Criftus wrote:
·Interleaving is the scrambling of ROM code caused by various means (so you'd prefer to have a deinterleaved ROM when emulating)?
More or less, yes. Interleaving is is caused by the copier that dumped the ROM image. Rather than each bank being dumped in order such as 1234 it comes out 2143 or similar. Why was this done you ask? One reasons is so you couldn't use ROM images made by one copier with another. More reasons were discussed before, but I don't remember any more of them.
·The Static RAM definition was given already (thanks Agozer!). One question though: when a tool asks if you'd like to 'disable Static RAM', would this only affect carts that used battery backup? With carts that didn't store information either enabling/disabling it shouldn't make a difference, right?
In general that's correct. Some games however have actual additional RAM chips rather than battery backup mapped to SRAM. I would imagine it would impact these games as well. I'm don't know enough about this to answer for sure.
I still don't quite understand what LoROM & HiROM is though. As far as the document is concerned it states that these terms define where the ROM information is stored (either between 1-32kb, or 33-64kb of the ROM). Why wouldn't you naturally place that information at the beginning? Are there ways to convert a HiROM to a LoROM for consistencies sake, or vice versa? I know it's not important, really, but the games could all be in one type, I'd take it.
LoROM and HiROM are the way the physical cartrige is layed out and how it is addressed by the SNES. You should search for a document on the SNES memory map for additional information. HiRom games are stored in 64K chunks starting at C0:0000 and up to FF:FFFF for a maximum normal size of 32megabits. LoROM is stored in 32K chunks starting at 80:8000 or 00:8000. Theres quite a few more details, so you should go read up on a SNES memory map document if you want to know more. It turns out be a bit more complex than you first guess. It took me awhile before I understood why the first 32K chunk in Hi-Rom was in the same place the first 32K chunk in LoROM is and get all the mirroring down.
http://members.tripod.com/FDwR/docs/snesmem.txt
This will probably make you even more confused.
The data IS at the beginning in the actual ROM chip, however the way the cartridge is physically connected to the SNES, the data is read at a different address from the SNES's perspective.
You cannot convert from LoROM to HiROM or vice versa. It will break most every single address in the entire game.
· Are there any ROMs that require having a header, or would be damaged by removing a header? I say this because I use GoodTools, and it doesn't distinguish between Headered/Unheadered ROMs (ie. two copies of "cart.smc"- one is 524,288, the other 524,800 ... GoodSNES won't catch a difference between the two). Again with the consistency - I'd like to have my ROMs as consistent as possible. I dunno. Weird I guess.
· The newest version of GoodSNES gives you the option to convert ROMs to non-interleaved - could this potentially damage the ROM? There was mention of something along those lines in the document, but it was fairly complex and I'm not sure I got what was intended out of it. Something about deinterleaving an interleaved ROM interleaves it? lol
Maybe I totally mixed it up.
Anyways, thanks for the help so far. Cheers. -Criftus
Headers are added to the ROM by the copiers that dumped them so they can be loaded back into the copier using the correct mapping(LoROM/HiROM SRAM etc..). They are NOT actually part of the ROM chip and therefore not used by the emulators and you can safely remove the 512 byte header from any ROM and not damage it.
GoodSNES doesn't differentiate between header and no header because it does not matter and the ROM will function perfectly either way. Headers are only important if you use a copier or you are going to apply an ips patch. Sometimes translators or hackers work on a ROM with a header. Even though the header information is still of no use, the patch can only be applied to another ROM with a header for the offsets of what data was changed to be correct.
Deinterleaving the ROM will simply unscramble it and put the data in the right order. Deinterleaved ROMs are the unofficial standard in the scene. Again, a translation patch or hack however that was made on a interleaved ROM will still require an interleaved ROM for the offets to be right.
Interleaving a ROM should nto damage it in any way unless it was interleaved using a format that isn't correctly supported by whatever tool you are using to deinterleave it.
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It's more like adding to my information aside from correct my terminology of the standard.