Re: Rebooting options; what's kept around?
Posted: August 28th, 1984, 8:06 am
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From: info-mac@uw-beaver (info-mac)
Newsgroups: fa.info-mac
Subject: Re: Rebooting options; what's kept around?
Message-ID:
Date: Thu, 26-Jul-84 13:36:36 EDT
Article-I.D.: uw-beaver>.1332
Posted: Thu Jul 26 13:36:36 1984
Date-Received: Fri, 27-Jul-84 07:29:58 EDT
Sender: daemon@uw-beave
Organization: U of Washington Computer Science
Lines: 56
From: Mark H. Nodine
From what I can tell, you are partly right and partly wrong about what gets
kept when the Mac is turned off. The clock is not kept in memory (otherwise
it would not continue to advance when the power is turned off), but rather
is kept by a single timer chip (which also has an alarm) and which is
powered by a battery. The Mac documentation implies that this battery
will need to be replaced every couple of years.
The information about the desktop is not kept when the Mac is turned off.
All of this probably comes from some "default" arrangement of the desktop
when it reconstructs the disk. If the desktop information were, in fact,
kept by the Mac, then you would not lose all of your folder information,
since that is essentially an optical illusion created by the desk manager.
Of some interest, however, is that there are 20 bytes of non-volatile RAM
in the Macintosh. I don't know of any documentation for them other than
what is in the comments for sysequ.h, but here is what I glean (if anybody
has any further information, please let me know):
Byte 1 validation field (? is this like a serial number?)
Byte 2-4 odometer (I guess you can figure out how
much you have been using your Mac)
Byte 5-8 port configurations
Byte 9-12 alarm time
Byte 13-14 default font id
Byte 15
bit 0-3 keyboard repeat threshold (in 4/60ths)
bit 4-7 keyboard repeat rates (in 2/60ths)
Byte 16 print stuff (This may be how MacWrite keeps
track of the information about
your printer, such as cut sheet,
which it seems to remember without
fail regardless of what disk you
run from)
Byte 17
bit 5-7 volume control
Byte 18
bit 0-3 double time (in 4/60ths)
bit 4-7 caret blink time (in 4/60ths)
Byte 19
bit 0 english/metric
bit 3-7 country code (!)
Byte 20
bit 0 paranoia level (?)
bit 1 mouse scaling (must be linear vs. velocity)
bit 2 keyclick
bit 3 boot disk (? This could be useful.)
bit 4-5 menu flash (?)
bit 6-7 help level (?)
That's all the info and guesses I have.
Enjoy,
Mark
Posting-Version: version B 2.10 UW 5/3/83; site uw-beaver
Path: utzoo!watmath!clyde!burl!ulysses!mhuxl!houxm!houxz!vax135!cornell!uw-beaver!info-mac
From: info-mac@uw-beaver (info-mac)
Newsgroups: fa.info-mac
Subject: Re: Rebooting options; what's kept around?
Message-ID:
Date: Thu, 26-Jul-84 13:36:36 EDT
Article-I.D.: uw-beaver>.1332
Posted: Thu Jul 26 13:36:36 1984
Date-Received: Fri, 27-Jul-84 07:29:58 EDT
Sender: daemon@uw-beave
Organization: U of Washington Computer Science
Lines: 56
From: Mark H. Nodine
From what I can tell, you are partly right and partly wrong about what gets
kept when the Mac is turned off. The clock is not kept in memory (otherwise
it would not continue to advance when the power is turned off), but rather
is kept by a single timer chip (which also has an alarm) and which is
powered by a battery. The Mac documentation implies that this battery
will need to be replaced every couple of years.
The information about the desktop is not kept when the Mac is turned off.
All of this probably comes from some "default" arrangement of the desktop
when it reconstructs the disk. If the desktop information were, in fact,
kept by the Mac, then you would not lose all of your folder information,
since that is essentially an optical illusion created by the desk manager.
Of some interest, however, is that there are 20 bytes of non-volatile RAM
in the Macintosh. I don't know of any documentation for them other than
what is in the comments for sysequ.h, but here is what I glean (if anybody
has any further information, please let me know):
Byte 1 validation field (? is this like a serial number?)
Byte 2-4 odometer (I guess you can figure out how
much you have been using your Mac)
Byte 5-8 port configurations
Byte 9-12 alarm time
Byte 13-14 default font id
Byte 15
bit 0-3 keyboard repeat threshold (in 4/60ths)
bit 4-7 keyboard repeat rates (in 2/60ths)
Byte 16 print stuff (This may be how MacWrite keeps
track of the information about
your printer, such as cut sheet,
which it seems to remember without
fail regardless of what disk you
run from)
Byte 17
bit 5-7 volume control
Byte 18
bit 0-3 double time (in 4/60ths)
bit 4-7 caret blink time (in 4/60ths)
Byte 19
bit 0 english/metric
bit 3-7 country code (!)
Byte 20
bit 0 paranoia level (?)
bit 1 mouse scaling (must be linear vs. velocity)
bit 2 keyclick
bit 3 boot disk (? This could be useful.)
bit 4-5 menu flash (?)
bit 6-7 help level (?)
That's all the info and guesses I have.
Enjoy,
Mark