Date: Fri, 28 Jun 1996 15:21:41 +0200 (MET DST) From: grog@lemis.de (Greg Lehey) To: ajohn@mail.bcpl.lib.md.us (Anil John) Cc: questions@FreeBSD.org (FreeBSD Questions) Subject: Re: Compiling kernel for ATAPI CD-ROM error - fatal signal 11- what is it? Message-ID: <199606281321.PAA12957@allegro.lemis.de> In-Reply-To: <01BB6462.E7F53500@ppp15.bcpl.lib.md.us> from "Anil John" at Jun 27, 96 07:57:42 pm
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Anil John writes: > > Greg Lehey[SMTP:grog@lemis.de] wrote: >> >> OK, you're not done yet. So it's pretty certain that you have a cache >> problem. Now you need to find out whether it's a hardware problem or >> incorrect configuration. Many BIOSes have cache burst configuration >> options (cache wait states, or burst configurations like 3-2-2-2 or >> 2-1-1-1 or some such). The cache is 128 bits wide, but the memory bus >> is only 32 bits wide, so it needs 4 cycles to transfer a cache line. >> The 3-2-2-2 means that the first transfer takes 3 bus cycles, and the >> following ones only 2. I'd guess that you have your cache set up for >> too few cycles. >> > > I know what you mean The above settings are in my BIOS on my other machine. > But I have an old Award BIOS on my system and I do not know what the > corresponding items are. The relevent options on it are (* marks what I > had when I got errors): > > Decoupled Refresh: Enabled*/Disabled > Relocate 256k/384k: Enabled*/Disabled > Video BIOS Cacheble: Enabled/Disabled* > System BIOS Cacheble: Enabled/Disabled* > > External cache scheme: Wr-Through*/Write-Back > Combine Alter & Tag Bits: Enabled*/Disabled > Memory hole at 15Mb Addr: Enabled/Disabled* > Cache Timing Control: Normal/Fast/Turbo* > DRAM Timing Control: Normal/Fast* > Fast DRAM: Enabled*/Disabled > Burst Write: Enabled/Disabled* > CPU Write Back Cache: Enabled*/Disabled > P24T Cache Replace BLAST: Enabled/Disabled* OK, at a guess I'd change these ones: > Cache Timing Control: Normal*/Fast/Turbo > DRAM Timing Control: Normal*/Fast > Fast DRAM: Enabled/Disabled* If that fixes the problem, it will also slightly slow down the machine (probably not enough to be noticable). If you really want to squeeze out the last 0.5% performance, you can then gradually try speeding things up. The trouble is, you can easily get the machine into a marginally unstable situation where it fails in strange ways only when your back it turned. Greg
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