cdl@mplvax.EDU (Carl Lowenstein) (03/22/89)
Some time back, there was mention in this group of using the DTC (Data
Technology Corp) 11-2 Host Adapter to run a SCSI device from the LSI-11
Q-bus. This registered in my subconscious but I didn't save anything
from it.
So -- two questions:
1) Can the DTC 11-2, which is fundamentally a SASI host adapter, be
used to control a SCSI device (disk, in particular).
2) Can any SASI host adapter which can assert a variable device ID
control more than one SCSI device, if one is careful to avoid
overlapping operations?
Advice is solicited. Of course, I expect to write my own software
handlers, because the DTC 11-2 just passes command packets along to the
disk drive and doesn't pretend to be MSCP or anything clever.
--
carl lowenstein marine physical lab u.c. san diego
{decvax|ucbvax} !ucsd!mplvax!cdl
cdl@mplvax.ucsd.edujlohmeye@entec.Wichita.NCR.COM (John Lohmeyer) (03/25/89)
In article <834@mplvax.EDU> cdl@mplvax.ucsd.edu.UUCP (Carl Lowenstein) writes: > [stuff deleted] >1) Can the DTC 11-2, which is fundamentally a SASI host adapter, be >used to control a SCSI device (disk, in particular). > >2) Can any SASI host adapter which can assert a variable device ID >control more than one SCSI device, if one is careful to avoid >overlapping operations? I would answer a qualified yes to both questions. You won't get great performance because you will have to be careful not to overlap I/O, but it _should_ work. I am not familiar with the DTC 11-2, but if it is really old, it probably has the following characteristics: No arbitration Doesn't drive the ATN signal Doesn't generate or check parity Only provides the target ID during selection (does not include its own) All of these things were permitted in SCSI-1, but are now disallowed in SCSI-2. Unless you have a very new disk that is religious about these things, it probably will work with the DTC host adapter. One caveat: many vendors do not do a lot of testing for compatibility with SASI. So, you may find bugs in how they handle the lack of these features. Good luck, John Lohmeyer j.lohmeyer@wichita.ncr.com
michaele@enky.UUCP (Michael Enkelis) (03/28/89)
Look in the unsupported devices directory on BSD 2.10 for a SCSI driver for UNIX (DW.c). It was tested (writen) for a DTC 11/2 Q-bus SCSI interface. Also there is a DTC 11/2 driver for a QIC-36 tape cartridge drive there (TC.c). -- _ _ _ __ ' ) ) ) / /) / ` / /) / / / o _. /_ __. _ // /-- __ /_ _ // o _ / ' (_(_(__/ /_(_(_(<_(/_ (___, /) )_/ <_(<_(/_(_/_)_