== The Weekend Hack ==

'''Alan Kotok''' writes;

When the PDP-1 first arrived at the Lab, it came with a REALLY BAD assembler, called FRAP (Fredkin's Assembly Program). As I recall, it clattered it's way down the paper tape input in one direction, and then completed the assembly by running the tape backward thru the reader. The TX-0 (alias TMRC) hackers were already spoiled by MIDAS and knew what a "good" assembler was. So we kept after Jack Dennis to authorize a project to write a good PDP-1 assembler. He was never enthusiastic about this. So we finally made him a deal: We would produce a MIDAS-like assembler for the PDP-1 "over the weekend", which would work well enough to assemble itself on the PDP-1. If we succeeded, we'd get paid for our time (which, as I recall, was $1.75/hr). If not, we worked for free.

He took the deal. On Friday night we parcelled out among half a dozen or so of us all the subroutines in [MACRO]. Each person was to transliterate the code, function for function, to PDP-1 code. No innovation allowed. Subroutine calling conventions were agreed. Some new I/O routines had to be written. Work proceeded around the clock. All the assembly was done on the TX-0. As I recall, even though the PDP-1 used a different text encoding, 8 track paper tape, and different Flexowriters, we stuck with the TX-0 code and 7 track tape. The photo reader had adjustable guides to allow the narrower tape to work.

On Monday morning, Dennis arrived and we demonstrated the new assembler working.

We won!

== The Chess Hack ==

'''Alan Kotok''' writes;

In 1959 I and a small group of undergraduates working under Prof. John McCarthy began working on a real chess program for the IBM 704. This work eventually turned into my bachelors thesis, but that is another story.

Anyway, since I had some credibility around the laboratory on chess programs, we decided to put together a "hack" reminiscent of the "chess machines" of 18th century fame. At the time (must have been around 1962), we had the TX-0 and PDP-1 in adjacent rooms at RLE. We strung a couple of coax cables between them and set up an early "network". (Hmm. As I think of it, computer networks were NOT common then. Did we invent that, too?)

We programmed both computers to buffer a line of text from the keyboard of the other machine and to print the line on its own typewriter-terminal. In the TX-0 room we stationed a few good chess players. I sat in the PDP-1 room waiting for a sucker to wander by. Eventually one did, and I enthusiastically told the person that we had received a new, expert chess program from another PDP-1 site. I invited this person to play. (I forget who was the first sucker.) Anyway, we would type in the moves, and, sure enough, after a while responses would come back. We had this person really convinced until an illegal move came back and a not-very-computer-like argument ensued over the terminals.