Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!cis.ohio-state.edu!tut.cis.ohio-state.edu!ucbvax!mtxinu!ed
From: ed@mtxinu.COM (Ed Gould)
Newsgroups: comp.lang.postscript
Subject: Re: Resetting printers
Message-ID: <1991May14.051843.9800@mtxinu.COM>
Date: 14 May 91 05:18:43 GMT
References: <1991May10.213352.27548@slhisc.uucp>
Reply-To: ed@mtxinu.COM (Ed Gould)
Organization: mt Xinu, Berkeley
Lines: 21

>There have been several comments in the context of "I don't want
>to switch my LaserPrinter" ...  number of times before I damage the
>EEROM. If [the page count] doesn't live in the EEROM and is therefore
>updated on a page basis, where does it live?  My page counter is
>still going strong after 50000 pages!

It's true that EEPROMS have a limited number of times that they may be
erased and rewritten.  It's also true that the printers maintain the
count in EEPROM.  However, they use some cleverness to avoid just
rewriting the same location for each page.  I no longer remember just
what they do, but I remember something about using multiple words of
EEPROM to store the count.  I can also imagine retaining the count in
RAM until power-off, and then writing into EEPROM, depeiding on whether
there is enough power storage to guarantee time to complete the EEPROM
write.  It is a real issue with printer designers, though.

-- 
Ed Gould			No longer formally affiliated with,
ed@mtxinu.COM			and certainly not speaking for, mt Xinu.

"I'll fight them as a woman, not a lady.  I'll fight them as an engineer."