rbutterworth@watmath.waterloo.edu (Ray Butterworth) (09/21/88)
It seems that most of our random problems were caused by noise from a cable that wasn't properly shielded and grounded. The controller boards are produced by different companies, and so not all Exabytes will behave the same way. Thanks to all the people that responded to my question. Nearly all the responses indicated that they were happy with the drives. The only complaints were about the slow response time for changing tape motion (e.g. backspace, rewind), and that it is impossible to see the tape itself to visually determine where it is and what it is doing. This latter feature is definitely very frustrating. A word of warning to UNIX users though: One of the simple tests I tried was cat /etc/termcap >$TAPE cat $TAPE >/tmp/termcap diff /etc/termcap /tmp/termcap and both cat's exited successfully, even though the diff showed differences in the files. Like most UNIX software, cat doesn't check the return status of close() or fclose(), so if anything goes wrong during the close of the file the error is silently ignored. These devices use a very large buffer, and in many cases the tapes don't even start to move until the write-end-of-file command is issued by the device driver in the close. If anything goes wrong and the data isn't written correctly, the close() function returns an error status but everything simply ignores it. If you are writing (or buying) software that is going to write to these devices, I strongly suggest you make sure that it checks the return value of close().