Complementary to our collection of original hardware and software systems there are a few hardware projects where we develop own equipment for purpose of facilitating our historic machine operations.

CDC 7155/885 Disk Subsystem Emulator
Presentation (PDF, 1091kB)

While we own and operate several CDC 7155 disk controllers and CDC 885 14″ disk drives we have found it expedient to create an emulation of this disk subsystem by use of modern technology. Reason is reliability under our very strange operating conditions: Since we operate only on Saturdays and do not spend too much money for air conditioning we have a 20 degree C temperature cycle per week. This has proven devastating for the CDC 885 drives. They work very well under constant temperature conditions, but not under these very special circumstances as we have found out. For reliable operation of our CDC mainframe computers we therefore built the disk emulator, based upon modern IDE disks for storage and modern DSP technology for the controller.

Presentation (PDF, 868kB)
Paper (PDF, 926kB)
MUNIAC is a 12-bit parallel computer in vacuum-tube technology, design started in 1998. Since we could not obtain any original vacuum-tube machine we designed and built this one. A new design based upon parts and technology as available in 1959 has significant advantages:
* complete documentation available
* sufficient spare parts available
* all undocumented know-how available

An introduction to computer design with vacuum tubes is found here (PDF, 1090kB)
There exist also various books on the topic which we carry in our library:
R.K.Richards, Digital Computer Components and Circuits, van Nostrand, Princeton, 1957
H.J.Reich, Theory and Applications of Electron Tubes, McGraw-Hill, New York 1944
J.F.Rider, Inside the Vacuum Tube, J.F.Rider Publisher Inc., New York, 1945
R.K.Richards, Arithmetic Operations in Digital Computers, van Nostrand, Princeton, 1955
ERA, High-Speed Computing Devices, 1950, Charles Babbage Institute Reprint Series for the History of Computing Vol. 4, Tomash Publishers, Los Angeles 1983
M.Campbell-Kelly, M.R.Williams, Eds., The Moore School Lectures, 1948, Charles Babbage Institute Reprint series for the History of Computing Vol. 9, MIT Press, Cambridge, and Tomash Publishers, Los Angeles, 1985
G.Haas, Grundlagen und Bauelemente elektronischer Ziffern-Rechenmaschinen, Philips technische Bibliothek, Eindhoven 1961
K.Steimel, Elektronische Speisegeraete, Franzis Verlag, Muenchen, 1957
Essential Characteristics, General Electric, without date, and other Vacuum Tube reference data books