6128: Disk management with AMSDOS ? Howto create / manage disks ?

[evrieze]

Have a 6128 without system disks. I noticed that CP/M can only be booted from drive A:

But how do I create / format / copy a system disk ? 

I managed to hook an external 3.5" FDD, and wire it so that it responds as drive A: and B:, and it can start CP/M from the 3.5" drive.

They only solution I found so far is make a special cable, connect the 3" CPC drive to a PC, and use CPCdiskXP to create a system disk.

But is there an easy way to copy the 3.5" system disk to a 3" floppy ?

[CraigsBar]

So your external drive us both a and b at the same time? How does the internal drive react or is it disconnected?

If you have an Abba switch and can boot from the external drive as A: then the internal drive is B: and you can use disckit to copy the system disk.

[evrieze]

After studying the article on the ABBA switch, and recoiled from the efforts required, I decided to try it a little different, and succeeded as follows:

1) I prepared a 3.5" system floppy disk (true DD or HD+taped off) CP/M system disk on a PC with internal FDD ( USB FDD not suitable ), formatted and copied the "cpmplue1.dsk" image onto it.

2) I disconnected (temporarily) the data plug from the CPC internal 3" drive.

3) An external 3.5" FDD and separate power supply was attached to the 6128 such as described here :
Guide on how to connect a 3.5" drive to a CPC6128/664 - CPCWiki

4) The jumper linking pin 11 to 12 was inserted so that the external drive is both A: and B:
In my case no other wiring was was needed. (RDY signal already at pin 1 (/34))

5) Switch on and start |CPM. Then set B: as the default drive.

6) Remove the jumper wire mentioned under 4)

7) Connect the data cable to the 3" CPC drive (while CP/M still runs). We now have the 3"drive on A: and external 3.5" on B:

8 ) Run DISCKIT3 from B: and Copy the B: disk to A: (this will automatically format A: as a system disk, and then copy).

Picture insert doesn't work, but try this one: Shared album - evrieze - Google Photos

[CraigsBar]

Abba is not that difficult. If I can do it.... Anyone can lol. And it is the most useful solution. As you can have the 3.5 inch as a or b, and the internal drive is always the opposite.