Date: Tue, 02 Apr 96 16:42:09 -0800 From: Cy Schubert - ITSD Open Systems Group <cschuber@uumail.gov.bc.ca> To: freebsd-hardware@FreeBSD.ORG Subject: Parity Errors 2 Message-ID: <199604030042.QAA04463@passer.osg.gov.bc.ca>
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I've managed dig up more information about the parity errors I've been getting.
I've had the machine looked at and according to the repairman I need to increase
my wait states from zero to one for memory reads and writes. His rule of thumb
is that 486DX33 requires at least one wait state with 70ns simms (120MHz
Pentiums require 5 while 486SX25's can get by with zero wait states). He also
warned me that setting too many wait states will also cause parity errors and
under Windows, general protection faults.
DMA timeout, e.g. DMA transfers that reach/exceed the limit of 7.8 microseconds,
and flakey sram chips were also mentioned as causes of NMI signals.
Secondly, the last kernel dump I've got shows that port 0x61 has both high
ordered bits being zero (actually all bits are zero). Apparently the high order
bit (bit 7) indicates a parity error on the motherboard while bit 6 indicates an
IOCHCHK.
Either way I'll try the box out with one wait state.
Regards, Phone: (604)389-3827
Cy Schubert OV/VM: BCSC02(CSCHUBER)
Open Systems Support BITNET: CSCHUBER@BCSC02.BITNET
ITSD Internet: cschuber@uumail.gov.bc.ca
cschuber@bcsc02.gov.bc.ca
"Quit spooling around, JES do it."
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