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System Configuration. Customization, Initialization & Administration. Configuration – System Initialization. The system operator supplies parameters instructing the system to load : The bootstrap code on the IPL volume is loaded into storage at address 0 and control passed to it
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System Configuration Customization, Initialization & Administration
Configuration – System Initialization • The system operator supplies parameters instructing the system to load : The bootstrap code on the IPL volume is loaded into storage at address 0 and control passed to it The bootstrap the reads the IPLTEXT program IEAIPL00 which is given control and the complex task of loading the system starts
Configuration - Hardware Management Console (HMC) – Support Element (SE)
Configuration - Provide device address of SYSRES and SYS1.IPLPARM 1000 0CE3W1
z/OS System Definitions D IPLINFO SYSTEM IPLED AT 08.41.25 ON 01/29/2007 RELEASE z/OS 01.07.01 LICENSE = z/OS USED LOADW1 IN SYS1.IPLPARM ON 0CE3 ARCHLVL = 2 MTLSHARE = N IEASYM LIST = (W1,SV,VN) IEASYS LIST = (00,LV,SV,VN) (OP) IODF DEVICE 0CE3 IPL DEVICE 1000 VOLUME VIMVSB D PARMLIB PARMLIB DATA SETS SPECIFIED AT IPL ENTRY FLAGS VOLUME DATA SET 1 S VPMVSD VENDOR.PARMLIB 2 S VTMVSG SVTSC.PARMLIB 3 S VTLVL0 LVL0.PARMLIB 4 D VIMVSB SYS1.PARMLIB
z/OS System Definitions • IPL loadparm SYS1.IPLPARM(LOADxx) PARMLIB(IEASYSxx) SYS1.IPLPARM(LOADW1) IEASYM (W1,SV,VN) INITSQA 0000K 0512K IODF 00 SYS1 MVS 00 Y NUCLEUS 1 NUCLST SV N SYSCAT VPMVSB113CMASTERV.CATALOG SYSPARM (00,LV,SV,VN) SYSPLEX SVSCPLEX PARMLIB VENDOR.PARMLIB PARMLIB SVTSC.PARMLIB PARMLIB LVL0.PARMLIB PARMLIB SYS1.PARMLIB
z/OS System Definitions z/OS is highly configurable to best serve a customers workload System definitions (system parameters) are read during z/OS initialization The values of many system parameters can be changed dynamically Default values exist for the majority of system parameters More matured systems change the defaults as their workloads change It is important to develop a back out plan for any system definition change
z/OS System Definitions SVTSC.CLIST(SYSLIB) PROC 0 ALLOC SHR REUSE FI($PARMLIB) DA( - 'VENDOR.PARMLIB' - 'SVTSC.PARMLIB' - 'LVL0.PARMLIB' - 'SYS1.PARMLIB') ALLOC SHR REUSE FI($PROCLIB) DA( - 'VENDOR.PROCLIB' - 'SVTSC.PROCLIB' - 'LVL0.PROCLIB' - 'SYS1.PROCLIB') ALLOC SHR REUSE FI($STCJOBS) DA( - 'VENDOR.STCJOBS' - 'SVTSC.STCJOBS' - 'LVL0.STCJOBS') ISRDDN EXIT
Configuration - systems are operational & connected to CF (Coupling Facility)
Configuration - IEAIPL00 • IEAIPL00 prepares the system by clearing central storage to zeroes then defines storage areas for the master scheduler • SYS1.NUCLEUS is located and a series of modules loaded which construct the normal environment of control blocks and subsystems • The first part of the Nucleus Initialization Program is then loaded
Hdw IPL IRIMs Nucleus Initialization Program (NIP) Test Block Inst (clean Stor) SCPINFO Get Loadparm Set autostore status on Find LOADxx Find IODF Load Nucleus Build UCBs Load Prefix Reg IRIMs Complete System Parameters Master Catalog No NIP Console; use HMC Use NIP Console Device Pathing to all online Non-DASD Device Pathing to offline tapes • Load from IPL DASD Device • System reset • Build IPL Read CCW • Enable subchannel for IPL Device • Seek Cyl 0, Head 0, Rec 1 (DASD) • Read R1, R2, R4 (Hardware reads R1) • Hardware IPL complete Device Mapping - UCWs to UCBs IPL Flow ( 1 of 4)
