z/VM: CP Commands and Utilities Reference - z/VM - IBM

SAVESYS
Messages
v If neither the old copy nor the new copy is a system service NSS, the new
copy may be saved
v If either the old or the new copy is a CP system service NSS, the new copy
cannot be saved.
6. If a skeleton system data file exists for an NSS with the specified system
name, the data is saved into it. If no skeleton NSS file exists, but there is a
DCSS skeleton file with the same name, the data and storage keys (but not
the virtual machine environment) are saved into the DCSS skeleton file,
exactly as if the SAVESEG command had been issued.
7. The contents of and storage keys for pages defined as or defaulted to “no data
saved” on the DEFSYS command are not saved in the NSS system data file
when the SAVESYS command is processed. When referenced by a user who
IPLs the NSS, storage contents and keys are zero.
8. A named saved system (NSS) is loaded through the IPL command. A saved
segment is loaded through DIAGNOSE X'64'.
9. If the MACHMODE parameter was used on the DEFSYS command that
defined the NSS, then SAVESYS can be used to save the NSS only when the
virtual machine is in an architecture mode specified by the MACHMODE
parameter. If the NSS was defined without the MACHMODE parameter, then
SAVESYS can be used when the virtual machine is in any architecture mode.
10. When an NSS is defined using a MACHMODE parameter with more than one
architecture mode, the NSS is known as a multimode NSS. Multimode NSSs
have less virtual machine environment information saved by SAVESYS and
restored by IPL than a single-mode NSS. Only the following architectural
entities are saved by SAVESYS and restored by IPL of a multimode NSS:
v Storage and storage keys
v The program Status Word (PSW)
v General purpose registers
v Floating-point registers
v The prefix register
Note that the saving and restoring of storage is under control of
page-descriptor codes, such as EW and EN, specified on the DEFSYS
command. Also, the restored general register contents may be replaced with
parameter data specified by the PARM operand on the IPL command. See the
description of the PARMREG parameter of the DEFSYS command and the
PARM parameter of the IPL command for more information.
Immediately after the NSS is restored by the IPL command, all other
architectural entities not mentioned above, such as timers or other registers,
have the initial-CPU-reset values appropriate for the architecture mode in
which the NSS was IPLed.
11. When CMS is built, the SAVESYS must be done in concert with an IPL. The
IPL should be done as follows:
IPL cuu PARM SAVESYS
1182 z/VM: CP Commands and Utilities Reference
See the z/VM: Guide for Automated Installation and Service for information on
how to SAVESYS the CMS nucleus.
12. If you use DEFine STORage CONFIGuration and define more than one
storage extent, SAVESYS will save pages in page ranges that are located in
the second and higher storage extents. However, you cannot load the saved
system after it is saved until storage is changed so that the saved system
loads below the start of the second defined storage extent.