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Unix v4 Tape Found

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Re: Unix v4 Tape Found

#41

Post by themafia »

accrual wrote: post #19
fsckboy wrote: post #13

Earlier quoted context omitted.

> 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 200…

> structures on the disc aren't as stable.

Which is why the format has generous error correction built in.

Re: Unix v4 Tape Found

#42

Post by codezero »

Spooky23 wrote: post #23
codezero wrote: post #16

Earlier quoted context omitted.

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 c…

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.

Re: Unix v4 Tape Found

#43

Post by lexurco »

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.

Re: Unix v4 Tape Found

#44

Post by codezero »

accrual wrote: post #20
codezero wrote: post #16

Earlier quoted context omitted.

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 c…

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…

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.

Re: Unix v4 Tape Found

#45

Post by stephen_g »

CamperBob2 wrote: post #37
glenstein wrote: post #36

Earlier quoted context omitted.

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 huma…

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.

Re: Unix v4 Tape Found

#46

Post by ForOldHack »

lexurco wrote: post #43

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.

Re: Unix v4 Tape Found

#47

Post by ForOldHack »

ForOldHack wrote: post #46
lexurco wrote: post #43

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'…

Of course I found it, AFTER I hit post...

https://retrocomputingforum.com/t/b-a-simple-interpreter-com...

Re: Unix v4 Tape Found

#48

Post by squarefoot »

retrac wrote: post #10
accrual wrote: post #9

> 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…

> 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.

Re: Unix v4 Tape Found

#49

Post by shanoaice »

CobrastanJorji wrote: post #34

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).

Re: Unix v4 Tape Found

#50

Post by debugnik »

hunter2_ wrote: post #40
kragen wrote: post #28

Earlier quoted context omitted.

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

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