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Zibri
Account closed
Registered: May 2020
Posts: 304 |
New life for your underloved datassette unit :D
The first phase of testing just ended.
(Still in the packaging and refining phase)
But I wish to share with you all my latest accomplishment.
You might want to check this out:
https://twitter.com/zibri/status/1450979434916417540
and this:
https://twitter.com/zibri/status/1450979005117644800
The fastest example (11 kilobit/sec) has the same (or better) error rlsilience as "turbo250" but it is 3 times faster.
The slowest one (8 kilobit/sec) has the same error resilience as the standard commodore slow "save", but it is 100 times faster and twice as fast as turbo250.
;)
Notes:
1) faster speeds are possible if the tape is written with a professional equipment or hi-fi with a stabilized speed and virtually no wobbling.
2) if the tape is emulated (tapuino or similar projects) the speed can go up to 34 kilobit/sec.
3) even with datassette, higher speeds are possible but the highly depend on the status of the tape, the datassette speed and azimuth. |
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Trurl
Registered: Mar 2002
Posts: 61 |
True. What might be the real problem with the duplication then, since I'm in the understanding that there were real problems at that stage? |
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Martin Piper
Registered: Nov 2007
Posts: 722 |
Quote: i kindof doubt that was actually a problem - those machines were also used for high quality audio tapes, which is much more demanding than data tapes.
Well back in the day, sometimes turbo loaders needed to be tweaked to get reliable duplication because the professional companies weren't producing accurate product. |
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Martin Piper
Registered: Nov 2007
Posts: 722 |
This page quite usefully does a bit of analysis on the speeds of various loaders: https://www.luigidifraia.com/c64/docs/tapeloaders.html |
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Zibri
Account closed
Registered: May 2020
Posts: 304 |
Quoting GroepazWell, i guess we can expect shitty belts are being replaced and azimuth setting is somewhat okish - but anything besides that, not so much. It still boils down to the expected variations between individual c2n - which unfortunately we dont have datasheets of, but we can still do a couple calculations to atleast get an idea of what to expect.
And there's the beauty of parameters.
My loader can (and does) work even on datassettes in bad conditions like Neo-Rio's aand still keep a respectable speed.
Like with cars, is up to the user to have an "OKish" car and go on dirt roads (bad tapes) or to fully tune their car and test it on a track :D
I like more the second, some like more the first.
Hence the speed setting which allows a full range of possibilities (131 * 4 possible parameters cobinations!)
I just use ten of them in the speed setting but it's fully customizable for every need, keeping always the best possible speed and reliability. |
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Zibri
Account closed
Registered: May 2020
Posts: 304 |
Quoting Martin PiperThis page quite usefully does a bit of analysis on the speeds of various loaders: https://www.luigidifraia.com/c64/docs/tapeloaders.html
I know.. that's where I learnt about Evil Dead, found the tape, reconstructed a clean master and started working on my turbo.
:D |
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SLC
Registered: Jan 2002
Posts: 52 |
Quote: Quoting Martin PiperThis page quite usefully does a bit of analysis on the speeds of various loaders: https://www.luigidifraia.com/c64/docs/tapeloaders.html
I know.. that's where I learnt about Evil Dead, found the tape, reconstructed a clean master and started working on my turbo.
:D
Reconstructed? Would be interested in seeing what it looks like compared to the real tape.
And while we're at reconstructing... you're wrong about Giana disk orrie, btw. The protection pattern is if I don't remember incorrectly consisting of 128 repeats, not 112.5 or whatever you concluded with (I checked an original dump). Written in speed zone 2 but with a slightly higher RPM than the rest of the floppy. |
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chatGPZ
Registered: Dec 2001
Posts: 11386 |
Quote:131 * 4 possible parameters cobinations!
so that is the metric for how good the loader is? |
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Zibri
Account closed
Registered: May 2020
Posts: 304 |
Quoting SLCReconstructed? Would be interested in seeing what it looks like compared to the real tape.
And while we're at reconstructing... you're wrong about Giana disk orrie, btw. The protection pattern is if I don't remember incorrectly consisting of 128 repeats, not 112.5 or whatever you concluded with (I checked an original dump). Written in speed zone 2 but with a slightly higher RPM than the rest of the floppy.
I am not wrong about it.
Check the document in the website.
From the loader code I got the exact timing range accepted and
re-created a "better" sync which is long exactly at the middle of the range. So my "WP" writes a better more centered one and assures more compatibility with out of speed drives.
About the evil dead reconstruction, I just removed the noise, cleaned up the tap and set all values as they should have been and not as they were read (with the classic +/- 1 variation.
If you are interested I can post it somewhere. |
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Zibri
Account closed
Registered: May 2020
Posts: 304 |
Quoting GroepazQuote:131 * 4 possible parameters cobinations!
so that is the metric for how good the loader is?
Clearly not your judgement. |
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Zibri
Account closed
Registered: May 2020
Posts: 304 |
Quoting SLCReconstructed? Would be interested in seeing what it looks like compared to the real tape.
https://github.com/Zibri/C64/raw/master/EvilDead_REMASTERED.tap |
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