>The DEC SCSI adapter is p/n 54-19288-01, and it is used with a mounting
>bracket p/n 74-39094-01. This mounting bracket provides a place to mount
>the SCSI adapter circuit board as well as the RX23. The RX23 is connected
>to the adapter with cable p/n 17-02221-02.
The SCSI adapter determines the driver type based on the
drive select number to which the drive responds. I don't
recall which drive select maps to which drive, but if
it comes up wrong try a different drive select.
Depending on the version of the hardware you have, the
adapter may deal with RX23 (3.5" 1.44MB), RX33 (5.25"
1.2MB), and RX26 (3.5" 2.88MB) drives. It will adjust
the model number it reports to the host depending on the
drive attached and it determines which drive is attached
by the drive select to which the drive responds.
Another variation between models is whether or not the
firmware hides the RX50 software interleave used by
PDP-11 and VAX systems (DECmates and Rainbows used a
different software interleave). IIRC, the firmware
version with knows about the RX50 software interleave
identifies itself as 5.7. For the life of me, I don't
recall whether the RX50 software interleave is tied to
the drive type or whether it assumes the floppy is an
RX50 if it discovers that it's 10 sectors per track,
80 tracks, 250KHz data rate (the controller is pretty
flexible and tries really hard to adjust itself to
the format of the diskette inserted, although it does
assume the whole world uses 512 byte sectors).
--
Roger Ivie
rivie_at_teraglobal.com
Not speaking for TeraGlobal Communications Corporation
Received on Thu Oct 19 2000 - 11:44:25 BST