Amiga 3000UX

[Kent Paul Dolan]

pal at ariel.ucs.unimelb.edu.au (Philip Leverton) writes:

   Our system only had 5 Mb of memory

mls at cbnewsm.att.com (mike.siemon) writes:

   AT&T/USL recommends a minimum of 6 Megabytes for OPEN LOOK

ford at amix.commodore.com (Mike "Ford" Ditto) writes:

   Also, remember that experienced AmigaDos users (and probably
   Commodore marketing types, too) think of a basic A3000 (4 Meg fast, 1
   Meg chip) as a "5 Meg" system, while Unix consideres this to be a "4
   Meg" system.

   The Amiga's "chip" memory, to Unix, is like the frame buffer memory
   on a graphics card. It is never used for the system's virtual memory.
   It is used for floppy and sound DMA, copper instructions, and
   (primarily) bitplane memory for the many virtual screens.

   This might change in a future software release, since there will be
   people with 4 Meg fast and 2 Meg chip, and they will need more system
   memory and certainly wouldn't come close to using the whole 2 Meg
   chip Ram.

   -=] Ford [=-

Yeep, Mike! _Never_ tell a graphics person s/he "wouldn't come close to
using" _any_ resource. The resource hunger of graphics processing is
insatiable and the stuff of legends.

Don't fix this "problem"; it's the wrong thing to fix. Fix the '020 and
'030 add on cards so that they can support more than 4 Meg of memory, or
provide a CBM 32 bit in the box expansion memory card that works with
them, and let Unix continue to think chip is off limits; it will make
life _so_ much simpler for all concerned, since it takes away the need
to "fix" Unix to do chip right, and mend the huge existing software base
to cooperate.

[If it turns out to make sense, you might arrange a way for it to be
still in the Unix flat virtual address space, but spoof Unix into
thinking it is already allocated. This could be done by moving the start
of the stack, or whatever's at the high end of virtual memory, down to
make room for chip or video card memory addressing during autoconfigure
time. This might work, since existing Unix software shouldn't try to
address past the base of the stack.]

Kent, the man from xanth.
<xanthian at Zorch.SF-Bay.ORG> <xanthian at well.sf.ca.us>