History

The original system with the architecture was designed and built at Computer Development Inc. between 1968 and 1970 by Richard Pasternak. Pasternak had previously designed several other minicomputers including the Varian 520I and Micro Systems model 800/810. This appears to have been part of a contract with Eldorado Electrodata Inc. Deliveries began in August 1970. Shortly after the release of the CD-200 system Pasternak became a vice president of Eldorado Electrodata and the machine from that point onwards only appears to have been marketed and produced by Eldorado. Leigh Brite, the director of engineering at Eldorado also describes himself as having been involved in the design.

The original processor was three boards that attached to a backplane bus with all the slots identical (unusual for the period). The bus is asynchronous to allow for different memory types and has a single address space for memory and I/O devices.

Unlike many vendors Eldorado actively marketed and sold hardware and boards to OEM vendors rather than only selling or leasing complete bundled systems as most minicomputer businesses did.

On Dec 2nd 1975, somewhere after Eldorado's fall from grace after serious problems with their calculator line, the minicomputer division was sold to Anderson Jacobson, a business that started in acoustic couplers and modems and had extended to many other peripherals some of which seem to be the same as Eldorado and Warrex sold. From somewhat earlier in 1975 Anderson advertised a turnkey accounting minicomputer that looks remarkably similar to the EE/Warrex machines.

Anderson Jacobson in turn sold the minicomputer rights to IPC and then on to Computer Development Inc. Whether that was the rights returning to Richard Pasternak is unknown.

However, prior to that, Warrex and two other companies had signed agreements with Eldorado such that if Eldorado went bankrupt they would receive the rights to produce and sell the EE200 technology. The Centurion CPU4 was based on the EE200 and that ISA continued on into the CPU5 and CPU6.

Known Cards

This is a list of currently all known cards, though we only have detailed information on a portion of these.The part number of the card indicates the chronological design. For example, card 01001 is the DSK/AUT card and was the very first card that Centurion designed. Card 01133 is the CMD card and was the 133rd unique Centurion designed card. Every PCB designed got a part number, including the PCBs for the front panel or any equipment that wasn't in the card cage.

Known Part Numbers

PN	Card	Notes
01001	DSK/AUT	Disk controller for CDC Hawk Drive
01002	DSK II	Disk controller for CDC Hawk Drive
01003	MEM	32K DRAM memory card
01004	MUX	Four-port RS-232 only MUX card
01006	PRT	Parallel printer controller card for ODEC Line Printer
01022	CPU5	TTL half of CPU5 processor card
01024	CPU5	AM2901 half of CPU5 processor card
01026	MUX	Four-port RS-232/current loop MUX card
01032	Backplane	14-slot backplane used in standard cabinet systems
01033	Front Panel	LED panel for CPU5/CPU6 that shows address, lvl, etc.
01037	CPU5	Daughter board with AMD SRAM chips to replace discontinued TI SRAM
01038	CPU5	Daughter board that contains jumper configurations
01039	Front Panel	Button panel for CPU5/CPU6 that has R/F, OPSYS, and SELECT
01062	MEM	128K DRAM memory card
01070	Backplane	7-slot backplane used in desk based systems
01081	DIAG	Low production diagnostic board for technicians
01103	Backplane	4-slot backplane used in Micro Plus systems
01119	CPU6	Multiwire AM2901 based CPU6 processor card
01123	FFC	TTL half of controller card for CDC Floppy/Finch drives
01127	FFC	AM2901 half of controller card for CDC Floppy/Finch drives
01133	CMD	Multiwire AM2901 based controller for CDC CMD drives (Phoenix, Lark, etc.)

Unknown Part Numbers

PN	Card	Notes
01---	CPU4	First card of the CPU4 processor
01---	CPU4	Second card of the CPU4 processor
01---	CPU4	Third card of the CPU4 processor
01---	CPU4	Fourth card of the CPU4 processor - DMA card
01---	CPU6	First card of two-card based version of CPU6 similar to CPU5
01---	CPU6	First card of two card based version of CPU6 similar to CPU5
01---	CMD	First card of AM2901 based, firecode checksum CMD controller
01---	CMD	Second card of AM2901 based, firecode checksum CMD controller
01---	CMD	Third card of AM2901 based, firecode checksum CMD controller
01---	CMD	First sub-card of firecode checksum CMD controller in separate box
01---	CMD	Second sub-card of firecode checksum CMD controller in separate box
01---	CMD	Third sub-card of firecode checksum CMD controller in separate box
01---	CMD	Fourth sub-card of firecode checksum CMD controller in separate box
01---	CMD	First card of AM2901 based, new CMD controller (similar to multiwire model)
01---	CMD	Second card of AM2901 based, new CMD controller (similar to multiwire model)
01---	FC?	AM2901 half of four-floppy disk controller card
01---	FC?	TTL half of four-floppy disk controller card
01---	FTC?	AM2901 half of streaming tape and finch drive controller card
01---	FTC?	TTL half of streaming tape and finch drive controller card
01---	TAP?	Paper tape reader interface card for Litton data tapes (internal use only)
01---	MUX	Eight-port RS-232 MUX card (not programmable)
01---	MUX	AM2901 smart MUX (never made it to production)
01---	MEM	4K Core memory card (CPU4 only)
01---	MEM	16K DRAM memory card (Fedder supplied)
01---	MEM	16K DRAM memory card (Centurion produced)
01---	MEM	64K DRAM memory card