Date: Thu, 31 Aug 1995 17:57:02 -0700 From: "Justin T. Gibbs" <gibbs@freefall.FreeBSD.org> To: "Rodney W. Grimes" <rgrimes@gndrsh.aac.dev.com> Cc: FreeBSD-hackers@freebsd.org Subject: Re: 4GB Drives Message-ID: <199509010057.RAA03740@freefall.FreeBSD.org> In-Reply-To: Your message of "Thu, 31 Aug 95 17:51:02 PDT." <199509010051.RAA13303@gndrsh.aac.dev.com>
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>> Hmm. Are you sure that the drive will not disconnect even for a short time >> after receiving its command? > >Darn sure, I effectivly disabled disconnect/reconnect by tweaking the >buffer full/empty ratios and a few other parameters in mode page 2. Why not just turn off disconnections in SCSI-Select? :) >> >The data I need is being very difficult to obtain without spending major >> >dollars on a scsi bus analyzer and a large logic analyzer :-(. I guess >> >I could go out to the labs some weekend, but it is a pain to check in this >> >much equipment. >> >> I would think that a scope attached to the led line would be sufficient >> for most of the timing. > >Yes, it should be, but if I have things like command queueing occuring I >can not correlate the edge created in the stripe layer with the edge >created by the LED, it may be skewed by 1 cycle. Or I could go get a >$10k storage scope and use single events :-). You will need to pause the sequencer in order to change the status of the led anyway if you do it from the kernel, so the edges should be distinguishable between kernel blinks and sequencer blinks. >-- >Rod Grimes rgrimes@gndrsh.aac.dev.com >Accurate Automation Company Reliable computers for FreeBSD -- Justin T. Gibbs =========================================== Software Developer - Walnut Creek CDROM FreeBSD: Turning PCs into workstations ===========================================
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