AMD or Intel 80387 Math Coprocessor IC

From: Eric J. Korpela <korpela_at_ssl.berkeley.edu>
Date: Thu Mar 6 20:10:00 2003

> > I don't currently have a DRX2, but I do have a DRX, which is essentially
> the
> > same thing without the clock doubled core. The L1 cache made it about 20%
> > faster than an equivalently clocked 386. You had to explicitly turn on
> the
> > cache, and set regions as uncachable. (Caching the video card usually
> made
> > for problems.)
>
> Guess I want the DRX2 then. No sense in spending all that time on something
> just to have it be less than optimal. I'll have to dig up reference sheets
> on 'em.
>
> BTW, what do you run on the DRX? I'm upgrading an IBM P70 luggable, the
> target OSes are AIX-PS/2 and Solaris in particular, and then as many others
> as will work.

Sorry for the delayed response. I've used Linux, OS/2 Warp and Win3.1 on them.
Right now it's an OpenDOS machine.

Turning on internal cache requires ring 0 access. OS/2 required a device driver at
startup. Win 3.1 and DOS run a program from autoexec.bat. ISTR that the linux
kernel had support built in for the DRX. I don't know about AIX and Solaris.

There are also later model BIOS versions that turn on the cache at boot. I
don't know if the P70 would have that l turn on the cache at boot. I don't
know if a P70 would have an appropriate BIOS.

Eric
Received on Thu Mar 06 2003 - 20:10:00 GMT