Octane and wide scsi?
Vanne de Castle
uhmm, ive got a little problem with my Octane, it seems the external
scsi connector on the back is of the wide format, while my external
cd-rom is of the narrow kind (ie for myIndy and Indigo2).... sigh
how do i go about connecting this thing up? or would it be just easier
to use a twisted pair and connect up a network between 2 sgi boxen?
if so, any FAQ's regarding the network setup i should read to get this
going? i would prefer just a cable, but i havent found one yet...
Vanne
Dr. David Kirkby
end and 50 at the other. They generally seem to work with Suns, but
I've no idea about SGI Octanes.
The problem with such cables is that while the low byte of the scsi
connection gets terminated on your CD-ROM, the high-byte remains
unterminated. Whether or not the Octane has suitable circuitry to
terminate its own high-byte, leaving the low byte unterminated I don't
know. Either the user or service manual should state that - both of
which you can download.
One option, that is technically better, is to use a 68-50 pin
converter, monted directly on the Octane, with a 50 -> 50 pin cable
connecting that to your CD. You can get these from Adaptec that have
termination for the high byte built in. They don't terminate the low
byte - that you would do on your CD-ROM. However, they are not cheap.
I'd be tempted to spend less money on a used Sun 611 box, with an
external SCSI connector. These sort out termination automatically and
are very convenient. A couple of LEDs on the rear indicate if the low,
high or both bytes are being terminated. Sun 611 boxes are readily
available on eBay. They come in two types - one with a cutout for a
CD/tape etc, and the other with a closed face for a disk. Clearly you
would need the former.
Sorry I have not really answered your question - due to my lack of
knowledge specially of Octanes. However, hopefully I've explained why
going from 50 to 68 pins can causes SCSI termination problems and how
to be sure to avoid them.
--
Dr. David Kirkby,
Senior Research Fellow,
Department of Medical Physics,
University College London,
11-20 Capper St, London, WC1E 6JA.
Tel: 020 7679 6408 Fax: 020 7679 6269
Internal telephone: ext 46408
e-mail da...@medphys.ucl.ac.uk
muller
> scsi connector on the back is of the wide format, while my external
> cd-rom is of the narrow kind (ie for myIndy and Indigo2).... sigh
The Octane seams to be VERY fuzzy about external SCSI devices. You should
use a cable that terminates the 8 bits not used.
I got this from Reinhard Wolf:
http://www.intos.de, click in "Bitte Produktgruppe wählen" and select
"SCSI Kabel", thence click in "Untergruppe wählen" and select "SCSI
III (UW) Kabel mit Terminierung".
/Muller
Ian Mapleson
> The Octane seams to be VERY fuzzy about external SCSI devices. You should
> use a cable that terminates the 8 bits not used.
Strange, I use a 32X TEAC in an external case with Centronics 50-way
connectors just fine with my Octane (R12K/300 running 6.5.17m) just
with a simple ordinary 68/50pin cable.
Ian.
Robert PHAM
This wouldn't happen to be a Teac CD-532S? If yes, did you have any
problem getting audio over SCSI to work?.
TIA
Cheers
Robert
Benjamin Gawert
>> uhmm, ive got a little problem with my Octane, it seems the external
>> scsi connector on the back is of the wide format, while my external
>> cd-rom is of the narrow kind (ie for myIndy and Indigo2).... sigh
>
> The Octane seams to be VERY fuzzy about external SCSI devices. You
> should use a cable that terminates the 8 bits not used.
The Octane works perfectly with cables that don't terminate the upper 8
Bits. I'm using cables without termination for several years now on various
Octanes with various devices, and not had a single problem that could be
solved by using a cable with termination....
Benjamin
Gerhard Lenerz
> The Octane works perfectly with cables that don't terminate the upper 8
> Bits. I'm using cables without termination for several years now on various
> Octanes with various devices, and not had a single problem that could be
> solved by using a cable with termination....
