Date: Wed, 30 Sep 1998 12:54:58 -0500 From: Karl Denninger <karl@Denninger.Net> To: Tom <tom@uniserve.com> Cc: Dan Nelson <dnelson@emsphone.com>, Alfred Perlstein <bright@hotjobs.com>, current@FreeBSD.ORG Subject: Re: Long IDE probes? Message-ID: <19980930125458.A4304@Denninger.Net> In-Reply-To: <Pine.BSF.4.02A.9809301028550.7309-100000@shell.uniserve.ca>; from Tom on Wed, Sep 30, 1998 at 10:31:25AM -0700 References: <19980930113836.A4061@Denninger.Net> <Pine.BSF.4.02A.9809301028550.7309-100000@shell.uniserve.ca>
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On Wed, Sep 30, 1998 at 10:31:25AM -0700, Tom wrote: > > On Wed, 30 Sep 1998, Karl Denninger wrote: > > > IDE by definition is probed by the BIOS before boot. Either the disk is > > there or it is not, and you don't get out of POST and to Boot until that's > > determined. Therefore, a long wait there is COMPLETELY pointless. > > Huh? First of all, more than disks can be put on IDE, and the BIOS > doesn't know anything about that. Most BIOSes don't probe IDE at all, but > newer ones do it to avoid static settings in the CMOS. The hell it doesn't. I've got several machines with IDE hardware in them. All of them find things like CDROMs during the boot sequence (before loading an OS). > > SCSI devices similarly are probed by the adapter BIOS. Again, there is no > > reason for the long wait that I can fathom. > > For convienance only. Some adaptors don't probe. The adaptors don't > make this info available to the OS in any way, because the OS is supposed > to probe. The point isn't that probing is bad (its not). The point is that once the BIOS has taken the delay for spin-up, sent START commands to SCSI disks, etc., waiting AGAIN is a waste of time. Are the delay lengths reasonable? I don't know. Aren't there specs on this stuff from the IDE and SCSI camps? -- -- Karl Denninger (karl@denninger.net) http://www.mcs.net/~karl I ain't even *authorized* to speak for anyone other than myself, so give up now on trying to associate my words with any particular organization. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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