Cataloging a tape.

Anything Sinclair ZX Basic related; history, development, tips - differences between BASIC on the ZX80 and ZX81
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Paul
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Location: Germanys west end

Re: Cataloging a tape.

Post by Paul » Thu Aug 04, 2016 5:13 pm

I remember that in the past(Tm) C60 Cassettes were really cheap in germany (even for me!).
So when I needed to save something I always used a brand new tape, saved the program three times after each other (to enshure it could be reloaded) and then wrote the name of the program on it.
Thats it. Catalogue completed :lol:
Thats because when I started i always used the tapecounter and wrote down the positions. But the tape counter reset button was the first thing that broke.
And new cassette players were really expensive.
Kind regards
Paul
In theory, there is no difference between theory and practice. But, in practice, there is.

johnnyrockets
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Re: Cataloging a tape.

Post by johnnyrockets » Thu Aug 04, 2016 5:33 pm

Hi Paul,

Where do you live in Germany?

I have been to Germany five times for work.

I work for a company called Wacker Chemical. Located in Munich and Burghausen (near Austria, in Bavaria).

Really like the Bavarian area.


J

sirmorris
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Re: Cataloging a tape.

Post by sirmorris » Thu Aug 04, 2016 5:34 pm

Try this. It should print the names of programs it finds on tape.

I can't run this in EO though, I don't know why. It just fails to load. It's likely it won't work on the metal either. I don't have time right now to work out why - sorry.

I'm also unsure of what will happen when the program continues on to find the next title.. The program might need to be changed so that you need to only start listening again during the inter-program silence.
Attachments
names.p
(1.4 KiB) Downloaded 101 times

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RetroTechie
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Re: Cataloging a tape.

Post by RetroTechie » Thu Aug 04, 2016 8:28 pm

johnnyrockets wrote:And now as I read the "tape header" program my mind is completely blown to realize that a tape file exists in a "wav" format?!
Never, ever, in your life, tried to digitize a cassette tape I take it? :lol:

In digital form, .wav is the obvious format for a cassette tape recording. Drawback is that it's a rather inefficient way to store data as used by home computers like the ZX81. So for that purpose, there's usually some machine-specific formats that contain just the binary data as it winds up in the computer's main memory. With perhaps some type info or other meta-data included in the file.

For the ZX Spectrum, that's .tzx, .tap and a few disk image formats. For the ZX81, that's mostly .p files and perhaps .81, both of which basically contain the bytes as received from the BIOS routine when loading a real cassette tape.

Note that the .wav from the archive in my previous post isn't a digitized recording! Such .wav don't compress well since it's still a representation of the entire analog signal (even if a ZX81 would just pull a few 1's and 0's from that). Instead it's generated from the .p file in same archive. The .wav generated that way has only a very few sample values (with a 1:1 relation to the .p file used), and compresses so well that I often include it with .p files in the same archive for convenience. But that's only for .wav generated from .p file, and stored in compressed format like .zip. I'm not the kind of person to waste harddisk space on .wav's just because that space is cheap. ;)

For emulation purposes, you basically cut 'pieces of interest' from tapes, such that a tape counter becomes pointless.

Solid-state storage like ZXpand circumvent the analog route alltogether, and store the bytes directly on the flash card's silicon. 8-)

johnnyrockets
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Re: Cataloging a tape.

Post by johnnyrockets » Thu Aug 04, 2016 8:42 pm

RetroTechie wrote:
johnnyrockets wrote:And now as I read the "tape header" program my mind is completely blown to realize that a tape file exists in a "wav" format?!
Never, ever, in your life, tried to digitize a cassette tape I take it? :lol:

In digital form, .wav is the obvious format for a cassette tape recording. Drawback is that it's a rather inefficient way to store data as used by home computers like the ZX81. So for that purpose, there's usually some machine-specific formats that contain just the binary data as it winds up in the computer's main memory. With perhaps some type info or other meta-data included in the file.

For the ZX Spectrum, that's .tzx, .tap and a few disk image formats. For the ZX81, that's mostly .p files and perhaps .81, both of which basically contain the bytes as received from the BIOS routine when loading a real cassette tape.

