ray@mfgfoc.UUCP (Ray Lillard) (08/04/88)
A few weeks ago I posted a request for information regarding disabling of the instruction cashe on the Mac-II. I had heard the reason MacWrite and many other publicly distributed programs didn't run was related to the instruction cashe of the 68020. A summary of the two responses follows: dplatt@coherent.com (Dave Platt of Coherent Thought Inc.) writes: > Some programs do bomb on the II due to the fact that they use > self-modifying code that's incompatible with the 68020 cache. > There's a Control Panel device that can turn the cache off; > it will help some such programs. > MacWrite 4.5 is incompatible with the II for other reasons... > Turning off the cache doesn't help; the program still bombs. barrys@apple.com (Barry J. Semo of Apple Computer, Inc.) writes: > Hi. I'm afraid there is little you can do to get public domain > programs to work on a Macintosh II that don't already. (comments on lack of testing and rule following by commercial and non-commercial developers alike omitted) > Some programs, especially that use self modifying code, will > benefit from turning the instruction cache off. There is a > public domain Control Panel device called ToggleCache that > does this. My thanks to the above gentleman, -- Raymond Y. Lillard FOCUS Semiconductor Systems Inc. net: (sun!daver!mfgfoc!ray) 570 Maude Court att: (408) 738-0600 Sunnyvale, CA 94086 USA
mkao@crash.cts.com (Mike Kao) (08/05/88)
I have a CDEV that toggles the 68020 instruction cache. Good and peachy. Now
I'd like to know what an instruction cache is and what it does. Thanks!
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