS 2.0, which for the first time supported the subdirectories that are almost indispensable when working with hard drives .

XT variants

Furthermore, there was the XT than IBM 3270 PC with hardware emulation of a terminal type 3270 .

The IBM PC / 370 contained a / 370 -compatible CPU on two plug-in cards . The XT only served as an input / output unit. The PC / 370 was successfully used for program development for IBM mainframes.

A late model of the PC XT , the PC XT 286 ( type 5162 ) was only introduced on September 2, 1986. Instead of the 8088 - it has an 80286 - CPU , which made it a cheaper alternative to the IBM PC AT , which has been available since 1984 . Although the 80286 CPU in the XT 286 was only clocked at 6 MHz instead of 8 MHz in the PC AT , it achieves a higher speed due to its faster working memory. And it also has the 5.25 ″ floppy disk drive with a storage capacity of 1.2 Mbytes and half the height (1.75 ″) that was already introduced in the PC AT .

IBM also manufactured the EMR (ElectroMagnetically Resistant) XT for military and diplomatic applications. It was secured by careful shielding measures against "eavesdropping" on electromagnetic radiation in accordance with the American TEMPEST standard.

Expansion unit

The PCs XT and XT 286 can be expanded with the Expansion Unit Model 5161 by an identical housing with space for additional drives and expansion cards. For this purpose, a card with driver modules was inserted into the XT, which connected the bus of the XT with that of the expansion unit via a cable. The same option was available for the original PC.

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