The great thing about CP/M (and I'm talking about the 8-bit version here) was that it imposed a file system and made disk I/O uniform-- 128 byte sectors, regardless of how the information was actually formatted onto a drive. CP/M was really primitive when it came to console I/O, giving only about 3 functions for output and input each. No cursor positioning or screen control; basic TTY style I/O. And, while there was an IOBYTE facility to redirect I/O, implementation was very nonuniform between vendors. As a result, for other than simple command-line utility programs and compilers/assemblers and the like with minimal I/O requirements, most productivity and comms programs had to go to the hardware directly for display and communications. And that, I think was the innovation of programs such as WordStar and SuperCalc, and, to a lesser extent MODEM7 and Kermit--that you were running on an operating system that was basically designed for TTY I/O with no connectivity and the majority of systems were using CRTs and had modems. The problem became then how to make a single program work for everyone--and that was done with custom patch overlays. DRI, for its part, seemed to remain blissfully ignorant of both of these aspects. Likewise, it wasn't MS-DOS that was the great advance for the IBM PC platform, but rather the well-documented BIOS and I/O interfaces. Heck, PC-DOS 1.0 wasn't that different from CP/M-86--you still had to do your disk I/O through FCBs, just like CP/M. I believe, to this day, you can still issue your DOS calls by loading (CL) with the request number and calling TPA:0005. Cheers, Chuck