My classiccmp non-retirement :-)

[Tony Duell]

> Has anyone built a floppy drive from scratch? Without salvaging
> any mechanical parts or heads from an existing floppy? I'm
> assuming that electronic processing is not a problem (in
> principle) for either floppy disks or CDROMs/DVDROMs.

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