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... and still be read? My tapes for the old Elf II computer are 35+ years old and 20 years ago I have been told that they will not load anymore. Most still did, but I thought it would be great to find a way to load them with a PC and possibly reconstructing those that can't be loaded normally anymore.
Long ago I wrote a Win32 program in C++ that could load the tapes (sampled as WAV files) and then reconstruct the binary file. The real pain was to figure out the correct timing values for each particular recording.
Now I'm working on a new .Net version that supports the tape formats of similar computers, figures out the timing automatically and lets you manually edit 'bad' bits when nothing else helps. It's not finished yet, but it already as far as building a stream of bits and allows to edit them. Only the last step, taking the start bits, data bits and parity bits and converting them to bytes is still missing. Then I can save a simple binary file.
Here is the beginning of a good sample[^] The blue '1' to the left are the end of the leading beep' on the tape, followed by the first start and data bits in green.
Now look at this one.[^] The input signal is much weaker and I'm amazed how much he (self invented) algorithm still can read from it. There are two bits with invalid timing, both probably '1'. I could simply click on them to override their values, clean up all further errors (there are buttons to navigate to them at the top), and then this file can be rescued from east hyperspace.
Somewhere on these tapes are my first working machine code programs and I will not rest until I have recovered them all.
Edit: It's not a bug, it's a feature! In the old program I had to figure out the number of samples that make up a long or short pulse manually. That's why the WAV files had to be sampled with a specific sample frequency. The new program analyzes the samples and figures out the timing automatically. The sampling frequency has become unimportant. I just converted some oder WAVs which were sampled at a lower frequency without problems!
The language is JavaScript. that of Mordor, which I will not utter here
This is Javascript. If you put big wheels and a racing stripe on a golf cart, it's still a f***ing golf cart.
"I don't know, extraterrestrial?"
"You mean like from space?"
"No, from Canada."
If software development were a circus, we would all be the clowns.
modified 20-Jan-17 19:31pm.
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I've always found tape life to be a physical issue, with the magnetic medium flaking off the substrate.
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Luckily, that has not happened yet. I also used to save each program at least three times. Even if each recording can be recovered only partially, chances are good that I can patch together a complete file with a hex editor.
The language is JavaScript. that of Mordor, which I will not utter here
This is Javascript. If you put big wheels and a racing stripe on a golf cart, it's still a f***ing golf cart.
"I don't know, extraterrestrial?"
"You mean like from space?"
"No, from Canada."
If software development were a circus, we would all be the clowns.
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You could always just throw them in the bin and move on 
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Sometimes you must take a step back[^] to move on. I did not know what he was working on back then.
The bin would be a dumb place to put the old computer. I doubt that you could find 1000 of them in the entire world that still work. Back then one wth a very similar configuration as mine was sold on Ebay and went away for 2500 bucks, not that I would ever sell it.
The language is JavaScript. that of Mordor, which I will not utter here
This is Javascript. If you put big wheels and a racing stripe on a golf cart, it's still a f***ing golf cart.
"I don't know, extraterrestrial?"
"You mean like from space?"
"No, from Canada."
If software development were a circus, we would all be the clowns.
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PIEBALDconsult wrote: tape life to be a physical issue
I have taken apart and repaired many cassette tapes...either because they started dragging or the tape deck started eating it! Ah, the good old days! 
"Go forth into the source" - Neal Morse
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Can't help with your question, but wanted to say that what you're working on is totally 
[edit]And who knows, the Dept. of Defense might contract you to resurrect the bits on the aging 8" floppies they use for launching ICBM's!  [/edit]
Marc
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Hi Marc. It looks like my missile firing days are over. The NASA is also a good address, it seems. When I wrote the first conversion program, someone who was involved wrote a paper for the New Horizons mission. I posted a link in the reply to Dave Auld.
The language is JavaScript. that of Mordor, which I will not utter here
This is Javascript. If you put big wheels and a racing stripe on a golf cart, it's still a f***ing golf cart.
"I don't know, extraterrestrial?"
"You mean like from space?"
"No, from Canada."
If software development were a circus, we would all be the clowns.
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How long be able to read the data?
Inversely proportional to the importance of the data.
Rules for playing Javascript frameworks.
1. You can't win.
2. You can't break even.
3. You can't get out of the game.
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I don't have much experience of data tapes but I have worked extensively with old audio tapes. There are two main problems with old tapes, binder breakdown (sticky shed) and loss of lubrication. Binder breakdown can usually be temporarilly reversed by gently heating the tape to about 50 degrees C for a few hours. Loss of lubrication is rarer but tapes can usually be played on machines that have no stationary guides. It has to be said that these problems usually only affect certain brands - Ampex/Quantegy being the most famous for sticky shed.
