From sentto-2719433-18-980827861-gtoal=vt.com@returns.onelist.com Mon Jan 29 21:38:49 2001 Received: from b05.egroups.com (b05.egroups.com [208.50.144.96]) by admin.vt.com (8.8.5/8.7.3) with SMTP id VAA13682 for ; Mon, 29 Jan 2001 21:38:47 -0600 (CST) X-eGroups-Return: sentto-2719433-18-980827861-gtoal=vt.com@returns.onelist.com Received: from [10.1.4.54] by b05.egroups.com with NNFMP; 30 Jan 2001 04:11:58 -0000 X-Sender: gtoal@admin.vt.com X-Apparently-To: edinburgh-computer-history@yahoogroups.com Received: (EGP: mail-7_0_2_1); 30 Jan 2001 04:11:01 -0000 Received: (qmail 98360 invoked from network); 30 Jan 2001 03:57:49 -0000 Received: from unknown (10.1.10.26) by l8.egroups.com with QMQP; 30 Jan 2001 03:57:49 -0000 Received: from unknown (HELO admin.vt.com) (204.117.188.10) by mta1 with SMTP; 30 Jan 2001 03:57:48 -0000 Received: (from root@localhost) by admin.vt.com (8.8.5/8.7.3) id VAA13185 for edinburgh-computer-history@yahoogroups.com; Mon, 29 Jan 2001 21:24:33 -0600 (CST) Message-Id: <200101300324.VAA13185@admin.vt.com> To: edinburgh-computer-history@yahoogroups.com From: Graham Toal MIME-Version: 1.0 Mailing-List: list edinburgh-computer-history@yahoogroups.com; contact edinburgh-computer-history-owner@yahoogroups.com Delivered-To: mailing list edinburgh-computer-history@yahoogroups.com Precedence: bulk List-Unsubscribe: Date: Mon, 29 Jan 2001 21:24:33 -0600 (CST) Reply-To: edinburgh-computer-history@yahoogroups.com Subject: [ed-comp-hist] Tape formats Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Status: RO > I can read half inch VMS tapes at 800/1600/3200/6250 bpi. > I also have the TAPEANAL command which is useful for non-VMS tapes. > > best regards > > J. Gordon Hughes > jgh@cableinet.co.uk That's great news from Gordon; I think the chances of us taking him up on that offer are quite high :-) My own memory of tapes is from Unix, and I think what I remember is that they had very little structure at all; generally Unix tapes are a straight dump of a tar file to tape with cpio or dd. So if Gordon can physically read any tapes and just get the raw bytes in a file, I'm very confident we can strip any ISO headers etc off by hand in the worst case and recover the internal data. Actually I had forgotten this, but it's coming back to me now: I wrote lots of tape handling utilities when I was working at Acorn. I believe I kept sources. Guess what - they're on a 6250bpi tape :-) Oh dear, little bootstrap problem there :-) The only trickiness I remember was something about writing 'tape marks' which I think were 0-length blocks, and something about end of tape (or maybe end of dataset?) being denoted by a double tapemark. I seem to remember it was sometimes difficult to read past a double tape mark and make sure you got every dataset on the tape and not just the first one. I wonder what other kinds of tapes we'll find... Those tapes seemed huge at the time. I just looked them up on the net and they were in fact only 180Mb. We could store 450 of these tapes on a single 80Gb disk costing $300. Graham ------------------------ Yahoo! Groups Sponsor ---------------------~-~> eGroups is now Yahoo! Groups Click here for more details http://click.egroups.com/1/11231/1/_/_/_/980827862/ ---------------------------------------------------------------------_-> To unsubscribe from this group, send an email to: edinburgh-computer-history-unsubscribe@egroups.com