+1 for CMS UPDATE, 45+ years old and going strong. I've been irritated by the update-by-replacement theology since I first encountered it. The ability to easily look and see what lines were hit by an update without having to re-run diffs (which takes a long time, relatively speaking, especially when you're remote from your SVN server) is SO superior. We have several groups working on different layers of the same code. When the inevitable regression occurs, having to dig through diffs to figure out who changed what when is a major PITA.
In addition, I suspect/believe that update-by-replacement encourages more changes than necessary: that is, for 30 years, when I've made a change using XEDIT in UPDATE mode, I've ALWAYS looked at the resulting update before committing it, to make sure that I hadn't inadvertently/sloppily changed anything else (e.g., accidentally changed a comment, where "changed" might mean "typed over it and put it back, but XEDIT saw it as a change"). Add in the inevitable tendency of diff to pick the wrong lines as being changed (blank line/close curly braces, for example-this isn't diff's fault, it's that it can't tell) and diffs aren't even as useful as updates. Since I started working on z/OS stuff, I've been disappointed that there's no equivalent of XEDIT in UDPATE mode, and that IEBUPDTE isn't compatible with CMS UPDATE. I find that amazing-the productivity of being able to Just Edit The Damned File is huge. Maybe IBM has an internal editor they use on z/OS that creates IEBUPDTE-format updates a la XEDIT? I did an internal Brown Bag a year or so ago, in which I outlined the VM CNTRL/AUX/update theology, to a room full of bewildered-looking distributed folks. I did preface it with "Obviously the following isn't going to change how we do anything, but it might spark some ideas down the road..." ...phsiii ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
