Re: Tape baking page by Wendy Carlos

[Chuck Guzis via cctalk]

On 12/18/20 8:10 PM, Jim Manley via cctalk wrote:
> http://www.wendycarlos.com/bake%20a%20tape/baketape.html
> 
> Wendy Carlos is the performer who produced "Switched-On Bach", the
> soundtrack for "A Clockwork Orange", "Sonic Seasonings", and a bunch of
> other amazing recordings created on single-voice Moog synthesizers, using
> multi-track tape recorders equipped with the sound-with-sound feature, to
> build upwards of dozens of simultaneous chords and parts.

She was "Walter" back then.  I remember how much I didn't like the
album.   The Third Brandenburg was way too fast for those used to Otto
Klemperer tempi.   Of course, times change and that tempo seems to be
the current standard.   That third movement must be murder on the basses.

--Chuck

Re: Tape baking page by Wendy Carlos

[Jim Manley via cctalk]

http://www.wendycarlos.com/bake%20a%20tape/baketape.html

Wendy Carlos is the performer who produced "Switched-On Bach", the
soundtrack for "A Clockwork Orange", "Sonic Seasonings", and a bunch of
other amazing recordings created on single-voice Moog synthesizers, using
multi-track tape recorders equipped with the sound-with-sound feature, to
build upwards of dozens of simultaneous chords and parts.


On Fri, Dec 18, 2020 at 1:42 AM jim stephens via cctalk <
cctalk@classiccmp.org> wrote:

> I ran across a reference to this on FB.  It appears to be from 2008, so
> may be well known or obsolete material.
>
> The other interesting info at the end of the article is the contact name
> and info about someone who restores or works on tape heads.
>
> Might be interesting to at least contact and ask if he's still around
>
> http://www.wendycarlos.com/bake%20a%20tape/baketape.html
>
>
> Contact John French, at JRF Magnetic Sciences (973-579-5773) for further
> details on magnetic tape head restoration and storage, and other related
> services and products.
>
> FB page with the info.
>
>
> https://www.facebook.com/ReelToReelTapeRecorders/photos/a.532104240183459/3658145454245973/
>
> The fellow who does a lot of tape recorder (reel to reel) repair has a
> FB group worth dropping in on.  This is the link to a photo with a
> pretty bad Ampex head.
>
> thanks
> Jim
>

Re: Tape baking page by Wendy Carlos

[Patrik Schindler via cctalk]

Hello Jim,

Am 18.12.2020 um 09:42 schrieb jim stephens via cctalk :

> I ran across a reference to this on FB.  It appears to be from 2008, so may 
> be well known or obsolete material.
> 
> The other interesting info at the end of the article is the contact name and 
> info about someone who restores or works on tape heads.
> 
> Might be interesting to at least contact and ask if he's still around
> 
> http://www.wendycarlos.com/bake%20a%20tape/baketape.html

Thanks for sharing this interesting read! I have a bunch of analog audio tapes, 
some most likely also very old.

:wq! PoC

Tape baking page by Wendy Carlos

[jim stephens via cctalk]

I ran across a reference to this on FB.  It appears to be from 2008, so 
may be well known or obsolete material.


The other interesting info at the end of the article is the contact name 
and info about someone who restores or works on tape heads.


Might be interesting to at least contact and ask if he's still around

http://www.wendycarlos.com/bake%20a%20tape/baketape.html


Contact John French, at JRF Magnetic Sciences (973-579-5773) for further 
details on magnetic tape head restoration and storage, and other related 
services and products.


FB page with the info.

https://www.facebook.com/ReelToReelTapeRecorders/photos/a.532104240183459/3658145454245973/

The fellow who does a lot of tape recorder (reel to reel) repair has a 
FB group worth dropping in on.  This is the link to a photo with a 
pretty bad Ampex head.


thanks
Jim

Re: tape baking

[Alan Perry via cctalk]

On 5/1/20 4:19 PM, Chuck Guzis via cctalk wrote:

On 5/1/20 1:59 PM, Curious Marc via cctalk wrote:

Agreed. They sure are pressed in, then riveted in for good measure. You’d have 
to drill them out first. Not an easy modification.
Marc


PTFE 2mm ID 3mm OD tubing is a standard size.  That might fit.

--Chuck


All of the QIC-24 cartridges sitting next to me right now have posts 
that are machined with 1-2mm deep tape guides. I don't see how to 
install tubing over the posts and have the guides still do their job.


As I noted, I have tried isopropyl alcohol to clean them off but they 
still stick. Is this something that baking will help with? Maybe using 
acetone instead of alcohol to wipe the posts down as well?


alan

Re: tape baking

[Chuck Guzis via cctalk]

On 5/1/20 1:59 PM, Curious Marc via cctalk wrote:
> Agreed. They sure are pressed in, then riveted in for good measure. You’d 
> have to drill them out first. Not an easy modification. 
> Marc

PTFE 2mm ID 3mm OD tubing is a standard size.  That might fit.

--Chuck

Re: tape baking

[Curious Marc via cctalk]

Agreed. They sure are pressed in, then riveted in for good measure. You’d have 
to drill them out first. Not an easy modification. 
Marc

> On Apr 30, 2020, at 2:18 PM, Al Kossow via cctalk  
> wrote:
> 
> On 4/29/20 10:01 PM, Curious Marc via cctalk wrote:
>> Or replacing the posts with ones machined from Teflon or Delrin?
> 
> The posts are staked in. You might be able to make tiny rollers to go over 
> the pins
> Their working diameter isn't super critical
> 

Re: tape baking

[Steve Malikoff via cctalk]

Al reckoned
> On 4/29/20 10:01 PM, Curious Marc via cctalk wrote:
>> Or replacing the posts with ones machined from Teflon or Delrin?
>
> The posts are staked in. You might be able to make tiny rollers to go over 
> the pins
> Their working diameter isn't super critical

That's a good idea. Would cutting sections of an (empty) ink tube from a 
ballpoint pen work?
These are generally polypropelene and should be totally inert.

Steve.

Re: tape baking

[Curious Marc via cctalk]

I see the tape sticking to posts syndrome in my limited experience with HP QIC 
tapes also (DC100 / DC2000). The best I have come up with is wipe the posts 
with isopropanol. But I had not thought of lubricating them for a 1 time read, 
interesting idea. Or replacing the posts with ones machined from Teflon or 
Delrin?
Marc

> On Apr 28, 2020, at 3:37 PM, Alan Perry via cctalk  
> wrote:
> 
> 
> 
>> On 4/28/20 11:47 AM, Chuck Guzis via cctalk wrote:
>> I'm a bit surprised that this is even a "thing" in the audio business.
>> Restorers have been baking audio tapes for a long time.
> 
> That is acknowledged in the slides, isn't it?
> 
> "Thermal Baking: A popular, poorly understood remedy"
> 
> "Most common remediation (successfully used for decades)"
> 
> "No consistent baking procedures - to this day audio tape users argue about 
> about why it works."
> 
>> Isopropanol does not clean the sticky deposits from equipment--you must
>> use a stronger solvent.  Acetone, Perc or MEK generally does the trick.
> 
> I am trying to read a bunch of late 80s QIC-24 tapes (Sun/Computervision 
> install media). In addition to the normal QIC band problem, I am seeing 
> problems with the tape sticking on the metal posts that the tape goes around 
> to change direction towards the reels. Should I try wiping the posts with 
> acetone or wiping the tape with cyclomethicone? Should I be baking the tapes? 
> If so, what is a safe way to bake QIC cartridges?
> 
> alan

Re: tape baking

[Chuck Guzis via cctalk]

On 4/28/20 1:14 PM, r.stricklin via cctalk wrote:
> 
> On Apr 28, 2020, at 11:47 AM, Chuck Guzis via cctech wrote:
> 
>> Rather than try to clean the gunk off the tape, which is probably a
>> fool's errand, I coat the tape with cyclomethicone
> 
> Just as a word of caution, I've had at least one catastrophic outcome trying 
> this with a QIC tape. Use too much (when "not enough" isn't cutting it), the 
> belt can't do its job, and what I ended up with was a big knot.

Never tried it on QIC tapes; only 1/2" open-reel.   I despise QIC-family
(and by extension) Travan tapes.  Lots of frustration and heartache.

--Chuck

Re: tape baking

[r.stricklin via cctalk]

On Apr 28, 2020, at 11:47 AM, Chuck Guzis via cctech wrote:

> Rather than try to clean the gunk off the tape, which is probably a
> fool's errand, I coat the tape with cyclomethicone

Just as a word of caution, I've had at least one catastrophic outcome trying 
this with a QIC tape. Use too much (when "not enough" isn't cutting it), the 
belt can't do its job, and what I ended up with was a big knot.

ok
bear.

-- 
until further notice

Re: tape baking

[Adrian Stoness via cctalk]

sony PR-150 will jam a machine up and makes a squeeking type noise as well.

then theres sticky shed syndrom that leaves a nasty mess caugh shamrock
tape caugh caugh


On Tue, Apr 28, 2020 at 1:47 PM Chuck Guzis via cctalk <
cctalk@classiccmp.org> wrote:

> I'm a bit surprised that this is even a "thing" in the audio business.
> Restorers have been baking audio tapes for a long time.
>
> One thing not discussed (maybe it doesn't occur in audio) is that there
> can be issues in binder formulation, at least in digital tapes.  In
> particular, 3M tapes, most notably Scotch 701 and 777 formulations, have
> an issue where the binder "liquefies" under motion and solidifies when
> tape motion slows or ceases.  So, you may be running a tape through a
> drive just fine and then suddenly, everything freezes up as the tape
> becomes firmly "glued" to the heads or other objects in the tape path,
> usually with a loud squeal.
>
> In the current batch of 60 tapes from the late 60s-mid 70s, every single
> 3M tape exhibited this behavior.  It didn't matter if they'd been baked
> or not.  There was a note of this on Ed Thelen's site where someone had
> encountered this and given up.
>
> Isopropanol does not clean the sticky deposits from equipment--you must
> use a stronger solvent.  Acetone, Perc or MEK generally does the trick.
>
> Rather than try to clean the gunk off the tape, which is probably a
> fool's errand, I coat the tape with cyclomethicone, using a felt
> applicator in my cleaning machine--it doesn't take much to create a
> slippery film on the tape surface, perhaps 10 ml will do a 2400' tape.
> Cylcomethicone is non-toxic and relatively inert--and is somewhat
> volatile, so that it evaporates in a couple of hours, leaving the tape
> as it was.  Very slippery stuff, so don't spill it on the floor!  It
> does not appear to have a solvent effect on the binder, as nearly as I
> can tell.  It also doesn't appear to bother the equipment either.
>
> I've achieved 100% success using this method.
>
> I think it's interesting that tape quality tends to better the older the
> tape.  Audio Devices, Ampex and IBM Series 500 tapes tend to survive the
> best. Memorex seems to get worse, the younger it is.  (e.g. MRX III
> tends to behave better than MRX V).
>
> For whatever it's worth,
> Chuck
>

Re: tape baking

[Kevin Bowling via cctalk]

Out of curiosity has anyone tried running tapes at different temperatures,
for instance in a relative cold or hot environment? Either on a simple
winder or even a recovery drive.

