Trap Diagnostic Facility Todays Software Diagnostic Tool with innovative features for the z/OS...

Trap Diagnostic Facility

Today’s Software Diagnostic Tool

with innovative features for the z/OS software developer

Arney Computer Systems

Topics: Dynamic Program Intercepts (DPI)

• Diagnosis with no boundaries

• Intercepting startup

• SVC screening

• PC screening

• Branch Entry Intercept Breakpoints

• Inheritance and pass-through

Click for more information

Copyright Arney Computer Systems 2012-2014 2

http://www.arneycomputer.com/tdf/presentation/slide2.html

Topics: ISPF User Interface

• Menu and panel driven

• Connecting sessions and targeting subtasks

• Symbols

• Single step tracing

• Breakpoints and triggers

• Displaying and zapping storage

• Session recording and scriptingClick for more information



Topics: Advanced Features

• Program identification

• Dynamic non-interactive tracing

• Grouping tasks into single diagnostic unit

• Remote Debugging Facility

• Amode and Rmode 64-able




Dynamic Program Intercepts: Diagnosis with No Boundaries

• Uses z/Architecture Trap Instruction

• Unaffected by applications RTM exits such as ESTAEX

• Executes in all z/OS environments; task, SRB, cross memory, locked, and so forth

• Does not require any program modifications to use any features




Dynamic Program Intercepts: Startup Intercept

TDFHOOK startup intercept

• Replace EXEC= for specified system startup

• Specify program as PARM= followed by the application’s parameters

• Breakpoint is dynamically inserted after program load and before program is executed




Dynamic Program Intercepts: SVC Screening

Allows interception of target programs in ATTACH,LOAD, LINK and XCTL SVC calls

Allows interception of RTM exits in SPIE, ESPIE, STAE, and ESTAE SVC calls

Inserts automatic system breakpoints in key points in these calls

Does not modify any programs




Dynamic Program Intercepts: PC Screening

Allows interception of target programs using ESTAEX

Allows interception of target programs using IEAMSCHD to schedule SRBs

Inserts automatic system breakpoints in key points in these calls

Does not modify any programs




Dynamic Program Intercepts:Branch Entry Intercept Breakpoints

Allows interception of branch entry calls such as SETFRR

Operates like other dynamic intercepts except it is specified by a breakpoint

Set using the BEI command in the User Interface

Click for more informationCopyright Arney Computer Systems 2012-2014 9


Dynamic Program Intercept: Inheritance and Pass-Through

Allows debugging the target program without hooking any of the programs that attach it

Target programs that are loaded, linked, or XCTLed by inherited task are not hooked

Allows debugging shared code without affecting non-debugged tasks




ISPF User Interface: Menu and Panel Driven

Ease of Use

• Menu items to setup session, gather diagnostics, and perform utility functions

• Both line mode and panel driven command entry

• Responses are saved in a memory object allowing scrolling of prior responses





http://www.zosdebug.com/presentation/slide11.html

ISPF User Interface: Connecting a Session

Programs in breakpoints are placed in a system queue

ISPF list panel shows current list of programs and their status

From list, a user can connect, end or release a dispatchable unit




ISPF User Interface: Targeting Subtasks and Shared Code

Program intercept command allows specifying target programs for SVC/PC screening

Program identification command allows specifying shared code (private and common) and unidentified code

Target programs that are loaded, linked, or xctled by inherited task are not hooked

Click for more informationCopyright Arney Computer Systems 2012-2014 13


ISPF User Interface: Symbols

• Programs are automatically assigned symbols

• Can be user defined

• Can be used in any command instead of an absolute value

• Can have properties: Name, Value, PC#, ASN, Length

• Makes a recorded session reusable Click for more information



ISPF User Interface: Single Step

• Allows the tracing of a program, instruction by instruction

• Supports Program Call (PC) and Program Returns (PR)

• Ranges can be specified to limit the trace to one or more address ranges

• Automatically skips calls into system code




ISPF User Interface: Breakpoints

• Setting breakpoints allow stopping a program at designated points Can be set by placing the TDFHOOK

macro in the program source Can be set via command

• A command breakpoint is single use and removed when encountered




ISPF User Interface: Triggers

• Triggers are breakpoints that trigger setting another breakpoint

• Used to set a breakpoint in common code when called from a specific point

• Can only be set by command




ISPF User Interface: Displaying storage

• Any storage accessible by the debugged task can be displayed

• Many MVS control blocks can be formatted using the AS keyword

• Display has commands to display formatted data such as task structures and PC structures




ISPF User Interface: Zapping storage

• Can be entered as a line mode command

• Can be entered in a panel which will retrieve the verify data allowing confirmation before the replace

• Can be displayed via a display command and using the ZAP option overtyped in full screen mode




ISPF User Interface: Session Recording

• All commands entered in a session can be recorded

• Session recording can be edited

• Session recording can be saved and executed in a later session or at a remote site




Advanced Features: Program Identification

Identification of programs reused between system startups

Identifying unidentified programs for use in symbols

Identifying shared CSA programs for targets in traps

Identifying shared code attached multiple times




Advanced Features: Dynamic Tracing Facility (Future feature)

Specifically designed for use in the Remote Debugging Facility

Non-interactive collection of specified data

• Specified PSW and state information

• Access, Control and General Purpose Registers

• Specified data areas up to 2K total size




Advanced Features: Grouping (Future feature)

• Allows treating any number of tasks across any number of address spaces as a single diagnostic unit

• Used in conjunction with dynamic tracing to resolve complex inter-task issues

• Used in conjunction with symbols and session recording to create scripts for Remote Debugging Facility




Advanced Features: Remote Debugging Facility (Future feature)

TDF is designed to not only provide the developer with the ability to debug code but to also:

• Create scripts that can be executed offsite with a distributable component

• The offsite user executes job using script

• Data is shipped back and analyzed




Advanced Features: AMODE and RMODE 64

• Uses server with 64 bit memory object to track debugging sessions Isolates diagnostic storage from application Minimizes diagnostic footprint in the

debugged address space

• In, z/OS 1.13 and later, about half of TDF can execute above the bar




Trap Diagnostic Facility

Today’s Software Diagnostic Tool

for today’s software developer

www.zosdebug.com

www.facebook.com/arneycomputer

Arney Computer Systems

http://www.zosdebug.com/

http://www.facebook.com/arneycomputer

Trap Diagnostic Facility Todays Software Diagnostic Tool with innovative features for the z/OS...

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