Early days as a computer programmer

Here is an email chain between Ed Lazowska and I about the significant role that the UW’s computer systems played in the early years of Paul and I.

ED LAZOWSKA: Do you remember what computers you and Paul used on the UW campus in the 1970s? Also, there was a guy who built you a single-board computer. Do you remember who that was?

BILL GATES: There were quite a few computers at the UW that we used. Of course, we used the CDC 6400 and the Burroughs 5500 a lot by submitting punch cards. All the work I did was in Fortran – which was the first version of the Lakeside (High School) programming software and the program we used to print out Traf-O-Data traffic volume analyses. This was where we did our first work using UW computers.

There was a WANG calculator in the engineering building. In the same room there was a teletype. The UW had an unlimited account for logging into CCC PDP-10s (serial numbers 10 and 36) which we got access to. At first we just used the WANG device but that became boring after awhile.

There was a PDP-10 in the Physics Building which was by the fountain – now that building is Mary Gates Hall. That PDP-10 was almost entirely dedicated to scanning bubble chamber photos from particle accelerators, including the one at Stanford. Paul found out that it would complete its work after about 18 hours, so there were some free hours early in the morning. A friend had a key to the Physics Building so we went up there a lot of times.

There was also a PDP-10 in the Medical Center that we used sometimes. This was the Locke Computer Center. There were several PDP-11s in the medical area we got to use. For a few months I used a PDP-8 that we found in the medical area and played around with a lot of DECUS programs and wrote most of a BASIC interpreter.

There was another set of machines in the UW Computer Science area in Sieg Hall. They had an ARDS and an Imlac, so we got early exposure to the mouse and graphics stuff. Paul also used the Sigma 5 that was there. I never programmed that machine.

In terms of hours, the biggest usage was the PDP-10s at CCC, but the exposure to all of the UW’s machines was very helpful in thinking about various ways of programming things. The people there helped us learn a lot by loaning us manuals and by looking the other way when we took OS listings out of the garbage.

The first single board computer we did was an 8008. Paul Gilbert was our third partner in Traf-O-Data and he knew how to build things, so he actually did the wire wrapping. Paul and I went to Almac/Stroum Electronics and bought the processor for $360. It took a long time to build the machine but it actually worked. The most expensive piece was the 16-channel tape reader we had someone build for us. This computer used 256 bit memory chips if I remember correctly. The wire wrapped thing looked scary.