On Tue, Apr 28, 2020 at 11:47 AM Chuck Guzis via cctalk <
cctalk@classiccmp.org> wrote:

> I'm a bit surprised that this is even a "thing" in the audio business.
> Restorers have been baking audio tapes for a long time.
>
> One thing not discussed (maybe it doesn't occur in audio) is that there
> can be issues in binder formulation, at least in digital tapes.  In
> particular, 3M tapes, most notably Scotch 701 and 777 formulations, have
> an issue where the binder "liquefies" under motion and solidifies when
> tape motion slows or ceases.  So, you may be running a tape through a
> drive just fine and then suddenly, everything freezes up as the tape
> becomes firmly "glued" to the heads or other objects in the tape path,
> usually with a loud squeal.
>
> In the current batch of 60 tapes from the late 60s-mid 70s, every single
> 3M tape exhibited this behavior.  It didn't matter if they'd been baked
> or not.  There was a note of this on Ed Thelen's site where someone had
> encountered this and given up.
>
> Isopropanol does not clean the sticky deposits from equipment--you must
> use a stronger solvent.  Acetone, Perc or MEK generally does the trick.
>
> Rather than try to clean the gunk off the tape, which is probably a
> fool's errand, I coat the tape with cyclomethicone, using a felt
> applicator in my cleaning machine--it doesn't take much to create a
> slippery film on the tape surface, perhaps 10 ml will do a 2400' tape.
> Cylcomethicone is non-toxic and relatively inert--and is somewhat
> volatile, so that it evaporates in a couple of hours, leaving the tape
> as it was.  Very slippery stuff, so don't spill it on the floor!  It
> does not appear to have a solvent effect on the binder, as nearly as I
> can tell.  It also doesn't appear to bother the equipment either.
>
> I've achieved 100% success using this method.
>
> I think it's interesting that tape quality tends to better the older the
> tape.  Audio Devices, Ampex and IBM Series 500 tapes tend to survive the
> best. Memorex seems to get worse, the younger it is.  (e.g. MRX III
> tends to behave better than MRX V).
>
> For whatever it's worth,
> Chuck
>

Re: tape baking

[Al Kossow via cctalk]

On 4/28/20 3:37 PM, Alan Perry via cctalk wrote:

wiping the posts with acetone or wiping the tape with cyclomethicone? Should I be baking the tapes? If so, what is a safe way to bake QIC 
cartridges?




I bake the carts with the bands removed and the covers off in a food dehydrator

I also wrap the posts with lint-free cloth and use a rubber glue like fabric 
adhesive I found in the crafts section of wallmart
Obviously, I re-use the bases until the cloth becomes fouled

QIC tape is thin, I wouldn't recommend using any liquid on it, even as a 
lubricant. It is very easy to wipe the binder off

The brand of drive you use is really important. the direct drive tanbergs work 
the best

I went through about 100 computervision sun3 era carts last year. They weren't 
horrible, using reused DC150 belts
I didn't get the images uploaded before I got locked out of my lab.

Re: tape baking

[Alan Perry via cctalk]

On 4/28/20 11:47 AM, Chuck Guzis via cctalk wrote:

I'm a bit surprised that this is even a "thing" in the audio business.
Restorers have been baking audio tapes for a long time.


That is acknowledged in the slides, isn't it?

"Thermal Baking: A popular, poorly understood remedy"

"Most common remediation (successfully used for decades)"

"No consistent baking procedures - to this day audio tape users argue 
about about why it works."



Isopropanol does not clean the sticky deposits from equipment--you must
use a stronger solvent.  Acetone, Perc or MEK generally does the trick.


I am trying to read a bunch of late 80s QIC-24 tapes (Sun/Computervision 
install media). In addition to the normal QIC band problem, I am seeing 
problems with the tape sticking on the metal posts that the tape goes 
around to change direction towards the reels. Should I try wiping the 
posts with acetone or wiping the tape with cyclomethicone? Should I be 
baking the tapes? If so, what is a safe way to bake QIC cartridges?


alan

Re: tape baking

[Al Kossow via cctalk]

On 4/28/20 11:47 AM, Chuck Guzis via cctalk wrote:


For whatever it's worth


Magnetic tape recovery people live in silos

I doubt anyone at LoC has ever even heard of you or me, or that they will ever
see the years of discussions we've had on this subject. I wonder if
they he even talked to the LoC teams doing digital recovery.

The only thing of value I saw in the discussion were some theories of what
is happening chemically to the binder with application of heat.

Re: tape baking

[Chuck Guzis via cctalk]

I'm a bit surprised that this is even a "thing" in the audio business.
Restorers have been baking audio tapes for a long time.

One thing not discussed (maybe it doesn't occur in audio) is that there
can be issues in binder formulation, at least in digital tapes.  In
particular, 3M tapes, most notably Scotch 701 and 777 formulations, have
an issue where the binder "liquefies" under motion and solidifies when
tape motion slows or ceases.  So, you may be running a tape through a
drive just fine and then suddenly, everything freezes up as the tape
becomes firmly "glued" to the heads or other objects in the tape path,
usually with a loud squeal.

In the current batch of 60 tapes from the late 60s-mid 70s, every single
3M tape exhibited this behavior.  It didn't matter if they'd been baked
or not.  There was a note of this on Ed Thelen's site where someone had
encountered this and given up.

Isopropanol does not clean the sticky deposits from equipment--you must
use a stronger solvent.  Acetone, Perc or MEK generally does the trick.

Rather than try to clean the gunk off the tape, which is probably a
fool's errand, I coat the tape with cyclomethicone, using a felt
applicator in my cleaning machine--it doesn't take much to create a
slippery film on the tape surface, perhaps 10 ml will do a 2400' tape.
Cylcomethicone is non-toxic and relatively inert--and is somewhat
volatile, so that it evaporates in a couple of hours, leaving the tape
as it was.  Very slippery stuff, so don't spill it on the floor!  It
does not appear to have a solvent effect on the binder, as nearly as I
can tell.  It also doesn't appear to bother the equipment either.

I've achieved 100% success using this method.

I think it's interesting that tape quality tends to better the older the
tape.  Audio Devices, Ampex and IBM Series 500 tapes tend to survive the
best. Memorex seems to get worse, the younger it is.  (e.g. MRX III
tends to behave better than MRX V).

For whatever it's worth,
Chuck

Re: tape baking

[John Foust via cctalk]

At 05:56 AM 4/28/2020, you wrote:

>https://www.morressier.com/article/towards-understanding-thermal-remediation-degraded-archival-reeltoreel-audio-tapes/5e736c6bcde2b641284abb13

Lower right pic on "layers in contact" slide, looks like it was inverted...

- John

Re: tape baking

[Al Kossow via cctalk]

On 4/28/20 3:56 AM, Al Kossow via cctalk wrote:


https://www.morressier.com/article/towards-understanding-thermal-remediation-degraded-archival-reeltoreel-audio-tapes/5e736c6bcde2b641284abb13



https://listserv.loc.gov/cgi-bin/wa?A2=ARSCLIST;d144d59c.2004

tape baking

[Al Kossow via cctalk]

https://www.morressier.com/article/towards-understanding-thermal-remediation-degraded-archival-reeltoreel-audio-tapes/5e736c6bcde2b641284abb13

RE: tape baking (Rob Jarratt)

[Rob Jarratt via cctalk]

> -Original Message-
> From: Eric Smith [mailto:space...@gmail.com]
> Sent: 11 July 2017 04:02
> To: r...@jarratt.me.uk; Rob Jarratt <robert.jarr...@ntlworld.com>; General
> Discussion: On-Topic and Off-Topic Posts <cctalk@classiccmp.org>
> Cc: Rich Alderson <ri...@livingcomputers.org>; General Discussion: On-Topic
> Posts <cct...@classiccmp.org>
> Subject: Re: tape baking (Rob Jarratt)
> 
> On Mon, Jul 10, 2017 at 3:38 PM, Rob Jarratt via cctalk
> <cctalk@classiccmp.org> wrote:
> Do you have any videos (with sound!) of the LP20 operating?
> 
> The LP20 is just the printer interface. It looks exactly the same whether it's
> operating or not, and doesn't make any sound unless something is very very
> wrong.
> 


Oh! I didn't know that. The document I have on the configuration of the system 
I used says it has "One DEC LP20H line printer with a character set of 96 
characters operating at 925 lines per minute". Looks like I had not understood 
the nuance of the extra letter on the end.

Regards

Rob

Re: tape baking (Rob Jarratt)

[Eric Smith via cctalk]

On Mon, Jul 10, 2017 at 3:38 PM, Rob Jarratt via cctalk <
cctalk@classiccmp.org> wrote:

> Do you have any videos (with sound!) of the LP20 operating?
>

The LP20 is just the printer interface. It looks exactly the same whether
it's operating or not, and doesn't make any sound unless something is very
very wrong.

RE: tape baking (Rob Jarratt)

[Rob Jarratt via cctalk]

> -Original Message-
> From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Rich
> Alderson via cctalk
> Sent: 10 July 2017 20:05
> To: 'General Discussion: On-Topic Posts' <cct...@classiccmp.org>
> Subject: RE: tape baking (Rob Jarratt)
> 
> From: Michael Thompson
> Sent: Sunday, July 09, 2017 7:41 AM
> 
> > A while ago the Living Computers: Museum + Labs borrowed my LP20
> > controller so they could clone the boards for one of their PDP-10s.
> > Since they went through that effort they must have a big line printer.
> 
> LP27, specifically.  An OEM'd BP1500 from Data Products.  The LP20 lives in 
> the
> front end of the 2065 running Tops-10 v7.04.
> 


Do you have any videos (with sound!) of the LP20 operating?

Regards

Rob

RE: tape baking (Rob Jarratt)

[Rich Alderson via cctalk]

From: Michael Thompson
Sent: Sunday, July 09, 2017 7:41 AM

> A while ago the Living Computers: Museum + Labs borrowed my LP20 controller
> so they could clone the boards for one of their PDP-10s. Since they went
> through that effort they must have a big line printer.

LP27, specifically.  An OEM'd BP1500 from Data Products.  The LP20 lives in the
front end of the 2065 running Tops-10 v7.04.

We have other big printers on other big iron, of course.

Rich

Rich Alderson
Vintage Computing Sr. Systems Engineer
Living Computers: Museum + Labs
2245 1st Avenue S
Seattle, WA 98134

mailto:ri...@livingcomputers.org

http://www.LivingComputers.org/

Re: Line printer art: (was Re: tape baking)

[Charles Anthony via cctalk]

On Mon, Jul 10, 2017 at 4:19 AM, Martin Hepperle via cctalk <
cctalk@classiccmp.org> wrote:

> For those interested in viewing those line printer files but without a
> suitable printer I have hacked together a small Java program for viewing
> and
> exporting the files. Nothing great, but it does the job.  Try SMALLCAT
> first.
>
> I understood that the first column contains FORTRANish line advance
> characters, but I am not sure what the "-" means.
> Nevertheless the result looks reasonable.
>

Triple space (https://en.wikipedia.org/wiki/ASA_carriage_control_characters)

-- Charles

Re: Line printer art: (was Re: tape baking)

[Keven Miller(rtt) via cctalk]

Thanks for the fun exercise!
Nice job. I viewed SPOCK, MOON, ASTRONAUT.

