32 bit Macs (was Atari hard ) - test-drb@ccmp.vtda.org

4 Jun 1998

On  4 Jun 98 at 9:07, SUPRDAVE(a)aol.com wrote:

...
  they were all 32bit from the get-go, but i think the
memory adressing was
 24bit which means my IIcx can only goto 16meg maximum. there was also some
 issue about some applications wouldnt run because of the 24-32 bit
 discrepancy, and a program called mode32 was created to circumvent the issue.
 i got my copy of mode32 from connectix, who presumably made it.  
The IIX and IICX and SE/30 ROMs contained the 24bit addressing code. 
For System 7.0 --> 7.5.5, Connectix released the Mode 32 fix which 
permits the Macs with "dirty ROMs" to successfully address up to 128M 
of physical RAM and to use virtual memory as well. 

For System 6, you were stuck with 8M physical RAM on these machines. 
Apple did not support virtual memory at that time, but Connectix sold 
a VM kit. The kit also supported a Mac II fitted with a PMMU.

Can anyone clarify the memory situation for A/UX?

Phil

**************************************************************
Phil Beesley -- Computer Officer -- Distributed Systems Suppport
University of Leicester

Tel (0)116 252-2231
E-Mail pb14(a)le.ac.uk