Page 1 of 3

FastBoot/FastLoad on Pravetz 8D/Disk II

Posted: Sat Mar 31, 2018 12:31 pm
by Scalex
Here is a video of Oricutron running an adaptation of fastboot / fastload routines on Pravetz 8D with Disk II.
In the 80s, fastboot were very popular on Apple II especially on the underground french scene!



I do not know if this will be very useful on ORIC for future developments since the Pravetz with Disk II is rather confidential...
And I'm not very familiar with the ORIC, so I do not really know how is the transfer rate compared to Microdisc and Jasmin.

note: All the images come from Dbug's slide-show "Pushing the Envelope"
(credits: Dbug, Twilighte, Exocet, Vasiloric, Christophe Andréani and others.)

Re: FastBoot/FastLoad on Pravetz 8D/Disk II

Posted: Sat Mar 31, 2018 1:13 pm
by iss
Welcome! Your demo speed looks very impressive, congrats!
It will be really useful. Can you give more info, links, sources?

Re: FastBoot/FastLoad on Pravetz 8D/Disk II

Posted: Sat Mar 31, 2018 5:15 pm
by Scalex
Thank you ISS!

I will post a file (.DSK) as soon as possible.
If you have specific questions, I would be happy to answer them even if my english is not very good...

Re: FastBoot/FastLoad on Pravetz 8D/Disk II

Posted: Sat Mar 31, 2018 5:26 pm
by iss
Don't worry about your English - mine is bad enough too :).
I'm very interested in fastboot/fastload sources, where can I find them?
I've already added support of Pravetz's DISK][ interface to FloppyBuilder, but it works very slow.
My work is based on standard DOS-8D RWTS routine (which is actually 1:1 Apple's DOS 3.3 RTWS).

EDIT: here you can find my demo.

Re: FastBoot/FastLoad on Pravetz 8D/Disk II

Posted: Sun Apr 01, 2018 1:11 pm
by Scalex
I tested your demo. Very interesting approach!
Speed in Pravetz/FDC mode actually seems to be slow. Is it because of the use of standard DOS routines?
Or is slowness because of another issue?

But at the same time, it really seems that the Pravetz8D/FDC mode does not interest many people in the Oric community!
Capabilities seem anyway more limited than for other systems (microdisc/jasmin).
And from what I understand from other topics, almost nobody has such a configuration in real life...

Re: FastBoot/FastLoad on Pravetz 8D/Disk II

Posted: Thu Apr 05, 2018 11:18 am
by Scalex


Second and probably last of my tests with Pravetz8D/FDC (aka DISK II).
Still adapted from my past work on Apple II.

This time, purpose is to load images while music is played.

I will released this weekend .DSK files and source code for my previous test (fastload) and this one.
note : this test do not use the same loading routines as previous. Paradoxically, to hear "proper" music during the loading, it is necessary to slow the routine!

Images ((c) Marvel) were converted with PictConv (f6 mode). I took the opportunity to do tests with pre-processing (or not) before conversion.
Results are rather uneven...

Music is adapted from an AY file from ISHMA, cover of a well known musical theme by Lalo Schifrin!

Re: FastBoot/FastLoad on Pravetz 8D/Disk II

Posted: Thu Apr 05, 2018 12:57 pm
by iss
Very, very nice!
... and this is your first demo (same pictures in the same order, endless loop) without optimizations.
It's fast, but your time is better! :) It would be really very interesting (and useful) for me if you release sources.
fbtest-1.dsk.zip
(54.27 KiB) Downloaded 54 times
And here is a modified Pravetz ROM, which boots automatically (i.e. no need to type CALL#320).
pravetzd.rom.zip
(12.68 KiB) Downloaded 54 times
BTW, I recall what fastboot/fastload is and who are the "Underground" guys. If you look in the .C source in my archive from the other thread you will see nice commented dsk->nib part - this code is actually "borrowed" years ago from the same pirates :).

Re: FastBoot/FastLoad on Pravetz 8D/Disk II

Posted: Thu Apr 05, 2018 2:16 pm
by ibisum
Wow, this looks really fun! Great graphics work!

