NintendoAge

What check sum program used during NES era?

Xerxes — 2014-05-28T01:51:26 -05.00

My EPROM Programmer is one of those older models. It has a Hex Keypad on it and displays the checksum everytime you program a chip. Soemtimes it asks for you to type in the checksum ahead of time.

Throughout the 200-page manual, it refers to it as "sumcheck" for some bizarro reason. I get a laugh every time.

What check sum program used during NES era?

Xerxes — 2014-05-05T06:14:43 -05.00

Is HEX editor for the color index? Like dfdfdf or FFF (white). Just saying.

What check sum program used during NES era?

Xerxes — 2014-04-14T17:24:03 -05.00

0->1, but because the sum is more digits than the checksum it could go either way.

What check sum program used during NES era?

Xerxes — 2014-04-14T17:11:09 -05.00

Thanks bunnyboy. Bit rot only goes one direction right? Which way would it go? 1 -> 0 or 0 -> 1? Would we expect a check sum generated that way to increase or decrease with bit rot?

What check sum program used during NES era?

Xerxes — 2014-04-14T10:57:29 -05.00

They are just a plain sum of all the bytes, no crazy math. Many hex editors and chip programmers will show it to you when you load the file.

What check sum program used during NES era?

Xerxes — 2014-04-14T10:18:24 -05.00

I am curious if anyone knows what check sum algorithm was used during the NES era. I have noticed that some NES protos have check sums right on the EPROM. Check out the link below if you are curious what I am talking about. I know that these check sums were not created with md5 which is the one that I use. Does anyone know which one was used? It would have been nice if more developers would have done this as would tell us if we have a good dump with no degradation.

http://www.nintendoage.com/forum/messageview.cfm?catid=35&threadid=122782