Introducing DESQview 2.0 API Tools
Bringing new power to DOS.
For us, it's an unveiling of pleasure.
In the DESQview 2.0 view of the world there are three kinds of
DOS programs.
There's the DESQview-oblivious program, such as 1-2-3 or AutoCAD,
written with no consideration of DESQview, but still compatible
with DESQview.
There's the DESQview-aware program. It has been modified slightly
so that it runs efficiently in DESQview and concurrently with
other programs. Paradox, dBASEIII, and WordPerfect are
DESQview-aware.
Then there's the DESQview-specific program, like the DESQview
Datebook. It's written to take advantage of DESQview's power.
We've kept the knowledge of how to write DESQview-specific
programs under wraps too long. But if you look closely, you'll
discover DESQview 2.0 behind ICL North America's point of sale
system, MCI International's communication workstation, and
Strawberry Software's market research program, A-Cross, to name
only a few.
For you, a cornucopia of treasure.
Hidden deep inside DESQview 2.0 is a powerful API (Application
Program Interface) that lets programs control and interact with
DESQview and with other programs running in DESQview. For MIS and
DP departments building workstation solutions, the DESQview 2.0
API provides enormous benefits. For it brings OS/2 capabilities
(and even OS/2 look and feel if desired) to DOS.
Using the DESQview 2.0 API, a program can use all the DESQview
2.0 menu functions available to the user as well as the
power-packed capabilities built into DESQview--multitasking,
windowing, intertask communications, mailboxes, shared programs,
memory management, mousing, data transfer, menu-building, and
help.
So DOS programs can now act alone or together. Either within a
window or hidden behind one, they can do chores in silence or in
chorus, all the while utilizing the full power of DESQview, all
the while bringing you treasures you only dreamed 'til now were
possible.
The inner power of DESQview
A program taking advantage of the DESQview 2.0 API can display
information in windows and control the color, dimensions,
position and ordering of windows on the screen.
It can disable, limit or enhance the standard DESQview user
interface. Which means that you can have DESQview-like menus in
your program. Or menu bars and pull-down menus. Or IBM SAA-like
menus.
It can let DESQview handle all keyboard and mouse input to menus
and forms--yet still process keyboard and mouse input directly
when necessary.
It can schedule processing after a certain time interval or at a
certain time. It can spawn subtasks for performing background
operations such as printing, recalculating, and communicating. It
can communicate between the various tasks in the system.
Multitasking
DESQview supports true multitasking of existing DOS programs in
addition to programs written specifically for DESQview. So a user
can run multiple programs (Lotus 1-2-3, dBASE III and others) and
DESQview-specific programs (DESQview Datebook, Calculator, your
own program) concurrently. So a user can switch to whichever
program needs input and switch away while the program
recalculates or sorts in background.
Under DESQview, each program runs in its own "virtual machine",
thinking it has exclusive access to DOS, the keyboard, etc.
DESQview calls these virtual machines "processes".
DESQview calls the portion of a process that keeps track of which
instruction to execute next and what the register contents are a
"task" (or "thread"). Every program running under DESQview
consists, initially, of a single process running a single task.
DESQview-specific programs may create additional tasks within
their own processes and additional processes. Additional tasks
allow a portion of your program, the part that controls the
printer for example, to be run in background. Additional
processes allow whole new programs to be loaded and run
concurrently.
Presentation Management
Because DESQview lets you run more than one program at a time,
DESQview provides a way to view more than one program at a time
on the screen. DESQview does this by mapping each program into
its own "window" and by managing the display of multiple windows
on the screen.
To DESQview, windows are rectangular areas of displayable
information. They may be moved, resized, colored, and reordered
by either the user or by your program. Everything that is
displayed on the screen under DESQview is displayed in a window.
Multiple windows are not only useful for displaying several
programs simultaneously, but may also be used within a single
program to display menus, help screens, error messages. DESQview
provides facilities for storing complete descriptions of such
windows, (known by DESQview as "panels"), on disk or in your
program and displaying them with a single call to the API. These
panels may be as simple as one-line error messages or as complex
as data entry forms with multiple-choice and data entry fields.
