Saturn Backup RAM

Jameson

New Member
About a month ago I've started this topic at SegaXtreme. And now I finally found some time and wrote a megasimple parser. Now it only writes to the screen saves info, but I'm going to add extra functionality pretty soon.

Anyway, I want those of You with enough time to test this program. It runs in dos-mode and requires binary image filename as a command line parameter. Binary must be in native 512K mode (some emulators write'em in 1M mode adding 00h after every byte). But I'm going to write 1M<->512K converter today or tommorow anyway.

Well, here's the link : (changed to http://pdsoasis.newmail.ru/saturn/saturn.htm)

Fell free to write your comments here or to mail me.
 

Jameson

New Member
Well, I've inserted file type detection into source, now it will understand SSF's and some other emu's 1M files. I dunno if it's emulator or me, but SAT size seems to be shorter (it's divided by 2) in such files, so don't trust neither SAT size nor Ratio values for now.

Link change, now it will be http://pdsoasis.newmail.ru/saturn/saturn.htm

You can find format description there, and I think I'll upload source.

BTW, here,s the explanation of my terms:

Magic - 4th byte of every cluster header, meaning is unknown, but it's constant within save.

Cluster - 256 bytes of data, physical save granularity unit (it's because of Flash IC writing specs).

Block - 64 bytes of data, logical save granularity unit.

SAT - Save Allocation Table, this table includes links to clusters with save's data in corresponding order. SAT value in my program means just number of SAT entries.

Ratio - it's ratio between savesize in blocks and clusters. Minimal value is 1 (wheh save takes only 1 block), maximal value is almost 4.

Now I'm going to write Win32 GUI version, and save extraction in both raw and AR mode. Can someone mail me a long AR save? (>20 blocks) My mail is john_jameson at mail dot ru

Pleeease :unsure:
 

slinga

Member
Sounds like a really interesting program, I'll give it a whirl when I have some free time later on this week.

I'm a little unclear on this, but can you extract save game files from Saturn emulators with your program?
 

Jameson

New Member
Originally posted by slinga@Oct 26, 2003 @ 12:24 PM

I'm a little unclear on this, but can you extract save game files from Saturn emulators with your program?
Not yet, but I'm working on this subject now. Raw extraction will be easy, but I'm still unsure about AR-compatible extraction and maybe some other formats.

That's why I want to look at AR save.

One more problem is magic byte. It can be simply skipped while extraction, but it must be set while inserting save back to image. I still have no idea what it means, but I know it's somehow connected with save fragmentation.
 

Jameson

New Member
Well, finaly. I've completed Win32 version. Link is the same. Now it supports both 512K and 1M RAM image, and it can extract save games in raw mode.

But I've received kinda strange results with 1M image from SSF. I suppose it's emulator bugs, 'cause I've changed my algorithm and it still remains. Anyway, I need more data from emu's images.

Somebody with AR out there? I NEED any AR savegame.... Tasukete kudasai....
 

slinga

Member
Hey,

Try this site: http://www.agscc.com/gamesave-ss.htm

Also, what's the difference between an AR save and a Netlink save? If I recall correctly, I've used them interchangeably without any problems...I can verify and get back to you later on this week (extremely busy with school at the moment).
 

Jameson

New Member
Well, browsing some Saturn save archives (there were only 2 of them, thanx for the link, slinga) I've found out that some saves include both header and SAT while others do not. AR seems to include header (to keep names, date, region etc.) and SAT (kinda useless - it'll be recalculated while inserting anyway).

So now I've included a new feature - toggle header and SAT extraction. This will make possible checking both of those cases for AR and Netlink compatibility. Yes, and AR mode added (cluster system data extraction).

Still there are unknown bugs with emu-save (maybe it's a bad binary after all).

Now the only thing I need is a feedback. I'm gonna go test it myself, but with my Celeron 333 it'll take a few hours to save new game in Shining Force III for example. And I don't have a PC commlink yet.

Also I've received kinda RLE-compressed binary. It's a big pain even if it's RLE, but maybe i'll try to decompress or decode it.

Link is the same, feel free to download a new version.
 

Jameson

New Member
Oops! I just found a serious bug, it caused failing extracting save.

If someone ever downloaded this program, please do it again.
 

Jameson

New Member
At last, just finished v0.2. Now it supports all I need (if you need something else, mail me), but probably with some bugs. Save insertion is debugged only in no-AR no-header mode (IMHO it's the most difficult), and I'm not sure if it will work correctly in other modes.

Another problem is a documentation lack. My english is extermely bad, so I'm kinda scared to write docs. If you've got some questions, ask'em right here.

Hmm... it seems like my firewall won't allow me to upload binary now. I'll do it within a few hours.
 

Jameson

New Member
Finally uploaded. Use the same link up there.

Still there are many bugs. Well, I'll always welcome bugreports, comments etc.
 

Jameson

New Member
Well.... looks like nobody's using this stuff... but anyway. Just released v0.3. There are still some known bugs (incorrect SAT calculation in saves more than 400+ blocks, and missing country/time support in raw mode), and a lot of unknown. I'm waiting for bugreports. And finally I'm going to test it on a real hardware.
 

dhau

New Member
Dude, I am willing to help you out, if you will be patient with me and get in touch with me via IM programs and explain the purpose, the vision behind the project, short term and long term plans etc.
 
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