🚀 go-pugleaf

I am developing an application that must run unattended and will
write certain important (valuable) data to both the hard disk and
a diskette.  As added protection, I am looking for a way to mark
new bad clusters on the fly, so that they do not become part of
the files being written.

I was hopeful that DOS would do this automatically when the disk
write verify flag is enabled (Int 21h, Function 2Eh).  However,
my tests seem to indicate that DOS only reports a write verify
error, but it does nothing about the bad cluster itself, such as
flagging it in the FAT and trying the next available cluster.

Can anyone tell me if there are DOS services to (a) identify the
cluster that caused the write verify error and (b) flag the
cluster in the FAT before retrying the operation?  Or will this
be a lot harder than simply invoking some internal DOS services?

Any relevant information or tips would be appreciated.  Thank
you.

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