Coming soon! Steem SSE 3.7

[dlfrsilver]

Steven,

i got a look lately on the pasti of Mercs from us gold, available on atarimania. The STX file is said to be working on 512k of RAM, but with steem 3.7.0,
i get a pasti message saying the game tries to load track 82 sector 7 (not imaged), and then the game is stuck on track 48 sector 7.

Is it a steem bug, or a bad STX file ? Can you enlight me on this matter plz ? I have joined the file below

[kodak80]

Steven,

i got a look lately on the pasti of Mercs from us gold, available on atarimania. The STX file is said to be working on 512k of RAM, but with steem 3.7.0,
i get a pasti message saying the game tries to load track 82 sector 7 (not imaged), and then the game is stuck on track 48 sector 7.

Is it a steem bug, or a bad STX file ? Can you enlight me on this matter plz ? I have joined the file below

I tried your linked Mercs file and got the same error. However, I downloaded the STX from AtariMania and the STX works fine from there. Looks like you have a corrupt file.

[dlfrsilver]

Steven,

i got a look lately on the pasti of Mercs from us gold, available on atarimania. The STX file is said to be working on 512k of RAM, but with steem 3.7.0,
i get a pasti message saying the game tries to load track 82 sector 7 (not imaged), and then the game is stuck on track 48 sector 7.

Is it a steem bug, or a bad STX file ? Can you enlight me on this matter plz ? I have joined the file below

I tried your linked Mercs file and got the same error. However, I downloaded the STX from AtariMania and the STX works fine from there. Looks like you have a corrupt file.

I picked it from the site Atarimania...... i downloaded it again, and the problem is still there..... The game try to read Drive A Side 1 track 82 Sector 7 which is not in the STX image (so this means that the protection is uncomplete ! and therefore fails.....)

[npomarede]

I picked it from the site Atarimania...... i downloaded it again, and the problem is still there..... The game try to read Drive A Side 1 track 82 Sector 7 which is not in the STX image (so this means that the protection is uncomplete ! and therefore fails.....)

I checked the STX image you posted above with Hatari tos 1.04 + 512 k RAM and it worked, so I don't think the STX image is faulty. Maybe you need to enable some options in Steem.

[dlfrsilver]

We must wait for Steve answer then

the problem remains whatever the ram used (512k or 1 mb), and whatever the TOS rev used (1.02 or 1.62)

[kodak80]

Just gave it another go and it works if I set the disk to READ ONLY in Steem. If I turn off the READ ONLY setting I get the error. I had this with ANTAGO STX as well so I thought it was worth a try.

For some reason the Mercs STX I downloaded direct from AtariMania works without the READ ONLY setting for me. Both STX files are the same size. The zip file I downloaded from AtariMania is slightly smaller than the zip file containing Mercs on here though.

[galax]

The Mercs STX file uploaded here and the one from Atarimania are byte for byte identical (verified with a binary diff tool). They also both zip to the same size if the filenames are the same (the filename affects the size of the archive) and using the same zip tool (different zip programs may produce different file sizes). Could there be other differences between the way you have stored them locally, such as one being read-only or having different permissions, special characters in the file or directory name, etc.?

[dlfrsilver]

The Mercs STX file uploaded here and the one from Atarimania are byte for byte identical (verified with a binary diff tool). They also both zip to the same size if the filenames are the same (the filename affects the size of the archive) and using the same zip tool (different zip programs may produce different file sizes). Could there be other differences between the way you have stored them locally, such as one being read-only or having different permissions, special characters in the file or directory name, etc.?

None of those. I guess something is wrong in steem, because it worked a long time ago on old steem revisions.

[Steven Seagal]

I just tried the uploaded version of Mercs and it loads to game, STF, TOS100, so I guess it's possibly a config problem.

[dlfrsilver]

under hatari it works witgh TOS 1.04..... Can you have a look ?

[Steven Seagal]

under hatari it works witgh TOS 1.04..... Can you have a look ?

Why yes, I can!
It works too. But with TOS 1.02, it does as you described.

[dlfrsilver]

ok, so it's a TOS problem

Thanks for looking !

