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Both the "Castle of Illusion" and "Ghouls'n Ghosts" rolling demos have been released as 32KB dumps. However, I notice that both ROM headers specify a size of 128KB, and that it is necessary to pad the dumps to 128KB (using $ff bytes) in order for the checksums to be correct.

At first I thought there was probably a mistake in each header, but in fact the "Castle of Illusion" dump does come from a 128KB cartridge. Below, the first photo (from segacollect.com) shows that cartridge, and I believe the second (from atariage.com) does too (I have asked the owner of segacollect.com for confirmation). The second photo clearly shows a 315-5235 mapper chip alongside a D27C1000A-12 - the latter is a 128KB EPROM.

Would it be more accurate to release these dumps as 128KB, the last 96KB filled with $ff?

P.S. These are the only (non-homebrew) ROMs I have with a valid header (containing "TMR SEGA" and a non-zero checksum), where the header claims a ROM size larger than the size of the file.

DSC02873.JPG (33.85 KB)

000_8717.jpg (55.18 KB)

Usually we pad down dumps especially since prototypes are often found on bigger chips, or eg. later releases of some games or brasilian releases also would use bigger chips. In this case since the checksum relies on it you are right and it should be fixed.

Not sure what is the best way for us to spread and roll out fixed dumps at this point since we don't have an easy master repository to replicate (it is something I hope we can work on). I'll post them with a news post and I assume ROM DB will follow on.

PS: I own both cartridges, will give a check to Ghouls'n Ghosts later.

Bock wrote

Usually we pad down dumps [...] found on bigger chips.

I think that's the right approach. For example, if a 32KB game is found on a 128KB chip (padded with 96KB of $ff), it's still a 32KB game and should be released as such.

Quote

In this case since the checksum relies on it you are right and it should be fixed.

Yes, the headers tell us that the situation here is different to that in my previous paragraph. We don't have 32KB demos padded with 96KB of $ff, but 128KB demos which contain 96KB of $ff.

Bock wrote

I own both cartridges, will give a check to Ghouls'n Ghosts later.

You have a cartridge containing the same "Castle of Illusion" demo as is available at segacollect.com? If so, could you please give a final confirmation that it does indeed contain a 128KB EPROM?

Also, while you have the demo cartridges open, I presume they both use the 171-5486 circuit board? Would you be able to take some good-quality photos of (both sides of) one of these boards?

Thanks

I just found I had 2 castle of illusion.. now i am confused. :)
Let me dump and check them all again.

171-5486 board
315-5235 mapper
One 27c1000 eprom

Size: 262144 bytes (16 pages), CRC:1A2C1945
0 ; c3 3b 00 00 00 00 00 00 7b d3 bf 7a d3 bf c9 00 ; Sum:1A34C4, CRC:F82F5209
1 ; 00 04 00 03 02 01 00 05 00 06 00 06 00 05 02 07 ; Sum:382B93, CRC:9F3D2982
2 ; ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ; Sum:3FC000, CRC:690B37D3
3 ; ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ; Sum:3FC000, CRC:690B37D3
4 ; ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ; Sum:3FC000, CRC:690B37D3
5 ; ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ; Sum:3FC000, CRC:690B37D3
6 ; ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ; Sum:3FC000, CRC:690B37D3
7 ; ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ; Sum:3FC000, CRC:690B37D3
8 ; aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa ; Sum:2A8000, CRC:28C194E0
Same as pages: 09, 0A, 0B, 0C, 0D, 0E, 0F
9 ; aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa ; Sum:2A8000, CRC:28C194E0
Same as pages: 08, 0A, 0B, 0C, 0D, 0E, 0F
A ; aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa ; Sum:2A8000, CRC:28C194E0
Same as pages: 08, 09, 0B, 0C, 0D, 0E, 0F
B ; aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa ; Sum:2A8000, CRC:28C194E0
Same as pages: 08, 09, 0A, 0C, 0D, 0E, 0F
C ; aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa ; Sum:2A8000, CRC:28C194E0
Same as pages: 08, 09, 0A, 0B, 0D, 0E, 0F
D ; aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa ; Sum:2A8000, CRC:28C194E0
Same as pages: 08, 09, 0A, 0B, 0C, 0E, 0F
E ; aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa ; Sum:2A8000, CRC:28C194E0
Same as pages: 08, 09, 0A, 0B, 0C, 0D, 0F
F ; aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa ; Sum:2A8000, CRC:28C194E0
Same as pages: 08, 09, 0A, 0B, 0C, 0D, 0E

Ghouls'n Ghosts [Demo] - 01.jpg (771.3 KB)

Ghouls'n Ghosts [Demo] - 02.jpg (871.25 KB)

Ghouls'n Ghosts [Demo] - 03.jpg (916.26 KB)

Same configuration as Ghouls'n Ghosts, two identical cartridges.

