WDSC(4) | Device Drivers Manual (mvme68k) | WDSC(4) |
wdsc
— Western
Digital WD33c93 SCSI Bus Interface Controller
wdsc0 at pcc? ipl 2
The wdsc
driver provides an abstraction
layer between the SCSI hardware fitted to the Motorola MVME147 single board
computer (WD33C93), and the machine independent SCSI drivers described in
scsibus(4).
In addition to sending the required SCSI commands to target
devices on the SCSI bus, the wdsc
driver deals with
DMA, device interrupts, sync/async negotiation and target
disconnects/reconnects.
Too many to mention.
Negotiation of Synchronous SCSI data transfers has been
deliberately disabled in the MVME147's wdsc
driver
as it has proved extremely difficult to make it work reliably in this
mode.
The wdsc
driver does not respond well to
exceptional conditions caused by poor SCSI cabling and/or termination. In
those instances the machine is likely to require a hard reset to
recover.
The current wdsc
driver should be blown
away and replaced with a machine independent version.
February 17, 2017 | NetBSD 10.99 |