The bit in the article about the recovery procedure, which involves dumping info from the tape into '100-ish GB of RAM' and then using software to analyze it stuck out to me.
This video on the linked github page for the analysis software[1] is interesting:
I wonder if they'll find it suitable to bake [0] the tape first, which is quite popular in the audio restoration world but I'm not sure how much it applies to computer tape.
Please let there be an ultimate force in the universe that spared this tape from tape degradation and/or magnetization that it can be read and extracted into a raw dump fs that we can preserve for all time. (fingers crossed)
Tapes from back then haven’t held up over the years. It all depends on the environment it was stored in.
I remember reading we're nearing a timeframe where VHS and cassette tapes made in the <=1980s will start degrading pretty seriously. So if you own lots of VHS or camcorder tapes you have a relatively short window to save old family videos... or just deal with fuzzy images and bad audio.
> It is a '70s 1200ft 3M tape, likely 9 track, which has a pretty good chance of being recoverable.
Not old enough to have this kind of knowledge or confidence. I wonder if instead one day I'll be helping some future generation read old floppies, CDs, and IDE/ATA disks *slaps top of AT tower*.
You might be able to use that old floppy drive. But you won't be able to use that old Pentium machine the drive is in.
Because you will need several hundred gigabytes of RAM and a very fast IO bus.
The gold standard today for archiving magnetic media is to make a flux image.
The media is treated as if it were an analog recording and sampled at such a high rate that the smallest details are captured. Interpretation is done later, in software. The only antique electronics involved are often the tape or drive head, directly connected to a high speed digitizer.
> As for CDs, I don't see the rush; the ones that were properly made will likely outlast human civilization.
Printed ones will last a lot more, but writable ones will degrade to unreadable state in a few years. I lost countless of them years ago, including the double backup of a project I worked on. Branded disks written and verified, properly stored, no sunlight, no objects or anything above them, no moisture or whatever. All gone just because of time. As I read other horror stories like mine, I just stopped using them altogether and never looked back.
>As for CDs, I don't see the rush; the ones that were properly made will likely outlast human civilization.
recordable CD-Rs or DVD-Rs do not last close to that long, and those are the ones that hold the only copies of certain bits (original versions of software, etc) that people are most interested in not losing.
manufactured CDs and DVDs hold commericial music and films that are for the most part not rare at all.
Yes, good distinction. Recordable media will most likely contain data an individual intended to save. But because it's recordable, the dyes and structures on the disc aren't as stable.
Long-lasting, good quality mastered optical media is probably mass produced and has many copies, including a distinct and potentially well-preserved source.
It's probably fair to say that a lot of mixtapes (mix CDs?) from the early 2000s are lost to dye issues...
Not that it helps to recover older data, but things are better with Blu-ray today; at least if you buy decent quality discs. Advertised lifespans are multiple decades, up to 100 years, or even 500 years for "M" discs. And in the "M" disc case, it's achieved by using a non-organic dye, to avoid the degradation issues.
Just anecdata, but I had this concern when I worked in academia and we backed up all our data to writable DVDs. I was there 10 years after the start of the project and I periodically checked the old DVDs to make sure they weren't corrupted.
After 10 years, which was longer than the assumed shelf life of writable/rewritable DVDs at the time, I never found a single corrupt file on the disks. They were stored in ideal conditions though, in a case, in a closed climate controlled shelf, and rarely if ever removed or used.
Also, just because I think it's funny, the archive was over 4000 DVDs. (We had a redundant copies of the data compressed and uncompressed, I think it was like 3000 uncompressed 1k compressed) there was also an offsite redundant copy we put on portable IDE (and eventually SATA) drives.
My team used to maintain go-kits for continuity of operations for a government org. We ran into a few scenarios where the dye on optical media would just go, and another where replacement foam for the pelican cases off gassed and reacted with the media!
I was the procurement guy for many years, and we had no HVAC guy - we were in a state university, and there was nothing special about the DVDs we bought, they were from Newegg and other retail places, we did buy the most expensive ones because our grants allowed us to, so maybe that's a factor.
