From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on inbox.vuxu.org X-Spam-Level: X-Spam-Status: No, score=-3.6 required=5.0 tests=MAILING_LIST_MULTI, NICE_REPLY_A autolearn=ham autolearn_force=no version=3.4.4 Received: (qmail 4793 invoked from network); 27 Nov 2021 15:55:36 -0000 Received: from minnie.tuhs.org (45.79.103.53) by inbox.vuxu.org with ESMTPUTF8; 27 Nov 2021 15:55:36 -0000 Received: by minnie.tuhs.org (Postfix, from userid 112) id E379E9CEA8; Sun, 28 Nov 2021 01:55:33 +1000 (AEST) Received: from minnie.tuhs.org (localhost [127.0.0.1]) by minnie.tuhs.org (Postfix) with ESMTP id 7ECBF9CE5D; Sun, 28 Nov 2021 01:53:11 +1000 (AEST) Received: by minnie.tuhs.org (Postfix, from userid 112) id D37BE9CE5D; Sun, 28 Nov 2021 01:53:09 +1000 (AEST) Received: from rooster.satexas.com (rooster.satexas.com [207.235.90.2]) by minnie.tuhs.org (Postfix) with ESMTPS id DD14194942 for ; Sun, 28 Nov 2021 01:53:08 +1000 (AEST) Received: from localhost (localhost [127.0.0.1]) by rooster.satexas.com (Postfix) with ESMTP id 1D8AD1C2A8D for ; Sat, 27 Nov 2021 09:53:08 -0600 (CST) Received: from rooster.satexas.com ([127.0.0.1]) by localhost (rooster.satexas.com [127.0.0.1]) (maiad, port 10024) with ESMTP id 58580-08 for ; Sat, 27 Nov 2021 09:53:07 -0600 (CST) Received: from [192.168.147.6] (rrcs-71-42-153-195.sw.biz.rr.com [71.42.153.195]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: csauer@nwhillsumc.org) by rooster.satexas.com (Postfix) with ESMTPSA id 66E181C2A88 for ; Sat, 27 Nov 2021 09:53:07 -0600 (CST) Message-ID: <1ae0c3f8-fc2b-84a9-442b-e591dca591fd@technologists.com> Date: Sat, 27 Nov 2021 09:53:10 -0600 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; rv:91.0) Gecko/20100101 Thunderbird/91.3.2 Content-Language: en-US To: tuhs@minnie.tuhs.org References: <20211127152527.591D518C07B@mercury.lcs.mit.edu> From: Charles H Sauer In-Reply-To: <20211127152527.591D518C07B@mercury.lcs.mit.edu> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Virus-Scanned: World Net ProMail v2.0.0 Subject: Re: [TUHS] PL/I stuff - was: Book Recommendation X-BeenThere: tuhs@minnie.tuhs.org X-Mailman-Version: 2.1.26 Precedence: list List-Id: The Unix Heritage Society mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: tuhs-bounces@minnie.tuhs.org Sender: "TUHS" On 11/27/2021 9:25 AM, Noel Chiappa wrote: > > From: "Charles H. Sauer"k > > > I haven't done anything with 9 ktrack tapes for a long time ... > > I don't recall problems reading any of them. ... > > IMNSHO, it all depends on the brand/formulation of the tape. I've been > > going through old audio tapes and digitizing them > > The vintage computer community has considerable experience with old tapes; in > fact Chuck Guzis has a business reading them (which often includes converting > old file formats to something modern software can grok). > > We originally depended heavily on the work of the vintage audio community, who > pioneered working with old tapes, including the discovert of 'baking' them to > improve their mechanical playability. ("the binder used to adhere the magnetic > material to the backing ... becomes unstable" - playing such a tape will > transfer much of the magnetic material to the head, destroying the tape's > contents.) The notion of "baking" is slightly misleading. When done with audio tapes, the practice is to use a dehydrating oven at about 130F for about 24 hours. > It's amazing how bad a tape can be, and still be readable. I had a couple of > dump tapes of the CSR PWB1 machine at MIT, which I had thoughtlessly stored in > my (at one period damp) basement, and they were covered in mold - and not just > on the edges! Chuck had to build a special fixture to clean off the mold, but > we read most of the first tape. (I had thoughtfully ade a second copy, which > read perfectly.) > > Then I had to work out what the format was - it turned out that even though > the machine had a V6 filesystem, my tape was a 'dd' of a BSD4.1c filesystem > (for reasons I eventually worked out, but won't bore you all with). Dave > Bridgham managed to mount that under Linux, and transform it into a TAR > file. That was the source of many old treasures, including the V6 NCP UNIX. > > Noel > -- voice: +1.512.784.7526 e-mail: sauer@technologists.com fax: +1.512.346.5240 Web: https://technologists.com/sauer/ Facebook/Google/Twitter: CharlesHSauer