Re: FastBoot/FastLoad on Pravetz 8D/Disk II

Posted: Thu Apr 05, 2018 9:54 pm
by Scalex
Thank you guys!

@iss: very nice speed. I will look at your code more closely!

Re: FastBoot/FastLoad on Pravetz 8D/Disk II

Posted: Thu Apr 05, 2018 9:56 pm
by Chema
Really nice work! Congratulations!

Re: FastBoot/FastLoad on Pravetz 8D/Disk II

Posted: Sat Apr 07, 2018 12:03 pm
by Scalex
@Chema: thank you!

@iss: I love the way you use the $036D routine to load your own sectors. The RTS at $B800 is pure genius! ;)

As promised here the sources for FASTLOAD: https://github.com/Archange427/FASTLOAD

.DSK file is available in the release part.

Sorry but I don't know very well Github and its refinements! So I will improve my repository with time but the main seems to be there!

note: I will release later this weekend the sources and .DSK file for my second test.

Re: FastBoot/FastLoad on Pravetz 8D/Disk II

Posted: Sat Apr 07, 2018 8:22 pm
by iss
Scalex, you are really good how you found this nice little trick! Respect!
I've got the idea for RTS at $B800 like an "illumination" ;) trying to optimize the code size for FloppyBuilder, where one single sector have to contain boot code for Jasmin and for 8D. I'm sorry that I simply forgot to upload my code together with the DSK and so you have to waste your time to "dissect" and disassemble the image, now it's attached.
I want to run these test on real hardware, but I have problem with my controller - probably something is burnt...
I hope to fix it asap and post some videos.

Re: FastBoot/FastLoad on Pravetz 8D/Disk II

Posted: Sat Apr 07, 2018 9:34 pm
by Scalex
@@iss: thanks for your sources!

Btw I noticed something weird when running my two tests with Oricutron:
if we let the program runs for more than two minutes, we notice that the loading of the images becomes "linear". And then, he stays like that ad vitam aeternam!
In fact, with the interleaving I used, and seen how Oricutron seems to be programmed (at least the Pravetz8D+DISK II emulation), I think the loading should be linear from the beginning.
First, do you notice the same thing yourself?
And do you have any idea why this only happens after 2 minutes?
I do not know if it comes from my code or from emulation.
Any idea ?

You can download the .DSK of my second test in the release part of: https://github.com/Archange427/LOADZIC
Tomorrow, I will upload the sources. I have to clean up a bit before.

Re: FastBoot/FastLoad on Pravetz 8D/Disk II

Posted: Sat Apr 07, 2018 11:20 pm
by iss
About the 'linear' loading here is what happens:
when picture loop starts fastloader reads sectors: 09,0a,0b,0c,...,07,08... and so on until re-seek to track 1,
on the second loop sectors are read: 0a,0b,0c,0d,....,07,08,09... then seek again to track 1,
and yes, you guess it :) : 0b,0c,...,08,09,0a.
After approx 2 min the reading order become 'linear' i.e.: 00,01...., 0d,0e,0f and next re-seeks don't break this linearity.
Very interesting behavior and nice example of what 'skew' means :).

The emulation in Oricutron is very far from perfect, I added it to be able to run DOS-8D and some interesting old software and until now there was no demand for something better, but this will change and I think to add NIB support, which will provide as side effect the possibility to use any interleave. Also I think to add support of images with more than 35 tracks (maybe fixed to 40 and 80), my opinion about sectors is to leave them fixed to 16, still thinking how to implement emulation of double-side images... any ideas are welcome and highly appreciated!

Re: FastBoot/FastLoad on Pravetz 8D/Disk II

Posted: Sun Apr 08, 2018 7:40 am
by Scalex
AppleWin (https://github.com/AppleWin/AppleWin) is an Apple II 8bits emulator very accurate for the disk access. Could be a lead to follow...

But is it really worth it?
Seems that the Pravetz8D (with Disk II) is really a marginal machine nowadays even for Oric's lovers...
And there are already very good reading routines for Microdisc and Jasmin (thank you Defence Force!)