Types of OS-9 Windows

Unlike many operating systems, OS-9 has a built-in windows

program. This driver, the Windowing System, lets you lay one or

more smaller screen displays, called windows, on your screen

display.

With these windows, you can perform several tasks at the same

time. For example, suppose you are writing a business letter

using a word processor in one window. You can go to a spread

sheet program in another window, get a price quote you need,

return to the word processor, and include the price in the letter.

The Windowing System allows as many windows as your com

puter's memory can support, with a maximum of 32 at one time.

In OS-9, there are two types of windows: device and overlay.

Device Windows

A device window is one that can run a program or utility. This

is the type of window you would use in the word processor/

spreadsheet example given above. Each device window acts as an

individual terminal.

The device windows are designated as devices /wl - /w7. You

open a device window as you do any other OS-9 device. You tell

OS-9 the window's parameters including whether the window is

for text or graphics. If you want to run a process in the window,

you can start an execution environment, such as a shell, on the

window. (See "Opening a Device Window," later in this chapter,

and the DWSet command in Chapter 3 . )

Note: If you want only to send output to the device win
dow-without running a process in the window-do not
start a shell on the window.

Device windows cannot overlay each other, and their boundaries

cannot overlap.

1-1
OS-9 Windowing System

Overlay Windows

An overlay window is a window that you open on top of a device
window. (You can place overlay windows over other overlay win
dows, but there must always be a device window at the bottom of
the stack.) The purpose of overlay windows is to display com
puter dialog. You cannot fork a shell to an overlay window; how
ever, you can run a shell in an overlay window. Overlay windows
assume the screen type of the device windows they overlay.

Opening a Device Window

To open a device window, follow these steps:
1. If you want to allocate memory for the window, use OS-9's
iniz command. Type:

i n i z !w number ENTER

where number is the number of the device window you wish

to open (1-7). If you do not specify number, OS-9 uses the

next available device window number. .,

If you do not use the iniz command, memory is allocated

dynamically (as needed) to the window.

2. Next, you send an escape sequence to OS-9 that tells it the

window's parameters. These parameters include the screen

type, size, and colors. For example:

wcreate -5= 2 20 10 40 10 01 00 00 ENTER

or

display 1 b 20 02 1 4 0a 28 0a 01 00 00 E

sends the escape sequence for the next available window to

the DWSet command. The wcreate command lets you use

decimal numbers, while the display command requires

hexadecimal numbers.

1-2

Types of OS-9 Windows / 1

If you wish to send an escape sequence to a specific win

dow, route the command to that device. For example:

- wcreate -5= 2 20 10 40 10 01 00 00 >/w2
ENTER

sends the escape sequence to device /w2. The functions of

the codes, as used in the wcreate command, are as follows:

2 sets a screen type of 80 x 24 (text only).

20 starts the window at character/column 20.

10 starts the window at line/row 10.

40 sets a window size of 40 characters.

10 sets a window size of 10 lines.

01 sets the foreground color to blue.

00 sets the background color to white.

00 sets the border to white.

If you do not send escape sequences, OS-9 uses default

descriptors for the windows. The defaults are:

Size

Window Screen Type Starting Position (columns,

Number (chars./line) (horiz., vert.) rows)

1 40 (text) 0,0 27,11

2 40 (text) 28,0 12,11

3 40 (text) 0,12 40,12

4 80 (text) 0,0 60,11

5 80 (text) 60,0 19,11

6 80 (text) 80,0 80,12

7 80 (text) 0,0 80,24

3. Use OS-9's shell command to fork a shell to the window.

Type

shell i=lwnumber & ENTER

where number is the number used in the iniz or wcreate

command. The i = parameter creates an immortal shell.

Creating an immortal shell protects the window and its

shell from being destroyed if you accidentally exit the shell

using CTRL BREAK . If you omit the i = parameter, the shell

is forked to the next available device window.

You now have a window that can run its own tasks. Information

displayed in that window is automatically scaled to the window's

size.

1-3

OS-9 Windowing System

Opening an Overlay Window

To open an overlay window, use the Overlay Window Set func
tion. (See OWSet in Chapter 3, "General Commands.")

1-4