m o r e

Are you waking up wading in sweat ? The Bitrot FAQ   by Deleto.

ROM, EPROM and others

ROM means "Read-Only Memory". It is placed in a chip on a silicon circuit board,and a lot of technical products use them. There is one in your computer, in your car, inyour CD-player, maybe even one in your food-processor. There is also one (or more) in your2600 cart. It's where the actual game is put on. Collectors, gamers and programmers often callthe entire inside of the carts the ROM, or they refer to the game the ROM.
The "ROM-image" is (a grab from) the game-code (-data/program/software) fromthe actual ROM from a game. Game Emulators use these. It is produced (programmed) and storedon the computers used for development (Apple ][ back in the days) of the game.The images are then manufactured (not burned !) right into the chip in the factory.Once the chip has been made and the code is on it, the ROM can only be read. It is write-protected,like a Compact Disc.
ROMs come in variable Byte sizes, since not every game uses the same space.There are 2K (2 KiloByte), 4K, 8K, 16K and even 32K games (Fatal Run).

EPROM means "Erasable and Programmable Read-Only Memory".Basically, it is the same as a ROM, but you can Write on it, over and over, after you haveErased it. EPROMs have a small lense or window on the chip By shining intense Ultra-Violet Lightthrough it (for about an hour) you can erase the EPROM. For "burning"the data onto the EPROM, it has pins. A high voltage (+24/+21 VDC) is pulsed onto the EPROMSprogram-pin. It also has adress-pins and data-pins. Like ROMs, EPROMs come in variable sizes.
Carts and games for the 2600 that carry EPROMs inside are Loaner Cartridges and Prototypes, aswell as games with limited quantities like CubiColor  and Okie Dokie. Some ATARI 2600 game prototypes contain two EPROMs since a single one of a large K amount wasmore expensive then two half ones.

PROM is Programmable Read-Only Memory". This chip can not be erased. It has no window.

RAM means Random Access Memory and is the chip in your computer used to store various stuffon. It can be read-from and written-on infinite times. Do not confuse this with ROM, or yourHard Disk as some people do. For now, it has nothing to do with this FAQ.

Will EPROMs rot ?

The fading away of the stored code, is what's called "bitrot".There is not much known about this phenomenon though, and in fact there's no scientific andofficial evidence yet that EPROMs will. Most manufacturers don't tell the lifespan of thereEPROMs. One official source notes that the electrically charged code will simply "leak"out of the EPROM in 10 to a 100 years. There will be no physical damage though, and you can erasethe EPROM fully and put the image back on (if you would have it).
Some people suggest that EPROMs will erase themselves after about 20 years, and some haveindeed. Some never-before-seen O^2 games were found on a 4-in-one EPROM cart in Europerecently, but one of the four chips had rotten away. Yet this seems more like a random actthen a form of erosion. Physical rotting of the EPROM will occur too, but that will reallytake a lot of decades.

I'm still paranoid!

Well, if you are still worried over all this, you can preserve your EPROM in the following ways:

This FAQ is not really satisfying.

Perhaps, but this is all I could find out for now. Check out the "Dissecting a Proto" for detailed pictures and technical stuff that willscare your friends away. You can also have a look at some opened carts at theInside-Out page.
There are widely varying opinions on the subject, and as I already said, there are not manydocuments on bitrot. For now it will remain an unsolved mystery and time will just have to tell,like many things in life.

Thanks go out to Dan Boris for proofreading and teaching me all about ROM.

d r d e l e t o @ d d s . n l