Mike, is that the top of a list of performance/usability improvements for 64-bit addressing in general and in isolation? Or for a combined 31-bit-vs-64-bit, so that the difference in paging outweighs other losses?
A quote from Tom Ross, from a discussion here on 15 January 2015, which shortly afterwards went off-COBOL-topic... "AMODE 64 COBOL is still being worked on here at IBM. I (like the other poster) would like to know what you would do with AMODE 64 COBOL? Also, does everyone realize that AMODE 64 code will run slower than AMODE 31 code? We assume that AMODE 64 COBOL will be used for very specialized one-off cases to solve specific business problems, and that in general 99% of code will be compiled for AMODE 31 even after we ship AMODE 64 COBOL. Unlike AMODE 31, which we expected EVERYONE to move to (still waiting :-) we do not think very many users will need AMODE 64 in the next 10-15 years. We are gathering use cases and verifiable needs for AMODE 64 COBOL, so if you know of any, please SHARE! (get it? :-)" Unfortunately Tom did not return to the conversation to take up some of the questions raised. To turn around the questions asked about inter-language communication, what benefits are 64-bit addressing C/C++ and Java (and "software") bringing, and are they general or specialised? At the moment, I agree with Tom Ross (which is by no means always the case) and expect that few requirement would actually need 64-bit addressing in COBOL. When it becomes available, I seriously hope that it is only used when needed, not "change that compiler option now! We must have 64 because it is sexy". As well as plain slow-downs (unless offset by the no-paging and whatever else), for existing systems there will be subtle (worse) and not-so-subtle problems with pointers, indexes, index-data-items, and others. New calling-convention, fix all those Asm programs out there which are serving COBOL programs with information on number of parameters and name of CALLer, and such-like. Large amorphous lumps of data may well work best with 64-bit addressing for COBOL. It is unlikely that existing code if recompiled with 64-bit addressing COBOL will benefit. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
