From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: tuhs-bounces@minnie.tuhs.org X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on inbox.vuxu.org X-Spam-Level: X-Spam-Status: No, score=-0.5 required=5.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,HTML_FONT_LOW_CONTRAST,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 a96a6653 for ; Tue, 16 Oct 2018 18:05:04 +0000 (UTC) Received: by minnie.tuhs.org (Postfix, from userid 112) id ACA80A208E; Wed, 17 Oct 2018 04:05:03 +1000 (AEST) Received: from minnie.tuhs.org (localhost [127.0.0.1]) by minnie.tuhs.org (Postfix) with ESMTP id 69B13A208C; Wed, 17 Oct 2018 04:04:25 +1000 (AEST) Received: by minnie.tuhs.org (Postfix, from userid 112) id EAD26A208B; Wed, 17 Oct 2018 03:34:44 +1000 (AEST) Received: from mail-wm1-f54.google.com (mail-wm1-f54.google.com [209.85.128.54]) by minnie.tuhs.org (Postfix) with ESMTPS id 6F718A2089 for ; Wed, 17 Oct 2018 03:34:38 +1000 (AEST) Received: by mail-wm1-f54.google.com with SMTP id r63-v6so23289406wma.4 for ; Tue, 16 Oct 2018 10:34:38 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ccc.com; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=Tqzq9ICR0G44zGB4klKEj0MwoT7HxS626KfQ0mkQ3eA=; b=Hr6EmT1DScuHrwghUzNEz/aKW0WgVgyLANZXjm5WcX9D9+iNqpCbk3u0UoVGPg1daO dMHqG+21z3ZQJN7q2hYFlbcuEk7adjwlcmAJ///RrFR5LcNhEuEJHZokqHMhk3nNbt3d 9JluDLTOyXgQXqbN6PU+ClCCXweCjPM9fiB40= 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=Tqzq9ICR0G44zGB4klKEj0MwoT7HxS626KfQ0mkQ3eA=; b=gT96zZYN0t+lEmM03b56AnkKF+VGBJiGp3JFy29w4t0ynxygDQOYrJWJtOAvkyGqPq IC8IyFFsOF+HMCs1vEaslPDAeEA8rlLcZNxccIpFH2Lb4HZ6AfHjAfIxnzbV1qMC/PBt 2WKsxmYnomTkowQRglyKT+CI9N64KOfbfGOk79caijgL+IIoTLY8eKSrqgUtURsDquXC FRDUvwfZKezcwLARZi/KLSkdGyN285jUalpu/FTI3/EEDAnFLCY5GgbXDwkTJSOe0rHy dBnEbtOOEvrI25PBv4deqnQ38RmSxmj7uJ3uKw7K/XrTQAyxaY9ML4mIHHxozlnDZOcr RrtQ== X-Gm-Message-State: ABuFfogmT9fFlg+7Mx7qcf1FFVNhEoUEdzesckZE9xpZIJEHRdyMFHix Jbg4fcrDbZLA+UJndvhztIKY7ENTd2hw8jWGUA8m9Q== X-Google-Smtp-Source: ACcGV63SrCfPIV/gJ2Nb701C7G2Fs6hRtsY1bNIT/o4oLz+5ui+zFeZyfmOXK5EogQkFABNdGTtUxkBZ3cA3KIcRlLI= X-Received: by 2002:a1c:e12:: with SMTP id 18-v6mr16916111wmo.30.1539711276748; Tue, 16 Oct 2018 10:34:36 -0700 (PDT) MIME-Version: 1.0 References: <20181015195622.GB25749@minnie.tuhs.org> <4f20854e-6269-47aa-aeaf-9e2b93aa1201.maildroid@localhost> In-Reply-To: <4f20854e-6269-47aa-aeaf-9e2b93aa1201.maildroid@localhost> From: Clem Cole Date: Tue, 16 Oct 2018 13:34:08 -0400 Message-ID: To: William Pechter Content-Type: multipart/alternative; boundary="000000000000b527bb05785bf78b" Subject: Re: [TUHS] Ultrix Tape: Block Size? X-BeenThere: tuhs@minnie.tuhs.org X-Mailman-Version: 2.1.20 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 , cctalk@classiccmp.org Errors-To: tuhs-bounces@minnie.tuhs.org Sender: "TUHS" --000000000000b527bb05785bf78b Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable But Paul's comment is still right on - the controller for both was a 1MHz i8085 and just could not keep up. I hated both .. its' too bad DEC refused to use QIC. They did eventually use 4mm DAT on an SCSI (and actually OEM'ed the drive from HP it turns out). The 8mm [Exabyte Unit] was from CSS and many of us in UNIX land had them on our Alpha's - Tru64 supports as a 'latent' device - but the politics of the day were TK-50 and TK-70 was the DEC official drive. It's interesting until DEC sold off the team and DLT to Quantum, it was not very popular except at VMS sites since the Unix world knew that the SCSI driver had full support for the standard devices. To Quantum credit, they redid the controller (put in a 68K IIRC) and life got much better. But it was always way more expensive than QIC, 4 or 8 mm. Clem =E1=90=A7 On Tue, Oct 16, 2018 at 1:23 PM William Pechter wrote: > DEC Tape II was the serial driven TU58. > The TK50 was CompacTape or something like that. It was the predecessor o= f > a number of square tapes... > > See DLT on Wikipedia https://en.m.wikipedia.org/wiki/Digital_Linear_Tape > > Bill > > -----Original Message----- > From: Paul Winalski > To: Clem Cole > Cc: The Eunuchs Hysterical Society , cctalk@classiccmp.org > Sent: Tue, 16 Oct 2018 13:14 > Subject: Re: [TUHS] Ultrix Tape: Block Size? > > On 10/15/18, Clem Cole wrote: > > #$%^ - they >>weren't<< like DECtape from a reliability standpoint ... > > =E1=90=A7 > The original DECtape was extremely reliable. Not so the TK50. > Calling it "DECtape II" was an insult to the original DECtape. The > problem wasn't so much the drive itself, but the controller. In an > effort to reduce costs, DEC used a controller that had insufficient > buffering capability for a streaming, block-replacement tape device > such as the TK50. TK50s were prone to both data-late and overrun > errors. > > The block size is almost certainly 512 bytes. > > -Paul W. > --000000000000b527bb05785bf78b Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
But Paul's comment is still right on - the controll= er for both was a 1MHz i8085 and just could not keep up.
I hated bo= th ..=C2=A0its' too bad DEC refused to use QIC.=C2=A0 =C2=A0They did ev= entually use 4mm DAT on an SCSI (and actually OEM'ed the drive from HP = it turns out).=C2=A0 =C2=A0The 8mm [Exabyte Unit] was from CSS and many of = us in UNIX land had them on our Alpha's - Tru64 supports as a 'late= nt' device - but the politics of the day were TK-50 and TK-70 was the D= EC official=C2=A0drive.=C2=A0

