[Coco] Large file deletion fails on NitrOS9/6309

[Jeff Teunissen]

Tormod,
6x09 RBF will never make any file that crosses a 2048-cluster boundary
(it actually can't), but Toolshed has no facility preventing it from
making files that RBF will explode on when trying to delete them. On a
360K disk there is no possibility of a problem, but on a 720K disk
there is a possibility that (at most) 1 file will cause RBF to bug out
in an unpleasant way if it is deleted. CoCoSDC-sized images
manipulated by Toolshed could have more files RBF might have issues
with, but most SDC images as far as I know are "shipped" mostly empty,
so most shouldn't have more than 1 or maybe 2 unsafe files on them.

I have verified that it is possible to repair a file that crosses one
of the boundaries by breaking up the offending segment into two or
more, using exactly the same space but telling RBF that the file is in
chunks that work with its expectations.

Toolshed should probably be changed to make 6809-compatible files,
though that's at the cost of not being able to make files that are
more than about 18 percent the maximum size of a disk, which may not
be great for 68K/OS9000 images, though those are probably more likely
to have multiple sectors per cluster, and thus be able to have
segments that have more bytes in them, and therefore the limitation
isn't as severe.

Maybe make it dependent on a file that doesn't actually fit in the
proscribed number of segments? e.g. a 30MB file on a 127.9MB disk
might have 47 segments of 512K each, and the 48th segment is just
whatever's left, and hope for the best. Of course, a disk with 4
256-byte sectors per cluster would be limited to 96MB files before
potentially crashing the machine or causing data loss or leaking free
space.

On Sat, May 30, 2020 at 6:52 PM Tormod Volden <lists.tormod at gmail.com> wrote:
>
> On Fri, May 29, 2020 at 2:07 AM Robert Gault:
> >
> > Well I'd guess that the nightly NitrOS-9 builds are created with Toolshed which might then be a problem.
>
> I don't understand this statement. Do you mean any of the nightly
> NitrOS-9 build disks have files larger than 24MB? Actually none of the
> disk images themselves are that big.
>
> Tormod
>
> --
> Coco mailing list
> Coco at maltedmedia.com
> https://pairlist5.pair.net/mailman/listinfo/coco