jwm712@unhd.unh.edu (Jonathan W Miner) (01/25/91)
I have a friend who wants to be able to convert his DEC Rainbow to an IBM clone. What products are available, and what are their limitations? Thanks. -- Jonathan Miner | I don't speak for UNH, and UNH does not jwm712@unhd.unh.edu | speak for me! (603)868-3416 | Hacking to survive......
bcw@rti.rti.org (Bruce Wright) (01/31/91)
In article <1991Jan25.002213.3888@unhd.unh.edu>, jwm712@unhd.unh.edu (Jonathan W Miner) writes: > I have a friend who wants to be able to convert his DEC Rainbow to > an IBM clone. What products are available, and what are their limitations? > The short answer is to sell the Rainbow and get an IBM clone. Short of that, some measure of IBM compatibility can be achieved by running the MS-DOS 3.1 from Suitable Solutions (now defunct, at least as far as Rainbow support is concerned. I'm not sure if anyplace else still sells MS-DOS 3.1 - maybe the Rainbow User's Group). Revision B of MS-DOS 3.1 would be the one to get, if you can get hold of it. This customization of MS-DOS for the Rainbow allows some IBM programs to run OK. Secondly, you can get hold of a copy of Code Blue for the Rainbow. This (along with MS-DOS 3.1 and the patches that Suitable Solutions came up with for Code Blue to work with MS-DOS 3.1) allows a large number of IBM programs to run on the Rainbow. Thirdly, you can replace the Rainbow character ROM with an IBM-PC compatible character ROM which allows many of the IBM-PC characters to be generated on the Rainbow. It doesn't do anything about the 24-line screen on the Rainbow though (Code Blue does have a way of getting around this, but you still don't get a true 25-line screen). Two classes of programs have little or no hope of running on the Rainbow: 1) Graphics programs. The Rainbow graphics board is totally unlike any of the IBM graphics boards, so any graphics have no hope of running unless they run inside an execution environment like Microsoft Windows. (There is a version of Microsoft Windows for the Rainbow, from Leonard Berk Consulting in Canada - its main limitation is that it is monochrome only; it is best if you run it with a Turbow card or else it's a bit sluggish ...). 2) Communications programs. The communications controller for the Rainbow is not like that on most PC clones, and most communications programs for the IBM-PC do not use the ROM-BIOS communications routines because they are badly brain-damaged. If you are "lucky" enough that the program you're running uses the BIOS, then it will work with Code Blue, but this includes NO commercial software. (Exception: many communications programs that run under Windows and that use the Windows communications functions will work OK on the Rainbow). Other sorts of programs may or may not work. For example, some versions of the Norton Utilities work OK with the combination of MS-DOS 3.1B and Code Blue, and others don't. Some version of the Norton Utilities will even run on just MS-DOS 3.1B and no Code Blue (but not 4.5 and above). Fastback and similar programs can't be used in the most efficient ways since they rely on manipulating the floppy disk controller (different on the Rainbow), though some of these sorts of programs have ways of running in a reduced mode which uses only DOS functions and these _should_ work. The Rainbow isn't a bad little machine, but if you really want true IBM compatibility you need to get a clone. None of these products mentioned above gives you total compatibility, though if you use all of them then a surprising amount of IBM-PC code will work. But you'll never get _all_ IBM-PC code to work on the Rainbow. Good luck - Bruce C. Wright