lynch@batcomputer.tn.cornell.edu (Tim Lynch) (08/29/89)
We are considering adding a gigabyte or two of disk storage to an RT. Not having any experience in this, can someone make some recommendations? We can manage to get the cover off and do things like install controller cards. No problem there. What we are after isadvice on what disk vendor to consider, what controller cards might work, and what doesn't work, etc. Is SCSI available for the RT? How about 1/2 inch tape drives? Thanks for any leads, pointers, etc. Tim Lynch, Manager Chemistry Research Computing Facility Cornell University
buck@siswat.UUCP (A. Lester Buck) (08/30/89)
In article <8727@batcomputer.tn.cornell.edu>, lynch@batcomputer.tn.cornell.edu (Tim Lynch) writes: > We are considering adding a gigabyte or two of disk storage to an RT. Since the RT has an AT bus, you might say you are thinking of adding a gigabyte or two of disk storage to an AT. Gee, now you start to see some problems... > Not having any experience in this, can someone make some recommendations? > > We can manage to get the cover off and do things like install controller > cards. No problem there. What we are after isadvice on what disk vendor > to consider, what controller cards might work, and what doesn't work, etc. > > Is SCSI available for the RT? How about 1/2 inch tape drives? > > Thanks for any leads, pointers, etc. > > Tim Lynch, Manager Chemistry Research Computing Facility > Cornell University Yes, IBM supplies a SCSI host adapter for the RT, about $1100 list, I think. A separate set of SCSI drivers, available from your IBM rep (written in Austin), allow using Exabyte and 1/2" 9-track tape. As far as adding SCSI disks to an RT, you can use the IBM 9332, in 200 and 400 MB units (actually the 400 MB unit is a two logical unit disk in one package). But their prices are outrageous and this is 14"(!) technology, so I don't recommend them. [The IBM RT SCSI host adapter and VRM driver are about the worst SCSI implementation I have ever seen, and errors keep popping up. Just do a search on the IBMLINK problem list.] I do SCSI systems integration consulting and I got some CDC 8" SCSI drives running on an RT. These were the 1.2 GB/drive units. Under heavy use, they tended to drop off the bus for some reason that we didn't track down before sending them back. It could be either a CDC or IBM glitch. This problem might only show up with multiple SCSI drives, too. The problem with using third party SCSI disks is that they must be formated ahead of time and you must use the default mode select setup. If you must reformat or change the factory defaults at any time, then you must write your own RT AIX driver to access the VRM SCSI driver directly and give your own set of SCSI commands. This was no problem for me, since I already had the code designed, written, and debugged, but starting from scratch, this is a major undertaking. Other than that, you can use all IBM code and drivers for foreign SCSI disks (including mounting normally with the minidisk manager). You might also consider using the 15MHz ESDI drives with the IBM portable controller. I helped a client get that running, but there is a bug in the Installation and Maintenance disk formating routines that dumps core on large disks. You must munge the example disk driver on the "Device Driver Development Guide" disk to get access to the raw disk (bypassing the minidisk manager) and build the necessary bad track tables and minidisk partition table as documented in the VRM Tech Reference. Again, this is not exactly a trivial operation. Of course, in all of this, don't expect any help from IBM at a useful technical level, since all the IBM hot shots who originally worked on the RT jumped from that sinking ship long ago. It is entirely possible to ask questions that virtually no one can (or will) answer about VRM internals. -- A. Lester Buck ...!texbell!moray!siswat!buck
drake@sd2.almaden.ibm.com (Sam Drake) (08/31/89)
In article <8727@batcomputer.tn.cornell.edu>, lynch@batcomputer.tn.cornell.edu (Tim Lynch) writes: > Is SCSI available for the RT? IBM sells a SCSI adapter for the RT, and sells SCSI drives, the IBM 9332, which work on the RT. We're using about 2GB of 9332s on a server, and it all works fine. I'm not an official spokesman, nothing I say is correct. :-) Sam Drake / IBM Almaden Research Center