[Info-vax] Recovering messages from a MAIL.MAI file?

[gwilliams at cfa.harvard.edu]

I've been handed a zip file containing some MAIL*.MAI files
from a colleague.  They came from a VMS system that was
decommissioned some years back.  He has asked me to recover
the messages.  The externally-stored messages are easy, the
problem is the short messages stored within MAIL.MAI.

The zip file was not created with the -V flag ("save VMS
attributes"), so the unzipped MAIL.MAI does not have the correct
attributes.

By comparing to an active MAIL.MAI, I can use set file/attr
to set RFM:VAR. ORG:IDX, MRS:2048, RAT:NONE and BKS:5.  But I
see no way to set the prolog definition.

A working file:

MAIL.MAI;1                    File ID:  (668622,61,0)
...
File organization:  Indexed, Prolog: 3, Using 2 keys
                             In 3 areas

The unzipped file:

MAIL.MAI;1                    File ID:  (850295,86,0)
...
File organization:  Indexed

A search (using various keywords) of comp.os.vms didn't find
anything relevant.  Is it possible to modify as needed from the
command line?

Gareth