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#### IBM Personal Computer XT (and clones)

History and Trivia:
In early 1980, IBM decided to create a micro computer (up to this date, IBM produced only
mini and mainframe computers), they didn't really know what they wanted and they didn't
think for one second that producing micro computer was a profitable business! They asked
Digital Research (the authors of CP/M) to create an operating system for their new computer.
DR was not very interested, so they approached the then small company Microsoft (at this point
famous for it's BASIC language) to write this operating system. Microsoft wasn't capable of
doing it themselves, so Bill Gates bought up the rights to an OS written by a small company
called Seattle's Computers Products: QDOS (Quick and Dirty Operating System) which became
PCDOS and later MS-DOS.
The IBM PC wasn't very powerful (and was certainly less powerful than a lot of 8 bit
computers), the very first PC had only 16 KB RAM and no floppy disk units -- they used
cassettes. Notice that the functions to handle the cassettes were present in the operating
system up to MS-DOS 5. The PC was available with either CGA or MDA (on an MPA card). The CGA
adapter actually had an RCA composite output to hook it up to your TV if you did not want the
CGA monitor.
The IBM PC XT was the successor of the IBM PC. It's enhanced features included hard disk
capability, more memory, and no more tape port. Perhaps because of the name and fame of IBM,
the PC series became a standard and IBM dominated the computer market up until the end of the
80's. Clones of the XT, such as the Tandy 1000 became commonplace by the end of the decade.

The following PC's and compatibles are supported by, or currently under development in MESS:
IBM PC
Intel 8088 process with 4.77 Mhz clock.
IBM PC Junior
based on IBM PC
Special keyboard
CGA with 160x200x16, 320x200x16 and 640x200x4? colors
3 channel sound chip
IBM PC/XT
based on IBM PC
Intel 8086 instead of 8088, but only ram memory data bus
enhanced to 16 bit.
Tandy1000 Series
IBM PC Junior compatible graphic system.
Later the 640x200x16 graphic mode was also available.
Later models were delivered with EGA/VGA compatible graphic system/card.
IBM PC Junior compatible sound system.
In later models there was also a DAC channel available.
First series with own keyboard (own layout, different keys)
Tandy1000HX
First Tandy 1000 with EEPROM memory for configuration.
Delivered with 3,5 inch double density disk drive (720kb).
Amstrad PC1512/PC1640/PC6400/PPC664?/PC2086?
Packed IBM PC/XT functionality in few custom chips.
Power supply in the monitor was also used for the computer.
Serial Port,
Parallel Port,
Real Time clock with battery buffered cmos ram,
Graphics adapter,
mouse port for included mouse integrated in the motherboard.
Joystick port for cpc-joystick in the keyboard.
Amstrad PC 1512
(Schneider in Germany/Austria)
CGA compatible graphics system with special 640x200x16 graphics mode.
512 KB ram on board, sockets for additional 128 kb on board.
delivered as
PC1512SD (1 5,25 inch double density disk drive (360kb))
PC1512DD (2 5,25 inch double density disk drives)
PC1512HD10 (1 5,25 inch double density disk driver, harddisk controller and 10MB harddisk)
PC1512HD20 (....20 MB harddisk)
(monochrome (about 16 levels grays) or color monitor)
Amstrad PC 1640
(PC6400 in the US)
(Schneider in Germany/Austria)
EGA compatible graphics card and monitor
Amstrad PC2086
(Schneider in Germany/Austria)
VGA compatible graphics card and monitors?

created on Tue Jan 01 12:56:01 2002