Game sizes recorded for AD&D and Lock 'N Chase possibly incorrect?

[Hastor]

I recently got some cart readers and was checking my Intellivision games just to see what revision I had etc. However, I noticed something odd with these two titles, and was wondering if anyone here can shed some light on it. Note that I do not distribute dumps etc., I simply analyze my library, and I believe what I'm talking about here is ok.

Here's the facts as best/quickly as I can put them. I'm using kb here though I know Intellivision can use 10-bit words and be kw, but I'm not sure how/if that affects a rom size. I'm using kb cause that's the size I get and match up with 12/16kb games for other systems in size.

- These games, as typically distributed (and as often found in the roms used in modern console compilations) that match the no-intro database are 16kb

- I have two cart readers, an OSCR w/ Intellivision adapter, and a Maxflash Programmer from AtariMax, also w/ Intellivision adapter.
- These ARE 12kb games, and game data ends after 12kb, but the question for me is whether or not the rom is 16kb with padding, or actual 12kb between the two chips on each.
- In the known versions that match the no-intro db, Lock 'N Chase has all 00 after 12kb. AD&D has mostly FF, but a few other values sprinkled around for the last 4kb.
- The OSCR typically reads padding, but it produces a counting pattern based on the memory address after 12kb, which is its normal behavior if overdumping Intellivision. I've tested on known games, such as dumping an 8kb as 16kb and it results in the same pattern. When there is padding there, it will typically read it.
- The Maxflash by default dumps them as 12kb files. It is made to skip banks of all 00 by default, which would explain Lock 'N Chase potentially, but not AD&D. If I force it to overdump (which goes to 128kb and does not ignore anything) it fills any invalid address with FF. I get all FF aside from 12kb. This doesn't match with the 00 padding of Lock 'N Chase (there is no block of all 00 in the dump at all), and none of the banks of FF contain the extra characters as found in the known version of AD&D.
- Also worth noting I have two copies of Lock 'N Chase, from seemingly different prints (one can be opened w/ screwdriver, one can't), and both give identical results.

- What I get from either device does match the known versions for the 12kb of actual game data 100%

 

So it really seems there's only 12kb of readable data on these games, including any padding etc. However, my only thought is that somehow an 8kb chip could report itself as 4kb, and have 4k that would only be accessible by desoldering the chip, or something like that. I do like to ensure notes about stuff like this are recorded for preservation etc. I don't see why they would have only used 12kb for the game if they were gonna be given 16kb of chip space also. Any of these dumps load in an emulator and play fine, whether they are 12kb and regardless of what's in the padding. I like to record what's in the full chip including padding though, and definitely be sure of the size of the real hardware. The no-intro db is all about full chip as well, so I wonder if what they have may be wrong (I have found mistakes there before).

 

I did speak with the person that wrote the dumping script for Intellivision for OSCR, and they believe they are 12kb ROMs, but again, not sure if the chip could 'trick' what's reading it... kind of like a 32GB SD card showing up as 1TB when you get it cheap online... but in reverse.

I can provide pics of the chips if it would be helpful, they are GI chips that look the same with slightly different codes on them. Well, the big code is different. The number after "GI" is the same between the two chips in each cart (one has two GI 8233 and one has two GI 8232).

Appreciate any insight anyone has!
- 

Edited July 17 by Hastor

[mr_me]

Since Intellivision words are larger than 8 bits, it takes two bytes in a file to store one Intellivision word.  If you have an Intellivision rom file you can divide its size by two to get the cartridge rom size in words, less the padding.

 

Both AD&D and Locknchase are 6k cartridges, each having a 4k and 2k rom in the cartridge.  I think AD&D was the first Intellivision cartridge larger than 4k.

[Hastor]

16 minutes ago, mr_me said:

Since Intellivision words are larger than 8 bits, it takes two bytes in a file to store one Intellivision word.  If you have an Intellivision rom file you can divide its size by two to get the cartridge rom size in words, less the padding.

 

Both AD&D and Locknchase are 6k cartridges, each having a 4k and 2k rom in the cartridge.  I think AD&D was the first Intellivision cartridge larger than 4k.

Thanks, so one of the chips can only hold 2kw? It isn't just a 4kw chip that's half full?

I guess that also prompts me to ask, why are the commonly shared ones 16kb/8kw?

Edited July 17 by Hastor

[mr_me]

If they are GI roms, the part number should tell you the capacity.  RO-3-9504-xxx is a 2k rom and RO-3-9505-xxx is a 4k rom.  The 8233 is the date code.

[Hastor]

Thanks so much for helping to clear this up!

[Hastor]

@mr_me by the way, is there a place I can find the chip sizes and part numbers? I searched everywhere I could think of with all the numbers on the chips in various ways and didn't get anywhere.

[mr_me]

https://wiki.console5.com/wiki/RO-3-9504

That's the spec sheet for the 2k (20kb) rom.  I've also seen GI part number 9580-xxx on 8k cartridge roms.  There are also cartridge roms from AMI, Toshiba, and Sanyo.

 

Edited July 17 by mr_me

[mr_me]

10 hours ago, Hastor said:

Thanks, so one of the chips can only hold 2kw? It isn't just a 4kw chip that's half full?

I guess that also prompts me to ask, why are the commonly shared ones 16kb/8kw?

I'm not sure why all the 6k rom cartridges are 16kB rom files rather than 12 kB.  These files were created back in the 90s, maybe the rom dumper used back then worked in 4k increments or maybe the old emulator at the time required it.  The guy that dumped them back then is here on atariage, he might know.

Edited July 17 by mr_me

[Hastor]

13 hours ago, mr_me said:

I'm not sure why all the 6k rom cartridges are 16kB rom files rather than 12 kB.  These files were created back in the 90s, maybe the rom dumper used back then worked in 4k increments or maybe the old emulator at the time required it.  The guy that dumped them back then is here on atariage, he might know.

Maybe I'm a bit dumb about this, but who did dump them back then? Feel free to DM me if that is better. I'd love to ask them.

[mr_me]

That would be atariage user, Games For Your Intellivision, of Electronite.