Update DUMPER tool for Mini-Dumper format

[larsbrinkhoff]

The TENEX Mini-Dumper uses an older version, called 0, of the TOPS-20 DUMPER format.

[larsbrinkhoff]

The tape format is documented here:
https://github.com/PDP-10/tenex/wiki/DUMPER-tape-format

[larsbrinkhoff]

This has been verified with MINI-DUMPER to list the files on a tape, but there is a problem writing files.

MINI-DUMPER  13 APRIL 71

DUMP, LOAD, CHECK, OR SINGLE? L
SPECIFIC USERS? N
INTO SAME DIRECTORY(S)? N
TYPE MAG TAPE UNIT NUMBER: 0^_^_Saveset name

CANNOT GET JFN FOR FILE PS:<CUSPS>FOO.TXT;1;P777777;AOPERATOR
CANNOT GET JFN FOR FILE PS:<CUSPS>BAR.TXT;1;P777777;AOPERATOR
MOUNT NEXT TAPE IF ANY, TYPE C WHEN READY. TYPE N IF NO MORE: N^_
DONE.

@rcornwell, @rmaldersoniii, any idea why it's outputting ^_ characters?

[larsbrinkhoff]

^_ is a line break. The TENEX monitor says this:

EOL=37                  ;END OF LINE CHARACTER

and it's mostly handled in TTYSRV.

Was this dropped from TOPS-20? The output above is from running in V3A.

[larsbrinkhoff]

Also checked that DUMPER versions 3A(415) and 6(563) can read tapes made with "format 4" herein.