I had to recompile (at moment I'm set for java 6; and still novice at java)

"-" means triple space.

Keven Miller

- Original Message - 
From: "Martin Hepperle via cctalk" <cctalk@classiccmp.org>

To: <cctalk@classiccmp.org>
Sent: Mon 10 Jul 2017 05:19 AM
Subject: Re: Line printer art: (was Re: tape baking)



For those interested in viewing those line printer files but without a
suitable printer I have hacked together a small Java program for viewing 
and

exporting the files. Nothing great, but it does the job.  Try SMALLCAT
first.

I understood that the first column contains FORTRANish line advance
characters, but I am not sure what the "-" means.
Nevertheless the result looks reasonable.

A zip archive with a runnable jarchive and the source can be found at:
http://www.mh-aerotools.de/downloads/LineArtPrinter.zip

Martin

Re: Line printer art: (was Re: tape baking)

[Martin Hepperle via cctalk]

For those interested in viewing those line printer files but without a
suitable printer I have hacked together a small Java program for viewing and
exporting the files. Nothing great, but it does the job.  Try SMALLCAT
first.

I understood that the first column contains FORTRANish line advance
characters, but I am not sure what the "-" means.
Nevertheless the result looks reasonable.

A zip archive with a runnable jarchive and the source can be found at:
http://www.mh-aerotools.de/downloads/LineArtPrinter.zip

Martin

RE: tape baking (Rob Jarratt)

[Rob Jarratt via cctalk]

> -Original Message-
> From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Michael
> Thompson via cctalk
> Sent: 09 July 2017 15:41
> To: cctech <cct...@classiccmp.org>
> Subject: Re: tape baking (Rob Jarratt)
> 
> >
> > Date: Fri, 7 Jul 2017 21:19:03 +0100
> > From: "Rob Jarratt" <robert.jarr...@ntlworld.com>
> > Subject: RE: tape baking
> >
> > > I long to hear again the sound of the line printer that was attached
> > > to
> > the
> > > DECSYSTEM-20 I used to use. I think it was a drum printer but I
> > > don't
> > know
> > the
> > > model (I may have some materials around that mention the model, not
> > > sure where they are now though). I could never house one of these
> > > though, if
> > any
> > > still exist.
> > >
> >
> >
> > I looked it up, it was a DEC LP20H that they had. I'd love to hear one
> > of those running again. Do any still exist?
> >
> > Regards
> >
> > Rob
> >
> 
> A while ago the Living Computers: Museum + Labs borrowed my LP20
> controller so they could clone the boards for one of their PDP-10s. Since they
> went through that effort they must have a big line printer.
> 

I have been to LCM a number of times, but I live a *very* long way from there 
and I don't know when I am likely to go again. However, if I do, I will ask 
about any LP20s.

Regards

Rob

Re: tape baking (Rob Jarratt)

[Michael Thompson via cctalk]

>
> Date: Fri, 7 Jul 2017 21:19:03 +0100
> From: "Rob Jarratt" <robert.jarr...@ntlworld.com>
> Subject: RE: tape baking
>
> > I long to hear again the sound of the line printer that was attached to
> the
> > DECSYSTEM-20 I used to use. I think it was a drum printer but I don't
> know
> the
> > model (I may have some materials around that mention the model, not sure
> > where they are now though). I could never house one of these though, if
> any
> > still exist.
> >
>
>
> I looked it up, it was a DEC LP20H that they had. I'd love to hear one of
> those running again. Do any still exist?
>
> Regards
>
> Rob
>

A while ago the Living Computers: Museum + Labs borrowed my LP20 controller
so they could clone the boards for one of their PDP-10s. Since they went
through that effort they must have a big line printer.

-- 
Michael Thompson

Re: Line printer art: (was Re: tape baking)

[Jeff Woolsey via cctalk]

You know, I have about four different tapes with those Harbison posters
on them.  Different formats, too.  They're probably ubiquitous by now.

For those of you without printers who still want to see the posters,
asciitopgm from the netpbm package can be coaxed to do this.  See
http://netpbm.sourceforge.net/doc/asciitopgm.html .   Coals to
Newcastle, anyone?

-- 
  Jeff Woolsey
  j...@jlw.com

Re: Line printer art: (was Re: tape baking)

[Alan Frisbie via cctalk]

Al Kossow  wrote:

> Need to update my reader anyway soon, so I'm going
> to append something similar to what you did the new
> images I create, probably just a ascii text record
> and a label picture.

For the many hundreds of 9-track tapes I'm turning into
image files, I am also including an ASCII text file of
whatever information I can read from the paper label and
any related notes, plus several photographs of the reel
of tape and any labels.

Some of the labels are so faded that the only way I can
read them is to put them on the flatbed scanner, then
manipulate the color & contrast to bring out the writing.

Of course, the photos are many times larger than the
data file!

I'm trying to figure out how to best organize all this
data.   The best I've come up with so far is to put all
the files for one tape in a single directory, all with
similar names.   Suggestions would be welcome.

Before I got side-tracked with other projects, I had
imaged some 600 1600 bpi tapes.   Now I have about 400
800 bpi tapes to do.   The delay is that the room with
the 800 bpi drive (Cipher 910) is so full of "stuff"
that I can barely see the drive at the far side of the
room.   I'm sure than none of you people have this
problem!  :-)

Alan Frisbie

RE: Line printer art: (was Re: tape baking)

[Dave Wade via cctalk]

> -Original Message-
> From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Peter
> Coghlan via cctalk
> Sent: 07 July 2017 23:32
> To: General Discussion: On-Topic and Off-Topic Posts
> <cctalk@classiccmp.org>
> Subject: RE: Line printer art: (was Re: tape baking)
> 
> >
> > >
> > > If anyone's running Hercules or some other uses-EBCDIC emulator,
> > > here's the link to the .tap image file.
> > >
> > > https://app.box.com/s/8rxbihjjnw5zdkesym4cjwqswekufagh
> > >
> > > --Chuck
> >
> > Sadly I don't think that's much use on Hercules as it needs an AWS or
> > HET file. Is there a format converter any where?
> >
> 
> I think I recall managing to do that sort of conversion with VTAPECP which is
> part of something called VTAPEUTILS.  It looks like I used version 0.2.
> 
> Regards,
> Peter Coghlan.

Thanks Peter, 

Found those in SourceForge and managed to compile on Windows. Tape copied to 
.aws and first file loaded into VM...

Dave

RE: Line printer art: (was Re: tape baking)

[Peter Coghlan via cctalk]

>
> >
> > If anyone's running Hercules or some other uses-EBCDIC emulator, here's
> > the link to the .tap image file.
> > 
> > https://app.box.com/s/8rxbihjjnw5zdkesym4cjwqswekufagh
> > 
> > --Chuck
>
> Sadly I don't think that's much use on Hercules as it needs an AWS or HET
> file. Is there a format converter any where?
>

I think I recall managing to do that sort of conversion with VTAPECP which is
part of something called VTAPEUTILS.  It looks like I used version 0.2.

Regards,
Peter Coghlan.

Re: Line printer art: (was Re: tape baking)

[Chuck Guzis via cctalk]

On 07/07/2017 12:46 PM, Al Kossow via cctalk wrote:

> It is literally "you can't save everything, where would you put it?"
> 
> You can be completely buried by piles of unknown data on magnetic
> media.
And yet, I'll venture that it's a pretty safe bet that all of the data
recorded between 1955-1980 would occupy only a tiny part of what's being
lost on the web every week.

Brewster Kahle has an ambitious goal (and I'm grateful for the effort),
but I think it'll eventually come to bailing the Titanic with a teaspoon.

The NSA does a bit better, I'm sure.

--Chuck

RE: tape baking

[Rob Jarratt via cctalk]

> I long to hear again the sound of the line printer that was attached to
the
> DECSYSTEM-20 I used to use. I think it was a drum printer but I don't know
the
> model (I may have some materials around that mention the model, not sure
> where they are now though). I could never house one of these though, if
any
> still exist.
> 


I looked it up, it was a DEC LP20H that they had. I'd love to hear one of
those running again. Do any still exist?

Regards

Rob

Re: Line printer art: (was Re: tape baking)

[Al Kossow via cctalk]

yup

On 7/7/17 12:33 PM, Chuck Guzis via cctalk wrote:
> On 07/07/2017 12:04 PM, Al Kossow via cctalk wrote:
> 
>>
>> The way JBI did it was to digitize the capstan encoder as a clock
>> reference for tape motion obliquely referenced in 
>> http://storageconference.us/2008/presentations/3.Wednesday/5.Bordynuik.pdf
> They mention a 36-track tape head.  Were those pretty much stock 3490E
> heads?
> 
> --Chuck
> 

Re: Line printer art: (was Re: tape baking)

[Al Kossow via cctalk]

On 7/7/17 12:28 PM, Chuck Guzis via cctalk wrote:

> It brings up another aspect.   I've done a batch of tapes that had
> nothing more that the originator's name and an inventory number.   Upon
> recovering data, the customer had no idea what it meant or how it was
> created or even the system used to create it.

> 
> We're coming onto the "Linear B" era in computing I think, where
> knowledge is passing out of human memory. 
We have a VERY large collection of paper tapes from Whirlwind. They have
nice numbers on the outside of the boxes. We have no catalog. The best I've
been able to do is piece together a guess as to what non-secret projects they
were associated with based on the periodic MIT project reports. What is data
and what are programs, who knows? oh.. and they were stored in a basement and
the boxes are moldy.

There is a water mark where if something isn't of value enough to someone
to save and continue to pay for its preservation, it's dumpstered. While
it is nice to say things need to be preserved, if there isn't manpower or
space it won't be.

It is literally "you can't save everything, where would you put it?"

You can be completely buried by piles of unknown data on magnetic media.

Re: Line printer art: (was Re: tape baking)

[Chuck Guzis via cctalk]

On 07/07/2017 12:04 PM, Al Kossow via cctalk wrote:

> 
> The way JBI did it was to digitize the capstan encoder as a clock
> reference for tape motion obliquely referenced in 
> http://storageconference.us/2008/presentations/3.Wednesday/5.Bordynuik.pdf
They mention a 36-track tape head.  Were those pretty much stock 3490E
heads?

--Chuck

Re: Line printer art: (was Re: tape baking)

[Chuck Guzis via cctalk]

On 07/07/2017 12:17 PM, Al Kossow via cctalk wrote:

> I'm much less hopeful on any other parallel tape formats, since there
> are so few and the desire to recover any of that has been low.

It brings up another aspect.   I've done a batch of tapes that had
nothing more that the originator's name and an inventory number.   Upon
recovering data, the customer had no idea what it meant or how it was
created or even the system used to create it.

We're coming onto the "Linear B" era in computing I think, where
knowledge is passing out of human memory.  I noted that some years ago
with the mention of the Zodiac system.  Something like $200M initially
spent on it, when that was a lot of money.  Few documents remain and no
(AFAIK) data samples. I've heard estimates of 3M lines of code, all of
it gone.

