Computing at ESO through the ages

In this historical image, taken in 1974 in the ESO offices in Santiago, Chile, we can see the Austrian astronomer Rudi Albrecht, pencil in hand, poring over code in front of a teletype. He was working on software for the Spectrum Scanner attached to the ESO 1-metre telescope located at the La Silla Observatory. The data were processed in Santiago using the Hewlett Packard 2100 minicomputer which can be seen behind the printer (with two 7970 tape drives, a 7900 hard disk and a 2748 paper tape reader). This bulky computer, with one processor and a breathtaking 16 kilobytes of magnetic-core memory (!), stored the results on magnetic tape, ready for further processing by visiting astronomers on computers at their home institutes. To handle files on tape that were larger than the available memory, Albrecht developed a virtual memory system, which he contributed to the Hewlett Packard Software Center.