NIP Initialization Continued Build SCPHID TOD Allocate required Data Sets IGGN504, IGGN505 msg for missing data sets IOS120A may occur after responding to IGGN msg DASD Pathing SSCH to 32 devices at a time Redrive another device after I/O completes on a device Path testing - each path No 1.5 second timeout (no IOS120A during path testing) Device Characteristics-one path Self Description - each path (IOS291 msg) VOLSER Checking- one path for SDP products (all paths for other DASD) Duplicate VOLSER message (IEA213A-not SYSRES or IEA214A-SYSRES) At end of pathing - wait 15 seconds for any outstanding I/O to Complete Mark any UCB with outstanding I/O to test again later Purge all outstanding I/O requests IPL Flow ( 2 of 4)
DASD Subsystem Initialization CONSOLxx Processing GRS complex started ISG004I - For ring mode ISG300I - For star mode IXC306I - PO/PI structures allocated by 1st MVS Determine the state of sysplex policy structures Determine state of CF from the active CFRM policy IXC517I - able to use CF IXC518I - not using CF Find all other couple data sets Start PO/PI requests CTCs and structures per couplexx IXC305I on 1st MVS indicates signaling delayed until structure is allocated IXC418I msg issued - System active in sysplex • Determine state of CF paths • IXCL157I is issued if path is operational ( displays node descriptor information ) Determine the state of the sysplex systems (from couple data set) IXC404I - System(s) active or IPLing IXC405D - Reply I, J or R Find XCF couple data set IPL Flow ( 3 of 4) Use COUPLExx member of SYS1.PARMLIB
Master Scheduler Initialization IEE389I MVS Command Processing Available Send Sysplex and System Name to the HMC Other CPs brought online Write SYSNAME to Sysplex Couple Data Set Write SPID value to Couple Data Set if formatted with V5 (provides info for IOS431 message) Establish path groups for online DPS devices Redrive any outstanding I/O Requests IOS120I List all DASD Devices that I/O failed to complete IOS120A CONT or Wait message for each device with contention IPL Flow ( 4 of 4) Use MCS Consoles
SYS1.NUCLEUS IPL modules • IEAIPL10 00:00:00.000 ISNIRIM - READ SCPINFO • IEAIPL30 00:00:00.000 IPLWTO SERVICE • IEAIPL49 00:00:00.000 PROCESS LOAD AND DEFAULT PARAMETERS • IEAIPL14 00:00:00.000 BUILD LSQA/ELSQA FOR MASTER • IEAIPL06 00:00:00.000 IARMI - RSM BLOCKS, MASTER SGT • IEAIPL31 00:00:00.002 LOAD SERVICE • IEAIPL08 00:00:00.007 READ EDT INFORMATION FROM IODF • IEAIPL60 00:00:00.008 READ NCRS FROM IODF • IEAIPL11 00:00:00.018 FAST FIND SERVICE • IEAIPL42 00:00:00.018 READ NMLS FROM NUCLEUS (IEANYNNN MODULES) • IEAIPL51 00:00:00.019 SYSTEM ARCHITECTURE • IEAIPL04 00:00:00.020 ALLOCATE PFT AND SQA/ESQA • IEAIPL03 00:00:00.027 BUILD UCBS, ULUT, ETC. • IEAIPL43 00:00:00.032 FIND AND OPEN IODF DATA SET • IEAIPL07 00:00:00.037 UPDATE AMODE FOR NUCLEUS RESIDENT SVCS • IEAIPL09 00:00:00.054 IAXMI - PFT, MASTER RAB, ETC. • IEAIPL40 00:00:00.093 READ MLTS FROM NUCLEUS • IEAIPL71 00:00:00.120 BUILD DFT FOR EACH DEVICE • IEAIPL46 00:00:00.164 READ SCHIBS INTO IPL WORKSPACE • IEAIPL18 00:00:00.172 COPY AND RELOCATE EDT TO ESQA • IEAIPL70 00:00:00.208 UIM ENVIRONMENT - LOAD CBD AND IOS SERVICES • IEAIPL99 00:00:00.465 PAGE FRAME TABLE AND CLEANUP • IEAIPL50 00:00:00.774 IPL PARMLIB - PROCESS LOADXX AND NUCLSTXX • IEAIPL05 00:00:01.056 BUILD AND SORT NUCMAP • IEAIPL41 00:00:01.388 READ PDS DIRECTORY ENTRIES AND CESD RECORDS • IEAIPL20 00:00:01.688 TEST BLOCK STORAGE TO 2G • IEAIPL02 00:00:03.779 LOAD NUCLEUS MODULES
Configuration – System Parameters • SYS1.IPLPARM(LOADxx) IEASYM (W1,SV,VN) SYSCAT VPMVSB113CMASTERV.CATALOG SYSPARM (00,LV,SV,VN) • IEFSYSxx members where xx is 00, LV, SV, VN PARMLIB VENDOR.PARMLIB PARMLIB SVTSC.PARMLIB PARMLIB LVL0.PARMLIB PARMLIB SYS1.PARMLIB
Configuration - SYS1.IPLPARM LOADxx member startupparameters
