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- From: winders@aux.support.apple.com (Scott Winders)
- Newsgroups: comp.sys.mac.system
- Subject: Re: How do you zap PRAM under Sys7?
- Message-ID: <winders-300892202434@macwinders.support.apple.com>
- Date: 31 Aug 92 03:33:40 GMT
- References: <15179@umd5.umd.edu> <28627@vedge.UUCP>
- Sender: daemon@Apple.COM
- Followup-To: comp.sys.mac.system
- Organization: Apple Computer, Inc.
- Lines: 59
-
- In article <28627@vedge.UUCP>, brad@vedge.UUCP (Brad Fowlow) wrote:
- >
- > bwilliam@oyster.smcm.edu (Bill Williams) writes:
- > : >To reset: Hold Command-Option -p-r
- > :
- > : Yes, but WHY would I zap the PRAM? I've only heard of needing to do it
- > : if there are bizarre things going on (most recently posted of which is
- > : the "wecome to Mac" mac icon not showing up in color).
- >
- > Some things in the pram:
- > desktop pattern, mouse speed, sound volume, keyboard layout,
- > highlight color, -startup disk-, default app font.
- >
- > Incidentally, although the time is in pram, it isn't reset by a zap.
- >
- > cheers.
- > --
- > Brad Fowlow brad@vedge.com Visual Edge Software Limited
- > -------------------------------------------------------------
- > Language is the house of being.
-
-
- Actually, the time is not kept in PRAM, it is kept in the clock chip
- that contains the PRAM. And you are right, it is not reset when PRAM
- is zapped.
-
- FYI:
-
- The only Apple products that contain non-volatile memory are Macintosh
- systems and Apple LaserWriter printers; the Mouse, keyboards, scanners,
- tape drives, CD-ROM drives, disk drives, and display systems do not have
- non-volatile memory. The details of which are as follows:
-
- The Macintosh 128K, Macintosh 512K, and Macintosh 512KE contain 20 bytes
- of Parameter RAM (PRAM). These 20 bytes of PRAM are documented on pages
- II-369 to II-371 of Inside Macintosh Volume II.
-
- The rest of the computers in the Macintosh family have 256 bytes of PRAM,
- except for the Macintosh Portable which has 128 bytes. PRAM only contains
- configuration information, not user data.
-
- Not all of PRAM is cleared when using the by "hold down the Command, Shift,
- and Option keys while opening the Control Panel" method of System 6. The
- original 20 bytes of PRAM documented on pages II-369 to II-371 of Inside
- Macintosh Volume II are not cleared. Only the other 236 bytes that are
- considered confidential. This should be sufficient for your customers
- needs.
- Note: The Command, Option, r, p, method of System 7 clears all of PRAM.
-
- The same is true for the non-volatile memory in the LaserWriter printers
- that we sell. Only configuration information like page count, baud rate,
- emulation mode, and port to use are stored. The printer memory, like a
- computer's memory, is erased as soon as power is turned off.
-
-
- Scott Winders
- winders@aux.support.apple.com
-
- "My opinions are my own, not my employer's"
-