neil@uunet.uu.net (Neil Gorsuch) (05/16/89)
I recently posted some information on connecting SCSI disks to Sun workstations. An employee of Sun requested that I post the following clarification: > Sunos allows 4 SCSI addresses to be used for disks. On certain models, > such as 3/50's and 3/60's, you can put up to 2 disks per SCSI address.... __________ I'd appreciate it if you'd repost with the correct information (Sun Employees are not supposed to post...) below on SCSI configurations. Essentially, the number of disks is not limited or static. a) the kernel structures are not static - .../sundev/sc_conf.c gets remade with NSD set to the correct number based on the number of sd? lines in your kernel config file. b) .../OBJ/sd.h has nothing to do with it - .../sun3/KERNELNAME/sd.h is the file created by config and used by sc_conf.c when you make a kernel. c) There are 8 SCSI addresses, and 8 Logical Unit Numbers available in the Sun SCSI implementation - the Sun Host Adaptor take address 7, so there are 7 free. Asumming you have a tape at address 4, this makes more like 48 possible disks on a SCSI bus. 6 if you are using Embedded SCSI (direct) controllers with no LUN's. d) drive addresses may be specified in octal, and 011 for ctlr 1, drive 1 seems clearer to me - Consulting issues config files and instructions in this format. Someday the rest of Sun will too... __________ I stand corrected. I was telling the numbers that I knew would work, and I'm happy that it is indeed dynamic and that more than 4 disk drives can be added. The sd.h information that I had was from another Sun customer. However, because of scsi signal constraints, the most I have put on a single system is 4 disks and 2 tapes, and that took quite a bit of experimentation to make it work. Also, the only SCSI/ESDI convertor board that works for formatting and everything else that I know of is the Emulex MD21, which only allows disks to be addressed at LUNs 0 and 1. I have heard of an MD25, which allows 4 ESDI drives per SCSI id, but the real limitation is SCSI bus length and driver capabilities. Neil Gorsuch Uninet neil@cpd.com uunet!zardoz!neil (800) 433-6784 outside California (714) 546-1100 inside California
dupuy@cs.columbia.edu (Alexander Dupuy) (05/18/89)
> c) There are 8 SCSI addresses, and 8 Logical Unit Numbers available in the > Sun SCSI implementation - the Sun Host Adaptor take address 7, so there > are 7 free. Asumming you have a tape at address 4, this makes more like > 48 possible disks on a SCSI bus. 6 if you are using Embedded SCSI (direct) > controllers with no LUN's. I find this interesting, and yet puzzling, since we have run Exabyte tapes with the thumbwheel SCSI ID (=?= SCSI address) set to 7, and it seems to work fine. If in fact the Host Adaptor uses address 7, this would seem not to prevent tapes or disks from using this address as well (perhaps because they are not SCSI masters?). Here are the relevant lines from our GENERIC Sun-3 config: controller sc0 at vme24d16 ? csr 0x200000 priority 2 vector scintr 0x40 disk sd0 at sc0 drive 0 flags 0 disk sd1 at sc0 drive 1 flags 0 disk sd2 at sc0 drive 8 flags 0 #disk sd3 at sc0 drive 9 flags 0 tape st0 at sc0 drive 32 flags 1 tape st1 at sc0 drive 40 flags 1 #disk sf0 at sc0 drive 8 flags 2 tape smt0 at sc0 drive 48 flags 4 tape smt1 at sc0 drive 56 flags 4 controller si0 at vme24d16 ? csr 0x200000 priority 2 vector siintr 0x40 controller si0 at obio ? csr 0x140000 priority 2 disk sd0 at si0 drive 0 flags 0 disk sd1 at si0 drive 1 flags 0 disk sd2 at si0 drive 8 flags 0 disk sd3 at si0 drive 9 flags 0 tape st0 at si0 drive 32 flags 1 tape st1 at si0 drive 40 flags 1 #disk sf0 at si0 drive 8 flags 2 tape smt0 at si0 drive 48 flags 4 tape smt1 at si0 drive 56 flags 4 controller se0 at vme24d16 ? csr 0x300000 priority 2 vector se_intr 0x40 disk sd0 at se0 drive 0 flags 0 disk sd1 at se0 drive 1 flags 0 disk sd2 at se0 drive 8 flags 0 disk sd3 at se0 drive 9 flags 0 tape st0 at se0 drive 32 flags 1 tape st1 at se0 drive 40 flags 1 tape smt0 at se0 drive 48 flags 4 tape smt1 at se0 drive 56 flags 4 The smt driver is from Delta Microsystems. @alex -- inet: dupuy@cs.columbia.edu uucp: ...!rutgers!cs.columbia.edu!dupuy