> -----Original Message----- > From: IBM Mainframe Discussion List [mailto:[email protected]] On > Behalf Of Edward Jaffe > Sent: Tuesday, July 20, 2010 11:01 AM > To: [email protected] > Subject: History of Hard-coded Offsets (Was: TSSO problems) > > Scott Rowe wrote: > > 2) In OSWAITRC (the ESTAE for the OSWAIT TSO command), there is an NI > instruction to reset the wait bit in an AOF entry. The offset into the > AOF entry is hard-coded and ... > > I made one enhancement to TSSO years ago and got frustrated with it > because there were so many hard-coded offsets and lengths. Every change > I made seemed to break something else. I remember thinking, "this > program needs a major cleanup/restructure to be maintainable"! > > I've seen other "old" programs with many hard-coded offsets and lengths > and always wondered why this was such common practice back then. > > Was it because there were a lot of inexperienced assembler programmers > writing code? Was it because people thought the platform would not last > and treated every program as a "throw away"? Was it due to limitations > in the assembler itself?
I have always suspected some degree of inattention to detail and/or just plain lack of experience on the part of such programmers as the root cause myself. OTOH, programmers who have not had the experience of maintaining O.P.P.'s (Other People's Programs) in, for example, an ISV shop or a large business enterprise may not have had the "hard knocks" experience of the pain that supporting poorly written code can bring. It's so much easier to change one definition and have the position and length automatically propagated than to have to find all the places where the offset or length is hard-coded, but if you've never had the pain of having to fix such a problem you may not have learned the lesson. Just my USD$0.02. Peter This message and any attachments are intended only for the use of the addressee and may contain information that is privileged and confidential. If the reader of the message is not the intended recipient or an authorized representative of the intended recipient, you are hereby notified that any dissemination of this communication is strictly prohibited. If you have received this communication in error, please notify us immediately by e-mail and delete the message and any attachments from your system. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
