Path: utzoo!attcan!uunet!aplcen!haven!umbc3!bernie From: bernie@umbc3.UMBC.EDU (Bernard J. Duffy) Newsgroups: comp.sys.sgi Subject: Re: Pinnacle Magneto Optical Disks Message-ID: <4060@umbc3.UMBC.EDU> Date: 2 Oct 90 16:46:38 GMT References: <216*finn.drablos@sintef.no> Reply-To: bernie@umbc3.umbc.edu.UMBC.EDU (Bernard J. Duffy) Organization: University of Maryland, Baltimore County Lines: 82 In article <216*finn.drablos@sintef.no> finn.drablos@sintef.no (Finn Drablos) writes: >In our everlasting hunt for more disk space we have started to think >about magneto optical disks. We have been contacted by a company >selling Pinnacle systems, and we have been looking at the REO-650 >disk. It is a SCSI disk, and we want to connect it to a 4D25TG. But ... Finn, If you get an Optical drive working on a 4D25TG, let me know.... We've tried Genesis' Sony drive on our 4D/25 (that good old Sync SCSI) and it didn't work. It had a nasty problem when formating/testing platters where it took over the I/O SCSI system while it was doing the many read/writes to the drive. The system basically "hung" still and resumed after the operation was completed. I don't know if we were expecting too much, but the hard drives (CDC / WREN V[II]) units would not do that when we would do the fx -x format. We do one of their units on a 4D/220 and also had it on a 4D/20 (PI-Async SCSI) and it didn't have this side effect. We also tried Q-systems' unit and got similar problems. It also had some boot up problems where it failed the diags. and the IRIX would prompt for "Hit return to continue". Since we were having such a hard time with the optical drives, we decided to get 2 hard disks (760Mb) and an 8mm tape drive. The drives, which I believe operate in either SYNC or ASYNC SCSCI modes, have performed like all the other hard drives I have "sucessfully" placed on other machines. I quoted "sucessfully" because we had 4D/2xx systems that ran diags the drive could not handle. The Genesis OS patch in accidently fixed this problem. The 4D/20 systems never had any such problems (yeah for the ESD folks). It's been a real treat to hear that "SCSI termination" cry for the SGI folks. That battle cry only came from the ASD folks where they expected folks to be using SGI drives or ones that responded like SGI drives to SCSI commands few people or OSs use (connect/disconnect). The 8mm (Exabyte) has been difficult and I'm still trying to get it to work with the 2 extra drives. I have got it to work with just the one " /, /usr, swap " disk. It also "breaks" the boot up diags which results in my favorite "hit return to continue". I'll be trying the "C" (capital C boot flag) later today. If anyone has an 8mm working on a 4D/25 let me know. For you folks who need to deal with "SCSI termination" take this advice from my experience with 8 disk drives and 3 optical drives from vendors other than SGI (aka 3rd party) : Stick with the silver termination connector on the end of your SCSI bus (chain). With that setup, removal all SIPs, transistor packs (sp?) that provide "internal termination". Also set the power for the termination (TERMINATIOR POWER) to external. On most SCSI boards it's the first two jumpers of about 8 ... generally it's configured in the horizontal position : . . . . . . . the others are used to set the SCSI id --------- You can also leave it off, but we don't | . . | . . . . . want to be collecting these jumpers. --------- Remember one other thing : the SCSI id's only range from 0 to 7 , BUT one of them is used by the controller. I accidently set a device's id to 0 on a SGI and found out the odd way (no damage... the system's diags tried to communicate with a tape drive for SCSI checks ) There's one other thing... In contradiction to the SCSI "standards", some SCSI devices "require" to be placed in a particular order on a SCSI bus in order to work. They operate as if there was a termination problem when they were placed in the "wrong" spot. Typically this means the unit wants to be closer to the SCSI controller. I haven't had this problem with any of the hard drives I've installed. Sorry for the long message... it's just I've suffered enought with the cold war on this termination stuff / 3rd party devices / SCSI devices you had prior to moving up to a SGI. Bernie Duffy ... SCSI victim -- Bernie Duffy Systems Programmer II | Bitnet : BERNIE@UMBC2 Academic Computing Services - L005e | Internet : BERNIE@UMBC2.UMBC.EDU Univ. of Maryland Baltimore County | UUCP : ...!uunet!umbc3!bernie Baltimore, MD 21228 (U.S.A.) | W: (301) 455-3231 H: (301) 744-2954