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Unix v4 Tape Found

discuss.systems

91–100 of 104 posts

Re: Unix v4 Tape Found

#91

Earlier quoted context omitted.

If this is intended to accuse me of being a Charlie Kirk fan I can only conclude that you either did not read what I wrote (in which case, you should refrain from replying to it), or you are being dishonest on purpose.

I don't see how you made that leap. It was directly in reference to your reply: > I was on an automotive-focused instance. I did see a lot of that. They were more or less just rewriting what you wrote.

> They were more or less just rewriting what you wrote.

The literal opposite of what I wrote, actually, because "that" refers to "celebrating the murder of Charlie Kirk", an activity not much associated with fans of Charlie Kirk.

Re: Unix v4 Tape Found

#92
post #65

Earlier quoted context omitted.

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 see…

The weight limits are for public roads. Private logging roads can run whatever they want and Canada had(have?) some impressive rigs routinely hauling 100+ tons. Just do an image search for Hayes/Pacific logging truck.

Re: Unix v4 Tape Found

#93

Earlier quoted context omitted.

I don't see how you made that leap. It was directly in reference to your reply: > I was on an automotive-focused instance. I did see a lot of that. They were more or less just rewriting what you wrote.

> They were more or less just rewriting what you wrote. The literal opposite of what I wrote, actually, because "that" refers to "celebrating the murder of Charlie Kirk", an activity not much associated with fans of Charlie Kirk.

Ouch, yeah, thanks for the explanation. Total reading comprehension failure on my part.

Re: Unix v4 Tape Found

#94
post #89
post #68

Earlier quoted context omitted.

I tried setting that up, but now the trucker's union is refusing to talk to me, citing concerns that the platters will all spin up due to road vibration, derailing the truck in a ditch due to the cumulative gyroscopic forces. They remain unconvinced that chatGPT has told me it "should be fine", and have inquired as to whether I don't have better things to do than trying to win increasingly obscure and contrived argum…

AFAIK it's discontinued since, but AWS had a service where you could send data via a huge truck https://aws.amazon.com/blogs/aws/aws-snowmobile-move-exabyte... , it's absolutely not a fantasy.

Fascinating, I wasn't aware of that. They still offer an "AWS Snowball", which is 200 TB instead of 100 PB, but around the size of half a full size suitcase instead of a semi truck. You then ship that back and forth.

If you need 100 PB then moving 500 of those around seems a lot easier for everyone involved than managing a special snowflake truck.

Re: Unix v4 Tape Found

#95
post #5

Earlier quoted context omitted.

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...

Added up there too. Thanks!

Re: Unix v4 Tape Found

#96
post #10

Earlier quoted context omitted.

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 wha…

Don't forget about the mold that eats cd and dvds for breakfast. I saw a few dvds damaged by it

Re: Unix v4 Tape Found

#97

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.…

I used to be a digitial hoarder (now less so, but I still have what I hoarded, built over a 15 year period). When I moved overseas, I shipped my 120HDs (~600TB) in a container (120 HDs don't take up "that" much space (they all arrived in one piece, though 5 have died, though only 3 non recoverable, after the first one died, I made sure to image each one first and then writing it back (bitrot was a problem)).

anyways, in took 2-3 months for it to arrive (and most of that time it was waiting in either port), but by my calculation, I have needed to transfer it at a consistent 80MB/s or so (close to gigabit) to be able to net the equivalent transfer rate.

Re: Unix v4 Tape Found

#98
post #25

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.

Somewhat related, there are people doing amazing things by modifying VHS players and tapping into the raw output from the tape heads (bypassing all of the player's other electronics), and then using modern signal processing techniques to extract unbelievable great footage from old tapes.

Check out this extraction/decoding of a 1987 VHS recording of The Cure:

https://www.youtube.com/watch?v=ks1wE_NXWv8

Play if full screen at whatever the highest resolution your screen can take advantage of, It's amazing! Check out the quality of the big headshots of Robert Smith, the resolution of stuff like his hair is way beyond what I believed VHS to be capable of - based on growing up recording similar music acts in the 70s and 80s.

