Copy Protection; Bypassing Bios; Diskette Drive Differences - IBM 5170 Technical Reference

Copy Protection
Some modes of copy protection will not work on the IBM
Personal Computer AT due to the following conditions:
• Bypassing BIOS
• Diskette drive differences
• Write current differences
Bypassing BIOS
Copy protection, which depends on the following will not work
on the IBM Personal Computer AT:
Track Density: The High Capacity Diskette Drive records tracks
at a density of 96TPI. This drive has to double step in the 48TPI
mode, which is performed by BIOS.
Data Transfer Rate: BIOS selects the proper data transfer rate
for the media being used.
r ' \
Disk Base: Copy protection, which creates its own disk base
will not work on the High Capacity Diskette Drive. ­
Diskette Drive Differences
Copy protection, which depends on the following will not work
on the High Capacity Diskette Drive:
Rotational Speed: Copy protection using the time between two
events on a diskette will not work on the High Capacity Diskette
Drive.
Access Time: Diskette BIOS must set the track to track access
time for the different types of media used on the IBM Personal
Computer AT.
9-22 Compatibility