z14 z/Architecture-only mode (CZAM)

[Fish-Git]

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NOTE: issue #336 (Configuration-z/Architecture-Architecture-Mode and ESA/390-Compatibility-Mode Facilities) is also closely related to this issue.

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According to SG24-8450-01 "IBM z14 Technical Introduction.pdf" page 87:

z/Architecture mode: As announced on January 14, 2015 with Announcement letter 115-001, beginning with z14, all systems will only support operating systems running in z/Architecture mode. This applies to operating systems running native on PR/SM as well as operating systems running as second-level guests. IBM operating systems that run in ESA/390 mode are either no longer in service or only currently available with extended service contracts, and they are not usable on systems beginning with z14. However, z14 does provide ESA/390-compatibility mode, an environment supporting a subset of DAT-off ESA/390 applications in a hybrid architectural mode.

All 24-bit and 31-bit problem state application programs originally written to run on the ESA/390 architecture will be unaffected by this change.

Changes will need to be made to Hercules to support this new "z/Arch-only" execution mode.

Issues that immediately spring to mind are:

• IPL logic
• SIGP instruction
• Other?

This issue pertains directly to the "Configuration-z/Architecture-Architectural-Mode (CZAM) Facility" support listed in GitHub Issue #77 "MISSING Facilities support".

The CZAM "Configuration-z/Architecture- Architectural-Mode" Facility is facility bit 138.

[s390guy]

The file "CZAM_390-CM" has been uploaded to the hercules-390 groups.io file section. This document describes what is involved in each of the facilities.