[sms-castle_of_illusion-demo-256k-1.sms]
Size: 262144 bytes (16 pages), CRC:273C4370
0 ; f3 ed 56 31 fc df 18 60 7b d3 bf 7a d3 bf c9 ff ; Sum:1879DB, CRC:D85DCA5E
1 ; 0a 09 1a 0b 0c 0d 10 0e 2b 28 2c 2d 12 12 12 13 ; Sum:3A5D9D, CRC:C42DB239
2 ; ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ; Sum:3FC000, CRC:690B37D3
3 ; ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ; Sum:3FC000, CRC:690B37D3
4 ; ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ; Sum:3FC000, CRC:690B37D3
5 ; ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ; Sum:3FC000, CRC:690B37D3
6 ; ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ; Sum:3FC000, CRC:690B37D3
7 ; ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ; Sum:3FC000, CRC:690B37D3
8 ; aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa ; Sum:2A8000, CRC:28C194E0
Same as pages: 09, 0A, 0B, 0C, 0D, 0E, 0F
9 ; aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa ; Sum:2A8000, CRC:28C194E0
Same as pages: 08, 0A, 0B, 0C, 0D, 0E, 0F
A ; aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa ; Sum:2A8000, CRC:28C194E0
Same as pages: 08, 09, 0B, 0C, 0D, 0E, 0F
B ; aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa ; Sum:2A8000, CRC:28C194E0
Same as pages: 08, 09, 0A, 0C, 0D, 0E, 0F
C ; aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa ; Sum:2A8000, CRC:28C194E0
Same as pages: 08, 09, 0A, 0B, 0D, 0E, 0F
D ; aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa ; Sum:2A8000, CRC:28C194E0
Same as pages: 08, 09, 0A, 0B, 0C, 0E, 0F
E ; aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa ; Sum:2A8000, CRC:28C194E0
Same as pages: 08, 09, 0A, 0B, 0C, 0D, 0F
F ; aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa ; Sum:2A8000, CRC:28C194E0
Same as pages: 08, 09, 0A, 0B, 0C, 0D, 0E

The higher 128 KB of AA is what the board/cartridge return upon setting the mapper to read those pages. After that it wrap around from page 0.

Attached are the other cartridges I got from the same person (the guy who posted on AtariAge). He initially had double that but I only managed to purchase half of his lot. The rest went on auction to various collectors.
The dumps from Rupert at segacollect.com comes from that same seller (Ruper purchased 3 cartridges and kindly dumped them)

SMS Protos.jpg (509.89 KB)

Firstly, thank you for the photos - they are exactly what I was looking for.

Secondly, thanks for confirming that the demo cartridges each contain a single 27c1000 EPROM. This implies a maximum size of 128KB for each demo.

The $aa bytes seen on dumping are therefore not part of the demos. My guess is that the 171-5486 board is designed to hold two 128KB EPROMs and that these bytes are the result of trying to read from the empty "IC2" socket.

Once the $aa bytes are trimmed, the dumps are then as I expected: made up of the currently available 32KB followed by 96KB of $ff bytes. This 128KB is accessed in full by the SMS during checksum calculation, so should all be retained.

Hmm, the SMS reader I sent to Bock has an option for weakly pulling up the data bus to 00/55/aa/ff in order to recognize areas that are undriven, like empty sockets. This was to identify the true size of ROMs.

We recently fixed the software and maybe I left something in that didn't change it back to zero.

Author	Message
RetroSpark Joined: 08 Dec 2005 Posts: 488 Location: Melbourne, Australia	Rolling Demos of "Castle of Illusion" and "Ghouls'n Ghosts": ROM Size Posted: Tue Dec 13, 2011 6:55 am
	Both the "Castle of Illusion" and "Ghouls'n Ghosts" rolling demos have been released as 32KB dumps. However, I notice that both ROM headers specify a size of 128KB, and that it is necessary to pad the dumps to 128KB (using $ff bytes) in order for the checksums to be correct. At first I thought there was probably a mistake in each header, but in fact the "Castle of Illusion" dump does come from a 128KB cartridge. Below, the first photo (from segacollect.com) shows that cartridge, and I believe the second (from atariage.com) does too (I have asked the owner of segacollect.com for confirmation). The second photo clearly shows a 315-5235 mapper chip alongside a D27C1000A-12 - the latter is a 128KB EPROM. Would it be more accurate to release these dumps as 128KB, the last 96KB filled with $ff? P.S. These are the only (non-homebrew) ROMs I have with a valid header (containing "TMR SEGA" and a non-zero checksum), where the header claims a ROM size larger than the size of the file. DSC02873.JPG (33.85 KB) 000_8717.jpg (55.18 KB)

