Introduction to Debugging
TheVM/370 Control Program manages the resources of a single computer
such that multiple computing systems appear to exist. Each"virtual computing system,!! or virtual machine, is the functional equivalent of
an IBMSystem/370. Therefore, the person trying to determine the cause
of aVM/370 software problem must consider three separate areas:
1. The Control Program(CP), which controls the resources of the real
machine.
2. The virtual machine operating system running under the control ofCP, such as CMS, RSCS, OS, or
machine operatingCP or CMS is contained in this
book; information explaining how to debug applications programs is in
theVMLJ70
theVM/370 Interactive Problem Control System (IPCS) for debugging,
refer to the(IPCS) IPCS problem is caused by a virtual machine operating system
(other thanCMS and RSCS), refer to the publications pertaining to that
operating system for specific information. However, use theCP debugging
facilities, such as theCP commands, to perform the recommended
debugging procedures discussed in the other publication.
If it becomes necessary to apply aPTF (program Temporary Fix) to a
component ofVM/370, refer to the VMLJ70 PTFs,. How to Start Debugging
Before you can correct anyproblem
6 you must recognize that one existse Next, you must identify the problem, collect informaticn, and determine
the cause so that the problem can be fixed.When running VM/370
1 you
must also decide whether the problem is inCP, the virtual machine, or
the problem program.
A good approach to debugging is:1. Recognize that a problem exists.
2. Identify the problem type and the area affected.
3. Analyze the data you have available, collect more data if you need
it, then isolate the data that pertains to your problem.
4. Finally, determine the cause of the problem and correct it.Part 1. Debugging with VM/370 3
The
such that multiple computing systems appear to exist. Each
an IBM
of a
1. The Control Program
machine.
2. The virtual machine operating system running under the control of
machine operating
book; information explaining how to debug applications programs is in
the
the
refer to the
(other than
operating system for specific information. However, use the
facilities, such as the
debugging procedures discussed in the other publication.
If it becomes necessary to apply a
component of
Before you can correct any
6
the cause so that the problem can be fixed.
1
must also decide whether the problem is in
the problem program.
A good approach to debugging is:
2. Identify the problem type and the area affected.
3. Analyze the data you have available, collect more data if you need
it, then isolate the data that pertains to your problem.
4. Finally, determine the cause of the problem and correct it.
