How long will they last?

Don't bother with burning backups (after all, the backup will only last another 10 years), but dump the data (as a plain binary file) to a suitable archival storage medium. What I recomend is _before_ even powering up a machine is to dump all the ROMs, the PALs (an amazing number of classic computers have non-copy-protected PALS), etc to a PC-format disk. Then punch any really rare stuff onto paper tape (You may laugh, but I've _never_ found a paper tape that I can't read, and EPROM files are not that big in general). If the chips ever fail in the future, then It's easy to burn a new EPROM then. Well, there's no problem with standard electronic parts (resistors, capacitors, TTL chips, etc). I don't think you'll have any problems finding those in 15 years time. Other chips are more of a problem. AMD2900 bit-slice chips are getting hard to find, and a lot of minicomputers and their peripherals depend on them. But I'm not sure that if I buy any now they'll still be good in 10 years time. ASICs are a big problem. Basically, there's no hope if they fail. You can't copy them at home. The best thing to do is to figure out _exactly_ how they work, the timing of all the signals, etc, and to record that. If the chip fails, and you can't get one, then at least you can make a clone out of TTL or something like a Xilinx FPGA. I'd also recomend recording any information now that would be of use if the machine failed. If you know what you are doing, note down the voltages on the CRT electrodes in a monitor. The waveforms in the PLL of a disk controller, that sort of thing. Basically, annotate the service manual with details of _your_ machine. -- -tony ard12(a)eng.cam.ac.uk The gates in my computer are AND,OR and NOT, not Bill