Bock Site Admin Joined: 08 Jul 2001 Posts: 8653 Location: Paris, France	Posted: Tue Dec 13, 2011 10:37 am
	Usually we pad down dumps especially since prototypes are often found on bigger chips, or eg. later releases of some games or brasilian releases also would use bigger chips. In this case since the checksum relies on it you are right and it should be fixed. Not sure what is the best way for us to spread and roll out fixed dumps at this point since we don't have an easy master repository to replicate (it is something I hope we can work on). I'll post them with a news post and I assume ROM DB will follow on. PS: I own both cartridges, will give a check to Ghouls'n Ghosts later.

RetroSpark Joined: 08 Dec 2005 Posts: 488 Location: Melbourne, Australia	Posted: Tue Dec 13, 2011 10:21 pm
	Bock wrote Usually we pad down dumps [...] found on bigger chips. I think that's the right approach. For example, if a 32KB game is found on a 128KB chip (padded with 96KB of $ff), it's still a 32KB game and should be released as such. Quote In this case since the checksum relies on it you are right and it should be fixed. Yes, the headers tell us that the situation here is different to that in my previous paragraph. We don't have 32KB demos padded with 96KB of $ff, but 128KB demos which contain 96KB of $ff. Bock wrote I own both cartridges, will give a check to Ghouls'n Ghosts later. You have a cartridge containing the same "Castle of Illusion" demo as is available at segacollect.com? If so, could you please give a final confirmation that it does indeed contain a 128KB EPROM? Also, while you have the demo cartridges open, I presume they both use the 171-5486 circuit board? Would you be able to take some good-quality photos of (both sides of) one of these boards? Thanks

Bock Site Admin Joined: 08 Jul 2001 Posts: 8653 Location: Paris, France	Posted: Tue Dec 13, 2011 10:32 pm
	I just found I had 2 castle of illusion.. now i am confused. :) Let me dump and check them all again.

Bock Site Admin Joined: 08 Jul 2001 Posts: 8653 Location: Paris, France	Ghouls'n Ghosts [Demo] Posted: Tue Dec 13, 2011 10:39 pm Last edited by Bock on Tue Dec 13, 2011 10:59 pm; edited 1 time in total
	171-5486 board 315-5235 mapper One 27c1000 eprom Size: 262144 bytes (16 pages), CRC:1A2C1945 0 ; c3 3b 00 00 00 00 00 00 7b d3 bf 7a d3 bf c9 00 ; Sum:1A34C4, CRC:F82F5209 1 ; 00 04 00 03 02 01 00 05 00 06 00 06 00 05 02 07 ; Sum:382B93, CRC:9F3D2982 2 ; ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ; Sum:3FC000, CRC:690B37D3 3 ; ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ; Sum:3FC000, CRC:690B37D3 4 ; ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ; Sum:3FC000, CRC:690B37D3 5 ; ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ; Sum:3FC000, CRC:690B37D3 6 ; ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ; Sum:3FC000, CRC:690B37D3 7 ; ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ; Sum:3FC000, CRC:690B37D3 8 ; aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa ; Sum:2A8000, CRC:28C194E0 Same as pages: 09, 0A, 0B, 0C, 0D, 0E, 0F 9 ; aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa ; Sum:2A8000, CRC:28C194E0 Same as pages: 08, 0A, 0B, 0C, 0D, 0E, 0F A ; aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa ; Sum:2A8000, CRC:28C194E0 Same as pages: 08, 09, 0B, 0C, 0D, 0E, 0F B ; aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa ; Sum:2A8000, CRC:28C194E0 Same as pages: 08, 09, 0A, 0C, 0D, 0E, 0F C ; aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa ; Sum:2A8000, CRC:28C194E0 Same as pages: 08, 09, 0A, 0B, 0D, 0E, 0F D ; aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa ; Sum:2A8000, CRC:28C194E0 Same as pages: 08, 09, 0A, 0B, 0C, 0E, 0F E ; aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa ; Sum:2A8000, CRC:28C194E0 Same as pages: 08, 09, 0A, 0B, 0C, 0D, 0F F ; aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa ; Sum:2A8000, CRC:28C194E0 Same as pages: 08, 09, 0A, 0B, 0C, 0D, 0E Ghouls'n Ghosts [Demo] - 01.jpg (771.3 KB) Ghouls'n Ghosts [Demo] - 02.jpg (871.25 KB) Ghouls'n Ghosts [Demo] - 03.jpg (916.26 KB)