I have no doubts (hence my anecdata statement) that there could be bad DVDs in there, or that maybe over a longer time horizon that the media would be cooked.
Wow! That's pretty interesting. I can imagine wanting to store optical media in Pelican cases or similar for shock protection, ability to padlock, etc. But yeah -- what's the interaction between whatever interior foam they chose and the CD-R media and dyes? Especially after 10+ years of continuous contact?
Optical media is probably best stored well-labeled and in metal or cardboard box on a shelf in a basement that few will rarely disturb.
It was a really fun project. We basically made these disaster kits, with small MFPs, tools, laptops, cell radios and INMARSAT terminals hooked to Cisco switches (this was circa 2002-3) and a little server. We had a deal that let us stow them in unusual places like highway rest stops.
We’d deploy them to help respond to floods or other disasters.
One of the techs cooked up a great idea — use Knoppix or something like it to let us use random computers if needed. Bandwidth was tight, but enough for terminal emulators and things like registration software that ran off the little server. So that’s where we got into the CD/DVD game. We had way more media problems than we expected!
Cool tale! I have observed a mix of viable and unreadable user-burned CD media from the late 90s and early 2000s. It definitely depends on the quality of the media, quality of the burn/drive/laser, and how well it was stored interim.
My oldest disc is some bright blue Verbatim disk my childhood friend made for me so I could play our favorite game at home pre-2000. I have a bit-perfect copy, but the actual disc still reads fine in 2025 when I last tested it.
Yep, quality is definitely a factor here, as much as it can be. We had NSF funding pre-2008, so there was plenty of budget for quality media. We spared no expense, and while I stayed in a $60/night hostel in SF for conferences, our rewritable DVDs were the best money could buy at the time lol.
This seems to be how a lot of modern history is found.
I recently got to talk to a big-ish name in the Boston music scene, who republished one of his band's original 1985 demos after cleaning the signal up with AI. He told me that he found that tape in a bedroom drawer.
I remember at one point I browsed tuhs.org in an attempt to find the source code for the original B (the language predating C) compiler. I don't think it should be in the 4th edition. I still wonder if there's a copy somewhere. I know there are a few modern implementations, but it would be interesting to look at the original.
""Douglas McIlroy ported TMG to an early version of Unix. According to Ken Thompson, McIlroy wrote TMG in TMG on a piece of paper and "decided to give his piece of paper his piece of paper," hand-compiling assembly language that he entered and assembled on Thompson's Unix system running on PDP-7."
We are not worthy, friends. We are not worthy."
Tons of info, but not much source:
"The first B compiler was written by Ken Thompson in the TMG language around 1969. Thompson initially used the TMG compiler to create a version of B for the PDP-7 minicomputer, which generated threaded code. The B compiler was later rewritten in BCPL and cross-compiled on a GE 635 mainframe to produce object code, which was then re-written in B itself to create a self-hosting compiler. "
So... a B compiler would use GE 635/Multics as a OS.
Well, I won't debate whether "cool" is the right word. But ideologically I think federation is better than centralization when it can be made to work in practical terms, and Mastodon works.
Really. Where? Unhelpful answers of the form "Just install extension X for browser Y and use it to run script Z" are all anyone has ever been able to suggest when I've asked this question elsewhere.
If you click on Preferences, it's under Appearance which is the first section you see. You can change the site theme to a light option. At least on Mastodon.social.
There's no Preferences button. If there is, they've either hidden it well, or it's not visible without a login.
There should simply be a button -- a conspicuous one -- that toggles the color scheme. It's trivial to add such a button. It doesn't need to be tied to a user ID; it doesn't even need to set a cookie. The fact that no such button exists is a choice someone made, a poor choice that disregards decades of human-machine interface research.
Failure to go full Karen about goofy things like this has made the Web a little worse for almost everyone in one way or another. So... there ya go.
I really, really hope data can be recovered from this. I’ve read a bunch of the original sources, and such an ancient C would be especially interesting to study.
