Chuck Fillerup and the IBM 650

One of the items in a recent donation to the Computer History Museum was an IBM 650 computer. IBM announced this machine in 1953, and it used a magnetic drum for memory instead of core.

My first job when I graduated from UCLA in 1965 was at IBM Service Bureau Corporation. My mentor there was Dr. Chuck Fillerup. Chuck taught me a lot about programming while we worked together on several projects.

Chuck told me many stories about how challenging it had been for him a few years earlier to program the IBM 650, since memory was actually a rotating drum. The way a program transferred control from one piece of code to another could have a big impact on performance, especially if it caused the program to have to wait too much for drum rotations. I thought of Chuck when I set my eyes on the 650 sitting in the Computer History Museum warehouse.

IBM 650 computer in the Computer History Museum collection
IBM 650 computer in the Computer History Museum collection

IBM 7094, an ancient mainframe

In 2014, the Computer History Museum got a large donation from Paul Pierce. The donated collection included an IBM 650, IBM 709, and an IBM 7094.

When I first graduated from UCLA, the first machine I was paid to write software for was the IBM 7094. At the time the language being used to program it was Fortran II, since the 7094 was a “scientific” machine. IBM began selling it in 1962 and it used transistors instead of vacuum tubes. When it was new, such a machine cost about $3,000,000.

The image above is part of a donated IBM 7094 sitting in the Computer History Museum warehouse where Anna and I volunteer to help catalog and curate artifacts.

IBM 1401, an old friend

After we got trained on how to use a pallet jack (in the Computer History Museum warehouse), we could begin cataloging some of the “big stuff” in the collection.

Dick operating a pallet jack at the Computer History Museum warehouse
Dick operating a pallet jack at the Computer History Museum warehouse

I was happy that one of the first big objects we worked on was an IBM 1401 CPU. This was the first machine I worked on when I went through my new employee training at Service Bureau Corporation in 1965. When we weighed and measured it, we found that it tipped the scales at over 2000 pounds! It was so heavy we could just barely move it around with a pallet jack. And this was only part of a complete 1401 system.

According to an IBM website, this machine originally was rented for $2500+ per month, and there were once over 10,000 of them in service. IBM stopped selling the 1401 in 1971.

At Service Bureau we used our 1401 mostly to do card-to-tape operations so we could process the tape on a 7094, and to print data the 7094 wrote on tape when our batch job produced output. Our 1401 had 8K of memory. I did learn to program the 1401 in Autocoder (the 1401 Assembler), but I only wrote a few programs for it.

The Computer History Museum has restored another 1401 to a running state. It took several years to get it working.