TOPS-20 Release 2

• DEC-20-OT20A-D-MC9.tap labelled "QT010-AP TOPS-20-V2-INSTALL TAPE D" is from
  http://bitsavers.org/bits/DEC/pdp10/magtape/dec_distribs/TOPS-20/DEC-20-OT20A-D-MC9.tap.gz
  Additional information says "1600 BPI, July 6, 1977":
  https://www.computerhistory.org/collections/catalog/102773680

• Tape file number 6 is a DUMPER saveset:
  Saveset '"2-SYSTEM"' Fri Apr 15 11:54:20 1977

• The saveset was extracted with read20, but it didn't handle the DUMPER format very well.

• Richard Cornwell's SIMH installation script for TOPS-20 V3A is included, but doesn't work. Possibly due to wrong MTBOOT version.