ARCH level is a "problem" I have dealt with for 12 or so years. I say "problem" in quotes because it is not much of a problem -- you only have to revisit it once every two years, and even then it is not an urgent problem. So you don't need a solution that runs on autopilot -- you can just revisit your decision every two years or so.
You need a management policy. The one I have advocated to my management is "we will support the oldest hardware supported by the oldest supported release of z/OS." I point out that while there may be lots of customers out there running z9's, they probably are not buying a whole lot of OEM products. Currently that would be ARCH(10), representing the zB/EC12, supported by z/OS V2R4. Once V2R4 goes out of service it would become ARCH(11). But it is a Product Management decision, not a techie decision. (Do note that minimum ARCH levels do NOT change with every release: V2R4 and V2R3 were both ARCH(10), a two-ARCH leap from V2R2). How much does it matter? If yours is compute-intensive application that churns along all day, then it is probably important. For other situations it may be less important. You might want to do some benchmarks. And! There is a companion option, TUNE. Check that one out! Here's the good news. It's not like, say, a decision to start using EXR in your assembler code, where the way back requires real work. Let's say you settle on ARCH(10). And then let's say that in six months your SVP of Sales comes running in and says "I have a $300K opportunity if we can support a z9!!!" All you would have to do is change to ARCH(7) and do a build. It is just a management decision whether it is worth the bother to do the build, test and distribute. There is no real development "effort." Also, a cheat sheet: "marketing number" (like z16) is 2 greater than ARCH and 6 greater than HLASM ZS-n. IOW, z16 is ARCH(14) and ZS-10. Charles -----Original Message----- From: IBM Mainframe Discussion List [mailto:[email protected]] On Behalf Of Phil Smith III Sent: Monday, April 24, 2023 2:40 PM To: [email protected] Subject: Re: XLC architecture level question Thank you! Does that default change periodically? I suppose it must-is it always such that the default supports the oldest currently supported ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
