This is part of the PDP-1 restoration effort at the Computer History Museum.
Additional information on the project can be found at pdp-1.org.

As part of the restoration project proposal, as much of the existing documentation
and software will be scanned/read. Most binary tapes are checksummed, and will be
verified before being put into a final archive along with scans of the printed
documentation.

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Software at the Museum has come from multiple sources. Much of the paper tape came
from the one-of-a-kind PDP-1 in room 26-248 at the Research Laboratory for Electronics 
(RLE) at MIT, run by Jack Dennis along with the Lincoln Labs TX-0.

This system was in use into the mid-70's in Jack's lab, and was modified to support 
timesharing, more than one physical console, drums, tape, and other peripherals 
including a multi-channel music system.

Documentation on the system consisted of a series of sequentially numbered "PDP-xx"
memos. 

An index of the memos can be found at http://www.bitsavers.org/pdf/mit/rle_pdp1/memos.