From: pechter@gmail.com (William Pechter)
Subject: [TUHS] Determining what was on a tape back in the day
Date: Mon, 20 Nov 2017 18:35:25 -0500 [thread overview]
Message-ID: <3a7416ad-b695-77bc-92c3-d37e6fddccc1@gmail.com> (raw)
In-Reply-To: <alpine.BSF.2.21.1711211010380.780@aneurin.horsfall.org>
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Dave Horsfall wrote:
> On Mon, 20 Nov 2017, Random832 wrote:
>
>> For whatever it's worth, the tm(4) and ht(4) manpages from V5 onward
>> say "seeks have their usual meaning", and both drivers provide a
>> 'non-raw' device which is a block device and (according to the
>> manual) only supports tapes consisting of 512-byte records - the BUGS
>> section mentions that the raw device, conversely, does *not* support
>> seeking.
>
> Thank you; I dimly recall that seeks were implemented by the driver
> keeping track of whichever block was under the head, and skipping
> forwards or backwards accordingly, with simple arithmetic. I no longer
> have access to those sources, but we at UNSW certainly modified Unix
> rather heavily, so if that capability is not in the distributed
> version then it means that we modified it; this was over 30 years ago...
>
> It bloody well worked as a read-only file system; I take great umbrage
> at the implication that I am a liar, and I'm the sort of obstreperous
> bastard who neither forgives not forgets...
>
I know that a read-only filesystem for installs is possible. Pyramid
Technologies used a tape install filesystem called ROFS...guess what
that stands for...
We used it on both cartridge (QIC-150 iirc) and 9 track magtapes... So
there's no special type of drive needed.
It was created by dd-ing a chrooted specially constructed file tree
(IIRC). I constructed special ones at my
site with all the site specific info (passwords, groups, etc) on it for
emergency recovery.
It was used for their OS/x (BSD-SysV dual universe for their Risc CPU)
and DCOSx (SVR4 port to Mips R3000).
Bill
next prev parent reply other threads:[~2017-11-20 23:35 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-19 13:41 Noel Chiappa
2017-11-19 14:55 ` Clem cole
2017-11-19 21:00 ` William Corcoran
2017-11-19 21:19 ` Ron Natalie
2017-11-19 22:00 ` Dave Horsfall
2017-11-19 22:38 ` Lyndon Nerenberg
2017-11-19 22:40 ` Ronald Natalie
2017-11-19 23:41 ` Dave Horsfall
2017-11-20 1:02 ` Ronald Natalie
2017-11-20 1:18 ` Dave Horsfall
2017-11-20 18:12 ` Random832
2017-11-20 23:22 ` Dave Horsfall
2017-11-20 23:35 ` William Pechter [this message]
2017-11-21 0:01 ` Ron Natalie
2017-11-20 19:02 ` Paul Winalski
2017-11-19 14:55 ` Will Senn
-- strict thread matches above, loose matches on Subject: below --
2017-11-20 19:42 Noel Chiappa
2017-11-20 17:00 Noel Chiappa
2017-11-20 16:01 Noel Chiappa
2017-11-20 17:37 ` Will Senn
2017-11-19 20:46 Steve Simon
2017-11-19 18:45 Noel Chiappa
2017-11-19 17:49 Noel Chiappa
2017-11-19 18:35 ` Arthur Krewat
2017-11-18 19:23 Noel Chiappa
2017-11-18 21:32 ` Will Senn
2017-11-18 21:49 ` Warren Toomey
2017-11-18 18:34 Noel Chiappa
2017-11-18 18:37 ` Ronald Natalie
2017-11-18 18:40 ` Ronald Natalie
2017-11-18 21:51 ` Dave Horsfall
2017-11-18 21:07 ` Will Senn
2017-11-18 22:53 ` Clem Cole
2017-11-19 1:47 ` Will Senn
2017-11-18 16:39 Will Senn
2017-11-18 18:57 ` Clem Cole
2017-11-18 20:03 ` Don Hopkins
2017-11-18 22:37 ` Dave Horsfall
2017-11-18 23:16 ` Don Hopkins
2017-11-18 23:35 ` Arthur Krewat
2017-11-19 0:35 ` Steve Nickolas
2017-11-19 0:42 ` Don Hopkins
2017-11-19 1:04 ` Clem cole
2017-11-19 16:20 ` Arthur Krewat
2017-11-20 2:33 ` Lawrence Stewart
2017-11-18 21:26 ` Will Senn
2017-11-18 22:39 ` Clem Cole
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