SYSRES
The system residence volume: the disk holding the core z/OS libraries that a system starts from.
Also written system residence volume, IPL volume, SYSRES set, alternate SYSRES
SYSRES, the system residence volume, is the disk volume that holds the core z/OS system libraries, the ones a system is started from at IPL. Because z/OS is large, the libraries often fill several volumes, called a SYSRES set.
Sites normally keep more than one SYSRES set. The system runs from one while system programmers prepare another. To apply maintenance, they copy the current set, apply the new PTFs to the copy with SMP/E, and then IPL from the new set.
This makes changes much safer. The running system is never changed in place, and if the new level has a problem, the system can be IPLed again from the previous set, which is still there unchanged.
Sharing matters too. Several systems in a sysplex can start from the same SYSRES set, so they run exactly the same code. When people talk about "rolling out new maintenance", they often mean moving systems, one at a time, onto a new SYSRES.
Where can I learn this hands-on?
Right here, at ZedBank. You take a junior job at a simulated bank and learn each part of the work by doing it, with Zed beside you. There's nothing to install.
Start at ZedBankRelated
- IPLInitial program load: starting z/OS on a system, the mainframe word for booting.
- VolumeA single unit of disk storage with a six-character label, on which datasets are placed.
- SMP/ESystem Modification Program/Extended: the tool used to install and maintain z/OS and other software, keeping a record of every piece and every fix.
- PTFProgram temporary fix: a packaged fix from IBM for a problem in z/OS or another IBM product, installed with SMP/E.
- System programmerThe person who installs, configures, tunes and upgrades the operating system and its subsystems.
- DASDDirect access storage device, the mainframe term for disk storage.