Subject: Re: SCSI/disklabel questions
To: Michael Wolfson <>
From: Jason Thorpe <>
List: port-hp300
Date: 06/29/1998 00:04:08
On Sun, 28 Jun 1998 12:29:10 -0400 (EDT) 
 Michael Wolfson <> wrote:

 > As for the SCSI speed business, I should've been a little more clear:
 > I've never seen more than ~700 KB/s under normal usage (tar, cp, mv, ftp).
 > Using dd to read and write null data, I can indeed get 1.5 MB/s, but
 > that's still 1/2 the thruput I get on other platforms.  

That's mainly because the controller driver does not support synchronous

 > In any case, David Brownlee mentioned that SCSI could be noticably faster
 > once we get the machine independent SCSI drivers ported to hp300.  So,
 > this is kind of moot if that happens anytime soon.  Same goes for the DAT
 > issue (i.e. apparently most DAT drives would be supported with MI SCSI).

Strictly speaking, using the MI SCSI code would not speed up your transfers.
That is purely a controller driver issue.  (Yes, the controller driver needs
to be rewritten from scratch.)

However, your observation about supporting most DAT drives is correct.

 > To:
 > Subject: SCSI/disklabel questions
 > How are the bootblocks and disklabel arranged?  As best as I can
 >     determine, the label sits at sector 1, and the boot blocks surround it
 >     at sector 0 and 2 thru whatever.  This would make sense since improperly
 >     installed boot blocks can be wiped out by disklabel and vice versa.

That is correct, the disklabel lives "inside" the boot block.

 > The install notes recommend ofsetting the a partition by one cylinder,
 >     which is fine for disks with small cylinder sizes, but how much space
 >     is really necessary for SCSI disks? much as it takes to keep the boot block (which spills into the C
partition, making it FS_BOOT) from spilling into the A partition.

 > What other NetBSD platforms can/can't write disklabel and bootblocks for 
 >     hp300 machines (I know sun3x, sun3, and sparc can't)?

Huh?  sun3x, sun3, sparc, and hp300 can all write boot blocks to the disks
and write disklabels to the disk.

 > And, lastly, can anyone comment on why the HP-IB isn't available when one
 >     or more SCSI devices are attached (i.e. can't use HP-IB drives or
 >     tapes if a SCSI drive is plugged into my 400s)?  This used to work
 >     thru NetBSD-1.1.

"Um, I don't know."  I have used HP-IB and SCSI at the same time on my
hp380.  Define "can't use" .. they don't probe, a timeout occurs when they
are accessed, what?  I need specifics here :-)

Jason R. Thorpe                             
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