How security holes happen

Mark H. Harris harrismh777 at
Thu Mar 6 03:07:10 CET 2014

On Wednesday, March 5, 2014 7:40:05 PM UTC-6, MRAB wrote:
> The 6502 came from MOS Technology. Motorola made the 6800.

    Well, not exactly. The MOS 6502 is to the Motorola 6800 what the Zilog
Z80 was to the Intel 8080.  
    The same engineers who designed the 6800 moved out and then designed
the 6502; actually ended up in a law suit of sorts--- but I don't remember the
details. Anyway, the 6502 was bought outright by Commodore, and the rest
is history with the VIC20.
    The engineers at Intel did the same thing... moved out and started Zilog
(which still exists today) and began their work on the Z80.  By the by, the Z80
is still embedded in many applications today. Although, its not on a 40 pin dip
any longer; its a small square about the size of a postage stamp. That is what 
powers the TI 84+ and the TI 83+ graphing programable calculators. I do some
machine coding on the TI 84+ because it can be done on-the-device!
    The 68000 is the motorola chip that powers the TI89 graphing programable
calculator ( my favorite ).  Its not so easy to program it with machine code, because
the kernel binaries are not well documented (TI hides them) and the user community
hasn't probed it enough to know how does it really work.

> 5K? Luxury! I started with the Science of Cambridge Mk14. Including the
> RAM on the I/O chip, it had 640 bytes.

    Oh, I know. I thought 5k was a tremendous about of memory at the time, but we
soon built and expanded for the slot, added 16k of memory (hand wire-wrapped thank
you) and then plugged the VicMon (actually HES MON) into that.
    Do you remember the IAS (Maniac) at the Institute for Advanced Study (Johnny von Neumann's
baby) ?   It only had 5k of memory too!  They had to use punched cards or punched tape 
for intermediate results when they were doing their runs calculating the wave function for
the hydrogen bomb.   At the time, Johnny said, " there will never be a need for for than
five machines like this in the whole world!"


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