[Coco] Utility of large MPI (was: Re: ROM Cart registers)

Al Hartman alhartman6 at verizon.net
Wed Feb 3 08:55:10 EST 2016

Some comments:

1. All my floppy drives and floppies are working perfectly, and I wouldn't 
ditch them for any reason. If I'm ditching floppy drives, I don't need a 
physical Coco at all. Athana still makes new floppies, and it's as easy to 
backup old floppies to new media as it is to make disk images of them. I do 
both to cover myself.

2. My Dot matrix printer works perfectly (an IBM Graphics Printer, a 
rebadged MX-80). I don't need to print through Drivewire. Dot matrix 
printers are cheap or free at swapmeets and eBay. I have a serial to 
parallel adapter too.

I'm pretty sure we've already had a discussion that said an RS-232 port 
wouldn't be as fast as the bitbanger for Drivewire. But, I could be wrong. 
I'd rather see either wired or wireless ethernet on  the card with a 
modified HDBDOS Rom to use it instead of the bitbanger, freeing up the 
bitbanger for printing. If someone wants to code printing through DW, that's 
fine. But leave the ability to print normally alone for those of us who want 

In the Tony DiStefano book, he has a parallel port project, with code to 
redirect the bitbanger for printing to it. This port can be mounted inside 
the Coco, freeing up the cartridge port for a disk controller. That would be 
useful, so I could use DW and print at the same time. Except programs that 
print directly to the bitbanger and bypass the ROM in DECB won't work with 
this. Moving DW to a dedicated port makes more sense. Much less code to 
change, and a possible speed increase as well as flexibility with a wireless 

-[ Al ]-

-----Original Message----- 
From: Francis Swygert

Adding my own thoughts to this...
- With a CF or SD card, there is no need for a hard drive, except to 
transfer data from an old HD to the CF or SD. Cf seems to be easier to 
implement, but it's also an older technology that's getting harder to find, 
so I'd ditch it now! We already have an obsolete machine, why cripple it 
with waning tech now? Of course the IDE has already been implemented, and 
there are cheap IDE to SD and IDE to CF adapters that let the system read 
the memory cards as if they were HDs... so the IDE interface is probably the 
way to go. That would make one interface work for three different types of 
drives (physical IDE HD, SD card, CF card).

- No real need for a parallel port, unless you want to use implement it 
fully, as a bi directional port, so it can be used for other I/O projects 
and not just a printer. There are few modern printers with a parallel port 
(if any... most are made to keep old industrial stuff going, like the 
Panasonic dot-matrix printers still in production). There are also few with 
a serial port. A micro controller programmed to emulate a printer and send 
the signal through a USB port to drive a modern "dumb" USB printer would be 
a great idea. One font built in, then take the old MX-80 dot matrix graphics 
codes. That would let all existing CoCo software print, even in different 
fonts, since the old software used the graphics code to make different 
fonts. The ability to use a modern, inexpensive printer is imperative! I 
think I'd rather see a small box that plugged into the bit-banger port 
though. That would free the expansion slot for other things, and be 
transparent to use with DECB (RS-DOS) and OS-9.

- A floppy controller. I have mixed feelings on this. There is the nostalgic 
feel, but the things are wearing out and there are no new ones. The floppy 
discs themselves are getting old and wearing out as well. At this point, 
just about all CoCo software has been transferred to virtual disk files. I'd 
say a super CoCo cartridge with a serial port, IDE, and the printer driver 
described above would be great. You'd have to use an old floppy controller 
and DriveWire, or an older PC with a real floppy drive, to transfer old 
disks, but once what you have is transferred (or downloaded from others) you 
can pack the floppy up and use your super cart.

- Oh yeah, an RTC... mainly for OS-9 users. And some flash ROM space...

- For utility, put a single open slot on the super cart. It could be decoded 
in such a way that you could put a FDC in it. Would probably be hard to use 
all the "super cart" functions and the FDC at the same time, but even if 
limited to just the FDC and IDE with an FDC plugged in it would be useful 
for transferring files.

So lets see.... a SuperCart with IDE, an RS-232 port, RTC, and an additional 
cartridge slot would be sufficient for 90% of CoCo users needs.I'd make the 
cartridge port vertical, with some kind of snap on end support for the super 
cart in the CoCo and the one in super cart. Add the "printer dongle" to the 
bit banger and you have a great, compact system. If you have some special 
card or want to use a legacy card for something there is a connector for 
that. Heck, go ahead and buffer that extra port so it will support a 
y-cable... but is that really necessary? Few use the speech/sound pack or 
anything else, so with all the general I/O taken care of one extra slot will 
serve 90% of that 10% "my" fictional super cart wouldn't take care of...
Frank Swygert
Fix-It-Frank Handyman Service

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