Hacking (Q): DS Save files deleting themselves over time?

[2DSGamerdude]

hi all,
recently, I was playing my ds games on 3dsxl through the R4I Gold 3DS RTS,
and I have noticed something rather weird/strange with regards to ds game saves mostly (PSP/PS Vita/3DS/WII/GC/PS3/PS4/Switch saves don't do this),
not sure about GBA saves?

This issue mainly pleagues Ds games and I think, GBA games also?

I wonder why some ds games that should have data, (im positively sure they had save data),
don't, instead it's gone?

1) can save data for ds games or (for any game system) erase it's self over a period of time (years),
if they haven't been touched for some time?

I mean by system fault (corrupt), not user fault?

2) some games I tried yesterday that I remembered had data were:
Megaman ZX & ZX Advent, Summon night twin ages, sonic colors

they should have had the save data from back when, but instead have "new game" (no save data)

while others I tried, still retained their save data intact after all these years:

Lost magic (last save from 2015), Entrian odyssey, Tales of innocence, advance wars dark days.

yet, while some games still keep their saves intact no matter what, others simply delete themselves over time?

is this because the ds flashcard can't save said game save type or compatibly issue or is it hit and miss
when it comes to which games saves stay intact and which don't over a period of time?

all games are able to load up fine, just some that had data lose them for some weird reason?

3) does changing the RTC or any game system (DS/3ds/switch/PSP/PS3/PS Vita/PS4/WII), affect save data in any way?
like losing some critical progress or pushing progress of said game back? .

4) does save data in general erase or can it be lost (naturally) over time?
example, I have a ds, and I haven't touched it for some years now, will the game saves on my flashcard be intact
or will they be lost due to inactive play or corruption?

5) not sure if what save type the R4I Gold 3ds RTS uses?
is it game name.sav or Game name.nds.sav

thanx and hope someone can explain if possible why this can happen or why it does even,
some of these things have been confusing me for some time now.

 

[KleinesSinchen]

1) Of course save data can be lost. Any storage medium can and will fail at some point. For older systems using (battery powered) SRAM for saving this is obvious: If the battery is drained the save is lost. This is not a big deal: Even batteries from the 1980s are still working (games with integrated clock drain the battery much faster – about 8 years).
When it comes to flash memory I can’t give a good answer. Searching for data retention time gives me too much information for various types of flash memory. I guess the pretty small (in the sense of amount of data) chips in video games have pretty long data retention time even if not only unused but badly stored.

2) Now you are talking about flashcarts? I would say there are two problems:

• Flashcart software may have errors and this could lead to data loss.
• Data retention time depends on the used micro-SD.
  • Still strange if after years saves disappeared but all games are still intact. This does not sound like data corruption from the SD itself.

But this is more or less a non-issue since backing up .sav files from the SD is trivial.

3) Changing date/time may cause modern games to punish you mildly and reset time based events forcing you to wait again. This should not damage save data. The same effect is triggered when you put a Pokemon cart into a different 3DS. Seaman (Dreamcast) refuses to load a save if you rewind the clock (it would not make sense to allow this because the game is real time based. You would effectively do time travel to the past/changing the past).

4) See 1) and 2)

5) Does this matter? Simply backup all .sav files and rename if any other flashcart/emulator needs different names.

Edit: The same problem (data retention time) exists for saves on console internal NAND. But if the NAND starts losing data, this will render the console useless anyway. I have never seen a single game cartridge (flash memory) losing data after inactivity for years – same for consoles.

 

[2DSGamerdude]

I see, thanx for the answers to my questions, KleinesSinchen

um, maybe some of the ds game saves are just not in the .sav format, or if I rename them to .sav they may work again,

I did use the blue gateway ds card before using the R4I Gold 3ds RTS card im using now,
the blue gateway ds card used .nds.sav format I think, tho at some point when I used it on my new3ds xl it got cuoopurt and deleted everything from the sd,
the blue gateway card doesn't work well with 3ds, on the ds lite it works fine however.
I didn't loose any data from the blue gateway card as I backed it up before hand .