Configuration – System Log (Trail of IEE252I messages) • IEE252IMEMBERmember FOUNDINparmdsname • Explanation: This is an informational message that appears only in the hardcopy log when member member is found in parmlib dataset parmdsname • In the message text: • memberis the parmlib member name that is being processed. • parmdsnameis the parmlib data set where membermember is located. • SystemAction: • The system continues processing. • SystemProgrammerResponse: • Check the hardcopy to see if all the members in parmlib specified in LOADxx • or in operator input are being used correctly and are found in the correct parmlib data set. • Source: Master scheduler, IPL/NIP
Configuration - Nucleus Initialization Program (NIP) • Nucleus Initialization Program sets up system storage areas SQA PLPA FLPA MLPA CSA Private - User Region then NIP starts the master scheduler
Configuration - Master scheduler • The master address space starts all the other required address space and initializes the subsystems • Once JES is ready jobs can be started and VTAM and TSO will be started next. • The system is now available to do work
Configuration – Display IPLINFO and system PARMLIB concatenation
Configuration – Routine to easily find system parm and proc members
Configuration - IEASYS00 is read first. IEASYS00 has few parameters
Configuration - IEASYSLV is read 2nd. IEASYSLV has more parameters
Configuration - IEASYSSV is read 3rd. Duplicate parm values are overridden
Configuration - IEASYSVN the last member read has only one parm statement
Configuration - z/OS System Libraries • These are the most important system libraries SYS1.LINKLIB prime system software library • LNKLST concatenation SYS1.LPALIB system subroutines SYS1.NUCLEUS basic supervisor modules SYS1.PROCLIB system procedure JCL • PROCLIB concatenation SYS1.PARMLIB control parameters • PARMLIB concatenation
System search order for programs • Programs (load modules) must be in central storage and therefore in the virtual storage of the address space before they can run • System has a defined search order for a newly requested program
Search order for programs • JCL STEPLIB if present • JCL JOBLIB if present and no STEPLIB • Link Pack Area (LPA) • Dynamic LPA modules • Fixed LPA • Modified LPA • Pageable LPA • Linklist
SYS1.LPALIB • The Link Pack Area (LPA) is built at IPL time from the modules defined in the LPALSTxx member of parmlib. • SYS1.LPALIB is always the first library used unless overridden by a SYSLIB statement • Modules are loaded into common storage at IPL time and so are available to all address spaces
SYS1.LPALIB • Fixed LPA comprises those modules defined in IEAFIXxx that are fixed in central storage • Pageable LPA comprises most other modules whose pages are eligible to be stolen • Modified LPA has modules which are temporary replacements for PLPA modules and is searched first.
Configuration – JES JOB JCL Procedure Library JES2 JCL Procedure Librares are searched for JOB and STC PROCs //PROC00 DD DSN=SYS1.PROCLIB,DISP=SHR // DD DSN=SYS3.PROD.PROCLIB,DISP=SHR //PROC01 DD DSN=SYS1.PROC2,DISP=SHR ... //PROCnn DD DSN=SYS1.LASTPROC,DISP=SHR ... JOB JCL can have personal JCL Procedure Libraries search first //MYJOB JOB //MYLIBS JCLLIB ORDER=(MY.PROCLIB.JCL,SECOND.PROCLIB.JCL) //S1 EXEC PROC=MYPROC1 ...
Configuration - System Symbols • System symbols allow the use of a shared parmlib by two or more systems • Each symbol has a name which can be used in various places and then substituted at IPL time • Major uses are indirect cataloging and substituting system specific datasets such as the page data sets
Configuration -- Key z/OS & JES Configuration Manuals • MVS Initialization and Tuning Guide • MVS Initialization and Tuning Reference • JES2 Initialization and Tuning Guide • JES2 Initialization and Tuning Reference