Re: Waiting 15 seconds for SCSI devices to settle *groan*

[Bill Hacker <wbh@xxxxxxxxxxxxx>]

Wade wrote:

> On 02/12/05, Emiel Kollof <coolvibe@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. :-(