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View Full Version : CP/M-86 for IBM PC and XT version 1.1 on a 8088



Klee
March 6th, 2011, 02:45 PM
I was diagnosing my Beltron XT clone mb , it turned out to be a mounting screw shorting one trace to ground , and as it was booting up I grabbed a boot floppy .

I was thinking it was my MS Dos 6.22 360k boot disk but as it was booting I realized I grabbed the wrong one.

It booted anyway and works just fine on a 8088 XT clone mb .

Whats the deal , I thought CP/M 86 needed at least a 8086 cpu.:huh:

http://img163.imageshack.us/img163/9528/img0602va.jpg

http://img153.imageshack.us/img153/128/img0603yk.jpg

SteveH
March 7th, 2011, 02:36 AM
Whats the deal , I thought CP/M 86 needed at least a 8086 cpu.:huh:
The 8086 and 8088 belong to the same family and use the same instruction set. The difference being they way they talk to their peripheral chips; the 8086 has a full 16 bit data bus and the 8088 has an 8 bit [multiplexed?] data bus.

per
March 7th, 2011, 03:34 AM
The 8086 and 8088 belong to the same family and use the same instruction set. The difference being they way they talk to their peripheral chips; the 8086 has a full 16 bit data bus and the 8088 has an 8 bit [multiplexed?] data bus.

It's not even fully multiplexed. The 8088 is only 8 bits externally, and it will therefore work much like any 8-bit CPU interface-wise. However, the core and instruction set is fully 16-bit, and it will therefore have just the same execution capabilities as the 8086.

In other words, from the perspective from software; the 8088 is a fully 16-bit CPU. From the perspective from hardware; the 8088 uses an 8-bit interface.

Klee
March 7th, 2011, 11:06 AM
Ok now I get it.

I'm planing on running CP/M 3.0 but I have no boot CP/M boot disk so can I use CP/M 86 as a working enviroment to create a CP/M 3.0 running system?

Chuck(G)
March 7th, 2011, 12:45 PM
Possibly, but you'd be just as well off using MS-DOS--better tools.

JohnElliott
March 7th, 2011, 02:50 PM
The nearest equivalent for PC compatibles is Personal CP/M-86 version 2.0/4. While there is a CP/M-86 Plus, I'm not aware of a copy with a PC-compatible XIOS.