NMI Parity Errors while Parallel Printing

[Michael "Ford" Ditto]

In article <788 at rush.cts.com> bob at rush.cts.com (Bob Ames) writes:
>We've got a 3B1 which panics with NMI parity errors after 2-10 lines
>have printed through the parallel Port.

Have you tried the same printer & cable on another Unix PC?

My 3B1  has always done the same thing; I'm glad to hear I'm not the only
one, since that seems to point to a cabling problem or something.  Since I
only discovered the problem after the warrantee expired, I just resigned
myself to sending files to the Amiga for printing.  But now, I'll
investigate it further.

I suspect a bug in the lp device driver which only shows up under some rare
timing conditions which our printers somehow make happen.  The one I tried
is an Epson FX-85, with a "straight-through" cable with every pin connected.

>I developed a theory that somehow the parallel port drains some power
>and causes memory to forget.  I'll probably get 20 letters from people
>telling me how silly this theory is.  |-)

Hmmmm... doesn't seem too likely unless you have a marginal ram chip to
start with.  Also, I would expect that just having the printer connected
would be enough to cause such a problem, even if it wasn't printing.
-- 
					-=] Ford [=-

"The number of Unix installations	(In Real Life:  Mike Ditto)
has grown to 10, with more expected."	ford at kenobi.cts.com
- The Unix Programmer's Manual,		...!sdcsvax!crash!kenobi!ford
  2nd Edition, June, 1972.		ditto at cbmvax.commodore.com