I'll wager that there are hundreds of cases of this kind of thing.

--Chuck

Re: Line printer art: (was Re: tape baking)

[Al Kossow via cctalk]

On 7/7/17 12:08 PM, Paul Koning wrote:

>> And I'm moving towards flux-level archiving and away from using
>> stock tape transports.
>>
>> But then, I've been saying that for 15+ years now and haven't done it.
> 
> It would be great to have that capability, after the company that had it 
> before seemingly vanished.  Better yet if you can handle not just plain 7 and 
> 9 track 1/2 inch tape but also other formats.  3/4 inch tape would come to 
> mind (DECtape and friends).  There's one inch tape (CDC 626) though I'm not 
> sure if any has been preserved.  There's 1/2 inch 10 track tape 
> (Electrologica X1 and others).
> 
> Stuff like error correction data makes sense for such low level capture.  
> It's not so obvious if you're working with a conventional tape transport, 
> which simply tells you "read error, you're SOL" if the checksums are no good. 
>  


I guess you've tried contacting John then about the Xelctrologica tapes?

He sent me a prototype drive with 18-track (IBM 3480) head that I still haven't
gotten to work. Most of the code lives on a Virtex FPGA board with the A/D 
converters
attached and he never gave me the source or adequate instructions on how to 
talk to it

This only works because the 3480 and 90 still used 1/2" width tape.

DECtape recovery hasn't been a problem. It's pretty rugged stuff.

I'm much less hopeful on any other parallel tape formats, since there are so 
few and the desire
to recover any of that has been low.

Re: Line printer art: (was Re: tape baking)

[Paul Koning via cctalk]

> On Jul 7, 2017, at 1:29 PM, Al Kossow via cctalk  
> wrote:
> 
> 
> 
> On 7/7/17 10:26 AM, Al Kossow via cctalk wrote:
> 
>> I stopped beating that horse years ago.
> 
> And I'm moving towards flux-level archiving and away from using
> stock tape transports.
> 
> But then, I've been saying that for 15+ years now and haven't done it.

It would be great to have that capability, after the company that had it before 
seemingly vanished.  Better yet if you can handle not just plain 7 and 9 track 
1/2 inch tape but also other formats.  3/4 inch tape would come to mind 
(DECtape and friends).  There's one inch tape (CDC 626) though I'm not sure if 
any has been preserved.  There's 1/2 inch 10 track tape (Electrologica X1 and 
others).

Stuff like error correction data makes sense for such low level capture.  It's 
not so obvious if you're working with a conventional tape transport, which 
simply tells you "read error, you're SOL" if the checksums are no good.  

paul

Re: Line printer art: (was Re: tape baking)

[Al Kossow via cctalk]

On 7/7/17 11:10 AM, Chuck Guzis via cctalk wrote:

> I've puzzled over how to do tape flux-transition recording in any
> meaningful way.

The way JBI did it was to digitize the capstan encoder as a clock reference for 
tape motion
obliquely referenced in
http://storageconference.us/2008/presentations/3.Wednesday/5.Bordynuik.pdf

--

Thanks to the current administration, all of the NASA Nimbus data reports 
appear to have
dissapeared from the web.

mentions in
http://www.sciencedirect.com/science/article/pii/S2214242815000212#bb0035

"An examination of these 7-track tapes revealed they were in poor shape. The 
tapes iron oxide media was falling off the
acetate film backing. Fortunately, GSFC had just learned of a Canadian company, 
JBI Incorporated that had developed a
tape recovery process that could read the bits from magnetic tapes with a high 
degree of certainty. The JBI recovery
process involved using specially developed tape drives with 36 magnetoresistive 
(MR) heads, tape baking (10 h at 175°),
bit detection and processing techniques to read the 800 bit-per-inch, 7-track 
tapes. Based on the original Nimbus HRIR
system documentation, GSFC was then able to recover and rescue the observations 
from thousands of Nimbus HRIR digital
data tapes"

M. Hobish, D. Gallaher, G. Campbell, W. Meier
Dark data rescue: shedding new light on old photons
The Earth Observer May–June 2014, 26 (3) (2014), pp. 4-10


for example

gsfc.nasa.gov/nimbus/documentation/documents/N7_Recovery_Report_Jul16.doc

Re: Line printer art: (was Re: tape baking)

[Chuck Guzis via cctalk]

On 07/07/2017 10:26 AM, Al Kossow via cctalk wrote:

> I stopped beating that horse years ago. They also assume that all of the data
> blocks read correctly, they don't save the error correction data if the block
> had it, etc etc.
> 
> Need to update my reader anyway soon, so I'm going to append something 
> similar to
> what you did the new images I create, probably just a ascii text record and a 
> label picture.

I currently add 2 records (in TAP prefix/suffix format).   The first
starts with CR-LF "LOG" CR-LF;the second is identifiable as a JPEG
"JFIF" file.  Nothing more complicated than that.

At least the log identifies bad blocks and what the problem was insofar
as the reading software can determine.  That may be all that's available
on some SCSI drives.  Pertec-interface drives can pinpoint the frame in
error much of the time.

I've puzzled over how to do tape flux-transition recording in any
meaningful way.  One of the problems is encoding skewing information as
well as tape speed--unlike floppies, you have parallel tracks and tape
speed (reading and writing) isn't constant.  A good deal of the data
recovery circuitry in a 9 or 7 track drive involves deskewing and speed
compensation.

I recall looking at customer samples back in the day from CDC 669 drives
using a low-power microscope and developer and being gobsmacked at how
crowded things were at the start of a tape block.  The customer was
running the Navy Audit COBOL tests and the short block stop-start tape
I/O suite was giving the drives fits.  Spence Preston eventually flew in
and reworked the firmware over about two weeks so that things held
together--I didn't get any detail on the specifics of his fix.

I suppose that one could simply oversample the tape, recording
sub-frames every 100 nsec or so, but I haven't thought that one through.
 But it would be easy enough to do with a medium-power MCU.   Writing
the code to make sense of the data, perhaps not so much.

--Chuck

Re: Line printer art: (was Re: tape baking)

[Al Kossow via cctalk]

On 7/7/17 10:26 AM, Al Kossow via cctalk wrote:

> I stopped beating that horse years ago.

And I'm moving towards flux-level archiving and away from using
stock tape transports.

But then, I've been saying that for 15+ years now and haven't done it.

Re: Line printer art: (was Re: tape baking)

[Al Kossow via cctalk]

On 7/7/17 9:35 AM, Chuck Guzis via cctalk wrote:

> I've voiced my opinion before of being a bit surprised that neither AWS
> nor TAP makes any provision for metadata.   The tape data bits don't
> tell the whole story.


I stopped beating that horse years ago. They also assume that all of the data
blocks read correctly, they don't save the error correction data if the block
had it, etc etc.

Need to update my reader anyway soon, so I'm going to append something similar 
to
what you did the new images I create, probably just a ascii text record and a 
label picture.

Re: Line printer art: (was Re: tape baking)

[Chuck Guzis via cctalk]

On 07/07/2017 08:25 AM, Dave Wade wrote:

> The header is six bytes long. Two are the length of the current
> block. Two of the bytes are the length of the previous block, so you
> can do read backwards, two of the bytes contain flag bits. One of the
> flags says this chunk  is the first part of a real block, another the
> last part, so typically both are set for blocks less than 64K. For
> blocks, bigger than 64K they the  first chunk flag is set for the
> first 64K, the last chunk has the last chunk bit set, and any
> intermediate chunks have no bits set. Again this facilitates read
> backwards

Okay, that fills in a few gaps that the reference I cited didn't address.

Contrast with the SIMH .tap structure, where all blocks are prefixed and
suffixed with a 32-bit byte count, with certain high-order bits serving
as flags for error and EOI indicators, with a single 32bit word of zero
serving as tapemark.   Read-backward is straightforward.

The AWS format seems overcomplicated to me, but perhaps it's an artifact
of a 16-bit memory-limited implementation.  It's curious that, like TAP,
the byte counts are little-endian.

In any case, not a big deal to translate between the two.

My own implementation of TAP keeps the same basic structure as the SIMH
version, but appends a few records of metadata, including the log
session of the read of the physical tape and a JPEG of the original
tape.  I usually trim those off when I make tape data available for
other than the customer.   Almost all of my work is done with archivists
and the metadata is much appreciated.

I've voiced my opinion before of being a bit surprised that neither AWS
nor TAP makes any provision for metadata.   The tape data bits don't
tell the whole story.

--Chuck

RE: Line printer art: (was Re: tape baking)

[Dave Wade via cctalk]

> -Original Message-
> From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Chuck
> Guzis via cctalk
> Sent: 07 July 2017 08:11
> To: CCtalk <cctalk@classiccmp.org>
> Subject: Re: Line printer art: (was Re: tape baking)
> 
> On 07/06/2017 10:42 PM, Dave Wade wrote:
> 
> > Sadly I don't think that’s much use on Hercules as it needs an AWS or HET
> file. Is there a format converter any where?
> 
> Dunno, but it should be pretty simple.  TAP is discussed with the SIMH
> documentation and the AWS format is discussed here:
> 
> http://www.cbttape.org/awstape.htm
> 
> Mostly a matter of reworking headers.   The surprising thing is that I
> know that some IBM tapes can have 128KB records--I don't know how AWS
> accommodates this with only 2 bytes for a record length.
> 
> And "long block" tapes can theoretically have a single block that's the length
> of the physical tape, although one would be an idiot to do such a thing.  (cf.
> CDC CYBER NOS/BE 1LT driver)


The header is six bytes long. Two are the length of the current block. Two of 
the bytes are the length of the previous block, so you can do read backwards, 
two of the bytes contain flag bits. 
One of the flags says this chunk  is the first part of a real block, another 
the last part, so typically both are set for blocks less than 64K. For blocks, 
bigger than 64K they the  first chunk flag is set for the first 64K, the last 
chunk has the last chunk bit set, and any intermediate chunks have no bits set. 
Again this facilitates read backwards

> 
> --Chuck

Dave

Re: Line printer art: (was Re: tape baking)

[Chuck Guzis via cctalk]

On 07/06/2017 10:42 PM, Dave Wade wrote:

> Sadly I don't think that’s much use on Hercules as it needs an AWS or HET 
> file. Is there a format converter any where?

Dunno, but it should be pretty simple.  TAP is discussed with the SIMH
documentation and the AWS format is discussed here:

http://www.cbttape.org/awstape.htm

Mostly a matter of reworking headers.   The surprising thing is that I
know that some IBM tapes can have 128KB records--I don't know how AWS
accommodates this with only 2 bytes for a record length.

And "long block" tapes can theoretically have a single block that's the
length of the physical tape, although one would be an idiot to do such a
thing.  (cf. CDC CYBER NOS/BE 1LT driver)

--Chuck

Re: tape baking

[Ron Pool via cctalk]

Thanks, Chuck!

