In the case of memory, such fuse-programmable chips are normally referred to as PROM. Such as the TBP24S10 used in the Oric's video circuit. PAL programmable logic is also fuse-based. Rarely seen these days, but quite reliable indeed. There even exist some FPGA's using a fuse-based technology for their (one-time!) configuration (Actel, Lattice or MicroSemi iirc).mikeb wrote:The same applies for OTP (One Time Programmable) chips where you program them, once, by blowing fuses away.
What's normally referred to as One Time Programmable isn't fuse based but just 'UV' EPROMs in (cheaper!) plastic housing. So after programming you can't erase them since there's no window to shine UV light through. But same chip inside (same type # too), with all (dis)advantages that come with UV EPROMs. Still commonly found where programmed data isn't expected to be updated in the field. For example as video BIOS on older VGA cards. I still have an EPROM eraser, and a self-built EPROM programmer which I'm not sure if it still works (does/did 27(C)64 up to 27C040. 27C080 support would be easy to add). I intend to write a small program some time, that will read & count the # of 0's and 1's in an EPROM, put in one with all 0's programmed, put it under a hood together with an EPROM erase lamp, and then produce a nice graphical representation as you see the bits being erased (from 0 to 1). Should make for a nice live demo or YouTube video.