[SunRescue] Sun SCSI hard drive IDs

[Matthew Haas]

On Tue, 14 Sep 1999, Paul Pries wrote:
> 
> Concerning the SCSI priority chain there is a reason for this swap... :)
> If I remember correctly, the higher the address the higher priority the device
> han on the bus. Having the system disk on id0 will give it the lowest priority
> thus decreasing system performance. Letting it have id3 should be a nice
> middle way thing, giving the system disk a better response, yet having some
> higher priority addresses left for devices that need a higher priority to do
> their job, like tape devices and other slow things.
>

That actually makes a lot of sense... and especially for power tweaking
systems for max performance. I had since switched my two drives, so my
main drive is now ID1, but I don't know how much of a performance boost
would occur by running it as ID3... thanks for the info though.

That ID priority leads me to another question:

When daisy chaining devices off the SPARC (for me a CD-ROM on ID6 and my
other hard drive on ID3), does it make any difference which order they are
plugged in with regard to the SPARC? If the onboard SCSI controller uses
ID7 (I'm assuming),  should the devices be plugged in ID6 then ID3? Or
does it not matter... and I also assume there is no significance between
the upper and lower SCSI port on the 411 cases. And is any sort of
termination needed after a while? I've got a passive SCSI terminator which
can be stuck on or removed from the chain and it seems to make no apparent
difference.

Two more quickies:

In the PROM (2.9) on my LX... I assigned an arbitrary value of "linux" to
boot-file using its nice happy setenv command... after I did this I
realized if I ever wanted to try booting solaris off a CD it wouldn't be
straightforward... so... is there anyway to nullify boot-file back to its
default?

I read in the LX manual that the LX has an RS232 serial port capable of
"19200"... yet on bootup I am seeing the Zilog serial chipsets and such...
what is the serial capability of the LX? Can it handle 28.8 or 33.6k?

Thanks.
> 
------*-*-*----------------------------------------<< 207.127.232.247 >>--
      * * *       Atari 8-bit!  Battlestar: Galactica * DESCENT * 486
      * * *      400/800/XL/XE  Star Wars * SeaQuest * Voltron * Summer
  *  *  *  *  * 2600/5200/7800  Star Trek * WarCraft II * SPARCstation 2
   **   *   **  
--Slackware 4.0/Debian SPARC 2.1------!  ! ! L I N U X ! !  !-----2.2.12--