Once a panel has been displayed, your program can ask DESQview's
"field manager" to process all user input to the panel including
mousing and data entry editing. The field manager returns the
results to your program in a simple, field-oriented format,
independent of the appearance of the panel.
The use of panels and the field manager not only simplifies the
job of programming an application, but gives a consistency to the
user interface that makes the learning of new applications
easier.
Intertask Communications
So that DESQview-specific programs can rapidly exchange
information, DESQview provides a wide range of intertask
communications facilities. These facilities allow several
concurrently running tasks to exchange information or signals, to
lock access to common resources, to share common code and data,
and to interrupt each other to handle critical events. These
tasks can be in either the same or in different processes.
Intertask communication is the key to building complex
applications in a multitasking environment. Let's say, for
example, you are building a point of sale system, that handles a
dozen cash registers for a department store. Using DESQview you
could break your application up into fourteen tasks; one for each
of the cash registers, one to handle access to the pricing data-
base, and one to track sales and generate management reports. The
cash register tasks would process keystrokes from the clerk until
an item price is needed. They would then send a message to the
database task requesting the price. The database task would log
the sale and return the price to the sender of the request.
Meanwhile, the store manager could interact with the reporting
task to monitor sales, clerk performance, etc.
Data Transfer
DESQview supports two types of user-initiated data transfer. The
first type, called Mark and Transfer, lets a user mark text in
any window and transfer that text to any other application. The
application receiving the data can be DESQview-oblivious, seeing
the data as normal keyboard input.
More sophisticated transfers are possible between
DESQview-specific applications that support the DESQview Scissors
command. When the user marks data in such an application,
DESQview notifies the application that data has been requested
and lets the application determine exactly what data to supply.
The application may supply anything including text, formulas, or
even graphics images. When the user instructs DESQview to Paste
the data into another application, that application is also
notified so that the data can be handled appropriately.
The applications involved in a Scissors transfer can even use
DESQview's intertask communication facilities to setup a
"hot-link" between themselves so that subsequent changes to the
data are automatically reflected in both applications.
Memory Management
Programs running under DOS are typically given all of a PC's
memory to do with as they please. In a multitasking environment,
memory must be managed so that more than one program can be
loaded at a time and so that no single program is given more
memory than it needs. DESQview provides this management in a way
that adapts to the type of memory hardware available on your PC.
If your PC has 640K of conventional memory, DESQview is able to
multitask as many programs as will fit in memory at the same
time. Additional programs can be loaded but will cause the least
recently used programs to be suspended and swapped to disk to
make room in memory for the new ones.
If you have EMS 3.2 (Lotus-Intel-Microsoft Expanded Memory),
DESQview will swap programs to expanded memory instead of to
disk. This is so much faster than swapping to disk that the swap
time is almost not noticeable.
If you have EMS 4.0 or EEMS (AST-Quadram-Ashton Tate Enhanced
Expanded Memory) or a 386-based PC with an EMS 4.0 driver,
DESQview can actually multitask as many programs as will fit in
conventional and expanded memory. This can be as high as
32-Megabytes worth of programs. DESQview can also run a large
part of itself in expanded memory, giving a much larger maximum
program size.
Customization
Although DESQview is best known for its ability to run
off-the-shelf software concurrently, DESQview is an ideal
platform for developing customized vertical market applications
and workstations. In addition to providing multitasking and
windowing services, DESQview can be customized to provide the
user interface appropriate to a particular application.
This customization can take the form of restricting access to
certain DESQview menus, taking special action when certain menu
items are selected, or, in the extreme, disabling all access to
DESQview menus and providing the entire user interface as part of
the application.
In this latter case, the only part of DESQview that the user sees
is a copyright screen during start-up.
Portability
DESQview with its entire API runs on 8088, 8086, 80286 and 80386
PCs as well as the IBM Personal System/2s. This means that an
application that you write to be DESQview-specific can run on any
PC from a laptop dual-floppy PC to the very latest 386-based PC.
It can even run over a network on a diskless PC. Thus, the market
for your DESQview-specific application extends to the entire base
of existing and future DOS PCs.
