You are looking at PD6:<UNIX-C>000-TAPES-FROM-DECUS.TXT, last updated 30-May-89:

From: Ted Nieland - SRL <TNIELAND%[email protected]>
Re:   Tapes available from DECUS

The MSDOS, ADA, and UNIX-C collections have been submitted to the
DECUS Library.  They have been assigned part numbers as listed
below.

The MS-DOS collection was broken into two pieces (it would not fit
on a single TK50 tape).

Here are the part numbers:

SIMTEL20 Unix-C Collection VMS BACKUP Format............V-SP-88
SIMTEL20 Unix-C Collection TAR Format...................U-SP-105

SIMTEL20 MSDOS Collection Part 1 VMS BACKUP Format......V-SP-89
SIMTEL20 MSDOS Collection Part 2 VMS BACKUP Format......V-SP-90

SIMTEL20 ADA Collection VMS BACKUP Format...............V-SP-91

I will be attempting to update these collections in the DECUS
Library every six months or so.  I will be FTPing all files that
changed and removing the superseded files to get a current copy of
the archive, without having to get the entire archive again.

The address and phone number for the DECUS Library is:

The DECUS Program Library
219 Boston Post Road  BP02
Marlboro, MA  01752-1850

Phone: (508) 480-3418