System transfer utility

[eduardocasino]

I'm opening this pull request for review and discussion of a system transfer utility that I've written which copies the reserved sectors and the system files from one disk to another, making it bootable. The destination disk must be formatted. the syntax is:

sys [<src drive>] <dst drive>

Example:

A> sys b:
Transferring boot sectors:
rrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwww
Copying system files:
A:BDOS.SYS
rrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwww
A:CCP.SYS
rrrrrrrrrrrrrrrrwwwwwwwwwwwwwwww
Done.
A>

It also works with a single drive, asking for floppy swaps.

It checks for the existance of reserved sectors in both source and destination disks and does not attempt a transfer unless there is enough room in the destination, so it should be safe even if the platform does not support it. That means that it could be added to the MINIMAL_APPS group or just include it into the images of the platforms that make sense, like Apple ][ or KIM-1 with K-1013.

WARNING: Until the cpm_bios_seldisk() bug is resolved in llvm-mos, using this utility on an invalid drive can yield unexpected results.

[davidgiven]

I think this is definitely worth having. The biggest question is whether it should be combined with mkfs or format --- I think not, as they all do slightly different jobs, and it makes modularisation easier.

One note: if the number of reserved sectors differs between disks, it's a good bet that the BIOS won't work on the new disk, as it'll be looking in the wrong place for the filesystem. Would it make sense to check for equality rather than just checking for enough space?

[eduardocasino]

I think this is definitely worth having. The biggest question is whether it should be combined with mkfs or format --- I think not, as they all do slightly different jobs, and it makes modularisation easier.

Agreed, better to keep them apart.

One note: if the number of reserved sectors differs between disks, it's a good bet that the BIOS won't work on the new disk, as it'll be looking in the wrong place for the filesystem. Would it make sense to check for equality rather than just checking for enough space?

Absolutely, I didn't think of that. Changing it.

[davidgiven]

Merged --- cheers.

[eduardocasino]

Thanks. What it is pending is where to add the utility. MINIMAL_APPS? Per image?

Cheers.

[davidgiven]

BIG_APPS, I think, as it's no use without mkfs, which is there because it's a C program.