Waiting 15 seconds for SCSI devices to settle *groan*

[Bill Hacker]

Wade wrote:

On 02/12/05, Emiel Kollof <coolvibe at xxxxxxxxxxxxxxxx> wrote:

See subject for a pet peeve I've had for a while...

Might it be an idea to copy FreeBSD here and shorten that to, say, 
5 seconds by default? I know it's tunable, but it will shorten boot
 times a bit for people that are too lazy like me :)

That and 15 seconds seems a bit too long. Know of any hardware that
 actually needs that long to settle in? (and don't you guys go dig 
up the most antiquated SCSI peripherals that actually do need 15 
seconds ;) ) If yes, I'll just shut up about this.

Cheers, Emiel --


The real pain for me is, with GENERIC (eg, installation kernel), you
 end up waiting that time even when you don't have SCSI, can't it 
detect that theres nothing but IDE ?

It can nowadays, but could not in times past. (SCSI user since year ONE
and SMD before that).
Older on-device controllers said nothing to the host until they had all
their ducks lined up, so if you did not wait, you would not know they
were there w/o a re-scan.
And you might be unable to do that re-scan if the host-bus controller
had not seen devices and not grabbed a place at the table by loading its
BIOS code at boot time. (CP/M-86 & OS/2 anyway - FreeBSD was not yet a
factor..)
Newer on-device chips are *way* smarter, and will speak to the host
'instanter' with info about what they are (supposed to) have coming up,
so the host-bus controller will load its BIOS and report sizes, etc.
But nothing I still use regularly [1] needs even a 1 second delay - most
of it is reporting-in from silicon before system-board BIOS POST is
complete.  Motor spin-up is no longer the determinant.
Bill Hacker

[1] Discounting a still working pair of 20 MB beta Bernoulli II, a pair
of Syquest Puma 88, an NEC 2X 'MultiSpin' CD reader,
and such. Which get switched almost as seldom as the S-100 gear.
Makes one appreciate how much progress has been made. And shed
fewer tears over what one has *spent* on it over a lifetime. :-(