
Rethinking the Commodore 64 Memory Map (2018) - ljosa
http://www.c64os.com/post?p=57
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Darkphibre
Having architect elegant solutions, and watched much of the nuance of the
elegance languish in the ecosystem, I can't help but wonder: Did the original
creators have _exactly this_ in mind, and it's only just now being capitalized
upon?

~~~
ddingus
Perhaps, but it is more likely they provided many options, hoping it worked
out.

Sometimes it did not. We look back, and some machines were almost there, like
the Apple GS. Still great, but with just a bit more thought, could have been
amazing.

Many of the better effects on C64, and other computers, were actually
exploits. Bugs in the logic were found, then abused, then perfected.

Most of the better titles on the old 2600 (VCS), for example, exceeded
engineering specs. A bit of flexibility left in turned out to make all the
difference in the world.

Older machines used a combination of software and hardware. That combination
turns out to be quite potent over time as people continue to explore what may
be possible.

Some have coaxed better color, interlaced video, and more out of a C64,
despite that not being intended.

The memory map options were likely flexible, "just in case", and where that
was the thinking back then, it often became the max potential case.

~~~
Annatar
"Older machines used a combination of software and hardware. That combination
turns out to be quite potent over time as people continue to explore what may
be possible."

Makes me wonder what undiscovered things are possible with say, a SPARCStation
1+, or an Indigo2 R10000 when bit-banging the hardware directly.

~~~
ddingus
I have wondered that about SGI machines too.

One guy did explore the largely unused, shared memory graphics system that was
used on the O2 and NT workstations SGI made.

He made a very precise compositor. Was capable of many real time effects and
sub pixel accuracy. The thing could take huge images and do real time
transforms, effects at a couple hundred MHZ clock.

I ran it once, in the very early 00's. Can't for the life of me seem to
remember enough to get a URL.

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diydsp
It's great to see someone putting so much thought into this. I've been coding
heavily in hires (320x200) mode the last few weeks on this platform.

Having the memory banks swappable has all kinds of fun quirks. For example,
although the VIC-II could address many different 8K memory locations for the
hi-res screen, only four are okay, because others would be the character ROM
($1000 and $9000). Therefore, people tend to put the music code at $1000.

Also there's only one color memory for all the character mode pages and
character memory is the color memory for hires mode!

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sagebird
Zooming into the grid representation of 64KB of memory reveals some fun
artifacts. Tiny o’s appear kind of regularly. I don’t know what kind of
resampling would account for that... maybe a mistake or a counterintuitive way
to shift error among the cells?

~~~
duskwuff
The minor gridlines are dotted. The "tiny o's" appear where the spaces of two
lines are aligned, so four dots appear around the crossing point.

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ddingus
What I love about all this is we managed to get networked together in time to
enjoy the roots of computing together.

I had no idea the fun 8 bit, and older machines would still see development
and innovation.

Makes me happy, and I know there is fun to be had when I get old.

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jadbox
It's incredible the amount of research and brainstorming it took to develop
this solution. Does anyone know more about the author? Is this a hobby
project? Either way, these optimizations [system design] are super impressive.

~~~
csixty4
C64os is by Greg Nacu from the Toronto area. It's a hobby project along with a
portable c64 he's built that's more portable than an SX-64 and much more
versatile due to modern components.

