Re: New CBM-II discoveries

From: Michał Pleban <lists_at_michau.name>
Date: Sat, 07 Jul 2018 23:37:41 +0200
Message-ID: <5B4132A5.20207@michau.name>
smf wrote:

> You gave up the fun of creating a 6523, made it harder to write new
> software, it's an extra intel chip in a commodore machine and you've set
> a precedent:
> "Can you not replace these with the D8255 chip like was done on the 8088
> card?"

The card already has a 8088, 8087, 8259A, 8288A and 8284B. That seems
quite a lot of Intel chips already. It's an Intel processor card, after
all. And the 6523 was sitting on the 8088 side, which required a good
number of kludges to make it work - the 8255 fits with the 8088
perfectly, as it should.

I am not sure why you are so intent on writing software for the 6523.
There is NO NEED to write software for it. The code that accesses it is
already on the card, and provides an API interface which allows anything
that runs on the card to access IPC mechanisms without the need to know
how the sausage is made.

In my opinion, it is much better to create re-usable APIs which allow
software to run unmodified on a range of different hardware (which then
can be modified and upgraded as needed), than lock users into a narrowly
designed hardware design forever. And that's what the original card's
creators did - the card's BIOS provides an appropriate API. They already
anticipated that the software running on the card should not concern
itself with banging bytes back and forth between processors.

If someone chooses to hack the hardware directly, without accessing the
appropriate APIs, that _always_ creates problems with any future
hardware. A fastloader for a 1541 will not work on a 1581. Playing dirty
tricks with the OCS chipset will cause the software to not work on ECS
or AGA chips [or so I heard; I am not an expert on Amigas, but you get
the idea]. That's what APIs an libraries are for, and they are meant to
be used. The card has an API, and if you write software for it, use it
instead of reinventing the wheel.

As for the precedent, I alreay pointed out how the situation with the
graphic card differs radically from the 8088 card.

> What were the downsides to recreating a 6523?

Lack of time and skills needed to do that?

Regards,
Michau.
Received on 2018-07-08 00:00:06

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