transferring large files from Unix to DOS on diskettes, How?

[Leslie Mikesell]

In article <1991Jun19.153929.12438 at infonode.ingr.com> richard at xanth.b11.ingr.com writes:
>The mtools utilities work fine as long as the file fits on a single diskette.
>I understand DOS copy has the same limitation, but we have customers that
>create multi-megabyte files then want to transfer by diskette to a DOS
>machine. Is there any public domain utilities that can handle this? 
>Maybe a DOS version of cpio perhaps. 

A long time ago I tried to convince Emmet Gray (the author of mtools) that
he should add a variation to mread/mwrite that would work with pipes
and multiple disks, prompting as necessary, but perhaps he didn't see
the need for it.  There is in fact one or more variations of cpio for
DOS that will read/write the raw disks like the unix versions (PAX is
one, but I don't have the latest version).  However, this doesn't really
give quite the same effect unless you actually want to use the files
under DOS.  With discrete files written in DOS format you can (a) use
the DOS DIR command on all your disks, and (b) use a communications program
to transfer them to a unix machine that might not have compatible disk
drives - the ultimate in portability.  If you don't mind the requirement
that the destination disks be empty and flawless (so you know the size
ahead of time) it should be trivial to write a program that collects
a diskfull in a tmp file and then calls mwrite, repeating as necessary.
I'll probably do that the next time I work with something that zoo
or cpio |compress can't squeeze down to a 1.4M floppy.  I did a silly
script once that takes a list of filenames (generally from find) on
stdin and builds a set of zoo files that don't exceed a certain size.
It's silly because it copies the working file before adding each file,
then when the size is exceeded it goes back to the previous copy and
starts a new one.  Obviously this won't handle a single huge file but
it's nice for archiving source that may or may not ever be extracted
under DOS.

Les Mikesell
  les at chinet.chi.il.us