stevens@hsi.UUCP (Richard Stevens) (07/15/85)
We have an Emulex TC7000 in an Emulex V-Master on a 785 running 4.2, connected to a Kennedy 9400 tri-density tape drive. We have isolated a problem where a read from the drive returns the correct byte count but the final bytes of the buffer are not transferred into the user's buffer. The number of bytes of data that are missing in the buffer after the read is always a power of 2. Our test program writes out records of length 100, 200, ... 8000 bytes with each buffer having a specific pattern, then reads the tape back. The problem only occurs at a few of the record lengths. However, the alignment of the buffer in the user's address space affects which of the record lengths have a problem - a buffer that is page aligned yields different results from one that is not. We have had one other site with a similar hardware configuration run our little test program and they reported identical results (this after Emulex has swapped almost everything in sight). What I'd like to find is some other site with a real TE16/TU45/TU77 to run our little test, so that we can rule out the 4.2 ht driver. Emulex, of course, says that there are no known problems under VMS and they don't have a 780 with their TC7000 tape controller running UNIX at their facility. If you have the real DEC controller on a 780 or 785 please contact me and I'll mail you the 60-line program. Thanks. Richard Stevens Health Systems International, New Haven, CT ihnp4 ! hsi ! stevens