The full meaning is that z/OS disallows execution of the SVC instruction in many environments; e.g., when disabled for I/O interrupts, when holding a system lock, when in SRB mode, possibly some others, and now also if the SVC instruction is located above the bar. However, the one SVC 13 (or D, aka ABEND) is allowed in any environment, since the result of trying to execute an SVC in an unsupported environment results in an ABEND macro (SVC 13) issued by the operating system in order to drive RTM and clean up after the program that attempted to execute the original SVC instruction improperly. One way to remember the environments in which extra care must be taken is the acronym EUT, meaning Enabled, Unlocked, Task mode. EUT is used as a parameter on the SETFRR macro, which also mentions some other things that might not be allowed in these rarified environments.
Bill Fairchild Rocket Software -----Original Message----- From: IBM Mainframe Discussion List [mailto:[email protected]] On Behalf Of Ted MacNEIL Sent: Tuesday, October 25, 2011 7:16 PM To: [email protected] Subject: Re: ABEND0F8-20 >Only ABEND. All others disallowed. What does this response even mean? - Ted MacNEIL [email protected] Twitter: @TedMacNEIL ---------------------------------------------------------------------- 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 ---------------------------------------------------------------------- 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
