SUMMARY: SCSI disk on SPARCServer 490

From: Serkan Cil (
Date: Fri Feb 10 1995 - 07:19:50 CST


has anybody ever connected a SCSI disk on a SPARCServer 490 SCSI bus?
What are the limitations? Does it have to be a SCSI-1 disk? Can a
SCSI-2 disk work well? Or should I forget about it?

Response Summary:

. One can connect a SCSI disk to a 490.
. The transfer mode on the SCSI bus is limited to only async transfers.
  So the disk must support async transfers.
. Actual operating mode is SCSI-1. But, because SCSI-2 standard involves
  SCSI-1 commands (i.e. it is backward compatible) a SCSI-2 disk does not
  make trouble.
. The problems encountered are mainly
      the poor performance when compared with IPI disks
      sometimes "reset errors".

Original Responses:

I thank to all sun-managers listed below:

"Dugal James P." <>
John DiMarco <>
Steinar Haug <> (Kevin Sheehan {Consulting Poster Child}) (John Justin Hough) (Martin Achilli) (SJ Higa)
Mike Rembis 66520 <>
Curt Freeland <>
robert@Rational.COM (Mike Phillips 3788)

From: "Dugal James P." <>

Serkan, I have three 4/490 servers (running SunOS 4.1.3_U1)
and I use the original SCSI controller with several disks which
I believe claim to be SCSI-2: Micropolis 1908 and 1924.
I also have an Exabyte 8500 tape unit (5GB). No problems seen.
I hate to think of the performance we've given up by using such
a slow SCSI controller, though.

We had to add a SCSI tray to the original chassis.


John DiMarco <>

... A SCSI-2 disk won't normally use SCSI-2 features unless the controller asks for it. You should be fine unless you configure your disk to initiate synchronous negotiation on power-up, which will confuse the asks for it. You should be fine unless you configure your disk to initiate synchronous negotiation on power-up, which will confuse the SCSI controller.


Steinar Haug <>

We used to have a 490 with various SCSI disks attached, both SCSI-1 and SCSI-2. The SCSI controller on the 490 is only SCSI-1, so you won't be able to use any of the SCSI-2 features like synchronous transfer - but in general it'll work just fine. It worked for us.


... SCSI-1/SCSI-2 should both work as I recall. Same rules as for the other early esp interfaces.

--- (John Justin Hough)


I hooked an older SCSI CDROM too it with out problems, so that if it were one of the older 669 or 324MB Hard Disks it would probably work. There are problems when you try to use SCSI-II devices on a SCSI-I bus. If the target device won't "auto down grade" then you'll be out of luck. This happenned ealier in the week when we tried to use a 424MB (Seagate SCSI-II drive in synchronous mode) hard disk from a Sun in a year old Mac (external SCSI is SCSI-1).

--- (Martin Achilli)

We have a SparcServer 4/470 with 5 SCSI disks and a tape drive connected to it. There is also an IPI controller with two IPI disks.

The SCSI disks are SCSI-I type, but I have also connected a SCSI-II disk drive with no problems. You will need the appropriate cable and terminator if the disk is external, otherwise I think you can install the disk internally. I'm not sure how the 4/490 is different from the 4/470, they should be quite similar.

To install an insternal disk you must

1. remove the front panel, I think you just snaps off 2. at the top of the cabinet you will see a number of screws, these hold a sliding metal cage. 3. onnce you have unscrewed you must pull out the metal cage 4. you then remove the lid of the metal cage by unscrewing 5. IF the 4/490 is the same as the 4/470 you can install up to 4 full height 5 1/4 inch devices in the tray, if there is already a tape drive you can only install three full height devices 6. if you are missing the power cables or the SCSI cables I would make them, that's what I did. Otherwise you have to figure out with Sun the part number, order them... wait a long time... they are pretty simple standard cables 7. the same goes for the screws to hold the disk drives. Just buy them yourself 8. Remember to set the SCSI id's correctly, IF the 4/490=4/470 you also need a short SCSI cable from the cpu board to the cage. In this case you must terminate internally your last SCSI device.

--- (SJ Higa)

We had a 490 here a few years ago that needed more disk space. I connected two SCSI-1 disks (SPARC 1+ P-boxes) to the 490's SCSI port. I had no problems with this setup. Of course, the performance was not comparable to the IPI disks inside the 490; but this was only meant to be a temporary solution. I think SCSI-2 disks should work also.



We used to run SCSI disks on both the onboard SCSI bus and on a second SCSI controller on our 470s ( same cpu as a 490 just in a pedastel cabinet) no problems at all both SCSI 1 and SCSI 2 disks as I remember it. We have since upgraded the 470s to 670s and replaced the VME SCSI controller with S-bus ones and added differential SCSI ( as well as the IPI that have always been on it)


Mike Rembis 66520 <>

SCSI-1 ----- no problem.

SCSI-2 ----- sometimes reset errors - nothing major experienced here.

--- (Paulo Licio de Geus)

I've done thsto a 390, which is close to the 490. No problems with the SCSI disks I plugged in (only 100 and 200 MB by then, I think).

The interface has limited speed, but I think it should work with all current drives.


Curt Freeland <>

... I have Fujitsu M2654ESA and Seagate ST12400N drives (both are SCSI-II) on two different 4/490 systems.



... No special requirements necessary as far as scsi1 or scsi2 are concerned (as long as you use the apprpriate host adapter). but I did it as an FE at Sun. That's what the cage above the card cage is. If you have an 8mm tape inside the system, the disks will go in the same place as the 8mm. Just remember, disks are addressed as scsi id's 0-3, tapes are 4 & 5, and CD's are 6.

--- (Mike Phillips 3788)

Have done it on a 470 with 3 x SCSI-2 disks with no problems.

______________________________________________________________________ Serkan Cil, UNIX Systems Admin. e-mail: Bilkent University phone: 90 (312) 266 4000/2293 Computer Center fax: 90 (312) 266 4126 Bilkent, 06533 Ankara, TURKEY ----------------------------------------------------------------------

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