On Thu, Jul 6, 2017 at 3:05 PM, Chuck Guzis via cctalk <
cctalk@classiccmp.org> wrote:

> On 07/06/2017 11:43 AM, Paul Koning via cctalk wrote:
>
> > EBCDIC is easy, just grab an IBM Green Card.  I'd recomment not using
> > a translation if possible, since translations are likely to be lossy.
> > There are EBCDIC characters that have no ASCII analog.
>
> All else being equal, I'd agree--but you can either work with a .tap
> file or the individual filemark separated files, which means that you'll
> also have read the label records and interpret them to get the file name
> and blocking.
>
> All in all, if you're not used to this, the ASCII should do.
>
> --Chuck
>
>


-- 
Ron Pool 

Re: tape baking

[Ron Pool via cctalk]

I'd love to also get a copy.  ASCII would be my preference.

On Thu, Jul 6, 2017 at 2:20 PM, Chuck Guzis via cctalk <
cctalk@classiccmp.org> wrote:

> On 07/06/2017 11:09 AM, Mark J. Blair via cctalk wrote:
>
> > Did you apply it to the whole tape prior to reading it, or did you apply
> it in place on the tape drive while reading the tape?
>
> The whole tape--I ran my tape cleaner at low speed and used a strip of
> 1/2" thick synthetic felt glued to a large PVC pipe fitting as the
> applicator.  Needless to mention, it was on the supply side of the
> cleaner, or else the tape wouldn't have made it through.   The
> lubrication lasted for two reads of the tape.
>
> I think I did a moldy tape of Noel's last year this way also and got the
> whole thing.
>
> > Are they online anywhere? I wouldn't mind taking a look at them.
>
> No, but I can put a copy up on my Box account.  Do you want the original
> EBCDIC .tap image or the ASCII-translated files?
>
> --Chuck
>
>


-- 
Ron Pool 

RE: Line printer art: (was Re: tape baking)

[Dave Wade via cctalk]

> -Original Message-
> From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Chuck
> Guzis via cctalk
> Sent: 06 July 2017 21:03
> To: General Discussion: On-Topic and Off-Topic Posts
> <cctalk@classiccmp.org>
> Subject: Re: Line printer art: (was Re: tape baking)
> 
> On 07/06/2017 12:41 PM, Ethan Dicks wrote:
> 
> > I got it from the Box link.  Thanks!
> 
> If anyone's running Hercules or some other uses-EBCDIC emulator, here's
> the link to the .tap image file.
> 
> https://app.box.com/s/8rxbihjjnw5zdkesym4cjwqswekufagh
> 
> --Chuck

Sadly I don't think that’s much use on Hercules as it needs an AWS or HET file. 
Is there a format converter any where?

Dave 

RE: Line printer art: (was Re: tape baking)

[Dave Wade via cctalk]

> -Original Message-
> From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Ethan
> Dicks via cctalk
> Sent: 06 July 2017 20:02
> To: Chuck Guzis <ccl...@sydex.com>; General Discussion: On-Topic and Off-
> Topic Posts <cctalk@classiccmp.org>
> Subject: Line printer art: (was Re: tape baking)
> 
> On Thu, Jul 6, 2017 at 1:59 PM, Chuck Guzis via cctalk <cctalk@classiccmp.org>
> wrote:
> > It worked--I retrieved a tape of line printer art from Princeton quite
> > successfully.  Oddly, nobody was interested in a copy of the files.
> 
> I'm interested!  I'm about to read a card deck for an old work associate who 
> is
> reasonably sure it has some ASCII art on it (it's unlikely to be a "lost" 
> picture,
> but there's always a chance).

Me too. A few sites on-line have copies of these pics...

> 
> > Go figure.  Perhaps nobody owns a line printer that takes continuous
> > forms any more.
> 
> I still have at least one LA180, some LA100s, and probably several more
> tractor-feed wide-carriage printers including one medium-sized
> DataProducts line printer.  What I don't have is an abundance of paper
> - I have some, but not like 30 years ago when it was easy to get partial boxes
> for free or cheap.

I also have an LA100 plus a wide carriage daisy wheel...
... I got a few boxes when some showed up on E-Bay in the UK..

> 
> Feel free to PM me a link to where I could get a copy of these art files or
> reply here with it.

Thanks for the link.

> 
> -ethan

Dave

Re: Line printer art: (was Re: tape baking)

[Charles Anthony via cctalk]

On Thu, Jul 6, 2017 at 3:18 PM, Chuck Guzis via cctalk <
cctalk@classiccmp.org> wrote:

> You know, I do a fair amount of this stuff.  The confidential/secret
> stuff I keep that way (e.g. 100 tapes that I'm doing for NASA this
> summer), but there's also a fair amount of public stuff that I do have
> permission to share.   I've done the hard work in translating the data
> to something recognizable (e.g. CDC 6-bit display code) but don't have a
> clue as to what to do with it, if anything.
>
> I'll occasionally post an offer over at VCFed, but have never gotten
> much interest going there, so I don't bother nowadays.
>
> Much of the data is already known; for instance, yet another set of AT
> Unix SysVR4 tapes.  (One wonders how many copies of this were made).
>
> But there are some tidbits that I haven't seen anywhere else.
>
> Any interest in this?
>
>
We are always looking for Multics software; especially the unbundled
network stack tapes.


-- Charles


>
>

Re: Line printer art: (was Re: tape baking)

[Paul Anderson via cctalk]

Just passing it on. If anyone is interested, last I heard Devon has 2
nice printers for sale in Florida.

On Thu, Jul 6, 2017 at 5:48 PM, Rob Jarratt via cctalk <
cctalk@classiccmp.org> wrote:

> > -Original Message-
> > From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Chuck
> Guzis
> > via cctalk
> > Sent: 06 July 2017 23:19
> > To: General Discussion: On-Topic and Off-Topic Posts <
> cctalk@classiccmp.org>
> > Subject: Re: Line printer art: (was Re: tape baking)
> >
> > You know, I do a fair amount of this stuff.  The confidential/secret
> stuff I keep
> > that way (e.g. 100 tapes that I'm doing for NASA this summer), but
> there's also
> > a fair amount of public stuff that I do have
> > permission to share.   I've done the hard work in translating the data
> > to something recognizable (e.g. CDC 6-bit display code) but don't have a
> clue as
> > to what to do with it, if anything.
> >
> > I'll occasionally post an offer over at VCFed, but have never gotten much
> > interest going there, so I don't bother nowadays.
> >
> > Much of the data is already known; for instance, yet another set of AT
> Unix
> > SysVR4 tapes.  (One wonders how many copies of this were made).
> >
> > But there are some tidbits that I haven't seen anywhere else.
> >
> > Any interest in this?
> >
>
>
> Perhaps it could be posted to a special area on BitSavers?
>
> Regards
>
> Rob
>
>
>

Re: tape baking

[Chuck Guzis via cctalk]

On 07/06/2017 03:57 PM, Rob Jarratt via cctalk wrote:
 11/730.
> 
> I long to hear again the sound of the line printer that was attached
> to the DECSYSTEM-20 I used to use. I think it was a drum printer but
> I don't know the model (I may have some materials around that mention
> the model, not sure where they are now though). I could never house
> one of these though, if any still exist.

What, no 1403s, or CDC 512s?

In the mid 80's, we had a couple of CDC/MPI line printers connected to
our VAX 11/750.   They were the typical large black soundproof
enclosures, and were very quiet, probably not more than 1000 LPM.
Definitely not the screaming banshee the 512 was, nor the rattling
machine gun that the 501 was.

I think the interface was Dataproducts, not Centronics, but I'm not sure
about that.

My favorite printer of about that time was the Teletype Dataspeed 40
band printer.   You could put it on a tabletop.  Speed was perhaps 150
lpm.  So just right for a small shop.   I think I've still got the
schematics for that one.

--Chuck

RE: tape baking

[Rob Jarratt via cctalk]

> -Original Message-
> From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Mark J.
> Blair via cctalk
> Sent: 06 July 2017 23:39
> To: General Discussion: On-Topic and Off-Topic Posts
<cctalk@classiccmp.org>
> Subject: Re: tape baking
> 
> 
> > On Jul 6, 2017, at 3:34 PM, jim stephens via cctalk
<cctalk@classiccmp.org>
> wrote:
> >
> >
> >
> > On 7/6/2017 10:59 AM, Chuck Guzis via cctalk wrote:
> >> Go figure.  Perhaps nobody owns a line printer that takes continuous
> >> forms any more.
> > I'm moving a Data Products 2230 this weekend.
> 
> Oooh, congratulations! I don't have a proper line printer yet, though I
have a
> number of small dot matrix printers and I can print on wide greenbar with
my
> LA120. I still hold out hope that I might find an LP32 someday to go with
my
> 11/730.

I long to hear again the sound of the line printer that was attached to the
DECSYSTEM-20 I used to use. I think it was a drum printer but I don't know
the model (I may have some materials around that mention the model, not sure
where they are now though). I could never house one of these though, if any
still exist.

Regards

Rob

Re: tape baking

[Guy Sotomayor Jr via cctalk]

> On Jul 6, 2017, at 3:39 PM, Mark J. Blair via cctalk  
> wrote:
> 
> 
>> On Jul 6, 2017, at 3:34 PM, jim stephens via cctalk  
>> wrote:
>> 
>> 
>> 
>> On 7/6/2017 10:59 AM, Chuck Guzis via cctalk wrote:
>>> Go figure.  Perhaps nobody owns a line printer that takes continuous
>>> forms any more.
>> I'm moving a Data Products 2230 this weekend.
> 
> Oooh, congratulations! I don't have a proper line printer yet, though I have 
> a number of small dot matrix printers and I can print on wide greenbar with 
> my LA120. I still hold out hope that I might find an LP32 someday to go with 
> my 11/730.

I have a DEC LP25 that is working reasonably well.  It’s usually hooked up to 
my 11/70.  Then of course I have an IBM 1403N1 (1100 lpm) for my IBM 4331 
mainframe.  But that has to wait until I figure out how to get 3-phase to power 
it!  ;-)

TTFN - Guy

RE: Line printer art: (was Re: tape baking)

[Rob Jarratt via cctalk]

> -Original Message-
> From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Chuck Guzis
> via cctalk
> Sent: 06 July 2017 23:19
> To: General Discussion: On-Topic and Off-Topic Posts <cctalk@classiccmp.org>
> Subject: Re: Line printer art: (was Re: tape baking)
> 
> You know, I do a fair amount of this stuff.  The confidential/secret stuff I 
> keep
> that way (e.g. 100 tapes that I'm doing for NASA this summer), but there's 
> also
> a fair amount of public stuff that I do have
> permission to share.   I've done the hard work in translating the data
> to something recognizable (e.g. CDC 6-bit display code) but don't have a clue 
> as
> to what to do with it, if anything.
> 
> I'll occasionally post an offer over at VCFed, but have never gotten much
> interest going there, so I don't bother nowadays.
> 
> Much of the data is already known; for instance, yet another set of AT Unix
> SysVR4 tapes.  (One wonders how many copies of this were made).
> 
> But there are some tidbits that I haven't seen anywhere else.
> 
> Any interest in this?
> 


Perhaps it could be posted to a special area on BitSavers?

