MSX cassette turbo loaders

By PingPong

Prophet (3767)

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16-08-2021, 09:47

hi, in the '80 there were a lot of turbo loaders in zx or c64 scene.
I'm wondering if those loaders were used also in msx in the commercial era and what baud rate could reach.
Anyone ever tryed also sw compression?

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By NYYRIKKI

Enlighted (5877)

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16-08-2021, 11:21

I guess the answer is pretty much just "No"... but there are always few exceptions to the rule:

https://www.youtube.com/watch?v=RbRB8p2Y0vY
https://www.youtube.com/watch?v=cM5AIsPTNOM

By PingPong

Prophet (3767)

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16-08-2021, 13:11

there were some loaders with border stripes but i do not know the speed. MSX could load @2400 bauds by default 1200. Those are relatively high speed for a standard tape. so maybe there should be no much room for improvements with old tape. For example speccy goes @1500 and c64 i think is below 500.

By mohai

Paladin (932)

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16-08-2021, 14:06

Some games were recorded in Speccy format, at least in Spain.
Some companies, such as Gremlin soft, Topo, Dro soft released their games in that format.
First a little loader contained the same routines in the Spectrum BIOS, so MSX can load those blocks.
Then, all other blocks were recorded in Spectrum format.
While loading, you could see the typical color glitches in the border.
We used to call this "turbo" format.
To avoid piracy, some companies re-released some games for the Spanish market and changed the loading routines to the "turbo" format. Some games, such as Out-run were recorded in this format for the Spanish market, but not for the British one.
Some companies, such as Byte Busters or Eaglesoft, used a little faster speed to record tapes. It is not 2400, but it is slightly faster than 1200, for sure.

By mohai

Paladin (932)

mohai's picture

16-08-2021, 14:08

NYYRIKKI wrote:

I guess the answer is pretty much just "No"... but there are always few exceptions to the rule:

https://www.youtube.com/watch?v=RbRB8p2Y0vY
https://www.youtube.com/watch?v=cM5AIsPTNOM

Nice! :)
Interesting loaders. No doubt, those were non-oficial releases.
I think they are Spectrum blocks. They sound to me as a such.

By CASDuino

Master (236)

CASDuino's picture

16-08-2021, 18:13

OTLA supposedly works for the MSX although I'm not sure at what baudrate and I've never been able to get it to work.
CASDuino will happily play CAS files at 3760 baud which seems to be the fastest speed the OpenMSX team have been able to get working on all MSX.
TZXDuino will play TSX files at up to 3600 baud but 2400 is the speed all games should load at.

By enribar

Paragon (1138)

enribar's picture

16-08-2021, 23:12

The most high-compression turbo format was invented in Italy for the "MSX HIT Parade" tapes.

By Manuel

Ascended (18162)

Manuel's picture

16-08-2021, 23:15

Are there any dumps of that?

By NYYRIKKI

Enlighted (5877)

NYYRIKKI's picture

16-08-2021, 23:46

PingPong wrote:

Those are relatively high speed for a standard tape. so maybe there should be no much room for improvements with old tape.

I bet there is quite a lot of room for improvement... The most obvious would be getting rid of the used "Kansas city standard" FSK-method... I once had this idea of coding each two bits by adding 2 to them and then sending out the resulting 3-bit value. I newer got to test the theory, but on paper it seems nice without resulting to any "hard to save" frequencies... but I actually think that there are lots of well tested methods out there that use wider range of different frequencies and therefore resulting to faster transfer speeds. I just have not seen them ported to MSX. The good thing on MSX used FSK is that it copes very well even if the cassette is not rotating exactly on constant speed... but naturally this safety costs speed.

CASDuino wrote:

OTLA supposedly works for the MSX although I'm not sure at what baudrate and I've never been able to get it to work.

I also think there is something seriously wrong with it... It seems to make bit errors even on optimal test environment. Maybe they calculated M1 waitstates wrong or something like that... I think it is mostly anyway meant for modern work arounds where the sound is not stored on real cassette, but on PC or similar.

By CASDuino

Master (236)

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17-08-2021, 00:46

NYYRIKKI wrote:

I also think there is something seriously wrong with it... It seems to make bit errors even on optimal test environment. Maybe they calculated M1 waitstates wrong or something like that... I think it is mostly anyway meant for modern work arounds where the sound is not stored on real cassette, but on PC or similar.

IT outputs as WAV so it is for digital playback rather than actual tape. The annoying part is that I have the source but it requires a library that came with Boorland C that you can't get hold of so even if you could find what's wrong you can't compile it into a working version.

Even on the Spectrum you can only really use it to speed up Snapshots rather than TZX or TAP. I suppose it could only work on up to 32k ROM files rather than CAS files but I don't know.

By saccopharynx

Master (165)

saccopharynx's picture

17-08-2021, 05:29

Quote:

I think they are Spectrum blocks. They sound to me as a such.

Red Point formatted games as ITM, which was a proprietary format they used. Blocks of ITM-formatted games were encoded as Spectrum Turbo Speed Data Block (ID 11). Then, a custom loader was used to read those turbo blocks. Real Time just stole the whole thing!!!