The ScreenMode editor, illustrated in Figure 5-8, lets you select the display mode for the Workbench screen. Since the modes have different properties and hardware requirements, review the descriptions provided here and in Chapter 7 to determine which modes are available on your system and best meet your needs.
Figure 5-8. ScreenMode Preferences Editor Window
The available display modes are listed on the left; the properties of the mode selected are displayed on the right.
The available display modes are shown in the Display Mode list. Scroll through the list to see all modes available. The available modes reflect the currently active monitor drivers. Place the associated monitor files in the Devs/Monitors drawer to have its display modes available at all times.
Select a display mode from the list by clicking on it. The selected mode is highlights. Select Save to use the mode and save it as the default in future sessions. Select Use to use the mode for the current session only. When trying different display modes, select Use rather than Save when you exit ScreenMode. When you have settled on the display mode you intend to use, save it. This makes recovery easier if you select a mode that is not compatible with you monitor. Select Cancel to exit the editor without making any changes.
If you select Save or Use while an application or Shell window is open on the Workbench screen, a requester appears, asking you to close any open windows other than drawers. When you have closed the last open Shell or application window, the Workbench screen automatically rests to the new display mode.
Your chosen display mode pertains only to the Workbench screen. Applications opening their own screens supply documentation of the display modes they support.
The Mode Properties display box lists information about the display mode selected. It displays screen sizes and maximum displayable colors for the selected display mode and other mode properties.
Screen sizes corresponding to the currently selected display mode are given in pixels. The first number represents the width of the screen; the second number represents the height.
The possible mode properties that can be displayed include:
Use the Width and Height text gadgets to customize the size of your Workbench screen. Enter a number between, or equal to, the minimum and maximum width and height. Once the number is entered, that number remains constant no matter what display mode is selected until the corresponding Default gadget is selected.
Entering numbers larger than the maximum or smaller than the minimum is the same as specifying the maximum or minimum.
The Default check box to the right of each gadget lets you select the default setting for the width and/or height. This equals the Visible Size.
You can specify a Width and Height much larger than the visible size. This extra-large virtual Workbench screen lets you open larger and more non-overlapping windows than otherwise possible, limited only by available Chip memory.
The Colors slider gadget lets you select the number of colors that can be displayed on the screen. The fewer colors selected, the faster the screen can be redrawn and the less memory used.
When AutoScroll is selected, the screen automatically scrolls when the mouse reaches the edge of the screen's visible portion. This is useful when you have defined a Width or Height for the screen that is larger than the visible size.
The Serial editor, illustrated in Figure 5-9, sets specifications for serial communication on your system.
Figure 5-9. Serial Preferences Editor Window
Serial information sent and received through modems or networks must be in a form compatible with the device with which you are communicating. Refer to the documentation packages that came with your serial device to determine appropriate settings.
The baud rate determines the number of bits transferred through the serial port each second. In serial communication, information is sent and received one bit at a time. Since characters are usually 10 bits (1 start bit, 8 data bits, 1 stop bit), dividing the baud rate by 10 approximates how many characters per second (cps) are transmitted.
The selected baud rate must match the rate of the device with which you are communicating. The larger the value, the faster the data is transferred. The available rates are: 110, 300, 1200, 2400, 4800, 9600, 19200, and 31250 baud. The current rate setting is shown to the left of the slider. The default setting is 9600.
The input buffer is an area of memory set aside for incoming serial data. The available sizes are: 512, 1024, 2048, 4096, 8192, 16384, 32768, and 65536 bytes. The current size is shown to the left of the slider. Use a larger buffer when working with a high baud rate or when the Amiga is performing many tasks. The default setting is 512.
Handshaking controls the flow of information through the serial port and the attached device. The same handshaking method must be set for both the computer and the device to allow communication. The available choices are:
Parity detects transmission errors by checking a bit of each character, called the parity bit, for its setting. The available parity settings are:
Bits per character specifies the number of bits that are sent through the serial port for each character and the number of bits expected for each character received.
This setting should correspond with the setting for parity. If parity is set to Even, Odd, Mark, or Space, set bits per character to 7 since some systems use the eight bit of data for parity checking. If parity is set to None, set bits per character to 8.
Stop bits are extra bits added at the end of a character to allow the computer to interpret spacing between words and indicate when a transmission ends. This applies to characters both sent and received through the serial port.
Slower processing computers usually require two stop bits. Computers that transfer information at 300 baud or faster generally require one stop bit. If you are using eight data bits, use only one stop bit or you may lose data during transmission.
If you have additional serial ports on your system, you can specify a default unit by adding a UNIT command line option or putting a UNIT Tool Type in the program's icon. The causes a Default Unit text gadget to appear in the Serial editor window. In this gadget, enter the unit number of the port that should be used when a particular port has not been otherwise specified. Entering 0 or 1 specifies the motherboard serial port. The documentation for your serial expansion device should give the unit numbers to use for its ports. Settings made in the Serial editor affect all ports.
