herr professor Posted July 2, 2003 Share Posted July 2, 2003 http://www.vgwiz.com/ Purty Cool! Link to comment Share on other sites More sharing options...
DEBRO Posted July 8, 2003 Share Posted July 8, 2003 Yeah, I've seen those and they look really cool. I have a question for the EPROM experts here. Would using a clear shell speed up the bit rot of an EPROM? Since the shell is clear it seems like the UV rays could get to the EPROM easier. Link to comment Share on other sites More sharing options...
EricBall Posted July 8, 2003 Share Posted July 8, 2003 Would using a clear shell speed up the bit rot of an EPROM? Since the shell is clear it seems like the UV rays could get to the EPROM easier. Typically you put a small label sticker over the window once you have finished programming the EPROM (properly labeled with a description of the contents of the EPROM). If you are really worried, use an EEPROM (electrically erasable) or an OTP (one-time programmable) which don't have windows. Link to comment Share on other sites More sharing options...
CPUWIZ Posted July 8, 2003 Share Posted July 8, 2003 Would using a clear shell speed up the bit rot of an EPROM? Since the shell is clear it seems like the UV rays could get to the EPROM easier. Typically you put a small label sticker over the window once you have finished programming the EPROM (properly labeled with a description of the contents of the EPROM). If you are really worried, use an EEPROM (electrically erasable) or an OTP (one-time programmable) which don't have windows. I'll second that, EEPROM's or OTP's are they way to go with these clear cases. Be warned though, they are more expensive than regular EPROM's. Link to comment Share on other sites More sharing options...
Thomas Jentzsch Posted July 8, 2003 Share Posted July 8, 2003 Wouldn't the clear case absorb UV too? Link to comment Share on other sites More sharing options...
+5-11under Posted July 8, 2003 Share Posted July 8, 2003 Thomas: possibly, but odds are, a black case will absorb more. Also on the website: Coming soon: Megacarts for the 2600 and 5200. hopefully they won't be too pricey. 5-11under Link to comment Share on other sites More sharing options...
Pitfall Harry Posted July 8, 2003 Share Posted July 8, 2003 Yeah, I've seen those and they look really cool. I have a question for the EPROM experts here. Would using a clear shell speed up the bit rot of an EPROM? Since the shell is clear it seems like the UV rays could get to the EPROM easier. A: The plastic shell may be clear (pass visible light), but it isn't visible light which erases an EPROM. Unless you forget to place the sticker over your EPROM's little window and expose the cartridge to an extremely intense source of UV radiation for a prolonged period of time, the translucence of the cartridge shell to visible light shouldn't really matter. What matters is what the cartridge shell is made of. Q. Why does placing an EPROM inside a plastic cartridge shell protect it from UV radiation and bitrot? A: UV radiation, particularly the UV light used in EPROM erasers (known as UV-C), has very low penetrating power. As soon as a photon of UV radiation smacks into an atom of matter it gets absorbed and that's the end of that. Placing an EPROM inside of a plastic cartridge shell provides excellent shielding from UV radiation simply because you are encapsulating it within a dense concentation of energy-absorbing matter. Q: But matter is everywhere, even in air. Why isn't the matter in air enough to stop UV light from causing EPROM bitrot? A: Air is a mixture of gasses, which is not very dense. The occasional photon of UV light smacks into a component molecule of air, but for the most part, UV light passes through it unobstructed. If you could somehow arrange to have millions of miles of air for a UV light source to pass through, then even air would be a decent shield for UV light. Unfortunately for the owners of videogames stored on EPROMs, the Earth's atmosphere is much too thin to act as an effective shield for UV light from the sun. Exposure to sunlight for long enough will eventually erase the data stored in an EPROM. Q: What if I keep my EPROMs indoors? Won't the roof and walls of a HOUSE provide adequate shielding from UV light and prevent bitrot? A: A house provides excellent shielding from the UV light of the sun. Keeping your EPROM carts indoors and away from other sources of UV light (tanning lights, halogen lights, EPROM eraser lights, etc.), is all the protection you can practically provide. Q: Ah, but a house has windows, which