z/OS System Anatomy Part 1 - Z Architecture

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UK Start Times

What do I need?

• webcam
• headphones with microphone
• sufficient bandwidth, at least 1.5 Mb/s in each direction.

What you will learn

On successful completion of this course you will be able to:

• describe the architectural principles governing CPU, Storage and I/O
• identify the state of a CPU and describe potential problem scenerios
• use IPCS and the debugging guides
• describe the principles of Virtual Storage
• describe the purpose of AMODE and RMODE
• describe a page fault and its consequences
• set up a flexible paging/swapping subsystem
• explain how dataspaces and hiperspaces work
• describe how an IPL works
• isolate problems during an IPL
• explain the concept of authorised programs.

Who Should Attend

This course is designed for those who wish to gain an in-depth understanding of z/OS systems in order to improve their proficiency in the z/OS environment.

Prerequisites

A good working understanding of the z/OS environment, from a technician's perspective.

Duration

4 days

Fee (per attendee)

£2300 (ex VAT)

This includes free online 24/7 access to course notes.

Hard copy course notes are available on request from rsmshop@rsm.co.uk

at £50.00 plus carriage per set.

Course Code

MSF1

Contents

Architecture

Component overview; Executing instructions; The Program Status Word (PSW);The control bits of the PSW; z/Architecture PSW; Pipelining; CPU components; Timing facilities; Registers in a z/Architecture machine; 64-bit registers and instructions; Using the registers; Updating the PSW; Instruction Length Code (ILC); Multiprogramming; The Load PSW (LPSWE) instruction; Interrupts; Interrupt types; SVC interrupt; I/O interrupt; External interrupt; Program interrupt; Machine check interrupt; Error handling philosophy; Restart interrupt; Interrupt action; The current PSW is saved; Interrupt considerations; System states; System state and the PSW; How the system runs; Real Storage; Addressing mode; Tri-modal addressing mode; Memory boundaries; Storage keys; Key operation; The PSW key fields; Fetch Protect; Multiprocessing; Prefixing; Address types; I/O components; Serial channels; Multiple paths; Real configurations; Hardware Configuration Definition (HCD); Dynamic Reconfiguration Management (DRM); Subchannels; Unit Address; Device Number; Subchannel Numbers; Logical Control Units (LCUs); Channel Command Words (CCWs); Starting an I/O operation; When an I/O interrupt occurs; Obtaining I/O status; The Subchannel Status Word (SCSW); An architectural summary; Review questions; Exercises.

Job Flow in z/OS

Once upon a time; System 360 architecture: Real storage, CPU, I/O; S/370 architecture: Main storage, CPU, I/O, DAS; S/370 XA: Main storage + Expanded Storage, CPU, I/O; ESA/370 and ESA/390; z/Architecture; Operating systems: S/360 operating systems, S/370 operating systems, S/370/XA operating systems, ESA operating systems, z/OS; A sample JOB; The role of MVS; MVS components; Job flow overview; Initialization; Creating a user address space; The Job Entry Subsystem; The initiator; Resource control; Program Manager; SFWJOB executed; Interrupts; Interrupt handlers and status saving; The dispatcher; Requesting I/O; Synchronizing I/O requests: WAIT, POST; The Recovery Termination Manager; The initiator/terminator; The Workload Manager; Job flow review.

Control Blocks, Dumps & IPCS

Introduction; Control block/data area; Information sources: Diagnostic manuals, IPCS manuals, MVS Data Areas Manuals; Control block header; Control block data area map: Data types, Bit flags; Cross reference table; Fields and subfields; Field redefinitions; Control block chaining; Finding control blocks - PSA and CVT; The Prefix Area (PSA); z/OS Prefix Area (PSA); Finding control blocks - UCB: UCB prefix stub (UCBPREFIX), UCB common segment (UCBOB), UCB device dependent segments (UCBMXT &UCBXPX); Dump types; Different dumps and where to put them; Dump formats; What is IPCS?; What comprises IPCS?; DDIR contents; Getting started with IPCS; Default values selection; Primary Option Menu; Data entry panel; Pointer stack panel: Line commands, Pointer types; Sample storage panel; Getting around in IPCS BROWSE: Scrolling and IPCS's PFKeys, 'Stack and Go'; FIND primary command; LOCATE primary command; Data Descriptor - types of addresses: LITERAL ADDRES, X, RELATIVE ADDRESS, SYMBOLIC ADDRESS; Using IPCS subcommands - IPCS; IPCS subcommands; Using IPCS subcommands: CBFORMAT, WHERE; Another WHERE example; Review questions; Exercise.

