On 19 Aug 99, at 18:32, Doreen D Augherton wrote:

>  I have a Tech-Built system.--AMD.K6.. -8 gigs - 64 Ram - Using a Canon
> BJC-610 printer.  I have Win-95 upgraded.  I use primarily Netscape but
> I also have IE.
> I am getting CMOS checksum errors - I/O port 378.
> Techie says I have two printer ports, one "on the board" and another he
> put in to make my printer work with this CPU back in 1997.  Now I am
> wondering why after many months of things being ok what might be causing
> the problem.
> The OnBoard Parallel Port keeps resetting itself to:  "378/IRQ7" and I
> must keep changing it to "Disable" in CMOS when I start up.
>  A while ago I  downloaded InternetExplorer 4.01 which caused a Win-95
> upgrade and I also had to upgrade the printer files from Canon's site.
> At this point I am wondering what in the system that would cause this
> "CMOS-Checksum" error problem that seems to appear the next time I boot
> up after I have used the printer.
> Any Suggestions?

  When you exit from CMOS setup, *saving your updated configuration*, the
updates get stored into the CMOS non-volatile RAM.  At that point, a checksum
of the data is also calculated and stored.
  When the machine boots, it retrieves the data, and calculates the checksum,
and compares it to what was stored.  If they don't match, something must have
changed ("corrupted") the stored data!  A checksum error is reported (you see
this!) AND THE CMOS DATA IS RESET TO DEFAULT VALUES WHICH ARE BELIEVED TO BE
"SAFE".  It is this "reset" that keeps resurrecting your on-board parallel
port.
  [I do not understand why it was necessary to add a second parallel port AND
set it to address 378, but that's beside the point.]

  Now, what could change the data in the CMOS between the time you save the
corrected config and the next reboot?  Well, the most *likely* cause is that
the battery which supplies the refresh power to retain those settings is
getting weak, and so some bits are "fading" before you reboot.  It's entirely
reasonable to expect a fresh battery to fix your problem.


David G

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