HP 3000 Manuals HP 3000 Manuals
Avoiding Common Problems
You might encounter a number of problems during migration. Most of these
problems are described in chapter 17, "Evaluating Changes You Need to
Make." However, there are some additional problems. These are problems
you can overcome:
* Lack of HP 3000 knowledge
* Underestimating migration time
* Unplanned modifications
Information about overcoming each of these problems follows.
Lack of HP 3000 Knowledge
Your migration will be easier if you already have some experience on the
HP 3000. If you do not have experience working on the HP 3000, take the
courses listed in "Learning How to Use MPE XL" in this chapter.
There are basic architectural differences between the HP 260 and the HP
3000. Be prepared to deal with the basic differences between the two
machines. If you are not prepared for these differences, migration
time might be extended while you try to plan new work methods.
The architectural change is one of the primary reasons for the
incompatibilities between IMAGE and FORMS. Programs that rely heavily on
features that are dependent on HP 260 architecture might be difficult to
migrate. Although the HP 3000 has subsystems to perform the functions of
some of these features, performance sometimes suffers. You will notice
that some features (like writing to the terminal) are slower on the HP
3000. Try to take advantage of the features that are faster on the HP
3000. This process takes time.
Underestimating Migration Time
The migration process is a series of steps. Most of the work is done
automatically by the migration aids. Be sure to allow time for moving
files to the HP 3000. Moving large applications and databases can take a
long time.
An overloaded development system hampers the migration effort, too.
Consider the number of users and the disk requirements when you move to
an HP 3000. Underpowered development systems can not provide adequate
response time; this slows the migration process.
The interpreter is generally too slow for a production program, so
compile your programs. Also consider what routines (if any) you want to
share among applications by putting them in an executable library (an
XL). Placing routines in an XL requires additional planning for entire
applications, not just individual programs.
Interpreter performance and compiler performance are two different
things. Sometimes the compiler can optimize executable code; the
interpreter can not do this. Migrated applications usually execute
dramatically faster when you make these changes and use compiler options.
Unplanned Modifications. Plan necessary modifications to code.
You can identify needed modifications by running individual programs
through the migration aid. The migration aid issues warning messages
whenever it finds a feature it cannot translate. Untranslatable features
are features that either do not exist in HP Business BASIC/XL or whose
behavior is noticeably different. The warning gives the line number
where the untranslatable feature was found. The migration aid adds the
following text to the line that contains the untranslatable feature:
CAUSE ERROR 1900 !***
The name of the untranslatable feature follows the exclamation point and
asterisks. Execution of this line generates error number 1900. The
error prevents generation of incorrect results in your migrated programs
and flags potential problems.
Look up the untranslatable features and see what is involved in changing
them to HP Business BASIC/XL. Untranslatable features are documented in
chapter 17, "Evaluating Changes You Need to Make," and in the online help
facility, available when you are in the migration aid (BBCT250.PUB.SYS).
From the migration aid prompt, just type "HELP" then the name of the
feature as it appears in bold in the warning.
This gives you a chance to plan necessary revisions or recoding before
actually beginning the migration.