 Previous Messages |
Posted By
Gaia
on 2010-04-11
14:22:00
|  Re: Interesting project
Well, it was an interesting read  But perhaps you meant to copy this to the Her Turbo thread? 
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Posted By
TLC
on 2010-04-09
14:19:37
| Re: Interesting project
Gaia: actually, MegaCopy V1.1 is "not" a Her Turbo descendant... it's rather a descendant of György Rétvári's C64 compatible turbo (the one whose listing you have found in that '86 Mikro Magazin ie. http://pcvilag.muskatli.hu/irodalom/mm/86/86112/kep.php?kepparam=m86112-5.jpg ). That's also the very reason of it successfully cooperating with "full-wave" TAP files (unlike HER, which sometimes breaks the rules implied by original full-wave TAP and can only be stored successfully in half-wave TAP files). As for the speed -- it's as fast as the usual C64 turbo tape format is. It's somewhat faster than HER, whose principle is similar to the method used here (...I'm wondering if the creator of HER Turbo had known C64 turbo tape routines previously to coding his routine), but the timing is shorter ie. the bitrate is higher. You can get an idea of how "fast" it is of the width of the color bars during load... one color bar is one byte... (that may make it something like 4-5 character rows per byte (strongly depending on the number of 0 and 1 bits, one of them takes longer as this is just pure FM encoding), ie. 6-7 bytes per frame... ie. around 300-350 bytes per second). ...I do remember of modified HER Turbo versions (none that I could have got hold of back in the time but whose recordings I used to receive from friends with whom I swapped stuff) whose timing has been tuned up similarly or just in a similar fashion.
The strong influence of Tape Messiah to MegaCopy is obviously a result of some level of envy :-D. It was a so enhanced and nice program, but I had "problems" with it (I had no floppy drive at the time) that I couldn't work around, nor could I (obviously) cure, being it (for me at the time) a relatively complex program (...and on top of that, it resided in the color and screen ram, making it pretty hard to test and being capable of list/edit it concurrently). I was also dissatisfied with the speed of all the turbos that I could get hold of, including Tape Messiah. From the other hand, there was this C64 compatible turbo, which was completely useless by itself but which also turned out to be relatively (very) fast in simple tests that I arranged. ...I disassembled it and extracted parts that I believed to be the "core" of the load/record processes (...I obviously didn't know how the "hell" tape recording should work (at all) at the time, I didn't even know that tape recording "works" through writing and reading values from the processor I/O port at $01... those were the days... :-D ). I knew what I should "support" at the end ie. what features of Tape Messiah should be "kept" at all costs (because they just ruled), together with this fast recording format and the other details that I missed and couldn't work around in TM. ...And that's what came out. Support for the extra short Kernal header was done "through" reading the Kernal disassembly and experimenting. The turboload routine could just "barely" fit in the tape buffer, it had to be re-written, even after that there weren't any free bytes left in the buffer... Support for autostart, disabling autostart on files (to be copied) and other stuff was also added by/after experimenting.
(Hmmm... Why did I write all that down now, anyway?... )
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Posted By
Gaia
on 2010-04-07
16:49:40
| Re: Interesting project
Up! The project page has been updated. In fact, both the schematics as well as the firmware are made public and freely available, so do not hesitate to start making USB-based TAP devices
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Posted By
Gaia
on 2009-10-13
15:23:59
| Re: Interesting project
I believe the "noise turbo" called Turbo 16 by Novotrade should be among the fastest, though it was notoriously unreliable (perhaps the two facts are correlated? )
Also, TLC's MegaCopy_V1_1 is very fast, as well as recommended though I have never checked how fast it exactly is (the KERNAL part IS the fastest possible and the turbo itself is admittedly a Her turbo descendant so that can give a hint).
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Posted By
Chicken
on 2009-10-13
13:07:43
 | Re: Interesting project
Sorry, no answer Many years ago I tested several turbo loaders to see which is the fastest. Unfortunately, I don't know where I put my results.
