OSBYTE &FF
OSBYTE &FF (255) - Read/Write startup Options
This is a copy of the keyboard links taken at last hard reset
b0..2=screen mode
b3 =if clear then the action of SHIFT/BREAK is reversed
b4..5=disk drive speed step time settle time head load
b5=0 b4=0 4ms 16ms 0ms
b5=0 b4=1 6ms 16ms 0ms
b5=1 b4=0 6ms 50ms 32ms
b5=1 b4=1 24ms 20ms 64ms
b6 =HADFS: 0=drive 1 external, 1=drive 1 internal, via OSWORD &7F
b6 =ENFS: 0=unPROTed on Break, 1=PROTed on Break
b7 =DNFS: 0=NFS priority, 1=DFS priority
b7 =ENFS: 0=use buffered I/O and raise PAGE by &300, 1=don't use buffered I/O
b7 =Master: screen mode b7
