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 not hardware compatible with the
IBM PC. It was slowly phased out after the introduction of the
PCD-2.[2] Which featured an IBM PC compatible design.
Hardware
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:
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]
A debug button (located next to the reset button) issued an NMI, by default dropping into a monitor ROM 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.
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:
LotusSpotlight, an application suite which consisted of a notepad, calculator, calendar, card file, phone book and file manager which could be launched on top of other running DOS applications[11]
Open Access, an office suite which included a database, a spreadsheet application, a charting tool, a calendar and a BBS terminal[12]
Hardware addresses on the PC-D differed from those on IBM compatible PCs, causing applications with direct hardware access to crash, unless adapted (recompiled or patched). Clean DOS application would rund flawless, this includes all Windows and GEM programs.