----------Original Message: Date: Sat, 19 Jan 2008 21:31:40 -0800 From: dwight elvey <dkelvey at hotmail.com> Subject: RE: Reading Polymorphic double density double sided disk Hi Mike I already have a index, sector seporator. I built it with a 7438, 7414 and 2 555's. It works fine. One could use a single 556 but 555s are easier to find. What I mean is that the disk has index into the disk as 0 to 799 sectors. The disk is 10 sectors so one needs to divide this index by 10 to get the track number and the remainder is the sector number. The original code handle a 32 sectored disk. Because 32 is a power of 2, doing the calculations were much easier. Divide by 10 is not as easy. See my next post. If anyone wants a schematic of my index, sector pulse seporator, I can scan it and send it out. Dwight -----------Reply: Oops; careless reading on my part; I'd read "separate *index* from sector," instead of "track." Probably because I've been playing with the opposite, generating HS sector pulses from the index, also with 555s... mike