[BBC-Micro] OT PC architecture

Michael McConnell soruk at eridani.co.uk
Thu Feb 18 18:15:29 GMT 2010


Rick Murray wrote:
> won't run on earlier hardware, however the concept predates the 
> introduction of the 386. Was any sort of Unix released for earlier x86s? 
> I ask because it seemed in numerous walks of life, MS-DOS suffered from 
> the 64K/640K limitations (ever had to start a game from a special boot 
> disc as loading your regular device drivers only left half a megabyte 
> free?); so did these Unixen suffer similar problems or did they work 
> around it? [or not exist at all?]

There was a version of Minix built for i86 (as they referred to it as). 
It would run on an 8086, and do some kind of protected mode on the 286.

A process had to fit inside 64K. As a result there were some quite scary 
workarounds, such as a program for uncompressing 'compress'ed files at 
16-bit compression (natively it couldn't do more than 13-bit due to the 
memory requirements), by running multiple copies of itself and using 
some form of inter-process communication! It wasn't fast.

The last version that will seemingly run on the 8086 is 2.0.3 (2.0.4 
only talks about 286s and higher, and Minix 3 makes no mention of 
anything earlier than i386).

-- 
-- Michael "Soruk" McConnell
    Eridani Star System

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