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Sunday, September 24, 2006

Successful power-on

We were able to power on about 3/4 of the systems we tried, although we didn't have much luck with the ECD 7x system. It booted to a point, but the Pertec floppy disk subsystem wouldn't seek to the right part of the disk.

No matter, the cassette systems loaded just fine, and people had a grand time playing spacewar.

Friday, August 11, 2006

An MMU? Cool

[Notes from another ECD hacker]

> ECD Micromind ... based on the 6502 processor, but
> had minicomputer features including:
> a 64M address space [the stock 6502 could only address 64k],
Only 64k virtual at a time. There was an MMU to remap it onto a
larger physical memory, but few, if any Microminds ever had more than
64k including video memory.

> a supervisor mode, and (possibly)

Don't think so.

> additional opcodes  (which the CPU board kept away from the 6502
> processor).

It had an illegal opcode ROM table that triggered a non-maskable
interrupt upon fetch of an illegal opcode. The 6502 was notorious for
doing unreasonably strange things when fed nonsense code...

Tuesday, July 11, 2006

John Holland - early ECD Micromind user

This is a link to a book mentioning
John Holland as an early Micromind user - John Holland did early work on Genetic Algorithms with his system, which is mentioned on page 190

Complexity: The Emerging Science at the Edge of Order and Chaos

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