Very proud to have had this found at my University :-)
From the information I've read, quite likely, given that Utah is pretty dry. Also the original data might be stored in its uncompressed form, so even if there were some non-extensive damage it might still be possible to recover some data based upon guessing with context (if it contains text source code, otherwise if it is just the binaries then not that easy).
Anyway, since nobody much seems to realise this is quite a big deal, I will share the explainer I wrote yesterday:
https://www.theregister.com/2025/11/07/unix_fourth_edition_t...
Unix V4 is otherwise lost. It was the first version in C.
The bit in the article about the recovery procedure, which involves dumping info from the tape into '100-ish GB of RAM' and then using software to analyze it stuck out to me.
This video on the linked github page for the analysis software[1] is interesting:
https://www.youtube.com/watch?v=7YoolSAHR5w&t=4200s
[1] https://github.com/LenShustek/readtape
Well, the tape may not survive its second pass across the read head, so it's good to capture the analog waveform in as much fidelity as possible.
I wonder if they'll find it suitable to bake [0] the tape first, which is quite popular in the audio restoration world but I'm not sure how much it applies to computer tape.
[0] https://en.wikipedia.org/wiki/Sticky-shed_syndrome
I don't know much about tapes but it seems to apply, since the post mentions it:
> I'm hoping I don't have to bake it, since that takes a day
What a fantastic talk! Thanks for sharing.
Interesting article. I agree it is kind of a big deal. Certainly worth the effort to try to restore
Please let there be an ultimate force in the universe that spared this tape from tape degradation and/or magnetization that it can be read and extracted into a raw dump fs that we can preserve for all time. (fingers crossed)
Tapes from back then haven’t held up over the years. It all depends on the environment it was stored in.
I remember reading we're nearing a timeframe where VHS and cassette tapes made in the <=1980s will start degrading pretty seriously. So if you own lots of VHS or camcorder tapes you have a relatively short window to save old family videos... or just deal with fuzzy images and bad audio.
> It is a '70s 1200ft 3M tape, likely 9 track, which has a pretty good chance of being recoverable.
Not old enough to have this kind of knowledge or confidence. I wonder if instead one day I'll be helping some future generation read old floppies, CDs, and IDE/ATA disks *slaps top of AT tower*.
You might be able to use that old floppy drive. But you won't be able to use that old Pentium machine the drive is in.
Because you will need several hundred gigabytes of RAM and a very fast IO bus.
The gold standard today for archiving magnetic media is to make a flux image.
The media is treated as if it were an analog recording and sampled at such a high rate that the smallest details are captured. Interpretation is done later, in software. The only antique electronics involved are often the tape or drive head, directly connected to a high speed digitizer.
And indeed that appears to be the plan Al Kossow has for the tape: https://www.tuhs.org/pipermail/tuhs/2025-November/032765.htm...
As for CDs, I don't see the rush; the ones that were properly made will likely outlast human civilization.
> As for CDs, I don't see the rush; the ones that were properly made will likely outlast human civilization.
Printed ones will last a lot more, but writable ones will degrade to unreadable state in a few years. I lost countless of them years ago, including the double backup of a project I worked on. Branded disks written and verified, properly stored, no sunlight, no objects or anything above them, no moisture or whatever. All gone just because of time. As I read other horror stories like mine, I just stopped using them altogether and never looked back.
>As for CDs, I don't see the rush; the ones that were properly made will likely outlast human civilization.
recordable CD-Rs or DVD-Rs do not last close to that long, and those are the ones that hold the only copies of certain bits (original versions of software, etc) that people are most interested in not losing.
manufactured CDs and DVDs hold commericial music and films that are for the most part not rare at all.
Yes, good distinction. Recordable media will most likely contain data an individual intended to save. But because it's recordable, the dyes and structures on the disc aren't as stable.
Long-lasting, good quality mastered optical media is probably mass produced and has many copies, including a distinct and potentially well-preserved source.
It's probably fair to say that a lot of mixtapes (mix CDs?) from the early 2000s are lost to dye issues...
