shebanow@apple.com (Andrew Shebanow) (05/24/89)
Just to set the record straight on the 32 Bit Mode discussions: although large parts of the ROMs are 32 Bit Clean, and can run in 32 bit mode, there are several crucial areas which are not. Most important of these is the Memory Manager, which initializes the System Heap at boot time, BEFORE any system patches can be installed (as Dave Berry pointed out). It would be very difficult (and very slow) to change heap formats at system patch time, and it would require patching out the entire Memory Manager and several other pieces of the toolbox, using up large amounts of precious physical RAM space. Although I could expound on this stuff forever, I'll summarize: under System 7.0, existing Mac II/IIx class machines will continue to run in 24 Bit Mode. Eventually, Apple will release new ROMS (for new and/or existing machines) that will support 32 Bit Mode. System 7.0 WILL be able to run with these ROMs (trust me :-)). I hope that this will end the confusion. I guess Tim wins this round :-). Andrew Shebanow Mr. Clean, MacDTS - All Opinions Are Mine, and Mine Alone -
tim@hoptoad.uucp (Tim Maroney) (05/25/89)
In article <2033@internal.Apple.COM> shebanow@apple.com (Andrew Shebanow) writes: >Just to set the record straight on the 32 Bit Mode discussions: although >large parts of the ROMs are 32 Bit Clean, and can run in 32 bit mode, >there are several crucial areas which are not. Most important of these is >the Memory Manager, which initializes the System Heap at boot time, BEFORE >any system patches can be installed (as Dave Berry pointed out). It would >be very difficult (and very slow) to change heap formats at system patch >time, and it would require patching out the entire Memory Manager and >several other pieces of the toolbox, using up large amounts of precious >physical RAM space. I was going to thank dwb for his information, but I kept getting an interp buffer overflow from the roughly six gigabyte References line, so I'll do it here instead; and thank you as well, Andrew. The heap reformatting issue is one that hadn't occurred to me. Apple can get its patches in fairly early; one way around the problem might be to use only a minimal System file consisting of the Memory Manager patch, then use another file to do most of what the system does now, switching to it inside the patch. Unfortunately, this would change the user appearance of the system folder, but it seems as if it would work. As for the physical RAM issue, is it really that much? Perhaps 32K at the most for both the Memory Manager and the Control Manager? Hey, Backdrop takes up almost that much space.... >Although I could expound on this stuff forever, I'll summarize: under >System 7.0, existing Mac II/IIx class machines will continue to run in 24 >Bit Mode. Eventually, Apple will release new ROMS (for new and/or existing >machines) that will support 32 Bit Mode. System 7.0 WILL be able to run >with these ROMs (trust me :-)). And the issue is settled in one fell swoop. Thanks again, dwb and Andrew. >I hope that this will end the confusion. I guess Tim wins this round :-). I'm sure no one is keeping score.... -- Tim Maroney, Consultant, Eclectic Software, sun!hoptoad!tim "I am of the opinion that my life belongs to the whole community, and as long as I live it is my privilege to do for it whatever I can." -- Shaw