Inside Macintosh: Operating System Utilities /

Chapter 7 - Parameter RAM Utilities

Summary of the Parameter RAM Utilities

Pascal Summary

Data Types

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 volume}
      misc:       Integer; {menu blink, startup disk, mouse scaling}
   END;
   SysPPtr        = ^SysParmType;

Routines

FUNCTION InitUtil: OSErr;
FUNCTION GetSysPPtr: SysPPtr;
FUNCTION WriteParam: OSErr;

C Summary

Data Types

struct SysParmType {
      char     valid;         /*validity status*/
      char     aTalkA;        /*node ID hint for modem port*/
      char     aTalkB;        /*node ID hint for printer port*/
      char     config;        /*use types for serial ports*/
      short    portA;         /*modem port configuration*/
      short    portB;         /*printer port configuration*/
      long     alarm;         /*alarm setting*/
      short    font;          /*application font number minus 1*/
      short    kbdPrint;      /*printer connection, auto-key settings*/
      short    volClik;       /*caret blink, double click, speaker volume*/
      short    misc;          /*menu blink, startup disk, mouse scaling*/
   };
typedef struct SysParmType SysParmType;
typedef SysParmType *SysPPtr;

Routines

pascal OSErr InitUtil      (void);
SysPPtr GetSysPPtr         (void);
pascal OSErr WriteParam    (void);

Assembly-Language Summary

Data Structures

SysParmType Data Structure

0	valid	1 byte	validity status
1	aTalkA	1 byte	node ID hint for modem port
2	aTalkB	1 byte	node ID hint for printer port
3	config	1 byte	use types for serial ports
4	portA	word	modem port configuration
6	portB	word	printer port configuration
8	alarm	long	alarm setting
12	font	word	application font number minus 1
14	kbdPrint	word	printer connection, auto-key settings
16	volClik	word	caret blink, double click, speaker volume
18	misc	word	menu blink, system startup disk, mouse scaling

Global Variables

GetParam	System parameter scratch
SPAlarm	The alarm setting
SPATalkA	The node ID hint for modem port
SPATalkB	The node ID hint for printer port
SPClikCaret	The double-click and caret-blink times
SPConfig	The use types for serial ports
SPFont	The application font number minus 1
SPKbd	The auto-key threshold and rate
SPMisc1	Miscellaneous
SPMisc2	The setting for mouse scaling, the system startup disk, and menu-blink time
SPPortA	The modem port configuration
SPPortB	The printer port configuration
SPPrint	The printer connection
SPValid	The validity status of parameter RAM
SPVolCtl	The speaker volume
SysParam	The low-memory copy of parameter RAM

Result Codes

noErr	0	No error
prWrErr	-87	Parameter RAM written did not verify
prInitErr	-88	Validity status is not $A8