16 Oct
2018
16 Oct
'18
1:56 a.m.
All, I received this request from Matthew who isn't subscribed to either
the TUHS or cctalk lists. He knows how to read the lists archives. Many
thanks for any help you can provide.
Cheers, Warren
----- Forwarded message from Matthew Whitehead -----
Date: Mon, 15 Oct 2018 08:25:39 -0400
From: Matthew Whitehead
Subject: Ultrix Tape Blocks
Warren,
I wonder if you can give me a referral. I want to install Ultrix-32
on my MicroVAX II using the ancient TK-50 tape drive. I know the tape
files are on your archive, but I need to know the block size for each
of the many files; it can vary a lot.
Who might be able to help me with this?
Matthew Whitehead
----- End forwarded message -----
16 Oct
16 Oct
3 a.m.
Be careful, TK-50 is different than 9-track. It's a streamer tape like
QIC, 4mm and 8mm. The blocking is done under the covers by the HW and the
blovk size if just how a DMA is done. I recommend that you pre-fetch the
read with dd or double-dd setting ibs=64k, obs=20b and conv=sync and pipe
the output to the reader (tar/cpio or the like) [if that fails try
obs=1b]. This should work well as can (TK-50 overall suck - don't set
your hopes high on anything with them -- they were DECtape from a
realiabilty standpoint, they were different from the reset of the world,
the performance was poor and they were expensive).
Anyway, by using dd or the like a front end, it will allow the read
streamer to read as fast as it can. The problem is that the way it works
under the cover does not shine with traditional UNIX I/O. BTW: ibs of
anything more than 64K on a VAX (or PDP-11) will not help because of the
dma size on the Unibus caps DMA read/writes at 64K. On a PMAX or (under
Tru64 on a Alpha), you can try using really large ibs sizes depending on
your physical memory size.
BTW: What will help the most is actually finding a copy of the old
double-dd program (from the UUNET archives) which forks off two child
procees to perform the actual I/O and alternates between the two processes
via pipe between them and controller - so one dd process is reading when
the other dd process is writing. [It used to be called: ddd before the Gnu
guys grabbed that name for the debugger]. The command line might be
something like: ddd ibs=64k obs=20b | tar xvpf -
FWIW: I wrote a version of a fast dd years ago that used pthreads and a
semaphore that I should still have kicking around. At one point when I
was dealing with streamer tapes for backup, I definitely ran it on Tru64
and FreeBSD, but I've forgotten where Ultrix fell.
ᐧ
On Mon, Oct 15, 2018 at 4:01 PM Warren Toomey <wkt(a)tuhs.org> wrote:
All, I received this request from Matthew who
isn't subscribed to either
the TUHS or cctalk lists. He knows how to read the lists archives. Many
thanks for any help you can provide.
Cheers, Warren
----- Forwarded message from Matthew Whitehead -----
Date: Mon, 15 Oct 2018 08:25:39 -0400
From: Matthew Whitehead
Subject: Ultrix Tape Blocks
Warren,
I wonder if you can give me a referral. I want to install Ultrix-32
on my MicroVAX II using the ancient TK-50 tape drive. I know the tape
files are on your archive, but I need to know the block size for each
of the many files; it can vary a lot.
Who might be able to help me with this?
Matthew Whitehead
----- End forwarded message -----
3:01 a.m.
#$%^ - they >>weren't<< like DECtape from a reliability standpoint ...
ᐧ
On Mon, Oct 15, 2018 at 5:00 PM Clem Cole <clemc(a)ccc.com> wrote:
Be careful, TK-50 is different than 9-track.
It's a streamer tape like
QIC, 4mm and 8mm. The blocking is done under the covers by the HW and the
blovk size if just how a DMA is done. I recommend that you pre-fetch the
read with dd or double-dd setting ibs=64k, obs=20b and conv=sync and pipe
the output to the reader (tar/cpio or the like) [if that fails try
obs=1b]. This should work well as can (TK-50 overall suck - don't set
your hopes high on anything with them -- they were DECtape from a
realiabilty standpoint, they were different from the reset of the world,
the performance was poor and they were expensive).
Anyway, by using dd or the like a front end, it will allow the read
streamer to read as fast as it can. The problem is that the way it works
under the cover does not shine with traditional UNIX I/O. BTW: ibs of
anything more than 64K on a VAX (or PDP-11) will not help because of the
dma size on the Unibus caps DMA read/writes at 64K. On a PMAX or (under
Tru64 on a Alpha), you can try using really large ibs sizes depending on
your physical memory size.