Bock Site Admin Joined: 08 Jul 2001 Posts: 8653 Location: Paris, France	Castle of Illusion [Demo] Posted: Tue Dec 13, 2011 10:59 pm
	Same configuration as Ghouls'n Ghosts, two identical cartridges. [sms-castle_of_illusion-demo-256k-1.sms] Size: 262144 bytes (16 pages), CRC:273C4370 0 ; f3 ed 56 31 fc df 18 60 7b d3 bf 7a d3 bf c9 ff ; Sum:1879DB, CRC:D85DCA5E 1 ; 0a 09 1a 0b 0c 0d 10 0e 2b 28 2c 2d 12 12 12 13 ; Sum:3A5D9D, CRC:C42DB239 2 ; ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ; Sum:3FC000, CRC:690B37D3 3 ; ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ; Sum:3FC000, CRC:690B37D3 4 ; ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ; Sum:3FC000, CRC:690B37D3 5 ; ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ; Sum:3FC000, CRC:690B37D3 6 ; ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ; Sum:3FC000, CRC:690B37D3 7 ; ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ; Sum:3FC000, CRC:690B37D3 8 ; aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa ; Sum:2A8000, CRC:28C194E0 Same as pages: 09, 0A, 0B, 0C, 0D, 0E, 0F 9 ; aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa ; Sum:2A8000, CRC:28C194E0 Same as pages: 08, 0A, 0B, 0C, 0D, 0E, 0F A ; aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa ; Sum:2A8000, CRC:28C194E0 Same as pages: 08, 09, 0B, 0C, 0D, 0E, 0F B ; aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa ; Sum:2A8000, CRC:28C194E0 Same as pages: 08, 09, 0A, 0C, 0D, 0E, 0F C ; aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa ; Sum:2A8000, CRC:28C194E0 Same as pages: 08, 09, 0A, 0B, 0D, 0E, 0F D ; aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa ; Sum:2A8000, CRC:28C194E0 Same as pages: 08, 09, 0A, 0B, 0C, 0E, 0F E ; aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa ; Sum:2A8000, CRC:28C194E0 Same as pages: 08, 09, 0A, 0B, 0C, 0D, 0F F ; aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa ; Sum:2A8000, CRC:28C194E0 Same as pages: 08, 09, 0A, 0B, 0C, 0D, 0E

Bock Site Admin Joined: 08 Jul 2001 Posts: 8653 Location: Paris, France	Posted: Tue Dec 13, 2011 11:00 pm
	The higher 128 KB of AA is what the board/cartridge return upon setting the mapper to read those pages. After that it wrap around from page 0.

Bock Site Admin Joined: 08 Jul 2001 Posts: 8653 Location: Paris, France	Posted: Tue Dec 13, 2011 11:01 pm
	Attached are the other cartridges I got from the same person (the guy who posted on AtariAge). He initially had double that but I only managed to purchase half of his lot. The rest went on auction to various collectors. The dumps from Rupert at segacollect.com comes from that same seller (Ruper purchased 3 cartridges and kindly dumped them) SMS Protos.jpg (509.89 KB)

RetroSpark Joined: 08 Dec 2005 Posts: 488 Location: Melbourne, Australia	Posted: Tue Dec 20, 2011 2:21 am
	Firstly, thank you for the photos - they are exactly what I was looking for. Secondly, thanks for confirming that the demo cartridges each contain a single 27c1000 EPROM. This implies a maximum size of 128KB for each demo. The $aa bytes seen on dumping are therefore not part of the demos. My guess is that the 171-5486 board is designed to hold two 128KB EPROMs and that these bytes are the result of trying to read from the empty "IC2" socket. Once the $aa bytes are trimmed, the dumps are then as I expected: made up of the currently available 32KB followed by 96KB of $ff bytes. This 128KB is accessed in full by the SMS during checksum calculation, so should all be retained.

Charles MacDonald Joined: 28 Sep 1999 Posts: 1197	Posted: Tue Dec 20, 2011 6:05 pm
Charles MacDonald Joined: 28 Sep 1999 Posts: 1197	Hmm, the SMS reader I sent to Bock has an option for weakly pulling up the data bus to 00/55/aa/ff in order to recognize areas that are undriven, like empty sockets. This was to identify the true size of ROMs. We recently fixed the software and maybe I left something in that didn't change it back to zero.

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