HELP VEDVERSIONS                   updated Mark Rubinstein  October 1985

    vedversions - User assignable: integer or FALSE (default)

This global variable controls the number of backup versions saved on
disk when a VED file is written.

The mechanisms are different on VMS and on UNIX, since VMS maintains
backup versions with different version numbers.

VMS
---

When the current file is written, then a new copy is made with a new
version number, one higher than the last one. If VEDVERSIONS is an
integer, then PURGE will be called, with

    KEEP=VEDVERSIONS

So that number of backup versions of the file will remain.   Using
VEDVERSION means that POPLOG has to call a DCL command, this can be slow
and you are advised to use *POP_FILE_VERSIONS instead.

UNIX
----

UNIX does not normally maintain backup copies of files and has no notion
of version numbers.  POPLOG however provides backup copies by attaching
minus signs ('-') to the file specification (shortening the name first
if necessary to keep the file name within the length limit).   For
example if you have a file called 'foo.p' which has two backup copies
then the most recent backup copy is called 'foo.p-' and the version
before that 'foo.p--'.  The number of versions of a file that POPLOG
maintains is controlled by the variable *POP_FILE_VERSIONS.

If VEDVERSIONS is an integer, then when VED does a write, it will
locally set the value of POP_FILE_VERSIONS to be the same as
VEDVERSIONS.  In this way the number of backup copies kept by VED will
be the same on a VMS machine and a UNIX machine if VEDVERSIONS is an
integer.

See also
    HELP * POP_FILE_VERSIONS