Virtual Storage Concepts

Introduction; What is a program?; Source code; Turning it into executable code; The compiler, The Binder, Relative Addresses; Real storage; Loading a program into real storage: Relocation, Base displacement addressing; Rules for loading programs; The problems with real storage: Fragmentation, Low MPLs; A solution? - Address translation tables; Find the code when you want it; Dynamic Address Translation; How DAT works?; Segments and pages; Segmentation; So how does DAT really work?; The 64-bit Virtual Address; Virtual address translation and DAT; The Translation Lookaside Buffer: Block numbers, The TLB; Goodbye fragmentation; Hello inactive code: Initialization code, Main functional code, Exceptional condition handling code, Termination code; Page stealing and the UIC: The UIC update process, UIC in z/Architecture; Auxiliary storage; Loading the program: Page stealing, Page out; Page faults; The External Page Table; Demand paging; Goodbye inactive code; MULTIprogramming; Virtual Storage capacity; Multiple Virtual Storages; What is an address space?; 64 bit addressing - region tables; Common storage; Dispatching an address space; Reloading the PSTO; Fixing, thrashing, etc.; Swapping; The dangers of inactivity.

z/OS Storage Management

Introducing, ... the lines; AMODE and RMODE; The z/OS address space - common storage; The Nucleus; The Link Pack Areas; The System Queue Area; The Common Service Area; Extended areas; The PSA; The Common Area boundaries; The z/OS address space - private storage; The LSQA/ELSQA; The SWA; The AUK; The USER region; Multiple address spaces; Identifying the address space boundaries; The GDA; The CVTSMEXT; Virtual Storage is not real!; VSM; RSM; ASM; VSM, the Virtual Storage Manager; SUBPOOLS; STORAGE KEY values; Requesting Virtual Storage; VSM validates...; Cellpools; How much space can I have?; REGION=6M; REGION=48M; REGION=0M (or 0K); A larger address space in z/OS290; 64 Bit Storage Map - memory sharing; Displaying HVSHARE & HVCOMMON; Characteristics of memory objects; Guard area; Using memory objects; The IARV64 'unshared' service; The IARV64 'shared' services and 'common' services; Large page support; LFAREA; How to foil (virtual) land barons!; JES defaults; The JCL REGION=; SMFPRMxx MEMLIMIT; The IEALIMIT exit; The IEFUSI exit; RSM, the Real Storage Manager; Allocating frames; Processing page faults; Table maintenance; Instructs; Page fault resolution: Synchronous, Asynchronous; Segments faults; Allocating Real Storage frames; Fetch protected?; Other characteristics; RSM's own address space; The RASP A/S; ASM, the Auxiliary Storage Manager; RSM's access method; Page Data Sets; The PLPA Page Data Set; The Common Page Data Set; Local Page Data Sets; VIO; Will the data always be in storage?; The address space: VSM, RSM, ASM; Review questions, Exercise - Lab.

Dataspaces and Hiperspaces

Objectives; I/O delay - what does it really cost?; Holding the data in the address space; Dual Address Space; Primary and secondary ASC mode; Dataspaces; Access Registers; Access Register ASC mode (AR mode); Using a dataspace; VLF, the Virtual Lookaside Facility; Hiperspaces; Creating hiperspaces; Review questions.

System Initialisation

Overview; A working system; Installation and initialization overview; Software delivery; I/O definition; Define the devices; Define esoteric group names; Define the NIP Console; HCD - 'active configuration'; LOADxx and the IPL process; Load Unit Address; The Load Parameter; The LOADxx member; IPL overview; The hardware IPL function; The IPL program; Load the nucleus; Load the UCBs; Map the Nucleus; Load NIP; NIP overview; Specifying system parameters; No overriding?; System address spaces; Building the PLPA; Building the FLPA and MLPA; Building the link list; LLA; Trustworthy code; Modeset; The Authorized Program Facility; Authorized libraries; Initialize any other processors; MSI overview; The SubSystem Interface; A communications protocol; IEFSSNxx; The Master Subsystem; How the SubSystem Interface works; Load the Master Scheduler; Starting JES; Processing the command; Starting other work; Review questions.