thecloud@pnet06.cts.com (Ken Mcleod) (07/02/88)
We all know (from a technote whose number escapes me at the moment) how
to tell what revision of the ROM a Macintosh Plus has got. If the word
at $400008 is $0075, you have a Plus, and the byte at $400002 indicates
the revision.
But...what is the "word" on SE and II ROM revisions? I was testing
for $0076 on a friend's new SE (straight from Apple) and never got it;
his ROM version is $0276. Does this mean that only the low-order byte
of this word should be examined? Is $02 the revision, or something else?
And what of the Mac II's ROM revisions? Is a technote forthcoming?
Hacking Aloud,
Ken McLeod ========================= ....... ======================
UUCP: {crash uunet}!pnet06!thecloud :. .: Chief Weapons of UNIX:
ARPA: crash!pnet06!thecloud@nosc.mil :::.. ..::: "Fear, surprise, and
INET: thecloud@pnet06.cts.com //// ruthless efficiency."darin@Apple.COM (Darin Adler) (07/05/88)
In article <259@hodge.UUCP> thecloud@pnet06.cts.com (Ken Mcleod) writes: > We all know (from a technote whose number escapes me at the moment) how > to tell what revision of the ROM a Macintosh Plus has got. If the word > at $400008 is $0075, you have a Plus, and the byte at $400002 indicates > the revision. > > But...what is the "word" on SE and II ROM revisions? I was testing > for $0076 on a friend's new SE (straight from Apple) and never got it; > his ROM version is $0276. Does this mean that only the low-order byte > of this word should be examined? Is $02 the revision, or something else? > And what of the Mac II's ROM revisions? Is a technote forthcoming? The word 8 bytes above the base of the ROM (not always $400008) contains the machine number in the high byte, and the ROM revision in the low byte. The "revision" byte at $400002 you refer to is actually the ROM checksum which is in the first four bytes of ever ROM. The reason for the Technical Note about Mac Plus ROM versions was the "widespread panic" of people who thought that radically different Mac Plus ROMs existed. Useful information you can glean from that note that applies to the Mac SE and Mac II ROMs as well is that if the checksum on two ROMs match, then they are identical. If you really want to use this information, the best way is to call Environs or SysEnvirons, both of which use this information to determine what kind of Macintosh your program is running on. Darin Adler AppleLink: Adler4 UUCP: {sun,voder,nsc,mtxinu,dual}!apple!darin CSNET: darin@Apple.com