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This is one of those programs that, although are interesting to experiment with, are kind of difficult to apply in a practical situation. But, because it is indeed something that can be done only on a C128, I thought it might still be of interest to someone here.

In a nutshell, C64 By 80 is a program that you run on your C128, while in GO64 mode, that allows you to use the VDC display while running BASIC 2.0. Why would you want to do this? Well, that's a good question. The most obvious answer that pops into my mind is that, if you're writing a program in BASIC 2.0 (for your Commodore friends that are unfortunate enough not to own a C128), doing so on the 80 column screen is a lot more comfortable. When you happen to have particularly long lines on the standard 40 column screen editor, they can be a little confusing to read. But, when viewing them displayed in the VDC's 80 column mode, they become much easier to comprehend.

Another nice feature of running BASIC 2.0 using the VDC is that you can use the C128's “FAST” mode, (that is, 2MHz speed). So, if you have a particular C64 BASIC program that runs a little on the slow side, you can speed it up by running it using the 80 column display.

Coding for the C64 in 80 column mode is one thing, but there are some drawbacks if you attempt to run unaltered or unprepared BASIC 2.0 programs using the VDC. The major issue is that, screen POKES do not work; this includes color POKES and character POKES. You'll need to use CONTROL codes for this sort of display commands. Of course, if you don't require your BASIC 2.0 programs to run on the VDC, then no problem, continue as normal and run the program in 40 column mode as usual.

There are a few extra “niceties” that come with C64 By 80 that help with programming in BASIC 2.0. You have a few extra CTRL-key commands at your disposal, like CTRL-A: Move the cursor to the start of the line, or CTRL-Z: Move the cursor to the end of the line, and CTRL-D: Delete the line the cursor is on. All of these new commands are outlined in the C64 By 80 user guide, which I've made available above.

All-in-all, this little OS enhancement program is quite unique and adds some versatility to the C128 and it's ability to help make programming in BASIC 2.0 a little easier. However, writing something specifically for the C64 using the 80 column mode isn't all that practical, in my opinion. I'd just assume write an 80 column program in the C128's superior BASIC 7.0 and be done with it. But, hey, you might have an idea that perfectly suites this particular niche that C64 By 80 provides.

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