[rescue] Sun Ultra 2 SCSI issues

Curtis H. Wilbar Jr. rescue at hawkmountain.net
Sat May 24 02:14:24 CDT 2003

>From: "Ryan Thoryk" <ryan at tliquest.net>
>To: rescue at sunhelp.org
>Date: Sat, 24 May 2003 01:49:45 -0500
>X-OriginatingIP: (ryan)
>Subject: [rescue] Sun Ultra 2 SCSI issues
>I've got a great Ultra 2 system (dual 250mhz, i love it), but weird stuff's
>been going on with the SCSI bus that the cdrom's connected to.  I replaced the
>old cdrom drive it had with a much newer Yamaha cdrw 8x8x24 drive.  I also
>tested the cabling, and it's fine too.  Now I know there's 2 scsi connectors
>on the motherboard, but for some reason the drive doesn't work on the left
>one; only the right.
>The problem is that some cds will have enormous amounts of read errors (I had
>huge troubles installing Solaris 9), and the drive freezes up sometimes and
>then slows down along with a bunch of head movements (both drives do the same
>thing).  I tested both drives on a Sparcstation 5 i've got, and they work
>perfectly on there.  Everything else works perfectly on this system.

If it weren't for the fact they work on another system fine, I'd say drive

Not sure how SCSI termination is done in an Ultra 2, but maybe you've got
an unterminated end of the buss, or a double terminated end, or some
termination in the middle....

>Another question I have deals with a Linux server I run (pc x86 dual ppro
>It's got a pnp/non-pnp switchable 56k modem for dialins (i love that modem so
>much), and a nice large DSL line.  The modem is set to use COM3 with irq4 and
>seems to be locking the whole system up usually after it hangs up the line,
>seemingly only on external dialins, not dialouts.  I have an mgetty setup
>along with pppd.  No messages can get dumped to the syslog because the freeze
>is more hardware related.  Has anyone experienced something like this before?

Is anything sharing IRQ4 (COM1 will use IRQ4 by default) ?
If COM1 is at IRQ4, is antything using it ?
If you don't need COM1 or COM2 and can disable them as to not exist,
then my standard suggestino would be disable COM2, and setup the modem to
be COM2.

Generally I hate IRQ sharing.... it is IMHO dangerous in the least, and
sometimes flat out doesn't work at all (even when it "should").

Generally I'm also finding the more tidbits I learn about X86 architecture
the more I hate it.  So many things about it just make me quiver.  It is
great to be able to still run DOS programs from the 1980s (in theory anyway)
but our modern computers have some really ugly "hacks" to keep all of
this backward compatability... ick ick ick...

The last thing I read (in an Intel motherboard doc as I recall) had to
do with explaining PCI interrupts and how they get mapped by some hardware
to ISA IRQs (which we all know there are not enough of).... an interesting
thing was it could deap with mapping the IRQs that way or another way
(which sounded a bit better) under OS control.... gotta wonder if PC
Unixes (Linux, BSD, etc) do this, or if they just stick with the PCI->
ISA IRQ mapping.... (for anyone interested the manual was for the 440GX+

>Ryan Thoryk
>Unix and Network Specialist
>ryan at tliquest.net
>rescue list - http://www.sunhelp.org/mailman/listinfo/rescue

-- Curt

Curtis Wilbar
Hawk Mountain Networks
rescue at hawkmountain.net

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