Note that the .wav from the archive in my previous post isn't a digitized recording! Such .wav don't compress well since it's still a representation of the entire analog signal (even if a ZX81 would just pull a few 1's and 0's from that). Instead it's generated from the .p file in same archive. The .wav generated that way has only a very few sample values (with a 1:1 relation to the .p file used), and compresses so well that I often include it with .p files in the same archive for convenience. But that's only for .wav generated from .p file, and stored in compressed format like .zip. I'm not the kind of person to waste harddisk space on .wav's just because that space is cheap. ;)

For emulation purposes, you basically cut 'pieces of interest' from tapes, such that a tape counter becomes pointless.

Solid-state storage like ZXpand circumvent the analog route alltogether, and store the bytes directly on the flash card's silicon. 8-)

Okay, whoa! Great information here, but some of it I don't understand.

- it sounds like a WAV would work, but just be a space hog?
- how does one generate a ".p" file?
- the ZXpand sounds pretty cool, how can I buy one? ;)


Thanks! Seriously thanks a lot for the help!


JR

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1024MAK
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Re: Cataloging a tape.

Post by 1024MAK » Thu Aug 04, 2016 9:24 pm

johnnyrockets wrote:Okay, whoa! Great information here, but some of it I don't understand.

- it sounds like a WAV would work, but just be a space hog?
- how does one generate a ".p" file?
- the ZXpand sounds pretty cool, how can I buy one? ;)
If you wanted, a modern computer sound card (or equivalent motherboard system) can record the cassette tape output from a ZX81 as a digitised audio file in the .wav format. However, it is an inefficient use of storage space (large files compared to the actual ZX81 data contained within it) because the audio signal that is captured and converted is imperfect with distortions. However, if a .wav file is generated by a modern computer from a digital file that represents the digital copy of the memory of a ZX81, because only a limited number of audio frequencies are used, the file size is reasonable.

".p" files were originally used only by emulators. So if you write a program on an emulator, when you save it, most will let you save it as a ".p" file. There are also various utility programs that convert between formats. Some will convert a ".p" file to an audio output, that you can feed to a real ZX81.

ZXpands are currently not available, but the producer hopes to produce a new batch soon. Watch on this forum for news...

Mark

johnnyrockets
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Re: Cataloging a tape.

Post by johnnyrockets » Thu Aug 04, 2016 9:51 pm

1024MAK wrote:
johnnyrockets wrote:Okay, whoa! Great information here, but some of it I don't understand.

- it sounds like a WAV would work, but just be a space hog?
- how does one generate a ".p" file?
- the ZXpand sounds pretty cool, how can I buy one? ;)
If you wanted, a modern computer sound card (or equivalent motherboard system) can record the cassette tape output from a ZX81 as a digitised audio file in the .wav format. However, it is an inefficient use of storage space (large files compared to the actual ZX81 data contained within it) because the audio signal that is captured and converted is imperfect with distortions. However, if a .wav file is generated by a modern computer from a digital file that represents the digital copy of the memory of a ZX81, because only a limited number of audio frequencies are used, the file size is reasonable.

".p" files were originally used only by emulators. So if you write a program on an emulator, when you save it, most will let you save it as a ".p" file. There are also various utility programs that convert between formats. Some will convert a ".p" file to an audio output, that you can feed to a real ZX81.

ZXpands are currently not available, but the producer hopes to produce a new batch soon. Watch on this forum for news...

Mark
Really cool!

I'd like to try some of these techniques this weekend, so thanks for the cool info! I'm going to search for one of those utility programs for conversion as well. Thanks again!

J

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mrtinb
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Re: Cataloging a tape.

Post by mrtinb » Fri Aug 05, 2016 7:46 am

mrtinb wrote:I have a scan from an old magazine at home. It contains a BASIC program (a "type in"), that reads a whole tape and lists all filenames on the screen.

I'll find it for you.
Sinclair User December 1982 page 56: Tape Reader.
Martin
ZX81, Lambda 8300, Commodore 64, Mac G4 Cube

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