Here's the software (and descriptions of the hardware and VHS player mods) they use:

https://github.com/oyvindln/vhs-decode

I suspect the recording technique/format on those is a similar analog signal on the tape - and from The Reg's article (quoting various sources) it sounds like they're already planning on similar approach:

"The software librarian at the CHM is the redoubtable Al Kossow of Bitsavers, who commented in the thread that he is on the case. On the TUHS mailing list, he explained how he plans to do it:

taping off the head read amplifier, using a multi-channel high speed analog to digital converter which dumps into 100-ish gigabytes of RAM, then an analysis program Len Shustek wrote: https://github.com/LenShustek/readtape

It is a '70s 1200ft 3M tape, likely 9 track, which has a pretty good chance of being recoverable."

Re: Unix v4 Tape Found

#99

Earlier quoted context omitted.

I don't see how you made that leap. It was directly in reference to your reply: > I was on an automotive-focused instance. I did see a lot of that. They were more or less just rewriting what you wrote.

> They were more or less just rewriting what you wrote. The literal opposite of what I wrote, actually, because "that" refers to "celebrating the murder of Charlie Kirk", an activity not much associated with fans of Charlie Kirk.

Thanks for the clarification.

TIL there's many Charlie Kirk haters amongst fans of cars?

Re: Unix v4 Tape Found

#100
post #65

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…

Dans Data (RIP that website, apparently) did this backup tapes to microSD cards update about 15 years ago.

He started with "Well, first we need to know how big our station wagon is. I hereby arbitrarily declare it to be a 1985 Volvo 240, which has 2.2 cubic metres of cargo capacity." and "I'm also going to assume that the wagon isn't really packed totally full of memory cards, such that they cascade into the front whenever you brake and will avalanche out of the tailgate when it's opened. Let's say they are packed almost to the roof of the car, but in cardboard boxes, which reduce the usable cargo capacity to a nice round two cubic metres."

The calculated "Assuming uniform and perfect stacking of objects of this volume, with zero air space, you can fit 24,242,424 of them into two cubic metres."

But he also addressed the packing problem, saying:

"In the real world there'd obviously be air spaces, even if you painstakingly stack the tiny cards in perfect layers. My size approximation, that ignores the more-than-0.5mm height of the thick end of the card, could make the perfect-layers calculation quite inaccurate. But if you're just shovelling cards into the boxes and not stacking them, though, there will be even more empty space between cards, and the thicker ends won't matter much.

To use a few words you may have to hit Wikipedia about - I know I did - a random close pack of monodisperse microSD-shaped objects will be considerably tighter than one for, say, spheres. I wouldn't be surprised if it only reduced the theoretical no-air-space density by 20%, provided you shake the boxes while you're filling them.

So let's stick with a 20% density reduction from random packing, giving 0.8 times the theoretical density of perfectly-packed cards. Or nineteen million, three hundred and ninety-three thousand, nine hundred and thirty-nine cards, in the boxes, in the station wagon."

He was writing in 2015, and settled on 16GB cards and being reasonable, getting 275 pebibytes. If we switched them to the 1TB cards mentioned upthread that'd be 17 exabytes in a 2 cubic meter stationwagon cargo area, or in a 67 cubic meter shipping container you'd get 575 exibytes. And that's the "load with a shovel and shack to pack down" number, so perhaps 720EiB if someone took that forever to carefully pack them.

Your 100 tons problem is real, it seems shipping containers (both 20 and 40 foot) seem to top out with a cargo payload of 28 tons. So let's call it "only" 161EiB shovel loads.

The font of all hallucinations and incompetent math tells me "The total amount of data on the internet is estimated to be around 40 zettabytes as of 2025, which is equivalent to 40,000 exabytes." So you'd only need 250 shipping containers or so to store a copy of the entire internet. And that's barely 1% of the capacity of a modern large cargo ship. I guess for reliability you'd use 500 shipping containers in redundant mirrored RAID1 config, each half travelling on a different ship.

Dan also noted: "Unfortunately, even if your cards and card readers could all manage 50 mebibytes per second of read and write speed, getting all of that data onto and off of the cards at each end of the wagon-trip in no more than 24 hours would require around 68,400 parallel copy operations, at each end."

That works out to 2.3 million readers for one parallel copy of one containers worth of data in one day. And 570 million for 250 container's worth.

https://web.archive.org/web/20250313181659/http://dansdata.c...

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