CP-M Z80 home brew computer circuit board

Les Hildenbrandt les at hildenbrandt.com
Wed Jun 18 08:21:35 CDT 2008

The 279x (1,3,7) series chips actualy had a working pll data seperator.
Here is a link to the 279x controller chip data sheet:
As I recall, the 179x series chips could not reliably do sector reads from disks formated on a 177x controller.  The 179x could do a track read of the disk.  Morrow provided a program with the Disk Jocky controller which would do track reads, then write the track back out creating a disk which worked well with either the 177x or 179x series controllers.  It was not a common issue, as very few people used single density once double density became available, and new single density disks worked well with either controller.


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