Bad Tracks where typically “Sync-Less” Tracks.
Monthly Archives: October 2012
Non-Standard format
Non-Standard format
Later on, only track 18 (the directory track) was standard! Everyone used custom disk formats to get better speed and store more data. – Jim Drew
Half Track Protection
Half Track Protection
Half tracks are something that the 1541 could not easily write without modifying the drive, or being able to get lucky and come up with a routine that would the half tracks 180 degrees out of phase (like I did with the Bounty Bob Strikes Back! copier. -Jim Drew)
Density – Frequency
Density – Frequency Protections
Changing the density level was a common trick for putting more data on a track, as well as preventing copiers from clocking in the data properly. – Jim Drew
Clock Bits Protection
Clock Bits Protection
This is a protection where invalid GCR was used. Most commonly known as ‘weak bit’ protection. This was the most difficult protection to detect unless you were using a 1541-II or 1571 disk drive. Neither of these drives would ‘float’ invalid bits like a 1541 does. So, you can easily spot these and correct the data before being re-written. – Jim Drew
Address Marks Protections
I do not know what this is, but some copy protection software mentioned this in their ad.
Anyone have information on this one?