JGS™ CLP Decompiler Product Description

ABSTRACT

Every computer program stores the same information in two different computer languages. The first is called the source language and consists of English-like instructions which can be understood by humans. If a programmer wishes to change the task which a program is to perform s/he changes the instructions contained in the source. However, these instructions cannot be understood by the computer. The computer can only process instructions written in machine language. In order to run the program, the source instructions must be run through a language translator called a compiler. The compiler creates a new version of the program, one written in machine language. In other words, the compiler translates programs written in a language understandable by humans into a language understood by the computer.

As long as the machine language version of the program exists on the computer system, the program can be run, and as long as the source language version exists on the system, the program can be modified, enhanced or debugged by the programmer. If the machine language version is accidentally destroyed, the source can be run through the compiler again, and a new machine instruction version is generated. But, if the source is accidentally destroyed, it can only be reached by the use of a decompiler, a programmer's tool which reverses the process of the original compiler.


MACHINE REQUIREMENTS

AS/400 ENVIRONMENT: The JGS utility will run on all models of the AS/400 system. Version 3 Release 1 or above of OS/400 is required.

DESCRIPTION

CAPABILITIES: JGS CLP generates new CLP source members from compiled CLP program objects which have been compiled using the ALWRTVSRC (*NO) option. The new source members are Functionally Equivalent to the original source members.

PERFORMANCE: Current benchmarks put the time required to decompile a program at approximately three times (3x) longer than the time required to compile the source member. That is, a member which would take 2 minutes to compile would take 6 minutes to decompile.

HIGHLIGHTS

Enhances/increases user programmer productivity in several problem solving areas:

	Determines which of several source members corresponds to currently running object programs.
	Retrieves modifications in current object missing from current source.
	Delivers Best Price/Performance for Recreating Existing Code.
	Simplifies Migration to New Platforms.
	Protects Investment in Existing Software for Which Source is Not Available.

SECURITY

Each copy of JGS CLP is tied to a particular CPU via the systems unique serial number to prevent unauthorized duplication of the software. In order to decompile a program object, the user must have *ALLOBJ authority over the object to be restored and *CHANGE authority to the source physical file where the new member is to reside.

LIMITATIONS

JGS CLP currently supports decompilation of CLP program objects compiled under CPF rel 8 through OS/400 V5R2.