Re: Tape baking page by Wendy Carlos
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
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
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
Re: tape baking
On 5/1/20 4:50 PM, Alan Perry via cctalk wrote: > 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? If you wipe with alcohol, can you still see crud on the posts? If so, you'll need something stronger. Acetone might do, or MEK. But if alcohol cleans the posts, that's not the problem. You could try backing, but I don't think that will work either if the problem is in the binder. --Chuck
Re: tape baking
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
RE: tape baking (Rob Jarratt)
> -Original Message- > From: Eric Smith [mailto:space...@gmail.com] > Sent: 11 July 2017 04:02 > To: r...@jarratt.me.uk; Rob Jarratt ; General > Discussion: On-Topic and Off-Topic Posts > Cc: Rich Alderson ; General Discussion: On-Topic > Posts > Subject: Re: tape baking (Rob Jarratt) > > On Mon, Jul 10, 2017 at 3:38 PM, Rob Jarratt via cctalk > 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)
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)
> -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' > 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)
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)
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)
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" To: 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)
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)
> -Original Message- > From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Michael > Thompson via cctalk > Sent: 09 July 2017 15:41 > To: cctech > Subject: Re: tape baking (Rob Jarratt) > > > > > Date: Fri, 7 Jul 2017 21:19:03 +0100 > > From: "Rob Jarratt" > > 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)
> > Date: Fri, 7 Jul 2017 21:19:03 +0100 > From: "Rob Jarratt" > 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)
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)
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)
> -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 > > 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)
> > > > > 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)
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
> 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)
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)
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)
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)
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)
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)
> 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)
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)
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)
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)
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)
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)
> -Original Message- > From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Chuck > Guzis via cctalk > Sent: 07 July 2017 08:11 > To: CCtalk > 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)
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
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
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)
> -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 > > 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)
> -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 ; General Discussion: On-Topic and Off- > Topic Posts > Subject: Line printer art: (was Re: tape baking) > > 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). 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)
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&T > 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)
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&T > 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
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
> -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 > Subject: Re: tape baking > > > > 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 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
> 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)
> -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 > 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&T 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
> 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
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
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)
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&T 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
> -Original Message- > From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Mark J. > Blair via cctalk > Sent: 06 July 2017 21:46 > To: General Discussion: On-Topic and Off-Topic Posts > Subject: Re: tape baking > > > > 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. > > Not necessarily, you need to get it to load *and read*. In other words a higher temperature will sort out the stickiness (well, it did for me anyway), but you could end up demagnetising it, like seemed to happen to me. I know someone said 55C wouldn't demagnetise my tape, but I certainly had trouble reading it afterwards, perhaps my oven went higher than 55C without me realising. Anyway, make sure you can read back whatever is on the tape before deciding you have the parameters right. Regards Rob
Re: tape baking
> 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
> 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)
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
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)
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
> -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 > Subject: Re: tape baking > > > > 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. > 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 > http://www.nf6x.net/
Re: Line printer art: (was Re: tape baking)
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
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)
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
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
> On Jul 6, 2017, at 2:35 PM, Mark J. Blair via cctalk > wrote: > ... > > I would enjoy seeing the ASCII translated files. I don't have any experience > dealing with EBCDIC-era stuff yet. 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. paul
Re: tape baking
> 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
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
> 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
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
> 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
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
> 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
> -Original Message- > From: Christian Corti [mailto:c...@informatik.uni-stuttgart.de] > Sent: 05 July 2017 08:48 > To: r...@jarratt.me.uk; Rob Jarratt ; General > Discussion: On-Topic and Off-Topic Posts > 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
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
> -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 > 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
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 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 >> Subject: tape baking >> >> >> https://strandgames.com/blog/magnetic-scrolls-games-source-code-recovered
RE: tape baking
> -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
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
> 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
> -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
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
Al Kossow 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
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
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
On 07/02/2017 01:29 PM, Rob Jarratt wrote: > That I don't know. I bought a small oven thermometer to check first, > which I grant is not very accurate or fast, but it didn't seem to > vary much. I also found some suggestions that fan ovens are a bit > more consistent, but have no real proof of course. Certainly you do need air circulation. I use a low-speed fan to stir up the air in my unit--it probably runs at a couple of hundred RPM, tops. The whole mess is protected by two (in series) thermal fuses that give up the ghost at 70C, mounted near the top of the box, where it's likely the warmest. I never thought of the type of oven used on the Great British Baking Show was suitable for magnetic media. ;) Great for cakes, though. --Chuck
RE: tape baking
> -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
> -Original Message- > From: william degnan [mailto:billdeg...@gmail.com] > Sent: 02 July 2017 18:57 > To: r...@jarratt.me.uk; Rob Jarratt ; General > Discussion: On-Topic and Off-Topic Posts > 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
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
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
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
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 > >