Subject: Re: freezing the scsi bus
To: None <>
From: der Mouse <mouse@Rodents.Montreal.QC.CA>
List: tech-kern
Date: 07/10/1999 12:00:30
>> I could do this [...], except for [...].  I could [...], except for
>> [...].
>> Thoughts, anyone?

> FreeBSD does this by freesing for a defined amount of time (15s ...),
> all is done in kernel.  Would this be enouth ?

I don't like that alternative much, if only because 15 seconds isn't
always enough time.  (It usually is, but when I discover I've got the
wrong cable, and then drop the terminator, and have trouble getting the
disk plugged in, and, and, and....)

> Detecting a key press in userland while the bus is [locked] is not
> reliable,

I think Auspex does it this way, but they have some advantages my code
wouldn't: (1) they can count on their console being a serial line (the
program doesn't run if it's not on the console) and (2) they don't have
a gazillion different ports to different machines to contend with.

> and doing it in kernel may not be easy (port dependant probably ...).

That was the conclusion I came to.

Perhaps it could be done by freezing the bus in software, then dropping
into whatever ROM monitor the system provides - or into DDB, if it's
compiled in.  Then when the user says "continue", it picks up again.

					der Mouse

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