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Path: sserve!manuel!munnari.oz.au!sgiblab!sdd.hp.com!caen!uunet!charon.amdahl.com!amdahl!JUTS!phoenix!gpw10 From: gpw10@phoenixcd.amdahl.com (Gary Ward) Newsgroups: comp.unix.bsd Subject: Re: Getting tapes to stream (was Re: What kind of tape is OK w/ 386BSD? Message-ID: <63Qw02h51c9901@JUTS.ccc.amdahl.com> Date: 1 Aug 92 05:51:19 GMT References: <28JUL199218203085@stars.gsfc.nasa.gov> <1992Jul29.161438.6372@mks.com> <55595@mentor.cc.purdue.edu> <1992Jul31.161715.12462@mks.com> Sender: netnews@ccc.amdahl.com Organization: Amdahl Corporation, Sunnyvale CA Lines: 40 In article <1992Jul31.161715.12462@mks.com>, fredw@mks.com (Fred Walter) writes: |> mm@mentor.cc.purdue.edu (Mike MacKenzie) writes: |> >I have a Wangtek 5150ES SCSI-36 tape drive and it works, but |> slowly. |> >It took over 12 hours to back up ~80 meg. I've tried various |> buffer |> >sizes with dd with no improvment. |> |> Wow, 12 hours ? What sort of hardware (386 ?) and how fast is it ? |> My Wangtek 5150EQ wasn't able to stream, but it didn't take that |> long... |> |> You could try 'ddd'. I don't recall where it can be found; probably |> on |> ftp.uu.net somewhere. It works by having two processes, one filling |> up a |> buffer whilst the other writes a buffer out; that way the tape drive |> always |> is being fed a buffer (no pauses while the buffer dd uses is |> refilled). |> Or some such thing. |> |> fred I have a similar program called "streamer" which I was unable to compile under 386bsd. I didn't try very hard, since it turned out to be pretty much unnecessary. Both cpio and tar have options to increase the blocking size. Use cpio with -B and with tar I used -b 50. In both cases, the drive streamed beautifully. -- +------------------------+---------------------------+ | Gary Ward | Amdahl Corporation | | gpw10@cd.amdahl.com | 1250 East Arques Avenue | | Phone : (408)746-8865 | P.O. Box 3470 M/S 142 | | | Sunnyvale, CA 94088-3470 | +------------------------+---------------------------+