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Unix v4 Tape Found

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Re: Unix v4 Tape Found

#71

Post by whizzter »

avar wrote: post #65
whizzter wrote: post #59

Someone in the Mastodon thread mentioned the Andrew Tannenbaum "Never underestimate the bandwidth of a station wagon full of tapes hurtling down the highway." So I wondered about a modern day equivalent, looked up 1tb micro-sd cards (sold locally for Nintendo Switch) and calculated that there'd be roughly space for 400 exabytes of data in a shipping container filled to the brim with SD-cards. (SDcard being 1tb for 1.…

Actually a shipping container full of micro-SD cards hurtling down the highway has lower overall bandwidth than a 56k modem. That's because whoever's attempting to load an ideal 400 million micro-SD cards into one will take approximately forever carefully trying to line up even one row of them on the floor of a shipping container, before having the whole thing fall over like dominoes. And even if they manage that, th…

100 metric tons is nothing really when it comes to trucking, logging trucks in Sweden are commonly hurling through down dirt roads at 70-80km/h with 70 ton loads (mostly limited to that because that's the maximum allowed weight without oversize escorts currently), the Finns are experimenting with 100 ton loads for logging purposes (for environmental reasons).

That's not even mentioning Australian road trains that seem to commonly pull around 150 tons with some being up to 200 tons (The load would be slightly spread out to more containers but still one truck-load).

Still, 400 million SD-cards is still a silly experiment.

Re: Unix v4 Tape Found

#72

Post by ekjhgkejhgk »

lewiscollard wrote: post #69
ekjhgkejhgk wrote: post #17

OT - Mastodon is seriously cool. If you haven't yet bothered, I suggest to everyone that you spend a bit of time exploring.

I was on Mastodon for three years. I deleted my account. When I found out that Charlie Kirk was murdered, my second thought was "well, best create yet another filter on Mastodon so I don't have to watch people celebrate Charlie Kirk being murdered" and when I caught myself having that thought I realised that being on Mastodon was a net negative for my wellbeing. (I didn't like the guy either, by the way, or at least…

I'm on mathstodon.xyz (mastodon for maths) and haven't seen any of that. So I guess it's the people you subscribe to.

But I have the freedom to decide what I want to consume.

Re: Unix v4 Tape Found

#73

Post by tgtweak »

Very interesting storage format too - Those tapes actually held quite a bit of data (comparatively) - around 45MB (Although this one is shorter ~1000ft and probably carries about 10-15MB which is close to V4's source code, binary and documentation size).

Re: Unix v4 Tape Found

#74

Post by tgtweak »

reactordev wrote: post #12

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.

There is one parity bit per 8 data bits, which is decently resilient - plus the recovery is pretty simple on the occasional bit flip. Combine that with the fact you can reference other sources to make up for missing/corrupted files - I think the chance that this is recoverable is pretty high provided the machine reading it is high quality. Checksumming on the source was unfortunately not commonplace until Unix 7, so it's unlikely there was any software-level integrity checks here. The tape looks like it was stored in a sealed container which is a very good sign. Those older tapes are actually more resilient than the later generation of tapes, and don't usually degrade the same way even with exposure to humidity.

Re: Unix v4 Tape Found

#75

Post by lewiscollard »

ekjhgkejhgk wrote: post #72
lewiscollard wrote: post #69

Earlier quoted context omitted.

I was on Mastodon for three years. I deleted my account. When I found out that Charlie Kirk was murdered, my second thought was "well, best create yet another filter on Mastodon so I don't have to watch people celebrate Charlie Kirk being murdered" and when I caught myself having that thought I realised that being on Mastodon was a net negative for my wellbeing. (I didn't like the guy either, by the way, or at least…

I'm on mathstodon.xyz (mastodon for maths) and haven't seen any of that. So I guess it's the people you subscribe to. But I have the freedom to decide what I want to consume.

> I'm on mathstodon.xyz (mastodon for maths) and haven't seen any of that. So I guess it's the people you subscribe to.

I was on an automotive-focused instance. I did see a lot of that.

> But I have the freedom to decide what I want to consume.

As do I; I had the freedom to delete my account, thus avoiding the need for any active measures to make my life free of schizoposting.

Re: Unix v4 Tape Found

#76

Post by jonathaneunice »

For context, I'm a geezer who got early access reading Lions' Commentary (6th Edition) and comparing it with 7th Edition source (running on a PDP-/something with no more than 128 KiB RAM). That was 1985, as Unix was spreading its way through universities. SIGSEGV haunts me to this day.

That was a full 40 years ago. And yet, 4th Edition is ancient history even to me.

Re: Unix v4 Tape Found

#77

Post by mbreese »

gregw2 wrote: post #70
avar wrote: post #63

Earlier quoted context omitted.

> This is rare enough that I'm pushing the recovery > of it up near the top of my project queue. The reader is left to wonder what the software librarian at the Computer History Museum could have possibly found recently that warrants a placement ahead of Unix v4 in their project queue. A copy of Atlantian Unix from the ancient Library of Alexandria?

Perhaps a prior promise to someone else?

Or you know... just the definition of a FIFO Queue. I mean, using a FILO Stack to organize your work would certainly be a choice...

Re: Unix v4 Tape Found

#78

Post by rtkwe »

mbreese wrote: post #77
gregw2 wrote: post #70

Earlier quoted context omitted.

Perhaps a prior promise to someone else?

Or you know... just the definition of a FIFO Queue. I mean, using a FILO Stack to organize your work would certainly be a choice ...

Definitionally if they're "pushing it near the top" they're not only using FIFO, there's a priority ordering involved...

My guess is there's stuff in progress and maybe they need to arrange access to or setup the readers for a tape that old and of potentially unknown format.

Re: Unix v4 Tape Found

#79

Post by nish__ »

rtkwe wrote: post #78
mbreese wrote: post #77

Earlier quoted context omitted.

Or you know... just the definition of a FIFO Queue. I mean, using a FILO Stack to organize your work would certainly be a choice ...

Definitionally if they're "pushing it near the top" they're not only using FIFO, there's a priority ordering involved... My guess is there's stuff in progress and maybe they need to arrange access to or setup the readers for a tape that old and of potentially unknown format.

Yes it's probably better to finish in progress stuff first.

Re: Unix v4 Tape Found

#80

Post by throw_await »

mmooss wrote: post #22
ekjhgkejhgk wrote: post #17

OT - Mastodon is seriously cool. If you haven't yet bothered, I suggest to everyone that you spend a bit of time exploring.

What makes it cool ?

No "algorithm" shoving ads down your throat. Just a timeline of the accounts you follow with the posts in chronooogical order.
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