On Friday 18 December 2009, jdow wrote:
>From: "Gene Heskett" <gene.hesk...@verizon.net>
>Sent: Friday, 2009/December/18 09:25
>
>> On Friday 18 December 2009, Per Jessen wrote:
>>>hc...@mail.ewind.com wrote:
>>>> re: CP/M
>>>>
>>>> No S-100 bus systems mentioned yet?
>>>>
>>>> My first home computer was a Godbout S-100 bus system running a dual
>>>> 8085/8088 CPU board. At that time, the future in operating systems was
>>>> going to be CP/M 86.
>>>
>>>I'm surprised nobody has mentioned the ZX80/1 yet. I've also got a
>>>Newbrain stashed away somewhere, manuals, circuit diagrams an' all.
>>
>> That's because the z-80 was only slightly less dain bramaged than the
>> 6502.
>>
>>>/Per Jessen, Zürich
>
>Actually the 6502 was a handy little chip once prices dropped. On one
>project we replaced a host of other chips with 6502s. They, plus a few
>extra components, make nice glass TTYs. You can also use one as a very
>flexible timer. It seems the guys in charge of the project went a
>little overboard on the 6502s. But it did work, was reliable, and did
>the job. For a 2-off design that's all you need.
True, for one or two-offs maybe. But it was short one very valuable
addressing mode, and needed about 2 more , maybe 3, more 16 bit wide pointer
registers before it could be said to compete with a 6809. Then when the
Hitachi 6309's secrets were discovered, those of us with 6809 code in our
dreams were ecstatic. Moto was too proud of the 6809, so it didn't get the
design wins it should have.
>You'll also find that the Z-80 design powers amazing amounts of gadgets
>in theaters and theme parks. (Several Z-80s were "on set" and in use for
>the animations in, for example, Team America, Harry Potter (I knew the
>Mandrake root's lines from LONG before it hit theaters. <sigh>), Total
>Recall, Chucky, and many others. (Gilderfluke makes some nice gadgets
>based on modern Z-80ish CPUs.)
I take that newer shrinks of the z-80 have fixed the "ignore the $EB command"
(switch foreground/background registers) the earlier ones ignored about 10 to
20% of the time? Zilog told me to go pound sand when I called complaining
about that bug in both of the chips I had at the time, Early 1982 IIRC. I
never touched the chip again, but the one in a timex 1000 I bought the kids
later either didn't suffer, or somehow managed to program around it.
>{^_-}
>
--
Cheers, Gene
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