BTW: What will help the most is actually finding a copy of the old
double-dd program (from the UUNET archives) which forks off two child
procees to perform the actual I/O and alternates between the two processes
via pipe between them and controller - so one dd process is reading when
the other dd process is writing. [It used to be called: ddd before the
Gnu guys grabbed that name for the debugger]. The command line might be
something like: ddd ibs=64k obs=20b | tar xvpf -
FWIW: I wrote a version of a fast dd years ago that used pthreads and a
semaphore that I should still have kicking around. At one point when I
was dealing with streamer tapes for backup, I definitely ran it on Tru64
and FreeBSD, but I've forgotten where Ultrix fell.
ᐧ
On Mon, Oct 15, 2018 at 4:01 PM Warren Toomey <wkt(a)tuhs.org> wrote:
All, I received this request from Matthew who
isn't subscribed to either
the TUHS or cctalk lists. He knows how to read the lists archives. Many
thanks for any help you can provide.
Cheers, Warren
----- Forwarded message from Matthew Whitehead -----
Date: Mon, 15 Oct 2018 08:25:39 -0400
From: Matthew Whitehead
Subject: Ultrix Tape Blocks
Warren,
I wonder if you can give me a referral. I want to install Ultrix-32
on my MicroVAX II using the ancient TK-50 tape drive. I know the tape
files are on your archive, but I need to know the block size for each
of the many files; it can vary a lot.
Who might be able to help me with this?
Matthew Whitehead
----- End forwarded message -----
3:34 a.m.
I'm glad you corrected because when they worked, they were awesome. When
they didn't, life had a lot of swearing in it... And when I was sysadmin
for the MicroVAX II that had them, I swore like a sailor....
Warner
On Mon, Oct 15, 2018 at 3:04 PM Clem Cole <clemc(a)ccc.com> wrote:
#$%^ - they >>weren't<< like DECtape
from a reliability standpoint ...
ᐧ
On Mon, Oct 15, 2018 at 5:00 PM Clem Cole <clemc(a)ccc.com> wrote:
> Be careful, TK-50 is different than 9-track. It's a streamer tape like
> QIC, 4mm and 8mm. The blocking is done under the covers by the HW and the
> blovk size if just how a DMA is done. I recommend that you pre-fetch the
> read with dd or double-dd setting ibs=64k, obs=20b and conv=sync and pipe
> the output to the reader (tar/cpio or the like) [if that fails try
> obs=1b]. This should work well as can (TK-50 overall suck - don't set
> your hopes high on anything with them -- they were DECtape from a
> realiabilty standpoint, they were different from the reset of the world,
> the performance was poor and they were expensive).
>
> Anyway, by using dd or the like a front end, it will allow the read
> streamer to read as fast as it can. The problem is that the way it works
> under the cover does not shine with traditional UNIX I/O. BTW: ibs of
> anything more than 64K on a VAX (or PDP-11) will not help because of the
> dma size on the Unibus caps DMA read/writes at 64K. On a PMAX or (under
> Tru64 on a Alpha), you can try using really large ibs sizes depending on
> your physical memory size.
>
> BTW: What will help the most is actually finding a copy of the old
> double-dd program (from the UUNET archives) which forks off two child
> procees to perform the actual I/O and alternates between the two processes
> via pipe between them and controller - so one dd process is reading when
> the other dd process is writing. [It used to be called: ddd before the
> Gnu guys grabbed that name for the debugger]. The command line might be
> something like: ddd ibs=64k obs=20b | tar xvpf -
>
> FWIW: I wrote a version of a fast dd years ago that used pthreads and a
> semaphore that I should still have kicking around. At one point when I
> was dealing with streamer tapes for backup, I definitely ran it on Tru64
> and FreeBSD, but I've forgotten where Ultrix fell.
> ᐧ
>
> On Mon, Oct 15, 2018 at 4:01 PM Warren Toomey <wkt(a)tuhs.org> wrote:
>
>> All, I received this request from Matthew who isn't subscribed to either
>> the TUHS or cctalk lists. He knows how to read the lists archives. Many
>> thanks for any help you can provide.
>> Cheers, Warren
>>
>> ----- Forwarded message from Matthew Whitehead -----
>>
>> Date: Mon, 15 Oct 2018 08:25:39 -0400
>> From: Matthew Whitehead
>> Subject: Ultrix Tape Blocks
>>
>> Warren,
>> I wonder if you can give me a referral. I want to install Ultrix-32
>> on my MicroVAX II using the ancient TK-50 tape drive. I know the tape
>> files are on your archive, but I need to know the block size for each
>> of the many files; it can vary a lot.
>> Who might be able to help me with this?
>> Matthew Whitehead
>>
>> ----- End forwarded message -----
>>
>
10:57 p.m.
On 10/15/18, Clem Cole <clemc(a)ccc.com> wrote:
#$%^ - they >>weren't<< like DECtape
from a reliability standpoint ...
ᐧ
The original DECtape was extremely reliable. Not so the TK50.
