Date: Mon, 5 Jun 1995 00:41:24 -0400 From: Temptation <temp@temptation.interlog.com> To: Mike Pritchard <mpp@legarto.minn.net> Cc: hackers@freebsd.org Subject: Re: why won't my tape drive keep streaming? Message-ID: <Pine.3.89.9506050008.B19767-0100000@temptation.interlog.com> In-Reply-To: <199506050254.VAA01688@mpp.com>
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I have the 29/28/27 cards, and 4 and 9gig Archive's. can you send me this
test program? I'd like to try my tape drives.
> I have an Archive 2150S SCSI tape drive attached to An Adaptec 2842VL
> controller. This drive is capable of writing 6MB+ per minute, but
> I rarely see that under FreeBSD (running -current). Often the drive will
> start out streaming, writing 5.5MB/min - 6MB/min. After a while,
> and for no apparent reason, the drive will stop streaming, and
> throughput drops down to as bad as 1MB/min - 3MB/min. This
> happens even on a totally idle machine with just the test program
> running.
> Reads from the tape drive don't seem to suffer from this problem.
>
> Basically the guts of the test program looks like:
>
> dev = argv[1];
> bsize = atol(argv[2]);
> bcount = atol(argv[3]);
> buf = malloc(bsize));
> fd = open(dev, O_RDWR));
> for (i = 0; i < bcount; i++) {
> if (write(fd, buf, bsize) <= 0) {
> perror("write");
> exit(1);
> }
> }
> --
> Mike Pritchard
> mpp@legarto.minn.net
> "Go that way. Really fast. If something gets in your way, turn"
>
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