[Steven Seagal]

Not that you weren't informed already, but...
I spare you what was already uploaded in that other thread (Chessmaster 2000)

http://ataristeven.t15.org/Steem_371_coming_soon.htm


"Dance with the Bits"

SCP disk images are very precise, but raw and quite large copies of floppy diskettes made with the Supercard Pro board. Data consist of delays between flux transitions, that's it. Contrary to "CAPS" (SPS) formats IPF and CTR and "Pasti" format STX, there's no plug-in to help emulation. The Atari ST emulator is in charge of everything.
Fortunately, Steem is coded in C++ and uses objects for concepts such as floppy disk, drive, controller, DMA chip, etc. The only new part is interpreting the delays as the correct bytes of data, read at the correct rate.



Dungeon Master



SWOOSH! By the way I fixed a little sound bug in 'Sampled YM-2149' option of v3.7.0...

Just like the game itself, the disk protection is interesting and much discussed.
It is precisely described here: http://dmweb.free.fr/?q=node/1429

The game mainly uses an elaborate and patented (US patent 4849836) fuzzy bits protection. Some bits are shifted to the left or the right compared with normal, and the WD1772 will think they're in the left or the right "cell".
EDIT: now that I actually read the patent, not sure it's the right one



This is handled in Steem by introducing 1-cycle randomness on the timing of those weak bits, and making sure that shifts are balanced (if a bit is interpreted as "early" the next one must be interpreted as "late"). A bit of a hack actually.



Level 2. After a while, the game checks fuzzy bits on sector 7. The CRC check fails, as it should. Fuzzy bits randomly form byte $68 or $E8. If it's anything else, the first gate won't even open for your party.



The second protection, impossible to write sector number 247 ($F7), is very common on the ST.
This sector is checked all the time by the game.



By the way, you should use a STW disk image to format and record progress.

Making a point

The point of offering SCP disk image support in short order, beside making players happy , is to show that our Steem development roadmap (new STW disk image format and new WD1772 emu to handle it as a timed flow of bytes) was valid. SCP support is an extension of STW support, and it appears as v3.7.1, not as a major new feature (would be 3.8.0). It was planned so.


Borrowing concepts

Having made that point, what about supporting all games? This is more complicated. The primitive flux-to-MFM decoder didn't use any "inspection window" and couldn't really correct for phase and frequency error like the real WD1772. This is why Starglider didn't work, for instance. Besides, the WD1772 emulation as written for STW support worked with MFM words rather than bits, and was confused with overlapping $C2 and $A1 sync marks.
To win some time to solve both problems (and because I really enjoy hacking), two other WD1772 disk controller emulations have been used as "source of inspiration" of Steem, that of MESS/MAME for the DPLL (digital phase-locked loop), with proper inspection window based on the correct algorithm as described in US patent 4808884 A, and that of CAPS/SPS for the data separator (bit shifter that finds the sync marks).
Better saying so than faking my "own" solution.

Transitions (fluxes) are sent to the DPLL, which sends back timing and bits, bits are sent to the data separator, which sends back data bytes and sync marks. Both parts do their magic without us needing to understand all of it (fortunately).

So you have this situation where some SCP disk images (notably Albedo; Jupiter's Masterdrive) run in Steem thanks to their competitor SPS (Kryoflux)!

EDIT: forgot introduction
EDIT: remove DM test request

[JimDrew]

Nice job with this! I have not found any .scp image file that does not work now with this version of Steem.

Yes, the data that the .scp files contain is nothing more than the duration of the flux transitions. You can take this same data and output it to a real computer and it will load just like there was a floppy drive. At some point I will finish the HxC emulation support (so you can use the variety of HxC control programs) and then you will be able to use the SCP hardware as a floppy drive.

[Steven Seagal]

I have not found any .scp image file that does not work now with this version of Steem.

Good news, also for the rest of emulation (timings, CPU...), some games have weird protections.
The beauty of it is that I still know nothing of various disk protections, like Copylock, No Flux Area, etc.
Like Tom Selleck would say I have "no need to know", that's the advantage of low-level emulation.
Only Dungeon Master's weak bits require some meddling/hacking for the moment.


Still not all has been tested...

[fusionsynth]

When I start Steem SSE 3.7.0 i get the following error-message :

Knipsel.JPG

It seems that i am missing a .dll-file. All previous versions worked ok. How can i solve this?

Does Steem 3.7.0 use another directX version?

