Date: Thu, 20 Feb 1997 15:37:15 +1100 From: Bruce Evans <bde@zeta.org.au> To: bde@zeta.org.au, msmith@atrad.adelaide.edu.au Cc: hardware@freebsd.org, se@freebsd.org Subject: Re: _big_ IDE disks? Message-ID: <199702200437.PAA19813@godzilla.zeta.org.au>
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>> I checked the specs for it. It really can do > 8MB/s except >> possibly on the inner tracks. > >Yup, this was a basic criteria for it being used instead of a SCSI >disk; by the time you compensate for the extra CPU overhead, I figured >that it would make a reasonable alternative to a ~3M/sec SCSI disk >(which was not available 8( ) The DORS-32160 is 5-6MB/sec, but you only nead a FireballTM to compete with that on transfer speed :-). >> from the buffer cache. If the CPU is a P5/166, then i586-optimized >> copyout is apparently not being used. I think the overhead would be >How do I go about ascertaining this? npx0 is enabled, and the kernel >was build with I586_CPU defined (obviously). The kernel it's running >is built with npx.c v 1.31.2.5. I can't think of a better way than using `cvs log'. It was reenabled in npx.c 1.31.2.6. Other ways: run a debugger and look at the vectors. Run `dd if=/dev/zero of=/dev/null bs=1m count=1000' and complain if the throughtput is much lower than 120MB/sec. Bruce
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