Re: Disassembly of the Z80 ROM of the C128

I had seen one story about the CPM developer Von Ertwine being a badass
hacker, funny that his wife was similarly inclined.

This happened on the night before the CES show presenting the Commodore
128, from Bil Herd's posting:

"The next day we meet up with the guy who developed CPM (Von) for the C128.
As I mentioned earlier, someone forgot to tell him about the silly little
ramifications of an 8563 bug. His 'puter didn't do it as he had stopped
upgrading 8563s on his development machine somewhere around Rev 4 and the
problem appeared somewhere around Rev 6. As Von didn't carry all the
machinery to do a CPM rebuild to fix the bug in software, it looked like CPM
might not be showable. One third of the booth's design and advertising was
based on showing CPM. In TRUE Animal fashion Von sat down with a disk editor
and found every occurrence of bad writes to the 8563 and hand patched them.
Bear in mind that CPM is stored with the bytes backwards in sectors that are
stored themselves in reverse order. Also bear in mind that he could neither
increase or decrease the number of instructions, he could only exchange
them for different ones. Did I mention hand calculating the new checksums
for the sectors? All this with a Disk Editor. I was impressed."
(http://c128.com/content/c128-story)

On Feb 27, 2017 3:46 AM, "smf" <smf@null.net> wrote:

> According to bill herds talks the z80 boot rom was hand assembled by the
> wife of the cpm developer, because they needed it urgently and he was out
> at the time.
>
>
> On 25/02/2017 15:00, David Wood wrote:
>
>> I thought the z80 source was in the wild, but I guess I'm mistaken.
>> Perhaps it's hiding on one of thte cp/m disks?
>>
>>
>
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>


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