Too bad mine doesn't know that. It refuses to pass POST with the
external Plextor attached via a 68pin/50pin HD cable (from Reichelt).
Gerhard
James Holden
I'll (almost) second that. I know it's not Octane, but my O2 has it's
system disk externally with a similar cable. No termination on the
high bytes and it all works just fine.
James
mike
I'll kinda third that :)
I've always used 68 to 50 pin cables on my CD drives, DAT drives, etc.. on my SGI's and never
with any problems.
If you look at the octane owners manual, it even states you can use a 68 to 50 pin cable:
"To daisy-chain an Ultra SCSI device to a Fast SCSI device, use a 68-pin to 50-pin Centronics
Fast SCSI cable. "
cheers!
mike
Wolfram Schubert
> Too bad mine doesn't know that. It refuses to pass POST with the
> external Plextor attached via a 68pin/50pin HD cable (from Reichelt).
Take a look at /var/sysgen/system/irix.sm and make an entry like that:
DEVICE_ADMIN: /hw/node/xtalk/15/pci/1/scsi_ctrl/1 ql_wide_enable=0
This sets your external SCSI bus to narrow(8bit)-mode. You can make
further entries for disabling wide-mode on selected scsi targets, just
read the examples there.
After saving, rebuild the kernel & reboot:
autoconfig -v (or -vf)
HTH,
Wolfram.
Btw - I use Reichelt BstNr. AK SCSI 121 (68->50pol Centronics) and AK
SCSI 121-11 (69->50pol Mini), both work with all my external devices
(Plextor 12x, Teac CD-R58S, 532S, HP 5p).
Benjamin Gawert
>> The Octane works perfectly with cables that don't terminate the
>> upper 8 Bits. I'm using cables without termination for several years
>> now on various Octanes with various devices, and not had a single
>> problem that could be solved by using a cable with termination....
>
> Too bad mine doesn't know that. It refuses to pass POST with the
> external Plextor attached via a 68pin/50pin HD cable (from Reichelt).
I'm using the same cables from Reichelt without problems. My Octanes were
also complaining when connecting my PX32TS CDROM to the external port, but
since they also did that with a terminated cable, and since the cheap cable
from Reichelt worked perfectly with other devices like an HP external CD
Recorder, or an ADIC DLT, I suspected it can't be the cable and wrote to the
Plextor support. They sent me a new firmware EEPROM for free, and now the
Plextor drive works perfectly with the Octane...
Benjamin
Vanne de Castle
and how much?
(the cable i mean :)
Vanne
Ian Mapleson
> This wouldn't happen to be a Teac CD-532S? ...
Indeedy it is!
> ... If yes, did you have any
> problem getting audio over SCSI to work?.
Never tried I'm afraid. I don't have space yet to plug in the speakers. :(
Yours,
Ian.
Gerhard Lenerz
> I'm using the same cables from Reichelt without problems. My Octanes were
> also complaining when connecting my PX32TS CDROM to the external port, but
> since they also did that with a terminated cable, and since the cheap cable
> from Reichelt worked perfectly with other devices like an HP external CD
> Recorder, or an ADIC DLT, I suspected it can't be the cable and wrote to the
> Plextor support. They sent me a new firmware EEPROM for free, and now the
> Plextor drive works perfectly with the Octane...
beginning to wonder if it is a termination problem, as I am not sure if
the terminator I am using is active or not.
Speaking of the Plextor: After all the various kinds of machines I installed
from it, this weekend it did "fail" for the first time (on an old VAX
Workstation).
Gerhard
Gerhard Lenerz
> I'll check that with some other external SCSI device. Personally I was
> beginning to wonder if it is a termination problem, as I am not sure if
> the terminator I am using is active or not.
Aha. Using internal termination on the Plextor all works fine. Ok, I
didn't check everything, but now the machine boots. So it was a typical,
yet unexpected, termination problem.
Gerhard