> lost to dye issues...
Not that it helps to recover older data, but things are better with Blu-ray today; at least if you buy decent quality discs. Advertised lifespans are multiple decades, up to 100 years, or even 500 years for "M" discs. And in the "M" disc case, it's achieved by using a non-organic dye, to avoid the degradation issues.
> structures on the disc aren't as stable.
Which is why the format has generous error correction built in.
It’s so obvious in retrospect but I never considered they would do this! Thanks for sharing.
Just anecdata, but I had this concern when I worked in academia and we backed up all our data to writable DVDs. I was there 10 years after the start of the project and I periodically checked the old DVDs to make sure they weren't corrupted.
After 10 years, which was longer than the assumed shelf life of writable/rewritable DVDs at the time, I never found a single corrupt file on the disks. They were stored in ideal conditions though, in a case, in a closed climate controlled shelf, and rarely if ever removed or used.
Also, just because I think it's funny, the archive was over 4000 DVDs. (We had a redundant copies of the data compressed and uncompressed, I think it was like 3000 uncompressed 1k compressed) there was also an offsite redundant copy we put on portable IDE (and eventually SATA) drives.
Thank your procurement agent and hvac guy.
My team used to maintain go-kits for continuity of operations for a government org. We ran into a few scenarios where the dye on optical media would just go, and another where replacement foam for the pelican cases off gassed and reacted with the media!
I was the procurement guy for many years, and we had no HVAC guy - we were in a state university, and there was nothing special about the DVDs we bought, they were from Newegg and other retail places, we did buy the most expensive ones because our grants allowed us to, so maybe that's a factor.
I have no doubts (hence my anecdata statement) that there could be bad DVDs in there, or that maybe over a longer time horizon that the media would be cooked.
Wow! That's pretty interesting. I can imagine wanting to store optical media in Pelican cases or similar for shock protection, ability to padlock, etc. But yeah -- what's the interaction between whatever interior foam they chose and the CD-R media and dyes? Especially after 10+ years of continuous contact?
Optical media is probably best stored well-labeled and in metal or cardboard box on a shelf in a basement that few will rarely disturb.
It was a really fun project. We basically made these disaster kits, with small MFPs, tools, laptops, cell radios and INMARSAT terminals hooked to Cisco switches (this was circa 2002-3) and a little server. We had a deal that let us stow them in unusual places like highway rest stops.
We’d deploy them to help respond to floods or other disasters.
One of the techs cooked up a great idea — use Knoppix or something like it to let us use random computers if needed. Bandwidth was tight, but enough for terminal emulators and things like registration software that ran off the little server. So that’s where we got into the CD/DVD game. We had way more media problems than we expected!
Cool tale! I have observed a mix of viable and unreadable user-burned CD media from the late 90s and early 2000s. It definitely depends on the quality of the media, quality of the burn/drive/laser, and how well it was stored interim.
My oldest disc is some bright blue Verbatim disk my childhood friend made for me so I could play our favorite game at home pre-2000. I have a bit-perfect copy, but the actual disc still reads fine in 2025 when I last tested it.
Yep, quality is definitely a factor here, as much as it can be. We had NSF funding pre-2008, so there was plenty of budget for quality media. We spared no expense, and while I stayed in a $60/night hostel in SF for conferences, our rewritable DVDs were the best money could buy at the time lol.
This seems to be how a lot of modern history is found.
I recently got to talk to a big-ish name in the Boston music scene, who republished one of his band's original 1985 demos after cleaning the signal up with AI. He told me that he found that tape in a bedroom drawer.
Will not be much different to the existing v5 source code, we can assume. https://minnie.tuhs.org/cgi-bin/utree.pl?file=V5/usr/source/...
I remember at one point I browsed tuhs.org in an attempt to find the source code for the original B (the language predating C) compiler. I don't think it should be in the 4th edition. I still wonder if there's a copy somewhere. I know there are a few modern implementations, but it would be interesting to look at the original.
