The CDC 6600 Architecture

The CDC6600 and its family members are part of the computer industry history. A decade before the Cray 1, the members of the CDC6000 family were not only expensive and the most powerful systems at the time of introduction. They were also lean and wonderful architectures ! The elegance was also conveyed in several publications (many by CDC), where all the necessary knowledge was explained from the ground up. All you needed to know was supplied, clearly laid out, not just hints for efficient programming. Basicly, you could rebuild your own computer by reading these books. 50 years later, they are invaluable reminders and tools, we can see where the computer industry comes from and realise that it is not that hard to do it ourselves, too. Thanks everybody for the great work !


These PDF files are mostly mirored from See also Scott's page at Thank you !
yg - 2012/01/13

Other links :

  • (pretty pictures !)

    From the last link :
    "In 1970, J. E. Thornton wrote a book called Design of a Computer: The Control Data 6600, which has been the standard reference on the CDC ever since. Long out of print, Mr. Thornton gave Tom Uban permission to scan the book and make it available on the net."

    I have mirored this amazing book here too. Here is a quote from Seymour Cray's foreword :

    "[...] A book describing the characteristics of a modern large-scale digital computer is a challenging undertaking. There is more detail information to be presented than is possible in a single volume. An overview of the system without being specific is generally too vague to convey the important characteristics that are of real interest. The author in this book selects special areas for detail treatment where those areas are unique to the machine described. These are interconnected with a general description of the system as a whole.
    The reader can rest reassured that the material presented is accurate and from the best authority as Mr. Thornton was personally responsible for most of the detailed design of the Control Data model 6600 system."


    Found thanks to Jonathan Jacky: I just discovered "the elephant book" (1963) !
    "It was the first RISC -- the RISC philosophy was laid out chapter-and-verse by Thornton in the "Elephant Book" -- Jim Smith
    (Local copy, mirored from


    Other manuals for the CDC 6000 Series Computer

    (not all are listed here, check this open directory)

    Version 2014-02-28
    20160515: Elephant book