La matematica con il computer v1 (Vifi Mondadori, 1983)

[toinet]

#915 - This is an Italian eduware to learn maths with the use of the BASIC language.

Protection type
This is an on-disk protection based on Apple's disk protection toolkit that was delivered/sold to some businesses to help them protect their software. That kind of protection was used in Ultima IV: the third header marker of the data field depends on the last character of a filename and all T/S pairs that belong to that file use the same third marker value.

Last but not least, when a protected sector is encountered, the next nibble read is put in the accumulator for the checksum instead of the usual #0 value.

How to copy
You will not get any disassembly of the original protection scheme as the method to copy the disk is:
1- format a DOS 3.3 slave disk (INIT HELLO)
2- boot the original disk, visited the monitor in my IIgs and saved memory (the $Bxxx area) in an upper bank
3- modify the read routine of the data field to call the protected one

What I did is:
- put the data read protected routine at $B600