I brought this topic up again some years ago...
http://plus4world.powweb.com/forum/12782
I guess we are too lazy to verify anything :D Do you have datasette? Then just try it :)
Rüdiger made a comment about commercially used turbo tapes in the thread mentioned above.
"Very fast is the Turbo Tape in the Turbo Plus cartridge. And the fastload from cascade games for the c-16 version of A.C.E."
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Posted By
YERZMYEY
on 2009-10-13
08:09:11
 | Re: Interesting project
Yeah, I'm watching his videos now.
I was wondering how fast the tape turbo is, on 264.
I mean:
1) in what time it would load entire 16Kb memory, in the turbo mode
2) in what time it would load entire 64Kb memory, in the turbo mode.
Of course by 16/64Kb I mean - approximatelly
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Posted By
Andras78
on 2009-10-06
01:39:14
| Re: Interesting project
Have you ever seen this? I take the contact with the guy, lets see the video. Amazing
http://www.luigidifraia.com/c64/dc2n/index.html
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Posted By
YERZMYEY
on 2009-10-05
09:05:37
| Re: Interesting project
Ha. So such a "tape-emulator" might be damn fast considering big amoung of programs with 16Kb only.
Sounds nice.
A pity that demos are not mostly in both forms at once (disk & TAP).
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Posted By
Chicken
on 2009-10-05
07:30:35
| Re: Interesting project
YERZMYEY...
Without going too much into detail: Basically, there are two kinds of "turbo tapes". Those that require some code/routine to be present in RAM (or a modified ROM/cartridge) to access the saved programs and those which are "included" in the saved program.
Turbo Plus - a very fast cartridge based turbo tape - belongs to the former category. Programs saved with that turbo require the cartridge to be present for loading the programs again.
The latter ones are more popular because everyone can load those programs. Simplified, the "turbo tape loader" is hidden in the file name. Only 16 chars are displayed the rest can be "used" for some code (e.g. a turbo loader) which is auto-started by redirecting some vectors. Very simple but very effective
Many (if not most) of the commercial releases include such a turbo tape. Among the well known ones are Novaload and the KINGSOFT turbo.
Both types of turbo tapes worked with a standard datasette (most ppl used the 1531 datasette) and thus, any device emulating the datasette should support both of them anyway.
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Posted By
TLC
on 2009-10-05
07:14:25
| Re: Interesting project
Yes, definitely was.
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Posted By
YERZMYEY
on 2009-10-05
06:17:55
| Re: Interesting project
I wonder if there is any turbo added to the device.
However I dunno if there was any habit to use turbo tape loading on 264.
| (no topic)
I wonder if there is any turbo added to the device.
However I dunno if there was any habit to use turbo tape loading on 264.
[edit]...because I bought the machine already with a diskdrive. ;)
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Posted By
retroscener
on 2009-10-05
05:33:15
 | Re: Interesting project
Oops, maybe forget the Q&A's. I Just read the link.
I take it then it isn't a datasette but like some USB flash drive you can also hook up to the C16/+4 and C64/128?
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Posted By
retroscener
on 2009-10-05
05:26:42
| Re: Interesting project
Sounds good.
2 questions:
1. Will it be connectable to the PC for TAP transfers?
2. Will it allow for differing volume frequencies, or will it save to cassette always on the correct setting?
Anyway, yayyyy, I just recieved some more C16 tapes from ebay. Never thought I'd see another copy of 'survivors' again
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Posted By
Chicken
on 2009-10-03
06:08:57
| Re: Interesting project
It is a nice project
Though, I do like "real" cassettes and for loading programs (especially demos) I'd prefer some "disk" (based) system.
Still, it's really cool that he thought about the plus/4, too Viva Espana :D
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Posted By
Luca
on 2009-10-03
05:27:07
 | Re: Interesting project
...and it won't be lost as project: he must graduate!
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Posted By
Gaia
on 2009-10-03
04:47:30
| Interesting project
Recently got a mail from a guy in Spain who is making a tape device to substitute the datasette. It will load TAP images instead of real tapes and will support version 2 TAP's as well (the native - "halved wave" - format of the plus/4).
http://pc23te.dte.uma.es/C2N-II/
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