I don't see why it shouldn't be possible to read one in 100 years time. With the technology of the day you could probably manufacture a suitable reader on your domestic 3D printer!
A 120 RPM disc? I thought that speed would imply a cylinder.
I've got a working 5.25" drive (connected to a BBC Master) on the desk next to me; I'm regularly asked to copy floppies much older than 20 years (and normally they read perfectly)!
An 8" floppy would admittedly be a bit more difficult; the CP/M machine is in the loft, but as far as I know it still works. I'm not sure if it will read hard-sectored disks but even so I could probably do a track read and recover the data that way.
Probably have a bit of trouble with the stylus, but play it back on a normal deck at 45 and speed it up digitally. No real problem.
Bit of a sore point this. I have an ancient computer here with a dead floppy controller, and data I'd like to keep (just for historical reasons - it's possibly the only copy of some of the source anywhere). Must get around to putting Kermit on this machine and that one and archive the disc. It's only a few megs...
Disc rot has happened a lot. Once air gets in they tend to lose their reflective. It was often worse on the old laserdiscs, they went a weird stained colour. The Pioneer players were better at scanning these than the other make.
Having said all of that though apart from a few very early cds I've had little problems with the home made or commercial ones, though the surfaces can get scratched. The other issue I have had is bad centring on front loaded players. This seems only to happen on the completely flat early cds. Later ones have a ridge on the playing side that helps a lot. One issue that can occur is that certain mechanisms get upset on home made cds that are recorded too fast. They tend to give up when searching out a track. I suspect either weak recordings or perhaps some form of eccentricity. Rewritable's and minidisc which use a much lower reflective medium seem to give problems a lot. Brian
What do the recording studios do these days. There seems to have been at least two generations of making masters into a digital format, but they must have something that lasts, presumably.
As I say, no issues with my ones, even commercial 1983 copy of Dire Straits Making Movies plays fine
Well all I'll say is that nothing is perfect, and I feel the issue is one of expansion rate of the media and the coatings.
As for acid free, even paper can have acid content, but I've not had much of a problem I'm going through my cds now attempting to catalogue them so I can say that I've not found a dud yet. Brian
Magnetic media - 1 year Optical media - 10 years Ordinary paper - 100 years Papyrus / Vellum / Parchment - 1000 years Baked clay tablets - 10,000 years (estimated)
Yes, and if I can't find one in working order, they're not hard to make from scratch or modify from another one. A lot of current hobby engineers are doing just this for 78 rpm and other speeds. People are even making machines to play and record cylinders.
The 5.25 inch yes, at the moment, until the drive dies at some unspecified future time. I can't read the 8 inch floppy, but there are still people who can.
The problem with current optical media in the future will be finding the specialist mchinery for making for the lasers used, and researching the coding used to store the data.
Analogue tape regularly lasts over 50 years. Most of my 20 year old floppies are still readable. The limit on VHS and Beta recordings seems to be the head life, or a few hundred plays, at which point the mechanics inside the cassetts become compromised.
About 50% failure rate on writeable media within that time, in my experience. 99% of my early commerially produced CDs will still play at
30 years.
As long as it's acid free, and not chlorine bleached.
If kept in a stable, dark, dry enclosure, up to 5000 years.
The technology's too new to know how long it will last yet.
I have a 30+ year old mini-computer (although some of the boards are only 20+ years old). 15 years ago, I thought it would be a shame if it died and I couldn't read any of the disks (or discs, as it calls them). So I set about saving some of the more interesting disk images. (I probably have some 50 exchangable disk cartidges, a mixture of 8MB and 25MB types, but I wasn't going to save them all.)
Having saved some images, I then had to write a program which understood the filesystem on them, and dump out the files. This was quite easy for me, as when I worked for the company, I wrote the filesystem checking, garbage collection and copy program, so I knew the filesystem structure inside-out.
Having done that, I started playing with the boot code from the disk, loaded it into memory, and interpreted the instructions. Eventually, I had a full emulator working (took a couple of years in spare moments), and I could link up the disk images, and run the operating system. I still play with it from time to time, and in particular, I use it as my personal benchmark when I get my hands on a new system, the measure being how much faster my emulator runs the OS than the original system ran. On a current Sandy-Bridge x86, it runs at 56 times the speed of the original minicomputer system.
As for the original machine - it still works just fine. The ethernet controller often doesn't work when it hasn't been used for a year, but reseating all the chips on it usually gets it going again. One of the disk drives has died, but I have 2 of each size (8MB and 25MB), so I can still read the original disks on it. Or at least, that was the state when I last booted it ~2 years ago.
You'll just need to load the app onto your iPhone65 which takes a photo of the disk with its 10Gigapixel camera using the coherent flash, and plays it directly from the photo image...
Was still in my early teens when it was first transmitted,made the tension cause by Daleks and Cybermen on Dr Who look like being savaged by a Teletubbie.
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