🚀 go-pugleaf

In article <1410034@hpcvca.CV.HP.COM> charles@hpcvca.CV.HP.COM (Charles Brown) writes:
>[stuff deleted]
>
>The particular spec involved the time from reset to ready.  The
>Commodore will not autoboot if that time is greater than (as I recall)
>four seconds.  The Miniscribe appears (from my informal measurements)
>to take about 5 seconds if warm booting with the head on track 2,
>about 8 seconds if warm booting with the head near the middle track,
>and about 14 seconds from power up.
>
The problem is not the time from RESET to ready, but the time from RESET
to response to commands.  Seagate drives have this same problem.  When the
drive is spinning up from cold start, it does not respond to selection at
all.  This looks to the driver software as if no drive is hooked up.  The
solution is to try for selection, if it fails wait a second and try again
up to a timeout limit.  However, SCSI drivers have to check 7 distinct
SCSI bus addresses to see if drives are hooked up (there is a way under
the new RDB scheme to shortcut this check, but that`s not important here).
If the driver were to assume that all drives took at least 5 seconds to
spin up, that would be 7*5 = 35 seconds of dead time on a cold boot.  Since
the majority of drives respond correctly, it does not make sense to
compromise systems with good drives for the few with bad ones (bad meaning
badly behaved).  This problem has been (sort of) addressed on the A590 and
A2091 by having a "Seagate" jumper on the board.  If this jumper is
installed, much longer timeouts are allowed when cold booting the system.

	Steve