IBM and Tektronix
IBM used a lot of Tektronix oscilloscopes in the design, development, manufacturing, and servicing of their computers. This first image from 1953 shows a Type 514 oscilloscope used to test the waviness of their disk platters.
This December 1958 TekTalk article describes the use of Tektronix instruments by IBM and their shipments of Tektronix oscilloscopes with their computers. You can also click on the image to view a larger resolution PDF.
This photo shows either Type 535 or Type 545 oscilloscopes used in RAMAC platter inspection. RAMAC was the name of the IBM 305 computer system introduced in 1956 but commonly is used to refer to the IBM 350 disk storage unit.
This photo from the 1965 Annual Report features a Tektronix dual beam oscilloscope (which he isn't looking at).
Tektronix oscilloscopes have been essential to the development and maintenance of IBM computers. For a time, the Tektronix 310 was a standard IBM service tool, being small enough for IBM Customer Engineers (as their service people were called) to carry to individual customer's premises.
With the introduction of the IBM 360 series computers in 1965, IBM needed a portable oscilloscope with speed and capabilities to match the more complex architectures. This called for dual vertical inputs, vertical bandwidth of 50 Mhz, and fast dual sweeps. Tektronix responded to IBM's request with the Type 453.
At larger accounts, IBM would leave a Tektronix instrument permanently.At about 59 minutes in the 2016 movie Hidden Figures, the computer room scene features a Type 545B oscilloscope with a G plug-in on a 500 series Scope-Mobile.
At least 12 Tektronix oscilloscopes are identified on the manufacturing floor for the IBM 1401 computer. Most, but not all, of the oscilloscopes are Type 545A with a CA plug-in.