CompuServe Messages

Jennifer, Actually there's a specific answer about how much memory you need to run Code Blue for certain (actually most) IBM applications, including WordPerfect: 768K. The answer has nothing to do with the size of Code Blue but with the way most IBM PC programs write to video. Because IBM, unlike the Rainbow, had no fast video function, the only way to get fast video display in the IBM is to address it directly, as if it were ordinary RAM memory. Fortunately, IBM's video memory ends at 768K, far less than the Rainbow' s maximum of 896K on a 100B or 832K on a 100A. So when Code Blue is run with the /V switch, it reads the Rainbow's RAM in the range of the IBM's video memory, then copies the information to the Rainbow's video memory. It scans so quickly that you don't notice the difference. There are some IBM programs, usually small utilities, that don't write directly to the screen. You only need Code Blue to get these to run to emulate the IBM's BIOS calls. But larger programs generally write to IBM video memory. Although the Rainbow 100As originally came only with adapter cards with fixed amounts of memory, DEC later came out with expansion cards that allow memory to be added in rows of either 64K or 256K chips, with one card being able to take any possible combination. An adapter allows this card to fit in the 100A, and it fits into the 100B without an adapter. If you have one of these expansion cards — or can get one, with an adapter, if necessary — all you have to do is fill it up with 256K chips, and you're in business. — Carl