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From: peg@psuecl.bitnet
Newsgroups: comp.misc,sci.electronics
Subject: Re: Non-volatile Memory--EEPROM
Message-ID: <66033@psuecl.bitnet>
Date: 16 Nov 89 00:28:57 GMT
References: <1308@rodan.acs.syr.edu> <65243@psuecl.bitnet> <1230@corpane.UUCP>
Organization: Engineering Computer Lab, Pennsylvania State University
Lines: 19

> Don't EEPROMS also have a problem with a limited number of writes?
> That is, after so many writes to the chip, it begins to degrade?
>
> They are great for storing data that needs to be changed and non-volitile (such
> as modems use to save parameters) but probably not so good for use in RAM
> replacement where there is a constant read-write situation.

You are absolutely right in that EEPROMs can only be written to so many
times before they fail.  I certainly would not recommend building a
computer with EEPROM for RAM.  Notice the letters ROM in EEPROM :) !

It depends very much on your application whether EEPROMs are useful.  If
you can put programs in ROM, run software in RAM, and only use EEPROM
for data storage you may be in good shape.  For example, many stage
lighting controllers use EEPROMs to store preset light levels.

Xicor claims about 500 k writes on average.  It depends greatly on
the ambient situation, apparently.

Paul