Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!interet!jim From: jim@interet.UUCP (User) Newsgroups: comp.misc Subject: Re: Exabyte (8mm) versus DAT (4mm) Summary: We have DAT, seems ok. Keywords: DAT, backup Message-ID: <1@interet.UUCP> Date: 11 Jul 90 12:50:33 GMT References: <9007061713.AA01816@stc06.CTD.ORNL.GOV> <1881@proa.SV.DG.COM> <2188@dino.cs.iastate.edu> Reply-To: jim@interet.UUCP (User) Organization: Interet, Maplewood, NJ Lines: 26 We have had a Wangdat DAT purchased from Apunix for three months with few problems. Once it refused to give back a tape, but holding down the eject button for 10 seconds got it out (undocumented feature). We are purchas- ing a second unit (for backup backup). We use cpio and shell scripts. I have no experience with Exabyte. We still keep a second set of backups on 9 track. Our total storage in use is about 800 Megs, and the greater capacity of Exabyte was not an advantage for us. DAT tapes cost $15.00 and seem to be going up in price. Our DAT is on a SCSI port on a Sun 3/60 running OS 4.0.3, and we upgraded to that OS from 3.5 to use the drive. Apunix supplies the driver. It is essential to enable scsi disconnects with scsi_disre_enable = 1 if you have an active disk on the scsi. The throughput we have gotten is only about 90 Kbytes per second max, and the bottleneck seems to be the sun 3/60 SCSI. Interesting questions are (1) is data-dat a real standard, and can the tapes be read by a different drive, (2) the hardware can seek, so will someone write a tape format which can find a file more quickly than cpio, which must read the tape sequentially, (3) the hardware can seek, so will someone write a block device driver enabling the drive to act like a slow disk drive; backup consists of cpio -p, find files with ls and cp. I am not associated with Wangdat or Apunix. If you want more info, mail to uunet!interet!jim, and I will reply or sumarize to the net. I am sorry I haven't had the drive longer, but maybe this helps a little.