[Steven Seagal]

When I start Steem SSE 3.7.0 i get the following error-message :

Knipsel.JPG

It seems that i am missing a .dll-file. All previous versions worked ok. How can i solve this?

Wrong thread!
http://www.atari-forum.com/viewtopic.php?f=94&t=27687

Does Steem 3.7.0 use another directX version?

Yes, that's the problem. It's for better fullscreen support.
The file is available on my site, as well as a build that doesn't use D3D9.
The best you can do is update your DirectX installation, but I can't help you more than that.

[fusionsynth]

Thanks! Yes i saw the other thread. I have updated my directx and now it works!

[Steven Seagal]

Nostalgia for a simpler format...
As noted by AtariZoll, you get this screen when using a bad copy of Chessmaster 2000 (ST, MSA):



How generous! Gives me an idea...



Using ProCopy... (not "AmateurCopy", I was being unfair, the sillier versions weren't official, you can see here that command $A0 is used, as it should). SCP disk in A:, STW disk in B:, single sided (which is why images are so big by the way).



One of the rare original games that will work as a STW disk image, but it's a nice one (if you like chess, that is).
Guess there will be no more complaints about size of STW files anyway, if you compare with SCP images.


Weak bit of emulation
Gotta admit it, the "weak bits" protections aren't handled very well yet. For this reason, SSE option 'Hacks' needs to be checked for it to be enabled.



Yes, Power Drift loads, but you may need to bash space bar once or twice before it passes the test...
And wait a minute... Bits are drifting because they are weak, aren't they supposed to be powerful in Power Drift?



Turrican



Turrican is well protected, the real difficulty here is sector data across the index pulse. Regular drives aren't precise enough, and this is one of the rare cases demanding 2 revs to load in Steem. You would need professional mastering hardware to reliably read/write such an image.


More screenshots
Check this thread :
http://www.atari-forum.com/viewtopic.php?f=102&t=27810



Other notes
- Because some image files are huge, they are loaded in memory track by track, and only if some reading is involved, like in commands seek with verify or read sector.
- There's a noticeable delay when the image must be unrarred/unzipped, maybe it would be worse with 7z.
7z isn't supported for the moment.
- Many (many!) protections are handled without us needing to know zilch about them, the exception being weak bits because of the random aspect to somehow emulate (due to variation in motor speed?)
- Contrary to usual, no game downloads available to illustrate the new feature. My web host is most generous, but those files are just too big. Check atari-forum to find some images.

[Steven Seagal]

Release planned for Sunday except if big bug appears.
Only 2 remaining sleepless nights for you!

[Steven Seagal]

Steem SSE 3.7.1 WIN32 has been released on 3 May 2015.

Features:

- Support for SCP disk images

This is the logical step after STW format, but we had to debug and improve
WD1772 emulation. At least the structure was OK.
Some code vaguely inspired by MESS and SPS projects for low level emulation
of the DPLL (inspection window) and sync timing ($A1 and $C2 marks).

All correctly imaged games loading!
Normally one rev is enough but some games may require 2 revs.
Weak bits (Dungeon Master) handled only if SSE option 'Hacks' checked.

- CPU exception stack frame legit fix for Aladin instead of previous hacks
(he he)

- Bugfix RAM 14MB no display
- Bugfix sound volume sliders start at 0
- Bugfix PSG noise delays with 'Sampled YM-2149' option (Dungeon Master)
- Bugfix PSG quantize for low periods (Union Demo text screens)
- Bugfix RAR5-compatible version of unrar.dll not recognised.
- Bugfix Microwire read data (Sleepwalker STE)
- Bugfix floppy disk gaps on READ TRACK (ProCopy on ST, MSA images)

- New patch: Gunship STX protection

- Links updated in general info; don't forget to copy steem.new

Download:

http://sourceforge.net/projects/steemsse/
http://ataristeven.t15.org/Steem.htm

[spiny]

awesome work

[dlfrsilver]

Thanks again Steven, for the great work you're doing on Steem. I'm so pleased with it !

[Steven Seagal]

And I'm pleased if it is useful, and who knows, that it, together with other tools, contributes to keeping the Atari ST alive.

[JimDrew]

Congrats on the release! Thanks for supporting the SCP image format. I know it was some work, but the end result now is that 100% of all Atari ST floppies can be imaged and used with Steem!