In addition to initializing system areas, MVS™ establishes system component address spaces. MVS establishes an address space
for the master scheduler (the master scheduler address space) and
other system address spaces for various subsystems and system components.
Some of the component address spaces are:
- *MASTER*
- Master address space
- ABARS, ABARxxxx
- 1 to 15 DFSMShsm secondary
address spaces to perform aggregate backup or aggregate recovery processing.
- ALLOCAS
- Allocation services and data areas
- ANTMAIN
- Concurrent copy support
- APPC
- APPC/MVS component
- ASCH
- APPC/MVS scheduling
- CATALOG
- Catalog functions. Also known as CAS (catalog address space).
- BPXOINIT
- z/OS UNIX System
Services
- CONSOLE
- Communications task
- DFM
- Distributed File Manager/MVS
- DFMCAS
- Distributed File Manager/MVS
- DLF
- Data lookaside facility
- DUMPSRV
- Dumping services
- HSM
- DFSMShsm
- HZSPROC
- IBM® Health Checker for z/OS®
- FTPSERVE
- FTP server(s); can be user-specified names.
- GDEDFM
- For each Distributed File Manager/MVS user conversation that is
active, an address space named GDEDFM is created.
- GRS
- Global resource serialization
- IEFSCHAS
- Scheduler address space
- IOSAS
- I/O supervisor, ESCON®,
I/O recovery
- IXGLOGR
- System logger
- JES2
- JES2
- JES2AUX
- JES2 additional support
- JES2CIxx
- 1-25 JES2 address spaces used to perform z/OS converter and interpreter functions
- JES2MON
- JES2 address space monitor
- JES3
- JES3
- JES3AUX
- JES3 additional support
- JES3DLOG
- JES3 hardcopy log (DLOG)
- JESXCF
- JES common coupling services address space
- LLA
- Link list
- NFS
- DFSMS/MVS Network
File System address space
- OAM
- DFSMSdfp Object
Access Method
- OMVS
- z/OS UNIX System
Services
- PCAUTH
- Cross-memory support
- PORTMAP
- Portmapper function
- RASP
- Real storage manager (includes advanced address space facilities
support)
- RMM
- DFSMSrmm
- RRS
- Resource recovery services (RRS)
- SMF
- System management facilities
- SMS
- Storage management subsystem
- SMSPDSE1
- Optional restartable PDSE address space. If the SMSPDSE1 address
space is started, SMSPDSE manages PDSEs in the LINKLST concatenatio
and SMSPDSE1 manages all other PDSEs.
- SMSVSAM
- VSAM record level sharing
- TCPIP
- TCP/IP for MVS
- TRACE
- System trace
- VLF
- Virtual lookaside facility
- XCFAS
- Cross system coupling facility
- VTAM®
- VTAM
- WLM
- Workload management
Figure 1. Virtual
storage layout for multiple address spaces
Address spaces differ in their ability to use system services depending
on whether the address space is a limited function or full function
address space.
- Limited function address space
If the specific initialization
routines provided by the components that use IEEMB881 enter a wait
state, pending Master Scheduler Initialization, STC does no additional
address space initialization. Thus, the functions that component address
spaces can perform are limited. Components with limited function address
spaces cannot:
- Allocate data sets.
- Read JCL procedures from SYS1.PROCLIB.
- Allocate a SYSOUT file through the Job Entry Subsystem.
- Use some system services because the components frequently run
in cross memory mode.
- Full function address space
If, after a component completes
its own initialization, it returns to IEEPRWI2 and completes STC processing,
the address space is fully initialized. Such an address space is called
a full function address space.
The component creating a full
function address space does not need to provide a procedure in SYS1.PROCLIB.
If specified to IEEMB881, a common system address space procedure,
IEESYSAS, will invoke a specified program to run in the address space.
For
example, if a full function address space called FFA is to be started
using the module IEEMB899, the component would ordinarily need to
supply a procedure of the following form:
//FFA PROC
// EXEC PGM=IEEMB899
The procedure will be
invoked as follows:
//IEESYSAS JOB
//FFA EXEC IEESYSAS
The procedure IEESYSAS
consists of the following statements:
//IEESYSAS PROG=IEFBR14
// EXEC PGM=&PROG
z/OS MVS Initialization and Tuning Guide
Copyright IBM Corporation 1990, 2014