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Dezaemon 2 Save Game Manager 3 : test on CD-R

Written by cafealpha no comments
As indicated in the title of this article, I tried to verify if Dezaemon 2 Save Game Manager 3 (DZ2SGM3) is working correctly from CD-R on an unmodded Saturn.


Dezaemon 2 Save Game Manager 3 (Beta v6.212)

The reason this video was taken is that somebody contacted me to know if DZ2SGM3 works correctly with an "all-in-one" ©®TM red cartridge. But as I don't own such kind of cartridge, I did my best with the few things I can use here.

Initial goal was to test public version (v6.274, 2018/12/28) with official memory cartridge on Saturn with modchip installed, but ...
  • My modded Saturn was buried too deep in my closet; I was too lazy to exhume it ...
  • The CD-R on which I burned public version of DZ2SGM3 didn't wanted to be read from Saturn; I was too lazy to re-burn it ...

So this ended in testing on an unmodded Saturn with Gamer's Cartridge  I couldn't test it by myself, but I'm confident DZ2SGM3 can be used on official memory cartridge and on "all-in-one" ©®TM red cartridge too. "It works, trust me I'm an engineer !"

I did my best to develop DZ2SGM3, but as of a self-produced project (developed on my free time, didn't begged any money for it and on the contrary, I pay my homepage provider to host it), I don't have the budget nor the time to test on all combinations of backup memory cartridges and modchips/ODE/Pseudo Saturn cartridge/whatever with this application.
So if someone is owning an "all-in-one" ©®TM red cartridge and appreciating shooting-up games, that would be cool to receive some feedback about DZ2SGM3 compatibility in the comments of this article



Additionally, I'm also sometimes asked what kind of cartridge is required to play Dezaemon 2 games.
The answer is both simple but also a bit complex too, so maybe it would be a good idea to write about it in this blog

The simple answer is "DZ2SGM3 is compatible with any cartridge providing in-game backup memory feature".
→ DZ2SGM3 was developed simply as an application using standard backup API detailed by SEGA and should work with any cartridge supported by this standard backup API.

Even if I'm the main developer and manufacturer of Gamer's Cartridge, that's not a reason to restrict my software projects to this specific kind cartridge  I kept support for a wide range of backup devices for the simple reason that it's cool to make more and more people appreciating games on Saturn


The complex answer comes from the two following points :
 - There are many kind of cartridges, and not all provide in-game backup memory
 - As DZ2SGM3 is not an official application, it is required for the Saturn to be able to boot applications from CD-R


Rather than writing boring theory about the internals of each kind of cartridge (is there somebody other than me interested in that ?), let's simply detail the compatibility status and the pro and cons and also the additional requirements needed to get DZ2SGM working for each kind of cartridge


① Official Memory Cartridge
That's the official memory cartridge, sold by Sega during the good old times Saturn was still a commercial product.
Because of that, production of theses cartridges stopped around 20 years ago and consequently cartridges available today may damage easily.
The only advantage is that it's an official product, made with genuine electronic parts ... but it's now a bit too late if you want any official support for repairing a broken cartridge
It's not possible to install Pseudo Saturn Kai on such kind of cartridge, so additional mod (installation of modchip or ODE) is required to use DZ2SGM.

Pro : Official product from Sega.
Cons : Contents may suddenly corrupt : don't use to store important save data.
Additional requirement : modchip or ODE


② Action Replay
The super famous Action Replay : main advantage is from being relatively cheap, widely available, and to provide 1MB/4MB expansion memory.

Disadvantage is that technology used in theses cartridge didn't changed significantly for the last 20 years and that in the meanwhile production of this technology (flash ROM and RAM) stopped. For that reason, quality may not be at the meet even if cartridge is sold as "brand new".

In-game backup memory feature is not available for such kind of cartridge : even if advertised as featuring "4M memory card", this is available only from cartridge :games aren't able to access it.
Additionally, this "4M memory card" is a bit ambiguous because it refers to the best effort when save data buffer (internally stored in cartridge 4M expansion memory) can be compressed into lower half of cartridge flash ROM = 128 KB ... if data can't be compressed then an error message will be displayed.
It would had been more honest to advertise that as "Guaranteed 128KB, maximum 4MB memory card not accessible from game", but this is a bit less sexy in term of advertising

Because of the lack of in-game memory feature, it is required to use a separate backup device (such as Saturn floppy disk drive) to use DZ2SGM.

Pro : Widely available, relatively cheap, and provides 1MB/4MB expansion memory.
Cons : In-game backup memory feature not supported.
Additional requirement : Saturn floppy disk drive.


