PDP-10 - Usage By CompuServe

Usage By CompuServe

One of the largest collections of DECsystem-10 architecture systems ever assembled was at CompuServe, which at its peak operated over 200 loosely-coupled systems in three data centers in Columbus, Ohio. CompuServe used these systems as 'hosts', providing access to commercial applications as well as the CompuServe Information Service. While the first such systems were purchased from DEC, when DEC abandoned the PDP-10 architecture in favor of the VAX, CompuServe and other PDP-10 customers began purchasing plug compatible computers from Systems Concepts. As of January 2007, CompuServe continues to operate a small number of PDP-10 architecture machines to perform some billing and routing functions.

The main power supplies used in the KL-series machines were so inefficient that CompuServe engineers designed a replacement power supply that consumed about half the energy. CompuServe offered to license the design for its KL power supply to DEC for free if DEC would promise that any new KL purchased by CompuServe would have the more efficient power supply installed. DEC declined the offer.

Another modification made to the PDP-10 by CompuServe engineers was the replacement of the hundreds of incandescent indicator lamps on the KI10 processor cabinet with LED lamp modules. The cost of the conversion was easily offset by the cost savings in electric consumption, the reduction of heat, and the manpower required to replaced burned-out lamps. Digital followed this step all over the world. The picture on the right hand side shows the light panel of the MF10 memory which is contemporaneous with the KI10 CPU. This item is part of a computer museum, and was populated with LEDs in 2008 for demonstration purposes only. There were no similar banks of indicator lamps on KL and KS processors.