My classiccmp non-retirement :-)

Yes, in the early days at of floppies, CDC reversed engineered by using "brassboards" and hand made heads on a lead screw. Primitive but very stable and we were able to read and write. Whole assembly weighed about 100 pounds so it wasn't anything you could sell. But it did the job. And was pretty easy to build using off the shelf components. Floppy media being contact recording saves most of the grief you get when trying to recover hard drive data. Tony Duell wrote: Another possibiliy is to assume that some (non-working) drives are still around, how hard would it be to get them working again. For both the CD-ROM and the floppy, I think all parts other than the head/laser pickup could be made in a good home workshop (Note, I am not claiming _I_ could do it, at least not yet). Now the winding on a floppy drive head could corrode and go open-circuit (this is a problem on some types of recording head, I am told it was due to acid from the fingers of the people who handled the wire when they were being wound). But I would think the semiconductor laser and photodiodes in a CD pickup was much more likely to fail with time. GIven the head, I think the electronics would be doable. The floppy drive would probably be easier, if only because all floppy heads used much the same read chain, so if you could find data on any floppy drive you could probably make something that would work. And if you get it wrong, you are not likely to damage the head. Whereas the CD pickup is a more complicated device to drive, if you get the laser current wrong it'll either not work (current too low) or not work ever again (current too high). And every manufacturer did his own thing, so you are not likely to be able to find a published circuit that will work. -tony Another possibility to consider is that technology might offer new tools. Some of the magnetic field imaging tools we use in the hard drive industry could easily give a visual image of every bit on a floppy. (Those old bits are so big that we could write several sectors into them now.) It would be extremely tedious to go from an image to data, but it is possible. One of the big problems would be understanding and translating all the different formats. The early 8 inch single sided drives used a variety of recording formats: FM, MFM, missing clock, etc. On this new technology to recover old - has anyone on this list been following the work being done on recovering sound from very old wax recordings using a laser? I saw a fascinating description of it in one of the IEEE pubs. They used the laser to track the path a needle would have to travel. Then converted the laser position to an analog signal to audio. Then a little DSP work to eliminate the clicks, hiss, etc. The original wax recordings were too delicate or damaged to use conventional means. The results were outstanding - one of the recordings was put up on the net for a while. I understand they are also using this laser technique to recover some of the sound tracks on the early talkies. I've also read recently about recovering very faded movie film by using short wave length laser scans, then digitise the results, and restore the original grey scale by converting the relative amplitudes. I haven't seen any of the results of this yet. Has anyone on the list seen these restorations? Billy