"Bill Garber" writes: >Yes, for example, I placed a superdrive controller in slot 5 of my IIe, >then attached the 800k drive. Leaving the 5.25 empty of disk, it sat >there waiting for one, never scanning down to slot 5 for the 800k. >Why? Whine to me please. ;-) This is standard behavior for an Apple ][ ][+ or //e. The //c //c+ and //gs are smarter. Why is this so? It is the Disk ][ controller card and the measly 256 bytes of PROM it has for the boot code (plus the fact that when it was written 3.5" drives were not even a gleam in the eye of their designers). The //c //c+ and //gs have newer code (and the ability to use code space outside the range $C600..$C6FF for this task) and detect the absence of a 5.25" diskette and scan down to the next lower slot (as do cards like Apple SCSI card or Apple 1MB RAMdisk card). Unlike the MFM <-> GCR problem, this problem can (and has been) solved in software (well, firmware anyway). I have a //e in which I have installed a modified set of CD & EF EPROMs. I made a small change to the code near monitor label SLOOP ($FABA) which originally starts at slot 7 and scans down to slot 1. My //e starts at slot 1 and scans up to slot 7. This was done so that I could use my SCSI card in slot 4 (where Pascal 1.3 could find it) and leave the Disk ][ controller in slot 6. Here is the original code: LDA #$C8 STX LOC0 ; X known to be zero at this point STA LOC1 SLOOP LDY #7 DEC LOC1 LDA LOC1 CMP #$C0 BEQ FIXSEV ; no bootable disk controllers STA MSLOT NXTBYT LDA (LOC0),Y CMP DISKID-1,Y BNE SLOOP ; try next slot DEY DEY BPL NXTBYT JMP (LOC0) ; go boot As you can see, it is up to the disk controller firmware to return to SLOOP if it cannot boot and the Disk ][ PROM doesn't. My mods were to make the code look like: LDA #$C0 <== start at slot 1 STX LOC0 ; X known to be zero at this point STA LOC1 SLOOP LDY #7 INC LOC1 <== move up the slots LDA LOC1 CMP #$C8 <== stop at slot 7 BEQ FIXSEV ; no bootable disk controllers STA MSLOT NXTBYT LDA (LOC0),Y CMP DISKID-1,Y BNE SLOOP ; try next slot DEY DEY BPL NXTBYT JMP (LOC0) ; go boot You also have to fix the ROM checksum byte otherwise the self test fails. -- David Wilson School of IT & CS, Uni of Wollongong, Australia