Calling it "DECtape II" was an insult to the original DECtape. The
problem wasn't so much the drive itself, but the controller. In an
effort to reduce costs, DEC used a controller that had insufficient
buffering capability for a streaming, block-replacement tape device
such as the TK50. TK50s were prone to both data-late and overrun
errors.
The block size is almost certainly 512 bytes.
-Paul W.
11:23 p.m.
DEC Tape II was the serial driven TU58.
The TK50 was CompacTape or something like that. It was the predecessor of a number of
square tapes...
See DLT on Wikipedia https://en.m.wikipedia.org/wiki/Digital_Linear_Tape
Bill
-----Original Message-----
From: Paul Winalski <paul.winalski(a)gmail.com>
To: Clem Cole <clemc(a)ccc.com>
Cc: The Eunuchs Hysterical Society <tuhs(a)tuhs.org>rg>, cctalk(a)classiccmp.org
Sent: Tue, 16 Oct 2018 13:14
Subject: Re: [TUHS] Ultrix Tape: Block Size?
On 10/15/18, Clem Cole <clemc(a)ccc.com> wrote:
#$%^ - they >>weren't<< like DECtape
from a reliability standpoint ...
ᐧ
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.
11:34 p.m.
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
ᐧ
On Tue, Oct 16, 2018 at 1:23 PM William Pechter <pechter(a)gmail.com> wrote:
DEC Tape II was the serial driven TU58.
The TK50 was CompacTape or something like that. It was the predecessor of
a number of square tapes...
See DLT on Wikipedia https://en.m.wikipedia.org/wiki/Digital_Linear_Tape
Bill
-----Original Message-----
From: Paul Winalski <paul.winalski(a)gmail.com>
To: Clem Cole <clemc(a)ccc.com>
Cc: The Eunuchs Hysterical Society <tuhs(a)tuhs.org>rg>, cctalk(a)classiccmp.org
Sent: Tue, 16 Oct 2018 13:14
Subject: Re: [TUHS] Ultrix Tape: Block Size?
On 10/15/18, Clem Cole <clemc(a)ccc.com> wrote:
#$%^ - they >>weren't<< like
DECtape from a reliability standpoint ...
ᐧ
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.
11:34 p.m.
On 10/16/18, William Pechter <pechter(a)gmail.com> wrote:
DEC Tape II was the serial driven TU58.
The TK50 was CompacTape or something like that. It was the predecessor of a
number of square tapes...
See DLT on Wikipedia https://en.m.wikipedia.org/wiki/Digital_Linear_Tape
My mistake. Yes, I was thinking of the TU58, a most miserable device.
-Paul W.
11:24 p.m.
On Tue, Oct 16, 2018 at 12:57 PM Paul Winalski <paul.winalski(a)gmail.com>
wrote:
The block size is almost certainly 512 bytes.
Which is what I said - the block siize is set by the HW.
But ... the issue is trying to get the TK-50 to stream. Hence the
traditional unix: dd ibs=64K obs=XXX | tar xvfp - trick.
This will tell the driver to read upto 128 blocks in one DMA and then pump
the bits into tar a 'XXX block' at a time (which is is usually 20b for
tar/cpio/dump et al and Ultrix obey's).
ᐧ
20 Oct
20 Oct
3:17 a.m.
On Tue, 16 Oct 2018, Paul Winalski wrote:
The original DECtape was extremely reliable. [...]
Indeed it was; a former boss used to tell the story of a salesman blowing
cigarette smoke onto it (back when smoking was socially acceptable) and it
just kept on working...
-- Dave
16 Oct
16 Oct
3:52 a.m.
If it is anything like installing NetBSD, which I have done on a
VAXstation with a DLT4 drive, it should be 512 byte.
So, while I do not know for sure for Ultrix and MicroVAX, 512 is
probably a good starting point? Hopefully someone else will *actually*
know.
Aaron
Warren Toomey via cctalk writes:
All, I received this request from Matthew who
isn't subscribed to either
the TUHS or cctalk lists. He knows how to read the lists archives. Many
thanks for any help you can provide.
Cheers, Warren
----- Forwarded message from Matthew Whitehead -----
Date: Mon, 15 Oct 2018 08:25:39 -0400
From: Matthew Whitehead
Subject: Ultrix Tape Blocks
Warren,
I wonder if you can give me a referral. I want to install Ultrix-32
on my MicroVAX II using the ancient TK-50 tape drive. I know the tape
files are on your archive, but I need to know the block size for each
of the many files; it can vary a lot.
Who might be able to help me with this?
Matthew Whitehead
----- End forwarded message -----
--
Aaron Jackson - M6PIU
http://aaronsplace.co.uk/
2038
days inactive
2042
days old
10 comments
7 participants
participants (7)
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Aaron Jackson -
Clem Cole -
Dave Horsfall -
Paul Winalski -
Warner Losh -
Warren Toomey -
William Pechter