③ Gameshark, and other clones
That's Action Replay without 1MB/4MB expansion memory and usually worse overall quality : if you have one still working, it is worth trying to use it but if that's not the case then considering for (at least) an Action Replay is usually wise decision.

Similarly to Action Replay, because of the lack of in-game memory feature it is required to use a separate backup device (such as Saturn floppy disk drive) to use DZ2SGM.

Pro : Worth using if you found a spare cartridge still in working condition.
Cons : No 1MB/4MB expansion memory. Poor hardware quality.
Additional requirement : Saturn floppy disk drive.


④ Memory Card Plus
That's more or less a Gameshark with a specific firmware installed. Main advantage of this firmware is that it allows games to directly access cartridge backup memory.

Similarly to Gameshark, hardware quality is questionable, which makes backup memory to be easily corrupted. Additionally, backup memory capacity is around 200 KB so that it usually can't handle more than three Dezaemon 2 user games.
Installation of Pseudo Saturn Kai will remove backup memory feature, so additional mod (installation of modchip or ODE) is required to use DZ2SGM.

The little side story about this cartridge is that its unique way of handling backup memory gave me the idea and motivation to develop Gamer's Cartridge
Back in end of 2012, I thought only mapped memory chip could be accessed as in-game backup memory.
But seeing that this cartridge was featuring only boot ROM (I tried to dump backup memory ROM, but didn't found anything there and instead there was a small firmware and save data stored in boot ROM area) made me realizing that anything could actually be shown as backup memory device to a game, which was the start point of Gamer's Cartridge project.

Pro : This gave me the idea to develop Gamer's Cartridge !
Cons : Access is not so reliable : whole contents can be wiped after writing one save there. Installing Pseudo Saturn Kai removes the memory cartridge feature.
Additional requirement : modchip or ODE.


⑤ "all-in-one" ©®TM red cartridge
That's the equivalent of Action Replay and official memory cartridge blended in a single PCB. Main advantage is to feature theses two cartridges in a single one, which is convenient for playing a wide range of games.

Major disadvantage is that similarly to Action Replay and official memory cartridge, technology used didn't changed significantly for the last 20 years and that in the meanwhile production of this technology (flash ROM and RAM) stopped. For that reason, quality may not be at the meet even if cartridge is sold as "brand new".

Additionally, similarly to official memory cartridge there is only limited save data integrity check available (file system is rudimentary, and only the first bytes of the ROM are check to verify if a backup memory cartridge is available or not), which is a design flaw from SEGA : it works fine in ideal conditions of cartridge correctly inserted and ROM not corrupted, but will ask to format the cartridge in all other cases.
That's acceptable if you just want to copy save data (there are plenty available in Pseudo Saturn Kai Save Data Manager, so have fun with them !) and play a little to a game, but not recommended if you want to play a RPG and won't stand to suddenly lose all your progression in the game.

Pro : Both official Memory and Action Replay in a same cartridge.
Cons : Contents may suddenly corrupt : don't use to store important save data.
Additional requirement : none.


⑥ Gamer's Cartridge
Well, that's my own cartridge project, so my opinion may be a bit biased, but it's recommended if you don't want your saves to be corrupted : as SD card file system is used, it is significantly stronger than the file system used on official memory cartridge.
It is also handy if you want to backup or share your save data because exporting saves to PC can be done by simply copying files from SD card.

Additionally, it features virtual floppy disk device support, which doubles the number of Dezaemon 2 user games simultaneously available : it is limited to 5 games with other backup memory cartridges (and count may be lower because of ROM size limitation) while a total of 10 games (5 on cartridge device, and 5 other ones on virtual floppy disk) can be handled by Gamer's Cartridge.

Moreover, DZ2SGM can be accessed directly from SD card so that there's no need to swap between DZ2SGM CD-R and Dezaemon 2 CD-ROM.
Major lack of this cartridge is the non-availability of expansion RAM. Also, as SD card access is not super fast, save data access is a bit slower than on other cartridges.

Pro : No risk of losing saves because of data corruption. Data can be easily backed up to PC or shared with other gamers.
Cons : Limited availability. 1MB/4MB expansion memory not available.
Additional requirement : none, and DZ2SGM can be run from SD card.



DISCLAIMER : play Dezaemon 2 (and other Saturn games) at your own risks ! I'm not responsible of any eventual damages caused to your save data, you Saturn, your cartridge, your dog or anything else !



SMALL REQUEST : I don't have the budget nor the free time to test DZ2SGM3 on all combinations and variations of cartridge and ODEs.
So it would be very appreciated to receive feedback about if it works on your own Saturn setup

Feedback can be left by simply adding a comment at the bottom of this article : it is free, doesn't requires any kind of registration, and takes something like 5 minutes to be written ♪ In advance, thank you for the feedbacks



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