FPT and WinFPT Reference Manual - Command-line Commands

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Migration - The Objectives

The objectives of a migration are:


A Migration Project

It is recommended that any significant migration project should involve the following steps:
Set Up the fpt Project

Capture the files which make up the code and set up an fpt project. It is recommended that the code is set up in 3 parallel directory structures, each with the same set of sub-directories:

  • an original_source directory tree which is write-protected and contains the directory tree for the code to be migrated;

  • a modified_source directory tree which will contain any files modified by hand;

  • an fpt_output directory tree which will contain the files re-written and systematically modified by fpt.

Please see Keeping a Directory Structure for a description of this procedure.

Check that you have the entire program. If you do not, you will need to create or identify replacements for missing components. The command SHOW MISSING SUB-PROGRAMS shows the routines which fpt has not read.

Check the Code for Errors

It is very important to do this before beginning the migration. Errors are very much less portable than correct code. An array reference out-of-bounds, for example, may hit an entirely different location on the new host and on the old.

Correct any errors and re-test the code on the original system. This version of the code, with the errors corrected, will form the base code for the migration and should replace the code in the original_source directory tree.

Plan Testing of the Migration
Plan the testing early in the migration. Set up a test suite which can be run quickly and easily on the original host. The record / replay facility may be valuable in setting this up.
The Migration Commands

Script the Commands to carry out the migration. As far as possible, maintaiin the code base which will compile and run on the original host and generate the migrated code automatically.

Attempt to make no changes to the code which are not required for migration. Changing the structure of the code may introduce errors or changes which will make comparison of the two systems more difficult.

The migration commands are described here.

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