From owner-freebsd-hackers Sun Jun 4 21:44:46 1995 Return-Path: hackers-owner Received: (from majordom@localhost) by freefall.cdrom.com (8.6.10/8.6.6) id VAA24254 for hackers-outgoing; Sun, 4 Jun 1995 21:44:46 -0700 Received: from temptation.interlog.com (temp@temptation.interlog.com [198.53.146.54]) by freefall.cdrom.com (8.6.10/8.6.6) with ESMTP id VAA24226 for ; Sun, 4 Jun 1995 21:44:35 -0700 Received: (from temp@localhost) by temptation.interlog.com (8.6.9/8.6.9) id AAA19948; Mon, 5 Jun 1995 00:41:25 -0400 Date: Mon, 5 Jun 1995 00:41:24 -0400 From: Temptation Subject: Re: why won't my tape drive keep streaming? To: Mike Pritchard cc: hackers@freebsd.org In-Reply-To: <199506050254.VAA01688@mpp.com> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: hackers-owner@freebsd.org Precedence: bulk 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" >