Regards

Rob

Re: tape baking

[Mark J. Blair via cctalk]

> On Jul 6, 2017, at 3:34 PM, jim stephens via cctalk  
> wrote:
> 
> 
> 
> On 7/6/2017 10:59 AM, Chuck Guzis via cctalk wrote:
>> Go figure.  Perhaps nobody owns a line printer that takes continuous
>> forms any more.
> I'm moving a Data Products 2230 this weekend.

Oooh, congratulations! I don't have a proper line printer yet, though I have a 
number of small dot matrix printers and I can print on wide greenbar with my 
LA120. I still hold out hope that I might find an LP32 someday to go with my 
11/730.

-- 
Mark J. Blair, NF6X 
http://www.nf6x.net/

Re: tape baking

[jim stephens via cctalk]

On 7/6/2017 10:59 AM, Chuck Guzis via cctalk wrote:

Go figure.  Perhaps nobody owns a line printer that takes continuous
forms any more.

I'm moving a Data Products 2230 this weekend.

Re: tape baking

[jim stephens via cctalk]

On 7/6/2017 1:25 PM, Al Kossow via cctalk wrote:

yup, the SAM HARBISON ones are classic, esp SPOCK
http://q7.neurotica.com/Oldtech/ASCII/
I thought you had put up the Harbison tape I sent on bitsavers.  If not, 
you can do so.  Prof Harbison said he had no problem with sharing it.  
The tape I got came thru Caltech, I think, and was a 370 format print 
record tape.


I'd be interested in a copy of your image, Chuck to see how it compares.

Not that much problem with converting the format, as my tape was in 
Ebcdic.  The tricky part is finding an impact printer which will render 
the levels properly.


thanks
jim

Re: Line printer art: (was Re: tape baking)

[Chuck Guzis via cctalk]

You know, I do a fair amount of this stuff.  The confidential/secret
stuff I keep that way (e.g. 100 tapes that I'm doing for NASA this
summer), but there's also a fair amount of public stuff that I do have
permission to share.   I've done the hard work in translating the data
to something recognizable (e.g. CDC 6-bit display code) but don't have a
clue as to what to do with it, if anything.

I'll occasionally post an offer over at VCFed, but have never gotten
much interest going there, so I don't bother nowadays.

Much of the data is already known; for instance, yet another set of AT
Unix SysVR4 tapes.  (One wonders how many copies of this were made).

But there are some tidbits that I haven't seen anywhere else.

Any interest in this?

--Chuck

Re: tape baking

[Mark J. Blair via cctalk]

> On Jul 6, 2017, at 11:50 AM, Chuck Guzis via cctalk  
> wrote:
> 
> I've uploaded the files to my Box account:
> 
> https://app.box.com/s/liuljs46noaz58grdwuj170mjh66qzm8
> 
> I have the permission of the owner to share these.  Note that many of
> them depend upon first-character FORTRAN carriage control.

I have downloaded the archive. I'll need to see if I have anything sitting 
around that understands the carriage control, or else hack up a quick script to 
convert the files to plain line-delimited text. Thanks!


-- 
Mark J. Blair, NF6X 
http://www.nf6x.net/

Re: tape baking

[Mark J. Blair via cctalk]

> On Jul 6, 2017, at 12:42 PM, Rob Jarratt  wrote:
> 
> 
> Why not give baking a go then? Or have I missed something? I would of course
> recommend trying with an unimportant tape first until you get a time and
> temperature that works for your setup.

Oh, it's on my get-around-to-it list. I'll start out experimenting with that 
random tape that has already shed a lot of oxide. If I can get it to load and 
rewind without sticking to the heads and rollers, then I'll know I have the 
parameters worked out.


-- 
Mark J. Blair, NF6X 
http://www.nf6x.net/

Re: Line printer art: (was Re: tape baking)

[Ethan Dicks via cctalk]

On Thu, Jul 6, 2017 at 3:01 PM, Ethan Dicks  wrote:
> On Thu, Jul 6, 2017 at 1:59 PM, Chuck Guzis via cctalk
>  wrote:
>> It worked--I retrieved a tape of line printer art from Princeton quite
>> successfully.

I reviewed the ASCII copy.  Several of the files, including JOHNDEAN
and MOON (I did not check 100% of them) are also in David Gessewein's
copy of line printer art from Princeton at:

http://www.pdp8online.com/ftp/ascii_art/ppt/

For MOON, as an example, once I trimmed the first 2 lines and the
trailing "form feed" line (a lone '1' in the first column), and
converted it to UNIX line terminators, was a 100% match.  The file
names are slightly different, but the picture body and even the
comments are the same.

> I'm about to read a card deck for an old work
> associate who is reasonably sure it has some ASCII art on it (it's
> unlikely to be a "lost" picture, but there's always a chance).

Thus my comment... it would be surprising to find a lost work at this
point, so it's worth looking, just in case.

I need to fire up my LA180 again - it will do the overstrike pictures.
I used it 30 years ago to print the high-detail photo of the cat that
was popular then.  Took a long, long time to print.

Thanks!

-ethan

Re: tape baking

[Al Kossow via cctalk]

yup, the SAM HARBISON ones are classic, esp SPOCK
http://q7.neurotica.com/Oldtech/ASCII/

On 7/6/17 10:59 AM, Chuck Guzis via cctalk wrote:

> It worked--I retrieved a tape of line printer art from Princeton quite
> successfully.  Oddly, nobody was interested in a copy of the files.

Re: Line printer art: (was Re: tape baking)

[Chuck Guzis via cctalk]

On 07/06/2017 12:41 PM, Ethan Dicks wrote:

> I got it from the Box link.  Thanks!

If anyone's running Hercules or some other uses-EBCDIC emulator, here's
the link to the .tap image file.

https://app.box.com/s/8rxbihjjnw5zdkesym4cjwqswekufagh

--Chuck

RE: tape baking

[Rob Jarratt via cctalk]

> -Original Message-
> From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Mark J.
> Blair via cctalk
> Sent: 06 July 2017 17:47
> To: General Discussion: On-Topic and Off-Topic Posts
<cctalk@classiccmp.org>
> Subject: Re: tape baking
> 
> 
> > On Jul 4, 2017, at 08:16, Al Kossow via cctalk <cctalk@classiccmp.org>
wrote:
> >
> > The 'out-gassed material' is water, which has been absorbed by the
> > binder, which is hydroscopic.
> 
> Has anybody experimented with drying media in a vacuum chamber at room
> temperature?
> 
> My abortive attempt to play with an old TK50 tape in a TZ30 drive was a
> disaster of sticking, oxide shedding, and manual unloading/respooling of a
tape
> that the drive could no longer handle. I had not tried baking the tape.
> 


Why not give baking a go then? Or have I missed something? I would of course
recommend trying with an unimportant tape first until you get a time and
temperature that works for your setup.

Regards

Rob

> I do plan to make some sort of media baking setup when that project
bubbles
> back to the top of the list. I wonder if pulling vacuum on a tape for a
while
> might also have the desired effect? I have a bottle of cyclomethicone on
order.
> I wonder if I might need to make some sort of reeling machine to apply it
to
> tapes? The TK50 tapes are particularly resistant to manual manipulation.
> Maybe I could make a machine to allow me to unspool a TK50 tape while
> wiping on cyclomethicone and then re-spool it, perhaps by hacking up a
drive
> mechanism.
> 
> --
> Mark J. Blair, NF6X <n...@nf6x.net>
> http://www.nf6x.net/

Re: Line printer art: (was Re: tape baking)

[Ethan Dicks via cctalk]

On Thu, Jul 6, 2017 at 3:01 PM, Ethan Dicks  wrote:
> Feel free to PM me a link to where I could get a copy of these art
> files or reply here with it.

I got it from the Box link.  Thanks!

-ethan

Re: tape baking

[Chuck Guzis via cctalk]

On 07/06/2017 11:43 AM, Paul Koning via cctalk wrote:

> EBCDIC is easy, just grab an IBM Green Card.  I'd recomment not using
> a translation if possible, since translations are likely to be lossy.
> There are EBCDIC characters that have no ASCII analog.

All else being equal, I'd agree--but you can either work with a .tap
file or the individual filemark separated files, which means that you'll
also have read the label records and interpret them to get the file name
and blocking.

All in all, if you're not used to this, the ASCII should do.

--Chuck

Line printer art: (was Re: tape baking)

[Ethan Dicks via cctalk]

On Thu, Jul 6, 2017 at 1:59 PM, Chuck Guzis via cctalk
 wrote:
> It worked--I retrieved a tape of line printer art from Princeton quite
> successfully.  Oddly, nobody was interested in a copy of the files.

I'm interested!  I'm about to read a card deck for an old work
associate who is reasonably sure it has some ASCII art on it (it's
unlikely to be a "lost" picture, but there's always a chance).

> Go figure.  Perhaps nobody owns a line printer that takes continuous
> forms any more.

I still have at least one LA180, some LA100s, and probably several
more tractor-feed wide-carriage printers including one medium-sized
DataProducts line printer.  What I don't have is an abundance of paper
- I have some, but not like 30 years ago when it was easy to get
partial boxes for free or cheap.

Feel free to PM me a link to where I could get a copy of these art
files or reply here with it.

-ethan

Re: tape baking

[Chuck Guzis via cctalk]

On 07/06/2017 11:35 AM, Mark J. Blair via cctalk wrote:

> I don't have a tape cleaner. Maybe I should make one. In particular, for 
> those damned TK50 tapes!

They do show up occasionally on eBay.  Mine was NOS from a government
surplus auction.  Complete but for the bottle of Freon TF, but I can
understand why that was confiscated.

> I would enjoy seeing the ASCII translated files. I don't have any experience 
> dealing with EBCDIC-era stuff yet.

I've uploaded the files to my Box account:

https://app.box.com/s/liuljs46noaz58grdwuj170mjh66qzm8

I have the permission of the owner to share these.  Note that many of
them depend upon first-character FORTRAN carriage control.

--Chuck

Re: tape baking

[Mark J. Blair via cctalk]

> On Jul 6, 2017, at 11:20 AM, Chuck Guzis via cctalk  
> wrote:
> 
> On 07/06/2017 11:09 AM, Mark J. Blair via cctalk wrote:
> 
>> Did you apply it to the whole tape prior to reading it, or did you apply it 
>> in place on the tape drive while reading the tape?
> 
> The whole tape--I ran my tape cleaner at low speed and used a strip of
> 1/2" thick synthetic felt glued to a large PVC pipe fitting as the
> applicator.  Needless to mention, it was on the supply side of the
> cleaner, or else the tape wouldn't have made it through.   The
> lubrication lasted for two reads of the tape.


I don't have a tape cleaner. Maybe I should make one. In particular, for those 
damned TK50 tapes!

> 
> I think I did a moldy tape of Noel's last year this way also and got the
> whole thing.
> 
>> Are they online anywhere? I wouldn't mind taking a look at them.
> 
> No, but I can put a copy up on my Box account.  Do you want the original
> EBCDIC .tap image or the ASCII-translated files?


I would enjoy seeing the ASCII translated files. I don't have any experience 
dealing with EBCDIC-era stuff yet.


