[comp.lang.postscript] real

eho@clarity.Princeton.EDU (Eric Ho) (11/25/89)

Does anyone out there know what is the correlation between max vm size (as
returned by vmstatus) and the actual amount of real ram residing inside a
Laserwriter+ ?  (e.g. is it a 1:1 match or something else ?)

Also, I wonder how many kinds of memories (including ROMs) are residing in the
Laserwriters and how they're used -- I always assumed that there is the eeprom
where all volatile params are kept and then there is the postscript
interpreter rom and then there is ram where all user stuff are temporarily
stored.  Is that right ?

Any pointers would be much appreciated.
--

Eric Ho  
Princeton University
eho@confidence.princeton.edu

woody@rpp386.cactus.org (Woodrow Baker) (11/28/89)

In article <EHO.89Nov24214927@clarity.Princeton.EDU>, eho@clarity.Princeton.EDU (Eric Ho) writes:
> Does anyone out there know what is the correlation between max vm size (as
> returned by vmstatus) and the actual amount of real ram residing inside a
> Laserwriter+ ?  (e.g. is it a 1:1 match or something else ?)
> 
> Also, I wonder how many kinds of memories (including ROMs) are residing in the
> Laserwriters and how they're used -- I always assumed that there is the eeprom
> where all volatile params are kept and then there is the postscript
> interpreter rom and then there is ram where all user stuff are temporarily
> stored.  Is that right ?
> 
> Any pointers would be much appreciated.
> --
> 
> Eric Ho  
> Princeton University
> eho@confidence.princeton.edu

Well, The laserwriter+ has 1.5 meg memory.  The page buffer uses approximatly
1 meg of memory (318 bytes per scanline * 3300 scanlines) for letter.  The
leftover .5 meg gets used by the font cache, and the interpreter, and the
program, and the.....Well, in a 2 meg machine there is about 500K of VM...
There are ROMS, EPROM, EEPROM, SRAMS, and DRAMS all present.  In some
machines the EEPROM is realy battery backed CMOS SRAM....

Cheers
Woody