PENSTONE@QUCDNEE1.BITNET (Sid Penstone) (09/23/86)
We have reecently installed a DR11-W parallel interface on a
VAX-11/750 which has RK07 disc drives. Both the discs and the DR11 use
the same unibus, through a unibus adapter.( There is also a magnetic
tape interface and a Floating Point Systems FPS-5100 on the bus, but that
is a different story.)
When we run DMA transfers with the DR11, we get occasional "DATA
LATE" errors, and finally error bits corresponding to "Addressing non-existent
memory". At the same time, data errors (parity) start appearing on the
RK07 discs. We are using the driver supplied with version 4.3 for the
DR11-W. We are guessing that possibly the buffer pages are not being locked
into memory properly for the unibus transfers, but wonder how the
discs ran before, since their driver calls the same system macros as the
DR11 driver.We now suspect that our FPS 5100 was doing something similar
earlier, but the sysmptoms were not as clear.
Does anyone out there have any experience with similar hardware
that might help us ? We do not have a software maintenance contract, and the
DR11-W is a "look-alike" from MDB.
Sid Penstone,
Dept of Electrical Engineering,
Queen's University,
Kingston, Ontario, Canada BITNET: PENSTONE@QUCDNEE1