-- 
Mark J. Blair, NF6X 
http://www.nf6x.net/

Re: tape baking

[Chuck Guzis via cctalk]

On 07/06/2017 11:09 AM, Mark J. Blair via cctalk wrote:

> Did you apply it to the whole tape prior to reading it, or did you apply it 
> in place on the tape drive while reading the tape?

The whole tape--I ran my tape cleaner at low speed and used a strip of
1/2" thick synthetic felt glued to a large PVC pipe fitting as the
applicator.  Needless to mention, it was on the supply side of the
cleaner, or else the tape wouldn't have made it through.   The
lubrication lasted for two reads of the tape.

I think I did a moldy tape of Noel's last year this way also and got the
whole thing.

> Are they online anywhere? I wouldn't mind taking a look at them.

No, but I can put a copy up on my Box account.  Do you want the original
EBCDIC .tap image or the ASCII-translated files?

--Chuck

Re: tape baking

[Mark J. Blair via cctalk]

> On Jul 6, 2017, at 10:59 AM, Chuck Guzis via cctalk  
> wrote:
> 
> That's what I do when baking doesn't do the trick; e.g. binder
> bleed-through.  But, as Al says, don't overdo it.  I used a thick felt
> wiper to deposit a thin film on a 2400' reel of tape.  I added more to
> the wiper about halfway through.  Perhaps 5 ml or less for the whole tape.

Did you apply it to the whole tape prior to reading it, or did you apply it in 
place on the tape drive while reading the tape?

> 
> It worked--I retrieved a tape of line printer art from Princeton quite
> successfully.  Oddly, nobody was interested in a copy of the files.

Are they online anywhere? I wouldn't mind taking a look at them.



-- 
Mark J. Blair, NF6X 
http://www.nf6x.net/

Re: tape baking

[Chuck Guzis via cctalk]

On 07/06/2017 09:58 AM, Mark J. Blair via cctalk wrote:

> Can the cyclomethicone be used to help address sticky shed on a tape?
> If it evaporates too quickly to apply it to an entire tape before
> reading, then perhaps by placing a wiper in the tape path to apply it
> during reading would work?
That's what I do when baking doesn't do the trick; e.g. binder
bleed-through.  But, as Al says, don't overdo it.  I used a thick felt
wiper to deposit a thin film on a 2400' reel of tape.  I added more to
the wiper about halfway through.  Perhaps 5 ml or less for the whole tape.

It worked--I retrieved a tape of line printer art from Princeton quite
successfully.  Oddly, nobody was interested in a copy of the files.

Go figure.  Perhaps nobody owns a line printer that takes continuous
forms any more.

--Chuck

Re: tape baking

[Mark J. Blair via cctalk]

> On Jul 6, 2017, at 09:55, Al Kossow via cctalk  wrote:
> 
> 
> 
> On 7/6/17 9:47 AM, Mark J. Blair via cctalk wrote:
>> Maybe I could make a machine to allow me to unspool a TK50 tape while wiping 
>> on cyclomethicone and then re-spool it, perhaps by hacking up a drive 
>> mechanism.
>> 
> 
> It evaporates too quickly.
> I have also seen it dissolve binder if you use too much.

Can the cyclomethicone be used to help address sticky shed on a tape? If it 
evaporates too quickly to apply it to an entire tape before reading, then 
perhaps by placing a wiper in the tape path to apply it during reading would 
work?

-- 
Mark J. Blair, NF6X 
http://www.nf6x.net/

Re: tape baking

[Al Kossow via cctalk]

On 7/6/17 9:47 AM, Mark J. Blair via cctalk wrote:
> Maybe I could make a machine to allow me to unspool a TK50 tape while wiping 
> on cyclomethicone and then re-spool it, perhaps by hacking up a drive 
> mechanism.
> 

It evaporates too quickly.
I have also seen it dissolve binder if you use too much.

Re: tape baking

[Mark J. Blair via cctalk]

> On Jul 4, 2017, at 08:16, Al Kossow via cctalk  wrote:
> 
> The 'out-gassed material' is water, which has been absorbed
> by the binder, which is hydroscopic.

Has anybody experimented with drying media in a vacuum chamber at room 
temperature?

My abortive attempt to play with an old TK50 tape in a TZ30 drive was a 
disaster of sticking, oxide shedding, and manual unloading/respooling of a tape 
that the drive could no longer handle. I had not tried baking the tape.

I do plan to make some sort of media baking setup when that project bubbles 
back to the top of the list. I wonder if pulling vacuum on a tape for a while 
might also have the desired effect? I have a bottle of cyclomethicone on order. 
I wonder if I might need to make some sort of reeling machine to apply it to 
tapes? The TK50 tapes are particularly resistant to manual manipulation. Maybe 
I could make a machine to allow me to unspool a TK50 tape while wiping on 
cyclomethicone and then re-spool it, perhaps by hacking up a drive mechanism.

-- 
Mark J. Blair, NF6X 
http://www.nf6x.net/

RE: tape baking

[Rob Jarratt via cctalk]

> -Original Message-
> From: Christian Corti [mailto:c...@informatik.uni-stuttgart.de]
> Sent: 05 July 2017 08:48
> To: r...@jarratt.me.uk; Rob Jarratt <robert.jarr...@ntlworld.com>; General
> Discussion: On-Topic and Off-Topic Posts <cctalk@classiccmp.org>
> Subject: RE: tape baking
> 
> On Mon, 3 Jul 2017, Rob Jarratt wrote:
> > All I could do was prop open the tape door with a paper clip. 45C in
> > my fan oven worked for me. 55C in my oven seemed to mostly demagnetise
> > the tape. Other ovens may be different, so it is best to experiment
> > with something that doesn't matter.
> 
> You can not demagnetize tapes at 55°C, that must be another effect, like
> crosstalk (which is an issue, especially with audio tapes) or something like 
> that.
> 


Perhaps I will try to read the tape again then.

Regards

Rob

RE: tape baking

[Christian Corti via cctalk]

On Mon, 3 Jul 2017, Rob Jarratt wrote:
All I could do was prop open the tape door with a paper clip. 45C in my 
fan oven worked for me. 55C in my oven seemed to mostly demagnetise the 
tape. Other ovens may be different, so it is best to experiment with 
something that doesn't matter.


You can not demagnetize tapes at 55°C, that must be another effect, like 
crosstalk (which is an issue, especially with audio tapes) or something 
like that.


Christian

RE: tape baking

[Rob Jarratt via cctalk]

> -Original Message-
> From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Glen Slick
> via cctalk
> Sent: 05 July 2017 03:12
> To: General Discussion: On-Topic and Off-Topic Posts <cctalk@classiccmp.org>
> Subject: Re: tape baking
> 
> After you got the TK50 tapes and the TZ30 drive working together, what
> computer system and software utilities did you use to recover the data from
> the tapes?
> 
> Did you first recover the data into a format that preserved blocking 
> information
> such as SIMH .TAP format? ( http://simh.trailing-
> edge.com/docs/simh_magtape.pdf )
> 
> Or did you directly extract the files from the tape by running something like
> TAR directly on the tape?
> 

I used a DECstation 2100 (MIPS architecture) running Ultrix. I used dd (block 
size 10240) to recover the tapes to a file on the 2100's disk. I ftp'd the dd 
file onto my normal PC for safekeeping, but I extracted the files from the dd 
file actually on the 2100. The tapes had been written using the "dump" utility 
and I just passed the dd file to the "restore" command to do the extraction. I 
didn't use SIMH to create a tap file but presume I could do so, now that I have 
the dd file.

I had wanted to find a way to clone tapes using VMS (I have more hardware 
running VMS than I do that runs Ultrix or any other flavour of Unix), but I 
suspect that the dd route is the only easy way to do it.

Regards

Rob

Re: tape baking

[Glen Slick via cctalk]

After you got the TK50 tapes and the TZ30 drive working together, what
computer system and software utilities did you use to recover the data
from the tapes?

Did you first recover the data into a format that preserved blocking
information such as SIMH .TAP format? (
http://simh.trailing-edge.com/docs/simh_magtape.pdf )

Or did you directly extract the files from the tape by running
something like TAR directly on the tape?

-Glen

On Sun, Jul 2, 2017 at 10:27 AM, Rob Jarratt via cctalk
<cctalk@classiccmp.org> wrote:
> Yes, that was me.
>
> Regards
>
> Rob
>
>> -Original Message-
>> From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Al Kossow
>> via cctalk
>> Sent: 02 July 2017 18:04
>> To: General Discussion: On-Topic and Off-Topic Posts <cctalk@classiccmp.org>
>> Subject: tape baking
>>
>>
>> https://strandgames.com/blog/magnetic-scrolls-games-source-code-recovered

RE: tape baking

[Rob Jarratt via cctalk]

> -Original Message-
> From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Noel
> Chiappa via cctalk
> Sent: 04 July 2017 15:53
> To: cctalk@classiccmp.org
> Cc: j...@mercury.lcs.mit.edu
> Subject: Re: tape baking
> 
> > From: Al Kossow
> 
> > You need moving air, though.
> > I'm not sure how you do that well in a TK50 style cartridge.
> 
> Hmm, maybe not? I start with the need for moving air - which I do not
dispute,
> just wondering what the needed effect is. I don't think it can be removing
out-
> gassed material, I think it has to be temperature leveling - making sure
the
> heat from the heat source is spread evenly? So one probably doesn't need
> moving air inside the cartridge, _if_ its temperature is even?
> 
> My _guess_ is that a TK50 cartridge left for a long time in a bath of a
constant-
> temperature gas will probably eventually come to an even temperature
> internally; some parts will warm faster than others, but eventually it
should
> 'soak' all the way through; no part will be able to _stay_ cooler. And
without an
> internal heat source, no part should be able to come to a higher temp.
> 
> I'm just wondering if there are internal (rubber) parts that won't like a
temp
> that high?
> 


I did mine for never less than 8 hours, although I did occasionally "top up"
with an hour or two if I needed to come back to a tape a couple of days
later. That seemed to fix the tapes that started to stick a bit again after
a while. I think you are right, that it is about thoroughly warming all the
tape, after 8 hours there should be no doubt that it will have percolated
everywhere. 45C isn't that hot, not much hotter than a very hot summer's day
in many parts of the world, so I would expect any cartridge to survive those
temperatures. In fact you prompted me to check, there is a little sheet that
comes with them and it actually says to store them at temperatures no higher
than 45C, I had never checked before!

Regards

Rob

Re: tape baking

[Al Kossow via cctalk]

On 7/4/17 7:53 AM, Noel Chiappa via cctalk wrote:
> > From: Al Kossow
> 
> > You need moving air, though.
> > I'm not sure how you do that well in a TK50 style cartridge.
> 
> Hmm, maybe not? I start with the need for moving air - which I do not
> dispute, just wondering what the needed effect is. I don't think it can be
> removing out-gassed material, I think it has to be temperature leveling -
> making sure the heat from the heat source is spread evenly? So one probably
> doesn't need moving air inside the cartridge, _if_ its temperature is even?

This came from personal experience and was also told to me by someone very 
experienced
in baking 1/2" computer tape. The 'out-gassed material' is water, which has 
been absorbed
by the binder, which is hydroscopic.

