NOP@GACVAX1.BITNET (Let there be...MORE light.) (01/11/90)
I ordered a SCSI Module for my Microbotics StarBoard 2 today. I'm going to get a 65M Segate drive on Saturday, and I need to know which kind of cabling to buy with it. Does the SCSI module use Mac-style 25 pin, or standard 50 pin cabling? Since you StarDrive people are listening, I'd like to ask for any hints on how to set up the drive and maintain it. I'm not at all afraid to mess with the MountList, but I don't want to rush madly in all directions. Thanks for your time, Jay Carlson nop@GACVAX1.bitnet "That's different. It's not the same."
MARKV@UKANVAX.BITNET (MARK GOODERUM - UNIV. OF KANSAS ACS - MARKV@UKANVAX) (01/12/90)
You need the 25-50 pin cabling (the Starboard has a 'Mac SCSI' connector.) For the Mountlist, leave the first two cylinders unused (0 and 1) for the new driver (don't have it, just heard about it) which (I think) supports the 'hardblocks' standard. Second, 'physically' format the drive with a 1:1 interleave, and leave it up to DOS to take care of the interleave. (With the Interleave= entry in the Mountlist.) Depending on your system your want a 2:1 or 3:1 interleave. 2:1 performs better, but under worst case condidtions (or less than mostly ideal even) 3:1 is better. Right now my drives are 2:1, but I will probably to to 3:1 the next time I reformat. (If you have some kind of processor accelerator like the CMI or something else you have enough extra horse power to get away with 2:1.) On interleave I've figured this out (at least the StarDrive.) Using drive timings, I've figured out that when you do 'low-level' format, and give an interleave of other than 1 or 0 (1:1) the drive does the interleaveing completly transparent to DOS. So if you Interleave 2:1 on formatting, your and Tell DOS Interleave=0 (or 1) you get 2:1 Interleave. However, if you tell DOS Interleave=2, you actually get 4:1 interleave becuase DOS does 2:1 on top of the drives 2:1. This was determined expirmentally with careful timing and some help from DiskPerf. For other things, just follow the sample entries for the 2090 in the Enhancer manual, just use StarDrive.device for the Device=. FFS does work with the StarDrive just fine. Finally, its and extra command from Floppy, but DO SetPatch before ANYTHING else. I solved a lot of intermittant crashes by moving SetPatch back to the beginning of my floppy Startup. Good luck Mark
DSR@CRNLNS.BITNET (01/12/90)
Comment: forwarded by CRNLNS/FMAIL v2.0 Comment: REPLY may not work. Comment: Network-Source: _LNS62::DSR (HEPnet/SPAN) Comment: Originally-From: DSR "Dan Riley" Comment: Originally-To: JNET%"i-amiga@ubvm" [apologies for any bogus messages I sent...we just upgraded to VMS 5.3, and the new DECwindows clients don't seem to like the MIT X11R4 server on my DECstation, so weird things have been happening] MARK GOODERUM - UNIV. OF KANSAS ACS - MARKV@UKANVAX writes: >For the Mountlist, leave the first two cylinders unused (0 and 1) for >the new driver (don't have it, just heard about it) which (I think) >supports the 'hardblocks' standard. The driver with Rigid Disk Blocks support doesn't exist yet--it's still being worked on. But do reserve a couple of cylinders. >Second, 'physically' format the drive with a 1:1 interleave, and leave it up >to DOS to take care of the interleave. (With the Interleave= entry in the >Mountlist.) Depending on your system your want a 2:1 or 3:1 interleave. This goes directly against my experience, my common sense, and Microbotics' recommendations. I've gotten the best performance using a DOS interleave of 0 (in the MountList), and hard formatting the drive with an interleave of 2:1 or 3:1 (which is better depends on the drive you are using). Using the DOS interleave adds lots of transfer overhead--with a DOS interleave of 0, FFS can request large contiguous reads whenever possible. With a non-zero DOS interleave, FFS has to send out a seperate request for every block, which adds overhead and restricts any optimizations the driver may make for large reads. With OFS, this makes little difference, but with the FFS it matters, since FFS is lots smarter. >On interleave I've figured this out (at least the StarDrive.) Mark's description is basically correct. I just wanted to note that there is an update to the StarDrive software which, among other improvements, does correctly explain the difference between DOS and SCSI interleaves, and gives some timings and recommendations. It also explains how to set up a MountList entry, and includes support for Adaptec adapters and fixes some bugs in the driver. I pulled my copy off the Microbotics support conference on BIX, but the docs specifically disallow any redistribution. Hopefully new StarDrives should come with the update--if not, call Microbotics and ask for it. -Dan Riley (dsr@crnlns) -Wilson Lab, Cornell University