PMFJI here, but it is my impression (please correct me if I am wrong) that XPLINK is the z/OS analog of the calling mechanism developed in Germany for z/Linux from the kernel on up to user space. Yes, it's fast, but it provides no call backtrace (i.e., no register saveareas) unless specifically requested at compile time. And the addition of savearea code obviously also impacts the speed of the calling-convention code.
IMHO there is no good excuse for not providing interoperability with any and all other calling mechanisms. It violates the standard of interoperability established by OS360 50 years ago, for little or no benefit to the existing program code base. Only "future" (i.e., unwritten) or "ported" code benefits from these poor choices. But perhaps that is the point, mainly to support "ported" code brought in from the "cloud". Peter -----Original Message----- From: IBM Mainframe Discussion List [mailto:[email protected]] On Behalf Of Tom Marchant Sent: Tuesday, April 22, 2014 9:22 AM To: [email protected] Subject: Re: Enterprise COBOL v5.1 and RDz v9.x On Mon, 21 Apr 2014 15:31:31 -0500, Paul Gilmartin wrote: >z/OS engenders enormous obstacles to migrating to an all 64-bit LE enabled >universe. Yes. Not the least of which is that the LE direction is to support 64-bit code only with XPLINK, and that there is no mechanism in LE for a non-XPLINK program to call an XPLINK program The design of XPLINK and XPLINK-64 currently precludes the mixing of the two. That means that the only migration from 31-bit code to 64-bit code in LE is to replace entire executable units, including all called programs, at the same time. IMO, the LE designers did a poor job when they designed XPLINK-64. In contrast, the MVS designers did a good job designing the calling conventions for 64-bit programs. 64-bit programs can easily be written to interoperate with 31-bit programs, and the 31-bit applications do not need to be changed to be able to work with 64-bit applications, provided that the 64-bit applications are designed with interoperability in mind. LE did not consider any such possibility or need. -- 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: INFO IBM-MAIN
