Siemens PC-D

From Wikipedia, the free encyclopedia
Jump to navigation Jump to search
Siemens PC-D
Siemens PC-D
TypePersonal computer
Release datePC-X: 1982; 37 years ago (1982)
PC-D: 1984; 35 years ago (1984)
Media5¼″ floppy disk, hard disk
Operating systemPC-X: SINIX, PC-D: MS-DOS 2.11
CPUIntel 80186 @ 8 MHz[1]
Memory128 KB – 1 MB

The PC-D and PC-X were personal computers sold by Siemens between 1982 (PC-X)/1984 (PC-D) and 1986. The PC-D was the first MS-DOS-based PC sold by Siemens, though it was not fully compatible with the IBM PC architecture. It was succeeded by the PCD-2.[2] The PCD-2 was fully IBM PC compatible.


Most of the hardware was identical. While the PC-X was equipped with 1 MB of RAM, a hard disk and a MMU, the PC-D came with 128 kB of RAM and a single 5¼″ floppy disk drive in its basic configuration.[1][3] More powerful configurations with 256 kB, 512 kB or 1 MB and either a second floppy disk drive or a hard disk with a capacity of 13 or 20 MB were also available.[1][4] The keyboard layout differed between the two models.

The PC-D had a certain level of compatibility with the IBM PC architecture but differed in a number of aspects:

  • Intel 80186 processor[1]
  • Double-density floppy disk drives with a proprietary 80-track format (729,088 bytes)[1]
  • Proprietary monochrome graphics adapter with a resolution of 640×350 pixels and black-on-white text mode (which could be inverted through a software tool)[1][3]
  • 12″ monochrome monitor, powered through the graphics card
  • V.11 serial ports for keyboard and mouse (the latter being optional)[1]
  • Different keyboard layout: among others, the PC-D had a Help key and keys to control a connected printer but only five cursor keys (←↓↑→ and Home)[1]
  • Both V.11 and V.24 ports for printers[1]
  • A parallel port was available only as an add-on; if not installed, LPT1: and LPT2: would address the serial ports
  • Proprietary VG96 Local Bus
  • The power switch could be inhibited in software
  • A debug button (located next to the reset button) to display the contents of the processor registers
  • The mainboard had a SCSI interface, although hard disks had a ST506 interface and were connected to a separate controller board.

Optional hardware included:

  • a two-button mouse[5]
  • the PT20 daisy wheel printer, the PT88 (Siemens' ink jet printer) or the PT89 (the A3 variant of the PT88)[4][5]
  • the UTC 101, UTC 421-1 or UTC 424-4 teletex controllers, the latter of which could also be used to network up to four PC-Ds[4][5]
  • a tape drive with a capacity of 45 MB[4]


The PC-D shipped with MS-DOS 2.11[1][3] (version 3.20 became available later), which was extended with a menu system through which users could launch applications without having to use the command line.[1] Application software included:

Hardware calls on the PC-D differed from those on fully IBM compatible PCs, causing most DOS applications to crash on the PC-D unless they were recompiled or patched, making them incompatible with IBM PCs. Windows applications could usually be exchanged between both platforms.

The PC-X shipped with SINIX.


  1. ^ a b c d e f g h i j k Siemens PC-D. Technische Daten. (German)
  2. ^ "Elmars Virtuelles Computer Museum" (in German).
  3. ^ a b c Siemens PC-D. Betriebssystem MS-DOS. (German)
  4. ^ a b c d e PC-D Hardware-Übersicht (German)
  5. ^ a b c Siemens PC-D (German)
  6. ^ Siemens PC-D. Textverarbeitung. (German)
  7. ^ Siemens PC-D. Tabellenkalkulation. (German)
  8. ^ Siemens PC-D. Bürografik mit CHART. (German)
  9. ^ Siemens PC-D. Datenverwaltung. (German)
  10. ^ Siemens PC-D. Programmieren in GW-BASIC. (German)
  11. ^ Siemens PC-D. Spotlight. (German)
  12. ^ Siemens PC-D. Open Access. (German)