Advanced Search
Apple Developer Connection
Member Login Log In | Not a Member? Contact ADC

Previous Book Contents Book Index Next

Inside Macintosh: Operating System Utilities /
Chapter 7 - Parameter RAM Utilities / Parameter RAM Utilities Reference
Data Structures


The System Parameters Record

The SysParmType data type describes a system parameters record.

TYPE SysParmType =
PACKED RECORD
   valid:      Byte;    {validity status}
   aTalkA:     Byte;    {node ID hint for modem port}
   aTalkB:     Byte;    {node ID hint for printer port}
   config:     Byte;    {use types for serial ports}
   portA:      Integer; {modem port configuration}
   portB:      Integer; {printer port configuration}
   alarm:      LongInt; {alarm setting}
   font:       Integer; {application font number minus 1}
   kbdPrint:   Integer; {printer connection, auto-key settings}
   volClik:    Integer; {caret blink, double click, speaker vol.}
   misc:       Integer; {menu blink, startup disk, mouse scaling }
END;
SysPPtr = ^SysParmType;
Field Description
valid
Contains information about the validity status of the clock chip. Whenever a write to the clock chip is successful, the value $A8 is stored in this field. The status is examined when the clock chip is read at system startup.
aTalkA
Contains the node ID hint for the modem port.
aTalkB
Contains the node ID hint for the printer port.
config
Indicates which device or devices may use each of the serial ports.
portA
Contains the baud rate, data bits, parity, and stop bits for the modem port. Bits 0-9 define the baud rate; bits 10 and 11 define the number of data bits; bits 12 and 13 define the parity; and bits 14 and 15 define the number of stop bits.
portB
Contains the baud rate, data bits, parity, and stop bits for the printer port. Bits 0-9 define the baud rate; bits 10 and 11 define the number of data bits; bits 12 and 13 define the parity; and bits 14 and 15 define the number of stop bits.
alarm
Contains the time at which the alarm clock should sound. The time is defined in terms of seconds since midnight, January 1, 1904.
font
Adding 1 to this field produces the font number of the default application font.
kbdPrint
Contains the settings for the printer and for the keyboard. Bit 0 designates whether the currently chosen printer (if any) is connected to the printer port (0) or the modem port (1). Bits 1-7 are reserved for future use. Bits 8-11 of this field contain the auto-key rate, whose value is stored in 2-tick units. Bits 12-15 contain the auto-key threshold, whose value is stored in 4-tick units.
volClik
Contains miscellaneous user settings, including the caret-blink time, double-click time, and the speaker volume setting.
misc
Contains more miscellaneous user settings. Bits 2 and 3 contain a value from 0 to 3 designating the menu-blink time. Because system software automatically calls both standard and nonstandard menu definition procedures many times, you should not need to worry about that value in parameter RAM. Bit 4 indicates whether the preferred startup disk is in an internal (0) or external (1) drive. If there is any problem with using the disk in the specified drive, the other drive is used. Bit 6 designates whether mouse scaling is on (1) or off (0).

Previous Book Contents Book Index Next

© Apple Computer, Inc.
6 JUL 1996

Get information on Apple products.
Visit the Apple Store online or at retail locations.
1-800-MY-APPLE

Copyright © 2004 Apple Computer, Inc.
All rights reserved. | Terms of use | Privacy Notice