Changes

An exception are the Vortex F1-S, F1-D, M1-S and M1-D drives. (How are they different?)

At the end of a successful read or write command, the program should send a ''Terminal Count'' (TC) signal to the FDC. However, in the CPC the TC pin isn't connected to the I/O bus, making it impossible for the program to confirm a correct operation. For that reason, the FDC will assume that the command has failed, and it'll return both Bit 6 in Status Register 0 and Bit 7 in Status Register 1 set. The program should ignore this error message.