DESQview 2.0 API Tools
Quarterdeck is developing a full set of tools to assist
developers in creating DESQview-specific programs and
workstations. The first five of these tools are:
DESQview API Reference Manual
This is the primary source of information about the DESQview API.
It contains all you need to know to write assembly language
programs that take full advantage of DESQview's capabilities.
The Reference manual comes with an include file containing
symbols and macros to aid you in development. AVAILABLE NOW!
DESQview API C Library
The DESQview API C Library provides C Language interfaces for the
entire set of API functions. It supports the Lattice C, Metaware
C, Microsoft C, and Turbo C compilers for all memory models.
Included with the C Library package is a copy of the API
Reference Manual and source code for the library. AVAILABLE NOW!
DESQview API Pascal Library
The DESQview API Pascal Library provides Pascal Language
interfaces for the entire set of API functions. It supports the
Turbo Pascal 4.0 and 5.0 compilers. Included with the Pascal
Library package is a copy of the API Reference Manual and source
code for the library. AVAILABLE OCTOBER 88
DESQview API Debugger
The DESQview API Debugger is an interactive tool that enables the
API programmer to trace and single step through API calls from
several concurrently running DESQview-specific programs. Trace
information is reported symbolically along with the program
counter, registers, and stack at the time of the call. Trace
conditions can be specified so that only those callls of interest
are reported. AVAILABLE NOW!
DESQview API Panel Designer
The DESQview API Panel Designer is an interactive tool to aid you
in designing windows, menus, help screens, error messages, and
forms. It includes an editor that lets you construct an image of
your panel using simple commands to enter, edit, copy, and move
text as well as draw lines and boxes. You can then define the
characteristics of the window that will contain the panel, such
as its position, size, and title. Finally, you can specify the
locations and types of fields in the panel.
The Panel Designer automatically generates all the DESQview API
data streams necessary to display and take input from your panel.
These data streams may be grouped together into panel libraries
and stored on disk or as part of your program. AVAILABLE OCTOBER
88
DESQview API Pulldown Menu Manager
The DESQview API Pulldown Menu Manager is an interactive tool to
aid you in designing pulldown menus. This DESQview API tool
assists you in giving your DOS program an OS/2-like look and
feel.
System Requirements
Personal Computers: IBM PC, PC-XT, PC-AT and Personal System/2
and 8088-, 8086-, 80286-, 80386-based personal computers that are
100% compatible with the IBM Personal computer.
Video Displays: monochrome, color graphics (CGA), enhanced color
graphics (EGA), video graphics array (VGA) of the IBM Personal
System/2, Hercules Memory; available separately: Micro Display
Systems Genius video driver
640K memory recommended
Expanded Memory (optional): Intel AboveBoard and compatibles
(EMS 3.2)
Expanded Memory Specification 4.0 and Enhanced Expanded Memory
(optional): AST RAMpage and EMS 4.0 boards; recommended for power
users wishing to multitask beyond 640K or to run programs larger
than 435K
Disk: Two diskette drives or one diskette drive and a hard drive
Mouse (optional): PC Mouse, IBM Mouse, Microsoft Mouse and
Microsoft Mouse compatibles
Communication port (required for DESQview Link)
Modem (for Auto-dialer and DESQview Link): Hayes Smartmodem or
compatible
Operating System: PC-DOS 2.0-4.0; MS-DOS 2.0-3.3
DESQview memory overhead: 640K PC's and 8088 & 80286 PC's without
expanded memory: 145K; 80286 PC's with extended memory: 85K; 8088
& 80286 PC's with enhanced expanded memory or 80386 PC's: 40K for
PC's with EGA/VGA displays; 0-10K for PC's with monochrome or CGA
displays
DESQview Companions memory requirements: Datebook: 55K;
Calculator: 30K; Notepad: 35K; Link: 80K; Quarterdeck Expanded
Memory Manager-386: 1.5K; Quarterdeck Expanded Memory
Manager-50/60: 16K
Media: DESQview and DESQview Companions available on either 5 1/4
inch or 3 1/2 inch floppy diskette
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