As we continue to work our way through our archive of photos, we run across some that are a bit out of the ordinary.  They may be humorous or unique but they stand out from the other photos. We will post new photos here monthly with the previous photos in the slideshow.

Our October Photo of the Month shows a Type 511A oscilloscope with a Remington-Rand UNIVAC (UNIVersal Automatic Computer) computer at the US Census Bureau in 1960. A UNIVAC I was delivered to the Bureau on March 31, 1951 to tabulate data from the 1950 Census. The UNIVAC I was the first successful civilian computer. The Bureau purchased a second UNIVAC I in the mid-1950s, and two UNIVAC 1105 computers for the 1960 Census.

Previously known for their firearms and typewriters, Remington-Rand was one of the leading computer manufacturers in the 1950s before IBM established dominance in the mainframe computer market later into the 1960s. Remington-Rand was acquired by the Sperry Corporation in 1955.

The 511A oscilloscope was likely used to calibrate the UNIVAC computer magnetic-core memory that was employed in through the mid-1970s. So-called core memory made use of ferroelectric rings that were incorporated into wired arrays, e.g. 32 x 32 cores, to form a 128 byte memory. The rings were magnetized in one orientation or the other based on the direction of the current used to write it. A separate “sense” wire was use to determine the state of the core. By using smaller cores and wires the cost was eventually decreased from about $1 per bit to about one cent per bit. Silicon-based memory replaced core memory because it was smaller, easier to use, eventually much cheaper, and obviously capable of reaching much higher densities.

It was common for computers to be sold with oscilloscopes in the 1950s and 1960s and this was especially true withTektronix instruments. This December 1958 TekTalk article describes how Type 531 and 535 oscilloscopes were shipped with every IBM 704 and 705 computer in the 1950s.

To add to the authenticity, a Type 545A oscilloscope even was used in a scene with Octavia Spencer in the 2016 movie Hidden Figures. That actual 545A used in the film has been donated to the museum and is on display.

Photo courtesy of the U.S. Census Bureau

Previous Photos of the Month