For historical accuracy, I'll add a few comments to what Paul said. > We did distribute DIFF with our 'Qlib' contributed library. ^ It was really called DIF. > But we didn't have the source and it generated stack overflows on larger > tasks. We did have the source code and I spent quite a bit of time studying it. However the stack space management was a fundamental part of how the code worked and it wasn't easy/possible to change. Because of customer complaints we stopped distributing Dif with our products several years ago. In Pascal News #18 (published around 1979) was a program called Compare. I typed this program in and used it extensively as an internal tool for many years. It was also distributed as part of Pascal/Robelle (a Pascal compiler for MPE V). I felt that the output from Compare was vastly better than the output from either Dif or Scompare (or the UNIX diff tool). Compare was written in standard Pascal using fixed-size buffers, so it had even worse stack problems than Dif. I believe that Scompare for MPE V didn't use the stack for storage of differences so that it didn't have the problems of Dif and Compare. > Dave Lo of our programming staff re-wrote it in Pascal. > Because I really liked Compare, I asked Dave Lo to work on it. Dave spent a lot of time seeing if we could produce a version for MPE V that didn't use the stack. While Dave worked hard on the problem, we never ended up with a version that ran fast enough. Dave did many other enhancements, wrote a test suite, user manual, and generally made Compare into a bonus product. > It is now called COMPARE and it only works on MPE/iX. It is a BONUS program > that is on every license tape that we send to our customers. If you are a Robelle customer and are on MPE/iX, you have a comparison tool in compare.pub.robelle. If you are not a Robelle customer, you can obtain Compare by purchasing our bonus products (available at a low price). Contact [log in to unmask] for more information on the bonus products. Scompare has many more features than our Compare program. For example, if you want to automatic source-code updates using comparisons between versions, you want Scompare from Aldon (you might need another product from them too). But if you are a Robelle customer, you should give Compare a try. Cheers, David Greer <[log in to unmask]>