The 'B' compiler was written in TMG-Compiler-Compiler. TMG (Transmogrifier)
https://github.com/amakukha/tmg
https://news.ycombinator.com/item?id=26722097
""Douglas McIlroy ported TMG to an early version of Unix. According to Ken Thompson, McIlroy wrote TMG in TMG on a piece of paper and "decided to give his piece of paper his piece of paper," hand-compiling assembly language that he entered and assembled on Thompson's Unix system running on PDP-7."
We are not worthy, friends. We are not worthy."
Tons of info, but not much source:
"The first B compiler was written by Ken Thompson in the TMG language around 1969. Thompson initially used the TMG compiler to create a version of B for the PDP-7 minicomputer, which generated threaded code. The B compiler was later rewritten in BCPL and cross-compiled on a GE 635 mainframe to produce object code, which was then re-written in B itself to create a self-hosting compiler. "
So... a B compiler would use GE 635/Multics as a OS.
Of course I found it, AFTER I hit post...
https://retrocomputingforum.com/t/b-a-simple-interpreter-com...
OT - Mastodon is seriously cool. If you haven't yet bothered, I suggest to everyone that you spend a bit of time exploring.
Mastodon is just a part of the larger Fediverse.
Yeah I guess I still haven't wrapped my mind around that other part.
What makes it cool?
Well, I won't debate whether "cool" is the right word. But ideologically I think federation is better than centralization when it can be made to work in practical terms, and Mastodon works.
It shoves dark mode down your throat whether you want it or not. What could be cooler than that?
There's an option
Which puts it one up over Hacker News!
Really. Where? Unhelpful answers of the form "Just install extension X for browser Y and use it to run script Z" are all anyone has ever been able to suggest when I've asked this question elsewhere.
If you click on Preferences, it's under Appearance which is the first section you see. You can change the site theme to a light option. At least on Mastodon.social.
There's no Preferences button. If there is, they've either hidden it well, or it's not visible without a login.
There should simply be a button -- a conspicuous one -- that toggles the color scheme. It's trivial to add such a button. It doesn't need to be tied to a user ID; it doesn't even need to set a cookie. The fact that no such button exists is a choice someone made, a poor choice that disregards decades of human-machine interface research.
Failure to go full Karen about goofy things like this has made the Web a little worse for almost everyone in one way or another. So... there ya go.
Preferences shows up in the sidebar (that has the login and signup buttons) if you have an account.
Otherwise it's up to the instance admin to choose the default.
And the admin should probably use the automatic setting. There is a feature request for a user preference when not logged in.[1]
[1]: https://github.com/mastodon/mastodon/issues/30193
That is a big deal; I don't remember anything that old being available on tuhs.org.
Check here https://www.tuhs.org/Archive/Distributions/Research/
This is amazing news for UNIX fans. Really hope the source can be recovered and put alongside the other historical UNIX source that's out there.
I really, really hope data can be recovered from this. I’ve read a bunch of the original sources, and such an ancient C would be especially interesting to study.
Very proud to have had this found at my University :-)
Finally we can see the naughty stuff they recorded!
What are the odds that a medium like that has successfully stored the full data without error?
From the information I've read, quite likely, given that Utah is pretty dry. Also the original data might be stored in its uncompressed form, so even if there were some non-extensive damage it might still be possible to recover some data based upon guessing with context (if it contains text source code, otherwise if it is just the binaries then not that easy).
From 1973. See https://en.wikipedia.org/wiki/List_of_Unix_systems
Other posts on this subject, none with discussion:
https://news.ycombinator.com/item?id=45846438
https://news.ycombinator.com/item?id=45844876
https://news.ycombinator.com/item?id=45842643
I've added https://oldbytes.space/@bitsavers/115505135441862982 and https://www.theregister.com/2025/11/07/unix_fourth_edition_t... to the toptext as well. Thanks!
Also this post from Rob Pike with interesting thread of a bit more information about tape recovery https://www.tuhs.org/pipermail/tuhs/2025-November/032758.htm...
https://news.ycombinator.com/item?id=45857695 has discussion