On 3/22/22 21:32, dwight via cctalk wrote: > Years ago when I was at Intel, they would take EPROMs that had only a few > defects and attempt to program them with specific applications. They would > then usually paint the window black and put on that particular product > number. When we needed EPROMs in the lab, we would take a pile of these that > were no longer used and scrape the paint off the window. Some would take the > desired program and some wouldn't. > I suspect that they can fuse identify specific bad EPROMs to use for such > harvesting. The fused value may be laser blown as well. My guess is that that > is the reason for the different ID number. If it will take pre-programming > with a particular data, it is worth harvesting. > This way they can find value in an otherwise unsellable product. I doubt the > harvesting methods have changed much over the years.
That's not surprising. Probably cheaper even for IBM than mask-programmed PROMs. --Chuck
