Course Code: 930
Length: 5 days

This course presents a detailed look at the various components, data structures and mechanisms used to implement the OpenVMS Alpha operating system. Topics include memory management, Files-11, and Booting OpenVMS. The basis of this offering will be toward the OpenVMS System Programmer. The materials will include SDA displays from live systems and kernel mode programs, in addition to the usual flow descriptions and data structure diagrams.

The course features giving the system programmer a living big picture of the operating characteristics and the interrelationships of the major OpenVMS subsystems. The majority of code will be presented in the C language and will be current as of Version 7.2 of OpenVMS. The Programmer should understand the implications of coding choices made when running in kernel mode and accessing components of OpenVMS subsystems. Along with coding, the Programmer should understand the impacts of SYSGEN parameter modification, as it affects the operational and performance characteristics of the system. The in-depth understanding of all major subsystems should aid in troubleshooting both crashes and hangs of the operating system. This understanding becomes more crucial as the complex web of OpenVMS becomes more intricate with recent changes in virtual addressing, threads, and the I/O subsystem. Students will come to learn the purpose and functional characteristics of data structures relating to the I/O and memory management subsystems. The student will also be made aware of the synchronization techniques required to access these subsystems in a clean fashion.

Who Should Attend

OpenVMS System Programmers

Prerequisites

Before taking this course, students should be able to:

• Complete the OpenVMS Alpha Programming Features I and II, and Internals I and II courses
• Read and ideally write code, in VAX macro
• Ability to program in DEC C

Benefits of Attending this Class

Upon completion of this course, students will be able to:

• Describe the dynamics and data structures associated with image activation
• Develop a better understanding of the metrics associated with paging
• Describe the data structures, dynamics, and performance considerations associated with FILES-11 volumes and files, as well as the run time processing of the extended QIO procedures (XQP)
• Describe the image activation process and its relationship to paging
• Describe the working set algorithms under OpenVMS
• Size process working sets
• Interpret paging metrics
• Set working set adjustment related SYSGEN parameters
• Analyze the layout of an image file
• Track page file usage
• Describe the layout and functions of data structures within the I/O database
• Describe the role of a driver in I/O processing.

Course Contents

MEMORY MANAGEMENT: IMAGE ACTIVATION

Memory Management Concepts
Virtual Address Translation
The Process Header
Creation of an Image File from Source Code
Image Activation
Layout of Virtual Address Space
Layout of Process Section Table
Layout of Working Set
Clustering on Pagefault Reads

MEMORY MANAGEMENT: PROCESS PAGING DYNAMICS AND STRUCTURES

Evolution of a Page Table Entry
Image and Process Sections
The Working Set List and Automatic Working Set Adjustment
The PFN Database
The Free Page List
The Modified Page List
Determining Pagefile Usage
Interpreting the $MONITOR Page Display
Swapper and Memory Reclamation Related Activities

MEMORY MANAGEMENT: GLOBAL PAGING

Shared Images and Global Sections
Global Section Data Structures
Global Section Dynamics
Known Files
Listing Known File Data Structures
The System Header

MEMORY MANAGEMENT: "BIG PICTURE" REVIEW

Image Activation
Making a Page Valid
Dynamics of a Page on the Free or Modified Page List
Dynamics of Page No Longer in Memory
Swapping Related Structures
The System Header

I/O: FILES-11

Files-11 Concepts
Directories
The File Header
The Files-11 Reserved Files
Examples of Usage of the Home Block and Index File to Locate File Headers

I/O: XQP STRUCTURES

The Extended QIO Procedures
File Open Related Data Structures
Data Structures Relating to Mounted Volumes
Locating the Volume Data Structures
Split IOs and Window Turns
File System Caching Parameters
Monitoring File Caching Effectiveness

GALAXYWIDE SHARED MEMORY SECTIONS

Galaxywide Shared Sections
Shared Page Tables

GALAXY LOCKS

OpenVMS Galaxy Locks

BOOTING/HALTING

General Booting Order
Console Actions
APB
SYSBOOT
EXEC_INIT
The SWAPPER
SYSINIT
SYS$MANAGER:STARTUP.COM
Shutting the System Down