[comp.periphs.scsi] Faster boot with AHA 1542 SCSI cont

neese@adaptx1.UUCP (05/31/91)

>/* ---------- "Faster boot with AHA 1542 SCSI cont" ---------- */
>Is there a way to shorten the boot time on a machine with an Adaptec SCSI
>controller? On my machine it takes almost a minute, an ESDI machine with
>the same autoexec and config is up in less then 15 seconds.

Consider this:
The 1542 has to figure what is out what is on the SCSI bus and then determine
which devices can be supported through the BIOS and then tell the system what
the parameters are for the drive, which we can't do until the drives are ready
on the SCSI bus.  A lot of this depends on the SCSI drive itself.  Some take
longer to become ready after a bus reset than others.  Some can take quite
a while, at power-up, to be ready.
An ESDI drive is in the CMOS table, so the system can make some assumptions.
1) The drive paramters are in the CMOS table. 2) There is a drive attached

The drive you are using on the SCSI bus will have the greatest impact.

			Roy Neese
			Adaptec Senior SCSI Applications Engineer
			UUCP @  neese@adaptex
				uunet!cs.utexas.edu!utacfd!merch!adaptex!neese

neese@adaptx1.UUCP (05/31/91)

>In article <ben.3234@epmooch.UUCP> ben@epmooch.UUCP (Rev. Ben A. Mesander) writes:
>>In article <1992@styx.sta.sub.org> stimm@styx.sta.sub.org (Stefan Timm) writes:
>>>Is there a way to shorten the boot time on a machine with an Adaptec SCSI
>>>controller? On my machine it takes almost a minute, an ESDI machine with
>>>the same autoexec and config is up in less then 15 seconds.
>>
>[..stuff about system checking deleted..]
>>
>>So try to think of the delay as your friend; checking your hardware before
>>your computer gets to by attempting to use it. A minute out of your day
>>is not much to ask...
>
>It is too much if you have to reboot your machine (for various reasons)
>several times an hour (or even several times a day), especially if you
>know the devices are ready!

Ah!  You know the drives are ready, but the 1542 doesn't.  It resets the bus
at a CPU reset and that causes the SCSI devices to go through all the
self test/diags as well as the 1542 doing it's diags.
We have to assume if you reset the bus, there may be a problem you need to
clear, so we reset the SCSI bus in case that is the problem area.

			Roy Neese
			Adaptec Senior SCSI Applications Engineer
			UUCP @  neese@adaptex
				uunet!cs.utexas.edu!utacfd!merch!adaptex!neese