From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on inbox.vuxu.org X-Spam-Level: X-Spam-Status: No, score=-0.3 required=5.0 tests=DKIM_ADSP_CUSTOM_MED, DKIM_INVALID,DKIM_SIGNED,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,HTML_MESSAGE,MAILING_LIST_MULTI, RCVD_IN_DNSWL_NONE autolearn=ham autolearn_force=no version=3.4.2 Received: from minnie.tuhs.org (minnie.tuhs.org [45.79.103.53]) by inbox.vuxu.org (OpenSMTPD) with ESMTP id 9ee34332 for ; Mon, 25 Nov 2019 22:57:35 +0000 (UTC) Received: by minnie.tuhs.org (Postfix, from userid 112) id 0524E9C5EA; Tue, 26 Nov 2019 08:57:34 +1000 (AEST) Received: from minnie.tuhs.org (localhost [127.0.0.1]) by minnie.tuhs.org (Postfix) with ESMTP id 88BC193D74; Tue, 26 Nov 2019 08:57:17 +1000 (AEST) Authentication-Results: minnie.tuhs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.b="hXilrewP"; dkim-atps=neutral Received: by minnie.tuhs.org (Postfix, from userid 112) id 9AD7393D74; Tue, 26 Nov 2019 08:57:15 +1000 (AEST) Received: from mail-ot1-f41.google.com (mail-ot1-f41.google.com [209.85.210.41]) by minnie.tuhs.org (Postfix) with ESMTPS id 1CE5193D71 for ; Tue, 26 Nov 2019 08:57:15 +1000 (AEST) Received: by mail-ot1-f41.google.com with SMTP id z25so14176874oti.5 for ; Mon, 25 Nov 2019 14:57:15 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=w7b5SnrD6erL+BKURtLTxvvOyfkWTZa+iyJIWTWs96c=; b=hXilrewP6HDw+azkfWiQjbe730O61TRg/lPWwSgCg2GWo7G8CVg9OH9QMvXORHTibk 1YB69gZKsNgegkl6xoRR66J8EszO8bvQCefDZG8oaZxVG7TnGjkEqP1wY/RObnCtmjGX 8Cv92catUFBirxJT7zD+vreQ8t0ifJTGA1sp85mrOuyxRUtt7lcyyOVWC/92xZ/H7A0b JpRyzCDzRS2k8tu0nCzidGDRx/COIbJqQ2c34NtoWT/geWXNsrtz46lQZlqgdbEMZOin TUSejOgH8gc0msaMmYn4VNNwnmS4moRZ1dcPcqCzGegioySrc3tjpczUW1N9lGwSMPRn S2yQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=w7b5SnrD6erL+BKURtLTxvvOyfkWTZa+iyJIWTWs96c=; b=ZPQ2tdnPH1HmS0QFvbGQijMNmIJP525x32SnYfmOZglCWiMWwkSF2w67OKnTIWXoRc 2jBwGJjUqLi2yfqKH7hcA62zTeZGbS6mL2j+7B/sZkibkK4Jj3BoQRy4iQXR3+0MENiB YS5fwdqwtISeplhHa8gXq7hKLPrdhTN++8tum1YDAqpGtbKlbRtXtXWJOGJ5hZjeYITO XHiSC0crLxQPZPcECXqi2G53/GbJb+6CIp+hc+aXNCsEPXfY29i7qnldlXDGl7MuNFCw d51iF/vJAEmfBhJct81Xwd2k5unmYsM+E5cGnGCK+85nFG6/+jz1w9j2tldbCKm0XfJi ilAQ== X-Gm-Message-State: APjAAAXIhMyhTPuddnkqzW0j7Lme5nSpesM3ffnCmnyNHsa95PlzZSO8 k+6dX7BZQlnKY7QYF6u2dmsf4fGrjftI1OVJGvo= X-Google-Smtp-Source: APXvYqwK5WWgiM2gWzmmr7D7bICZ34w0w++26kDIPwk45DWlsw3n93Z2AWBxMhuzmDZlTHe8l5UBCZ7ra6XBcBpCeuY= X-Received: by 2002:a05:6830:10d0:: with SMTP id z16mr121332oto.367.1574722634436; Mon, 25 Nov 2019 14:57:14 -0800 (PST) MIME-Version: 1.0 References: <20191124225239.GG18200@mcvoy.com> <20191125033642.GP18200@mcvoy.com> In-Reply-To: <20191125033642.GP18200@mcvoy.com> From: Henry Bent Date: Mon, 25 Nov 2019 17:57:00 -0500 Message-ID: To: Larry McVoy Content-Type: multipart/alternative; boundary="0000000000003ed320059833afb7" Subject: Re: [TUHS] Someone wants to use an exabyte 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: , Cc: The Eunuchs Hysterical Society Errors-To: tuhs-bounces@minnie.tuhs.org Sender: "TUHS" --0000000000003ed320059833afb7 Content-Type: text/plain; charset="UTF-8" On Sun, 24 Nov 2019 at 22:37, Larry McVoy wrote: > On Mon, Nov 25, 2019 at 02:29:02PM +1100, Dave Horsfall wrote: > > On Mon, 25 Nov 2019, George Michaelson wrote: > > > > >I just failed with a Sun DAT drive. Cable and card bought online, > > >recognized by the mt command, but all it does is eject tapes. > > > > They're worse than 9-track tapes, and that's saying something :-) > > Really? Are we talking about those tapes that looked like reel to reel > audio tapes but bigger? Like this? > > https://www.canajunfinances.com/wp-content/uploads/2013/04/9-Track-Tape.jpg > > Because those are 1000x more reliable than an exabyte tape, they just > worked. Pretty much no matter what, you can spool up that tape and it > will read. 30 years later it will read. > > Exabyte won't read 20 minutes later. > I think that certain amount of the reliability issue, as far as both the tapes and the drives are concerned, has to do with scale. Those 8mm Exabyte tapes (DDS tapes, too) are much thinner and hence more easily damaged than a large 9 track reel. If thin tape in a cartridge gets fouled up past a certain point, forget it, there's no salvaging that cartridge. If open reel tape gets damaged and you really need what's on it you can hope that the mechanism can read past the damaged part (a possibility), or as a last resort you could make a careful splice and then attempt to retrieve the rest of the data. One of the other issues, totally independent of tape, is the rubber chosen by the manufacturers for the drive belts and rollers. Some rubber, stored properly, will still be in usable shape after twenty or thirty years. The rubber on the rollers of my Sun QIC-150 drive? A goopy mess which rendered the drive useless as well as a tape. But yeah, about 15 years ago I was asked to retrieve some data from Exabyte 8200 tapes that had been written 10 years prior. I went through three drives and countless hours of frustration just to read a half-dozen tapes with some really important information on them. "Archive format" indeed. -Henry --0000000000003ed320059833afb7 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
On Sun, 24 Nov 2019 at 22:37, Larry McVoy= <lm@mcvoy.com> wrote:
<= div class=3D"gmail_quote">
On Mon, Nov 25, 2019 at 02:29:02PM +1100, Dave Horsfall wrote:
> On Mon, 25 Nov 2019, George Michaelson wrote:
>
> >I just failed with a Sun DAT drive. Cable and card bought online,<= br> > >recognized by the mt command, but all it does is eject tapes.
>
> They're worse than 9-track tapes, and that's saying something = :-)

