HP 3000 Manuals HP 3000 Manuals
Learning How to Use MPE XL
There are many architectural differences between the HP 260 and the HP
3000.
These differences extend to the environments of the two machines. If you
have not previously used an HP 3000, take any of the following courses
that apply to the products you use and the tasks you perform:
* Using the 900 Series HP 3000
Part Number pending
* 900 Series HP 3000: Programmer's Skills
* 900 Series HP 3000: System Operation Skills
* 900 Series HP 3000: System Management Skills
* VPLUS/3000 for Programmers
* TurboIMAGE DBMS/3000
Some differences between the HP 260 environment and the HP 3000
environment are discussed below. Many HP 3000 subsystems are similar to
those on the HP 260. Familiarize yourself with the new environment and
the commands needed for using the subsystems. Refer to the MPE XL
Reference Manual for more information about the HP 3000 environment.
The HP Business BASIC/XL interpreter can cause a heavy machine load.
This affects the performance of everyone using the system. Low-end
machines need plenty of memory to insure the full performance benefits of
the HP 3000.
Other suggestions depend on specific applications you are using.
Using the Compiler
In addition to an interpreter (the implementation of BASIC that exists on
the HP 260), HP Business BASIC/XL provides the ability to compile
programs. The program statements are translated into HP Precision
Architecture machine instructions, then your HP Business BASIC/XL program
executes as a separate, independent process. Performance improvements
for most applications are substantial. The overhead of running the
interpreter is also eliminated. Because BASIC/260 is strictly an
interpreter, that language includes a number of program statements that
are not compilable. Execution of these statements requires information
that is not available until run time, so the machine instructions cannot
be determined during compilation. The statements listed below are not
supported in compiled applications. Remove them from production programs
that will be compiled.
COMMAND GETSUB SECURE
DEFAULT MERGE TRACE
DELETE RESAVE PAUSE
LINK SAVE
GET SCRATCH
The statements above produce compile-time warnings. Most of them produce
run-time errors when they execute. (TRACE and PAUSE are ignored and you
can leave them in the program.)
You can skip these statements when you run your program by using the HP
Business BASIC/XL function, INTERPRETED in the predicate of an IF
statement that contains the statement. The function, INTERPRETED,
returns true when you execute a program in the interpreter, and false
when you execute the compiled version. The migration aid often uses this
function when changing the above statements.
The following HP 260 line is an example:
GETSUB "mysubs"
This is the migrated version of the BASIC/260 line above:
IF INTERPRETED THEN GETSUB "mysubs"
COMPILER OPTIONS. Compiler options, such as NO HALT CHECKING, NO ERROR
HANDLING, NO RANGE CHECKING, and NO REDIM, can make a big difference in
the amount of code generated and in the overall performance of a program.
In HP Business BASIC/XL, when you do not use compiler options, the
compiler produces code for error and exception handling that your
application might not need.
For more details about specific compiler options, refer to the the HP
Business BASIC/XL Reference Manual.
Use the ANALYST environment in the interpreter to estimate code savings
for specific compiler options.
Softkeys
Softkeys work differently on the HP 3000 than they do on the HP 260.
This affects both the general program flow and responses to any of the
input statements in HP Business BASIC/XL. The OPTION INPUTLOOPS command
(used in the migration aid) simulates HP 260 softkey behavior to control
input.
On the HP 260, softkeys can interrupt a program at any time, just as the
HALT key can. Specifically, softkeys can interrupt program when input
has been requested. After processing softkeys, the HP 260 program
continues to wait for input; softkeys do not terminate input statements.
On the HP 3000, however, you can only use softkeys when input is
requested. Softkeys can not be used for general program interrupts.
Softkeys terminate input statements in HP Business BASIC/XL. Any data
entered before you use a softkey is lost.
Relative Speed of Screen Updates
Screen updates are slower in HP Business BASIC/XL because MPE XL machines
do not use memory-mapped terminal buffers. Buffers provide an easily and
quickly accessible storage area in BASIC/260: BASIC/260 programs share a
storage area with the 260 terminal.
Slower screen updates are most noticeable in JOINFORM and other 260
applications that directly access the terminal. Change your JOINFORM
forms to VPLUS forms to maximize screen update speed and overall HP 3000
performance.
To minimize the effects of slower screen updates on your JOINFORM
applications, do the following:
* Avoid extra softkey changing.
* Eliminate redundant field clearing/updating.
* Cache data reading from screen.
Missing Features
The statements and features listed below refer to BASIC/260 hardware and
software features that are not applicable to MPE XL machines.
ATTACH# MEDIA/2501
BUFFER# Multitasking2
CATFILE PERFORM3
CATLINE PRINT LABEL
CHECK READ OFF#/ON# READ LABEL
Data Communications RELEASE#
DETACH REQUEST#
DIRECT RESTORE BIN
DOOR LOCK/UNLOCK SET DATE TO
DUPTEST SET TIME TO
Graphics SPACE DEPENDENT/INDEPENDENT
INDIRECT STORE BIN
LOAD BIN TIO/2504
Notes
1. HP Business BASIC/XL cannot read from or write to IBM diskette
media. However, there is a utility (DISCCOPY/3000) that can move
data from an IBM floppy disk to an HP 3000. See the FLEXIBLE
DISCCOPY/3000 User's Guide for details.
ASSIGN;EBCDIC DUPLICATE
ASSIGN;EBCDIK IBMDUMP
CREATE;CHAR IBMWREC
DELETE# LINPUT#
2. MPE XL has some intrinsics that allow you to control multiple
tasks. These intrinsics are different from multitasking on the
260. Refer to the process control section of your MPE XL
Intrinsics Manual.
3. Although MPE XL does not provide a facility like PERFORM, many
emulators (such as AdvanceLink and Reflection) provide record and
playback of keyboard interaction. To record and playback keyboard
interaction of VPLUS applications, use the Forms Tester. Forms
Tester only works within VPLUS.
4. The following statements are part of TIO/260. Some of these
capabilities are available through MPE operating system services.
You can replace the BREAK ON/OFF and ECHO ON/OFF statements with
calls to the MPE intrinsic FCONTROL. Refer to the MPE Intrinsics
Reference Manual for more information about the following
statements.
AREAD$ ON/OFF DISCONNECT#
BLOCK MODE ON#/OFF# ON/OFF INPUT#
BREAK ON/OFF ON/OFF OUTPUT#
ECHO ON/OFF ON/OFF TRIGGER#
ON/OFF BREAK# SEND#
ON/OFF CONNECT# SEND BREAK#