Q48399: Why QuickBASIC Is Incompatible with Many TSR Programs

Article: Q48399
Product(s): See article
Version(s): 4.00 4.00b 4.50
Operating System(s): MS-DOS
Keyword(s): ENDUSER | SR# S890801-3 B_BasicCom | mspl13_basic
Last Modified: 13-DEC-1989

This article summarizes Microsoft's response to the question of why
many TSR (terminate and stay resident) programs are incompatible with
Microsoft QuickBASIC for the IBM Personal Computers and compatibles.

For similar information regarding hardware incompatibility, query
on the following words:

   incompatible and video and hardware and QuickBASIC

This information applies to Microsoft QuickBASIC Versions 4.00, 4.00b,
and 4.50 for MS-DOS and to Microsoft BASIC Compiler 6.00, and 6.00b for
MS-DOS and MS OS/2, and to Microsoft BASIC PDS 7.00 for MS-DOS and
OS/2.

The QuickBASIC environment is a highly sophisticated development tool
tuned for simultaneous usability, speedy performance, and efficient
size, insuring a maximally responsive environment while retaining
capacity. One technique used to achieve this goal was to hand code the
majority of the speed-critical areas in assembly language, including
all parts of the language engine and I/O support. Our constant aim is
to create program development environments that are unmatched in the
areas of responsiveness and programmer productivity. The alternative
is to have a text editor environment capable of spawning off what are
fundamentally command-line tools.

The result of this challenging objective is a dynamic technical
accomplishment -- the QuickBASIC environment allows you to climb
inside the language "engine" and vary the execution paths, manipulate
your data, and edit and test your source code all without recompiling.
If QuickBASIC is ill-behaved when TSR software is also present, it's
the sort of behavior that hundreds of thousands of QuickBASIC
programmers have decided is well worth the cost for the benefits it
delivers.

The conflict with TSR software is difficult to avoid in the
ultrasophisticated low-level technology of QuickBASIC's magnitude.
While we make every effort to retain TSR and hardware compatibility,
we are faced with the challenge of identifying those configurations
that are important enough to support with added code (thus sacrificing
environment capacity), while trying to retain the maximum speed and
work space that the majority of users, not using that specific
configuration, not only appreciate but demand.

The alternative for people who want environments that do not take over
the machine is the more traditional and less responsive text editor or
command-line compiler programming technique, which is certainly
available to all QuickBASIC owners. But for those who appreciate the
unique advantages of BASIC in its instant environment and do not want
to trade productivity for low-level machine control, QuickBASIC is
available for them. And for many people, this is a very reasonable and
acceptable trade-off.

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