Micro Five system (PC Clone system)

[Chuck Guzis]

On 3 Dec 2007 at 20:58, jim s wrote:

> Initially intel had added such instructions to the dies and then enabled 
> them when they produced  what were called bondout parts for their In 
> Circuit Emulators, or ICE products.  when they came out with the 286 and 
> built their ICE they didn't disable it on the production parts.
> 
> The significance of LOADALL was that it offered a way to load not only 
> the registers that one normally could modify with architectural 
> instructions, but it could also modify others, some of which happened to 
> be the registers that were computed and were the actual memory pointer 
> registers for certain memory operations. 

LOADALL was probably one of the the  worst-kept secret in the 80286 
world (Intel did document it in a memo that soon made the rounds).  
Most 386 and 486 BIOSes even emulate the 286 LOADALL (the 386 and 486 
and P's have a different version of the instruction).  I think it 
finally went official in a DDJ article.

I hadn't realized that Micro Five was part of the brouhaha.

Cheers,
Chuck