ZOS

1
Z/OS

• Di Wang
• CS502 Term Project Report

2
Outline

• Z/OS Overview
• What is it?
• How big is it?
• What is its market?
• Z/OS Principles
• Task management
• Memory management
• File System
• I/O management
• Other essential features

3
Z/OS Overview

• What is it?
• Mainframe operating system
• -- Why mainframe?
• History of IBM mainframe OS
• IBSYS 1950s
• DOS/360 1966
• MVS 1974
• OS/390 1995
• Z/OS 2000

Latest stable release V1.9 September 28 2007
4
Z/OS Overview

• Welcome screen

5
Z/OS Overview

• How big is it?

Up to 54 processors per LPAR
127.75K channels
Up to 60 LPARs On a single server
up to 4 TB of real memory
6
Z/OS Overview

• Targets
• Enterprise Data Serving
• Enterprise Security
• Enterprise collaborative computing and SOA
• Workload management and resource optimization
• Market
• Enterprise on-demand business.
• It is positioned as a platform to manage and
  integrate IT operating environment

7
Outline

• Z/OS Overview
• What is it?
• How big is it?
• What is its market?
• Z/OS Principles
• Architecture
• Task management
• Memory management
• I/O management
• File System
• Other essential features

8
Z/OS Principles

• Architecture
• Subsystem software that operates in its own
  address space under the control of MVS
• Facility software that works under the control
  of MVS and provides interactivity to the user.

Time Sharing Option
Job Entry Subsystem
Customer Information Control System
DB2
Z/OS
Resource Access Control Facility
System Management Facility
Language Compiler, Linker, Loader
9
Z/OS Principles

• Task management
• Batch processing -- non-interactive, off-line
• Job -- cause one or more programs to execute
• JCL -- describes a batch job
• Job Scheduling
• Based on a complex schema of separate job
  classes.

10
Z/OS Principles

• Memory management
• Channel a path between a processor and I/O
  devices
• Hardware support
• Huge real memory
• cut down on paging and swapping

11
Z/OS Principles

• I/O Management
• I/O subsystem
• Workload Manager
• dynamically allocate or distribute server
  resources
• run multiple tasks across multiple images
• Connectivity
• ESCON
• FICON

12
Z/OS Principles

• File System
• File storage schema
• VTOC to locate the data sets that reside on a
  particular disk volume.
• A VTOC is added to a disk when it is initialized

13
Z/OS New Features

• Good News
• IBM will be investing about 100 million on the
  mainframe in next five years
• IBM mainframe was its only server line to have
  increased revenues last year
• Flexibility, scalability, security
• Larger capacities
• Unix System Services
• XML System Services

14
Z/OS

• Questions ?