let sunlight into the house. Is this how EPROMs which are kept only indoors get exposed to UV radiation and eventually fall victim to bitrot? A: Not really. Window glass blocks UV light very well, which is why the "little glass window" of an EPROM chip isn't really made of glass at all. It's made of quartz, because the atoms within the crystal structure of quartz line up like soldiers in neat little rows. UV light passes through the gaps in those neat little rows as if nothing was there. As far as UV light is concerned, nothing is there. Glass, on the other hand, has no crystalline structure whatsoever. Glass is a random sea of molecules, like a liquid. A photon of UV light doesn't have to travel very far through glass before it eventually smacks into a glass molecule and gets absorbed. Some UV light will get through glass, but the amount which does is statistically insignificant. Maybe 10,000 years of sunlight pouring through the closed window of a house is enough to cause an EPROM to erase, if other factors don't wipe it out before then. Other factors will wipe it out before then. Q: What other factors? A: Age. EPROMs are not designed to hold their data forever, and they don't. Manufactures typically quote a figure of 10 years before an EPROM's stored data becomes unreliable. If well cared for, an EPROM could last 20-25 years. But no matter how careful you are, no matter how successfully you minimize the exposure to UV light, your EPROMs aren't going to last much longer than 25 years before they begin to show signs of bitrot. Q: How does age alone cause an EPROM to bitrot? Each of the 1's and 0's stored within an EPROM is stored as a charge at the gate of a transistor. (Actually, it's only the 0's. A fully erased EPROM is an array of 1's). UV light erases an EPROM because it is the right wavelength to excite the electrons into leaking off the gate. Those data-holding electrons don't leak away on their own because of the insulative properties of the surrounding medium within the chip. But no insulator is perfect. The data-holding electrons will leak away on their own eventually, without the aid of a UV stimulus. And when that happens, a '0' reverts back to a '1,' and the data is lost. It's only a matter of time. Q: Are there any other factors I should be concerned about? A: Subjecting an EPROM to severe power impulses, especially those which result from "frying" a console to induce weird gaming effects, dramatically shorten the data life of an EPROM. ~~~~~~~~~~~~ I hope my EPROM mini-faq proves helpful! Ben Link to comment Share on other sites More sharing options...
Thomas Jentzsch Posted July 8, 2003 Share Posted July 8, 2003 Thanks Ben! I thought that a clear case absorbs UV as well as a black one (just like normal window glas does). And now I know it! Link to comment Share on other sites More sharing options...
DEBRO Posted July 8, 2003 Share Posted July 8, 2003 Yeah, thanks Ben. I knew someone here was knowledgable enough to answer my question. Link to comment Share on other sites More sharing options...
DEBRO Posted July 9, 2003 Share Posted July 9, 2003 One more question... Do EEPROMs and OTPs suffer from bitrot too? Link to comment Share on other sites More sharing options...
Nukey Shay Posted July 9, 2003 Share Posted July 9, 2003 From the explaination, they wouldn't as a result of UV radiation (since there is no way for it to penetrate the chip's casing anyway...not that they would be vulnerable to it). But all rom chips will eventually degrade. Link to comment Share on other sites More sharing options...
EricBall Posted July 9, 2003 Share Posted July 9, 2003 Do EEPROMs and OTPs suffer from bitrot too? Based on Pitfall Harry's excellent explanation, EEPROMs will be subject to the same problem. Some types of OTPs may not be. Those which are EPROMs without a window will be; while those which are based on fuses (so programming causes an actual physical change, not just an electrical one) should not be. Check the datasheets for more info. Link to comment Share on other sites More sharing options...
gavv Posted July 9, 2003 Share Posted July 9, 2003 Thanks Ben! I thought that a clear case absorbs UV as well as a black one (just like normal window glas does). And now I know it! And knowing is half the battle! gavv (sorry, tempted too much to not do it ) Link to comment Share on other sites More sharing options...
Like us on Facebook
Follow us on Twitter
AtariAge on Instagram
Watch us on YouTube
Chat on Discord
Recommended Posts
Archived
This topic is now archived and is closed to further replies.