Throwback 50+ years

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In my lab, before a Digital Equipment Corporation (DEC) PDP8-i with 8k of 12 bit memory, a Teletype, and an AXO8 interface box with 8 channels of a/d conversion (12 bit), 2 channels d/a conversion (10 bit) and 12 (?) digital i/o lines was purchased for $12,800, there were digital logic elements and a MAC panel with plug-in panel connections. The inputs and outputs of the digital logic elements (AND gates, OR gates, Inverters (NOT element), One Shots, Multivibrators, etc.) were wired to the back of the MAC panel. Wires were used to connect the inputs and outputs of the logical elements to form circuits that performed particular functions such as generating an event code that was recorded on one channel of an 8 channel analog tape recorder. The action potentials recorded from a single neuron were preserved on another channel, and other pertinent physiological data on the remaining channels. The wires were the "program" and a different program could be run by removing the panel with the wires and replacing it with another panel with a different set of wires that connected the inputs and outputs of the logical elements in a different manner.

The digital logic components are in the left relay rack. The MAC panel with wires are to the right, under the oscilloscope, and the 8 channel analog tape recorder is to the right of the MAC panel.

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David Sparks

I retired in 2005 after 40 years of research and teaching at the University of Alabama in Birmingham (24 years), the University of Pennsylvania (8 years) and the Baylor College of Medicine (8 years). Photography is my retirement hobby.

Nature photography, especially bird photography, combines a number of things that I really enjoy: bird-watching, being outdoors, photography, travel, messing about with computers, and learning new skills and concepts.  I now spend much of my time engaged in these activities.

David Sibley in the preface to The Sibley Guide to Birds wrote "Birds are beautiful, in spectacular as well as subtle ways; their colors, shapes, actions, and sounds are among the most aesthetically pleasing in nature."  My goal is to acquire images that capture the beauty and uniqueness of selected species as well as images that highlight the engaging behaviors the birds exhibit.