When I initially built my processing chamber ten years ago, I didn't have any 
fans in
it, and the results were not good. I put 9 boxer fans into the bottom, forcing 
air across
the surface of the tapes, which are mounted on a bar and held vertically, and 
the sticking
reduced a LOT.

When I process QIC carts, I take the covers off so the reels are exposed in the 
commercial
food dehydrator that I use. I've never tried just putting them in without doing 
that.

I'm skeptical that a TK50 would have been demagnetized by overtemp, the tape is 
much thinner
though, and I could see physical damage occurring if it got too hot.


https://www.google.com/patents/US6797072
http://www.richardhess.net/restoration_notes/USP5236790.pdf
http://www.tapeheads.net/showthread.php?t=35353

Re: tape baking

[Noel Chiappa via cctalk]

> From: Al Kossow

> You need moving air, though.
> I'm not sure how you do that well in a TK50 style cartridge.

Hmm, maybe not? I start with the need for moving air - which I do not
dispute, just wondering what the needed effect is. I don't think it can be
removing out-gassed material, I think it has to be temperature leveling -
making sure the heat from the heat source is spread evenly? So one probably
doesn't need moving air inside the cartridge, _if_ its temperature is even?

My _guess_ is that a TK50 cartridge left for a long time in a bath of a
constant-temperature gas will probably eventually come to an even temperature
internally; some parts will warm faster than others, but eventually it should
'soak' all the way through; no part will be able to _stay_ cooler. And
without an internal heat source, no part should be able to come to a higher
temp.

I'm just wondering if there are internal (rubber) parts that won't like a
temp that high?

Noel

RE: tape baking

[Rob Jarratt via cctalk]

> -Original Message-
> From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Al Kossow
> via cctalk
> Sent: 03 July 2017 20:39
> To: cctalk@classiccmp.org
> Subject: Re: tape baking
> 
> 
> 
> On 7/3/17 11:49 AM, Alan Frisbie via cctalk wrote:
> 
> > So, what are the currently-recommended tape baking temperatures and
> times?
> 
> In the range you're using. You need moving air, though.
> 
> I'm not sure how you do that well in a TK50 style cartridge.

All I could do was prop open the tape door with a paper clip. 45C in my fan 
oven worked for me. 55C in my oven seemed to mostly demagnetise the tape. Other 
ovens may be different, so it is best to experiment with something that doesn't 
matter.

Regards

Rob

Re: tape baking

[Al Kossow via cctalk]

On 7/3/17 11:49 AM, Alan Frisbie via cctalk wrote:

> So, what are the currently-recommended tape baking temperatures and times?

In the range you're using. You need moving air, though.

I'm not sure how you do that well in a TK50 style cartridge.

Re: tape baking

[Alan Frisbie via cctalk]

Al Kossow <a...@bitsavers.org> wrote:


https://strandgames.com/blog/magnetic-scrolls-games-source-code-recovered

and now we know why all the questions were asked recently


So, what are the currently-recommended tape baking temperatures and times?

I have been using 58C/136F for 24 to 48 hours with some luck, but I feel
that results could be better.   What are other people using?

I have several hundred more 800 bpi tapes to read, and my only 800 bpi
drive is pretty rough on tapes, so I want to get it right.   The drive
is a Cipher 910 vacuum column drive.

I also have about 100 TK50 tapes, if the temperature/time values are
different for those.

Thanks,
Alan Frisabie

Re: tape baking

[Chuck Guzis via cctalk]

On 07/02/2017 11:34 AM, Warner Losh via cctalk wrote:

> What's the theory behind baking floppies? For tapes it makes sense to
> help with self-adhesion, but what's the benefit to single surfaced 
> media that doesn't overlap?

I'll add one more type of failure to the list--where the binder bleeds
*through* the oxide to the front surface.  No amount of baking fixes
that and neither does running said tapes through a cleaning machine (the
type with a carbide scraper).  The tape sticks to rollers, guides and
heads like it was glued there.

I've been able to get past this by coating the entire tape length with a
thin layer of cyclomethicone using a felt wiper installed in my cleaning
machine.   It's not permanent as the cyclomethicone evaporates, but you
can get a couple of good passes before having to do the lube again.

The 1970s Scotch brand tapes seem to be subject to this.

--Chuck

Re: tape baking

[Ed via cctalk]

Yep  we handle a lot of  video  media.   Bake Bake  Bake!
 
Really  works  well. over t time  it  will revert   but... you can back 
again!
 
Ed#  _www.smecc.org_ (http://www.smecc.org) 
 
 
In a message dated 7/2/2017 11:46:06 A.M. US Mountain Standard Time,  
cctalk@classiccmp.org writes:

On  07/02/2017 11:34 AM, Warner Losh via cctalk wrote:

> What's the  theory behind baking floppies? For tapes it makes sense to 
help
> with  self-adhesion, but what's the benefit to single surfaced media that
>  doesn't overlap?

The audio tape guys pretty much took the lead on this  one, probably
because they ran into the problem earlier.

The reason  for baking is to ameliorate the problem of binder
degradation.  It  seems that baking at a mild temperature (there is a
patent on this method),  tends to "melt" the binder back into
workability.  If you've ever  stuck a floppy into a drive and heard a
loud squealing sound and wound up  with a cookie with "see through" rings
on it, you've experienced binder  failure.

There's quite a bit of information on this on the  web.

--Chuck

RE: tape baking

[Rob Jarratt via cctalk]

> -Original Message-
> From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Chuck Guzis
> via cctalk
> Sent: 02 July 2017 19:40
> To: cctalk@classiccmp.org
> Subject: Re: tape baking
> 
> On 07/02/2017 10:56 AM, william degnan via cctalk wrote:
> > Have you also experimented with diskettes using this technique.  May
> > apply in some cases.
> 
> Haven't we been here before, oh, about 2-3 years ago?  I bake just about every
> bit old old media I get in, nowadays with very good success.  I think Al uses 
> a
> food dehydrator; I have a custom-made insulated "hot box".  You can even get
> good results (with a bit of cyclomethicone) from old Wabash diskettes.
> 
> Optimum temp for me (by trial and error) is 58C.   Not enough to pucker
> the jacket on floppies, nor warp the reels on mag tape.
> 


When I tried 55C on one of my own TK50 tapes it looked like it got almost 
completely demagnetised. The lowest our oven (a fan model) would go was 40C but 
I found the tapes would still stick a bit, so I went up to 45C and that worked 
for me.

Regards

Rob

RE: tape baking

[Rob Jarratt via cctalk]

> -Original Message-
> From: william degnan [mailto:billdeg...@gmail.com]
> Sent: 02 July 2017 18:57
> To: r...@jarratt.me.uk; Rob Jarratt <robert.jarr...@ntlworld.com>; General
> Discussion: On-Topic and Off-Topic Posts <cctalk@classiccmp.org>
> Subject: Re: tape baking
> 
> Have you also experimented with diskettes using this technique.  May apply in
> some cases.
> Bill


No, I haven't had to. Generally the few floppies I have had to read have been 
OK. Another reply to this suggests it wouldn't be that useful anyway, and I 
certainly have never had a floppy disk stick to the heads.

Regards

Rob

Re: tape baking

[Chuck Guzis via cctalk]

On 07/02/2017 11:34 AM, Warner Losh via cctalk wrote:

> What's the theory behind baking floppies? For tapes it makes sense to help
> with self-adhesion, but what's the benefit to single surfaced media that
> doesn't overlap?

The audio tape guys pretty much took the lead on this one, probably
because they ran into the problem earlier.

The reason for baking is to ameliorate the problem of binder
degradation.  It seems that baking at a mild temperature (there is a
patent on this method), tends to "melt" the binder back into
workability.  If you've ever stuck a floppy into a drive and heard a
loud squealing sound and wound up with a cookie with "see through" rings
on it, you've experienced binder failure.

There's quite a bit of information on this on the web.

--Chuck

Re: tape baking

[Chuck Guzis via cctalk]

On 07/02/2017 10:56 AM, william degnan via cctalk wrote:
> Have you also experimented with diskettes using this technique.  May apply
> in some cases.

Haven't we been here before, oh, about 2-3 years ago?  I bake just about
every bit old old media I get in, nowadays with very good success.  I
think Al uses a food dehydrator; I have a custom-made insulated "hot
box".  You can even get good results (with a bit of cyclomethicone) from
old Wabash diskettes.

Optimum temp for me (by trial and error) is 58C.   Not enough to pucker
the jacket on floppies, nor warp the reels on mag tape.

--Chuck

Re: tape baking

[Warner Losh via cctalk]

I recently read 300-odd RX-50 diskettes. All but 10-15 read, many w/o
error, some with lots of errors. I'm guessing that baking won't help the
few that didn't read since they weren't stuck to the lining of the
diskette...

What's the theory behind baking floppies? For tapes it makes sense to help
with self-adhesion, but what's the benefit to single surfaced media that
doesn't overlap?

Warner

On Sun, Jul 2, 2017 at 11:56 AM, william degnan via cctalk <
cctalk@classiccmp.org> wrote:

> Have you also experimented with diskettes using this technique.  May apply
> in some cases.
> Bill
>
> On Sun, Jul 2, 2017 at 1:27 PM, Rob Jarratt via cctalk <
> cctalk@classiccmp.org> wrote:
>
> > Yes, that was me.
> >
> > Regards
> >
> > Rob
> >
> > > -Original Message-
> > > From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Al
> > Kossow
> > > via cctalk
> > > Sent: 02 July 2017 18:04
> > > To: General Discussion: On-Topic and Off-Topic Posts <
> > cctalk@classiccmp.org>
> > > Subject: tape baking
> > >
> > >
> > > https://strandgames.com/blog/magnetic-scrolls-games-source-
> > code-recovered
> > >
> > > and now we know why all the questions were asked recently
> >
> >
>

Re: tape baking

[william degnan via cctalk]

Have you also experimented with diskettes using this technique.  May apply
in some cases.
Bill

On Sun, Jul 2, 2017 at 1:27 PM, Rob Jarratt via cctalk <
cctalk@classiccmp.org> wrote:

> Yes, that was me.
>
> Regards
>
> Rob
>
> > -Original Message-
> > From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Al
> Kossow
> > via cctalk
> > Sent: 02 July 2017 18:04
> > To: General Discussion: On-Topic and Off-Topic Posts <
> cctalk@classiccmp.org>
> > Subject: tape baking
> >
> >
> > https://strandgames.com/blog/magnetic-scrolls-games-source-
> code-recovered
> >
> > and now we know why all the questions were asked recently
>
>

RE: tape baking

[Rob Jarratt via cctalk]

Yes, that was me.

Regards

Rob

> -Original Message-
> From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Al Kossow
> via cctalk
> Sent: 02 July 2017 18:04
> To: General Discussion: On-Topic and Off-Topic Posts <cctalk@classiccmp.org>
> Subject: tape baking
> 
> 
> https://strandgames.com/blog/magnetic-scrolls-games-source-code-recovered
> 
> and now we know why all the questions were asked recently

tape baking

[Al Kossow via cctalk]

https://strandgames.com/blog/magnetic-scrolls-games-source-code-recovered

and now we know why all the questions were asked recently