Tapes with a high bit density may suffer from problems with self erasure but this is something that happens in the first few months after recording. If a tape has been previously readable then it is unlikely to suffer.
Other issues could be fragile splices which will have to be remade but, apart from the leader tape, splices shouldn't be an issue with data tapes. Acetate based tapes are also far more fragile than more modern Mylar tapes but I'm not sure whether any data tapes were actually made with acetate bases.
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wow, and I tossed my old PDP-11 tapes a few years ago without pulling my programs off.
Programs that were for an OS that does not exist, on a hardware platform that died before the internet got famous.
But part of me would have loved to have read the tapes the way you did just to see them.
Nostalgia!
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There are always emulators that need some fodder and who would have thought that at least some of our stuff on the tape will actually be saved and distributed like that in the entire world?
The language is JavaScript. that of Mordor, which I will not utter here
This is Javascript. If you put big wheels and a racing stripe on a golf cart, it's still a f***ing golf cart.
"I don't know, extraterrestrial?"
"You mean like from space?"
"No, from Canada."
If software development were a circus, we would all be the clowns.
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Hi,
I know from the YoutubeAPI Getting Started Page[^] that a quota of 1,000,000 "cost points" per day exists.
But for me, as not a native speaker, the text is not quite clear...
If a video upload has a cost of around 1600 points (another SO question[^]), and each and every access counts, even the smallest read request, 1 million points is nothing...
If my app had just 1000 downloads (which is... well... nothing) there would not even be allowed to upload ONE video per day and user ...
Or is this count as 1 million points PER APP INSTALLATION? Then it would be enough, of course...
Could someone be so kind to look at the linked page and try to explain it in simpler, absolutely clear words for me?
(You need to scroll down a bit to the Quota section)
Thanks in advance!
Mike
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Nope, you got it correct.
You get so many points per day on your API access account (ID). It's not per application. It's any number of applications accessing the API using your API account (ID). The points are applied to the account, not the application using it.
So, yeah, 1,000,000 points isn't a lot. If you need more points, then you're going to have to start shelling out money to YouTube for them.
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I was so afraid, that I was right 
1,000,000 Thanks for clarifying this for me!
- removed as it might have led to misunderstanding -
Cheers, Mike
modified 21-Jan-17 11:03am.
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Yeah, good luck with "finding an alternative".
Google isn't stupid and the system DOES recognize abusers like that and can still cut off access.
The points system is in place because of abusers. If you're going to access the system more than most people you're going to pay for a larger chunk of maintaining the system. You can only get so much for free.
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Sure - my App is planned mainly for playing (not uploading) videos, but still it's true that I can watch as many yt-videos per day as i like on youtube.com, but not in an app.
I am currently looking through the iframe api (which has no quota) and i will see where i get by using a WebView control.
The javascript api allows video control (play/stop/pause) too. Maybe this fits already.
I would shift the decision about "how to upload the solution videos" (nvm, part of my app) to a later point in time then.
Cheers Mike
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You do know that using ANY other software other than the YouTube player is forbidden by the terms of service, right?
Good luck with that....
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Allow me to clarify...
If your player hides or otherwise omits the ads YouTube pushes in the player your, app is illegal. If your using the player provided by the API, it's not a problem.
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Nono, you're thinking I want to cheat youtube - let ME clarify: NO I DON'T.
I want to use it as official as anbody else. That's why I am looking at the google api's.
the iframe api seems to fit almost all of my needs. It instanciates a standard, OFFICIAL YT.Player object made by google.
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What does a Thesaurus eat for breakfast?
A synonym roll!
Got new meds from the VA the other day, haven't adjusted yet!
New version: WinHeist Version 2.2.2 Beta I told my psychiatrist that I was hearing voices in my head. He said you don't have a psychiatrist!
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Mike Hankey wrote: Got new meds from the VA the other day, haven't adjusted yet!
Dare I say that it's actually working? 
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Not long ago. Not far away.
The cry of a billions of souls.
| Ravings en masse^ |
|---|
| "The difference between genius and stupidity is that genius has its limits." - Albert Einstein | | "If you are searching for perfection in others, then you seek disappointment. If you are seek perfection in yourself, then you will find failure." - Balboos HaGadol Mar 2010 |
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That feels political.
Move to Soapbox?
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