[ColorForth] USB and other serial bit boffing

["Arthur W. Green" <goshawk@xxxxxxx>]

Mr. Plichota wrote:
> 1) The PC87 and PC98 roadmaps are mandating the total discontinuation of 
> "legacy" serial and parallel ports (and floppy disks). Although motherboards 
> still are available which provide them, laptops usually do not anymore. 
If colorForth persists on the PC, are there any propositions for the time when
floppy disks have simply been "outmoded"?

I am beginning to wonder about ZIP disks, which are *very slow* and CPU
intensive for what they are. I am personally appauled with them, but I can't
think of too many alternatives.

I am aware that someone did build a homebrew 68K-based Forth system using an
ancient SCSI ZIP drive. I will have to see if I can cough up the page if anyone
hasn't already seen it.

> The 
> PC is moving further away from a simple hacker-friendly (well, kind of) 
> machine and squarely into the big bu$ine$$ trap and is now totally useless 
> for hackers, scientists, and engineers to casually cobble up a simple 
> interface to another piece of hardware sitting on the lab bench. Treasure 
> your old machines: they are literally irreplacable.
> 
I am beginning to notice, and perhaps even wonder about alternatives for my own
"second generation" machine, if colorForth persists on the PC.

> 2) The wait states used to slow down accesses to the parallel port (if it 
> exists!) limit the bitrates you can achieve severely no matter how fast your 
> CPU is and there will be timing jitter due to interrupt and DMA activity. I 
> would not count on a standard USB peripheral's ability to adapt to 
> non-standard bitrates (standard = 1.2 and 12 M bits/sec) and a whole lot of 
> jitter.
I also figured this. That's why I was hoping in a twisted way to see if USB
couldn't be used in a limited fashion. I have lost most of my hope for that...

> 
> The only relatively simple idea I have right now that may rescue the notion 
> of casual invention on the PC is to develop a PCI card that provides 
> equivalent and hopefully better I/O than the past and limit the software 
> hurdle to mastering the art of PCI bus interfacing. Note that this does not 
> solve the problems involved with dealing with the gazillion different 
> motherboard chipsets, video cards, floppy disk controllers, etc., etc.
> 
This is a good idea. I rather like it, but I already plan for [in a worst case
scenario] two rather intensive PCI cards to be used under colorForth as well. I
could be looking at the potential problem of an unacceptable amount of delay for
"real-time" stuff simply because of PCI bus clogging.

> I have been experimenting with flat protected mode x86 code quite a bit 
> lately, and have been smacked in the face by the hardware incompatibilties 
> encountered when testing it on the various x86 PCs at my disposal. VGA color 
> text mode 3 (inherited at disk boot time), and LBA ATA (aka IDE) interfacing 
> (simpler and more uniform than floppy disk!) are one of the few constants I 
> have learned to trust, and those are hints to any colorForth codesmiths that 
> have the desire to release a generic normal character set version that anyone 
> can run without hardware compatibilty problems. Of course, one needs a spare 
> hard drive to play with, perhaps a tiny, orphaned 200 MB unit ;)
> 
Thanks for the heads up!

> I can contibute the DOS utility I have written (in NASM) to overwrite an LBA 
> hard disk from the MBR onwards with a binary file if anyone wants it. It is 
> hardcoded to use a fixed filename and runs off of a standard DOS 6.2 or Win95 
> system-formatted floppy. It can be easily modified by anyone with NASM.
> 
I would be interested in the source for that, too. If it isn't completely out of
line, why don't you post in plain-text on this list?

Thanks for your time.

Best regards,
-- Art
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