🚀 go-pugleaf

Hi - I'm just getting started in Assembly language programming on an
IBM 4381 using DOS/VSE (actually, an equivalent of DOS/VSE called MVT/VSE
from some third party company which isn't important).  I'm mentioning this
for background.  The problem I am having is I don't seem to be
able to define a large blocksize in a file using DTFMT (for tapes).  At
first I was thinking that this is a limitation of the assembler, but I would
tend to think that assembly wouldn't be very restrictive of such things.
My question is therefore, is there a maximum tape block size that I can
use, what is it, and is there something extra that I need to add to the
assembly to let the system know beforehand that I'm about to define a lot of
storage for buffer-IO area.  I've asked two company-internal people this
question and the answers I received were (1) People don't use Assembly with
tapes, so it was never set up that high anyway and (2) I think you have to
recompile your open and close macros.  (both of which seem a little on the
outer edge of reality).

All help and insight will be greatly appreciated.

...wilso_d@cs.odu.edu