It's interesting unt= il DEC sold off the team and DLT=C2=A0 to Quantum, it was not very popular = except at VMS sites since the Unix world knew that the SCSI driver had full= support for the standard devices.=C2=A0 =C2=A0To Quantum credit, they redi= d the controller (put in a 68K IIRC) and life got much better.

=
But it was always way more expensive than QIC, 4 or 8 mm.
=
Clem
3D""=E1=90=A7

On Tue, Oct 16, 2018 at 1:23 PM William Pechter = <pechter@gmail.com> wrote:
DEC Tape II was the serial driven TU= 58.
The TK50 was CompacTape or something like that.=C2=A0 It was the predecesso= r of a number of square tapes...

See DLT on Wikipedia https://en.m.wikipedia.org/w= iki/Digital_Linear_Tape

Bill

-----Original Message-----
From: Paul Winalski <paul.winalski@gmail.com>
To: Clem Cole <clemc@= ccc.com>
Cc: The Eunuchs Hysterical Society <tuhs@tuhs.org>, cctalk@classiccmp.org
Sent: Tue, 16 Oct 2018 13:14
Subject: Re: [TUHS] Ultrix Tape: Block Size?

On 10/15/18, Clem Cole <clemc@ccc.com> wrote:
> #$%^ - they >>weren't<< like DECtape from a reliabilit= y standpoint ...
> =E1=90=A7
The original DECtape was extremely reliable.=C2=A0 Not so the TK50.
Calling it "DECtape II" was an insult to the original DECtape.=C2= =A0 The
problem wasn't so much the drive itself, but the controller.=C2=A0 In a= n
effort to reduce costs, DEC used a controller that had insufficient
buffering capability for a streaming, block-replacement tape device
such as the TK50.=C2=A0 TK50s were prone to both data-late and overrun
errors.

The block size is almost certainly 512 bytes.

-Paul W.
--000000000000b527bb05785bf78b--