Really?=C2=A0 Are we talking about those tapes that looked like reel to ree= l
audio tapes but bigger?=C2=A0 Like this?

https://www.canajunfinanc= es.com/wp-content/uploads/2013/04/9-Track-Tape.jpg

Because those are 1000x more reliable than an exabyte tape, they just
worked.=C2=A0 Pretty much no matter what, you can spool up that tape and it=
will read.=C2=A0 30 years later it will read.

Exabyte won't read 20 minutes later.

I think that certain amount of the reliability issue, as far as both the = tapes and the drives are concerned, has to do with scale.=C2=A0 Those 8mm E= xabyte tapes (DDS tapes, too) are much thinner and hence more easily damage= d than a large 9 track reel.=C2=A0 If thin tape in a cartridge gets fouled = up past a certain point, forget it, there's no salvaging that cartridge= .=C2=A0 If open reel tape gets damaged and you really need what's on it= you can hope that the mechanism can read past the damaged part (a possibil= ity), or as a last resort you could make a careful splice and then attempt = to retrieve the rest of the data.

One of the o= ther issues, totally independent of tape, is the rubber chosen by the manuf= acturers for the drive belts and rollers.=C2=A0 Some rubber, stored properl= y, will still be in usable shape after twenty or thirty years.=C2=A0 The ru= bber on the rollers of my Sun QIC-150 drive?=C2=A0 A goopy mess which rende= red the drive useless as well as a tape.

But yeah,= about 15 years ago I was asked to retrieve some data from Exabyte 8200 tap= es that had been written 10 years prior.=C2=A0 I went through three drives = and countless hours of frustration just to read a half-dozen tapes with som= e really important information on them.=C2=A0 "Archive format" in= deed.

-Henry
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