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Task Manager
The TaskManager module has been updated to bring it up to date with the rest of RISC OS. The following changes have been made to the module :
- The TaskManager will warn users when the system is powered off without being safely shut down. This should encourage users to correctly shut down the system, rather than to merely turn off the system. Failure to shut down correctly may result in data loss.
- The 'System memory allocation' details in the main tasks display has had a number of the previously displayed regions removed :
- Screen memory (no longer centrally allocated; see the 'Video' areas within the 'Dynamic areas' section)
- Cursor/System/Sound (these are now separate areas, listed under the 'Dynamic areas' section)
- System heap/Stack (now presented as just 'System heap', as the system stack is a separate area - not listed)
- The 'System memory allocation' details still includes the 'Font cache', 'System sprites' and 'RAM disc' areas, despite these areas now being controlled by the relevant modules (FontManager, SpriteUtils and RamFS respectively).
- Physical dynamic areas are indicated by blue bars rather than red. This indicates that the areas are not part of normal allocatable memory.
- It should be noted that the list of memory regions is not complete. In particular, memory regions allocated to the page tables, to the system stacks and other system areas (for example the softloaded ROM) are not included.
- The memory size allocations beside each region are now listed as megabyte when they exceed 16M (rounded down). This makes the memory allocations easier to read.
- The information window no longer provides a hidden 'cookie' by clicking on the authors field.
- An 'i' icon in the information window provides additional information on the components within the system.
- The shutdown confirmation window will offer 'Restart' and 'Off' buttons. These can be triggered by the 'R' and 'O' keys respectively. The 'Off' option is only available on hardware with power control (see document Portable).
- The 'Exit' option has been removed from the menu, as it leaves the desktop without an obvious means of returning. Equivalent behaviour can be triggered by using Shift-Ctrl-F12 from the reset banner.
- The configuration applications can be accessed from the TaskManager menu by selecting the 'Choices...' option.
- The menu has an option 'Stand by' which will place the machine into a power conserving state. The power will not be removed, but hardware will be shut down and the system placed into a dormant state. This option is only available on hardware with power control (see document Portable).
Shutdown
In order to make shutdown more reliable and allow applications to force a reboot, the Task Manager shutdown controls have been updated. In addition to the standard bits that may be passed to TaskManager_Shutdown, new bits have been defined to provide additional functions.
SWI TaskManager_Shutdown
On entry
R0 = flags :
0 = Do not display restart dialogue
1 = Do not broadcast Message_PreQuit to clients
2 = Flag in NVRAM as a power down due to exceptional condition, eg. lack of power
3 = Send Message_Shutdown to all tasks
4 = Reject media requests (OS_UpCall 1 and 2)
5 = After shutdown has completed, reboot machine
6 = After shutdown has completed, power off machine
Other - Reserved
This SWI is used to request that the machine shuts down. The power off facilities will only function when present on supported hardware. See the Portable module description for more details on power control.
Acknowledgements service
Many components of the system are required to provide an acknowledgement of their licence to the user. The TaskManager provides a mechanism for this through the TaskManagerAcknowledgements service.
Service TaskManagerAcknowledgements (&42680)
On entry
R1 = &42680
R2 = pointer to code to call to add messages, or 0 to notify taskmanager that the acknowledgements have changed.
On exit
All registers preserved
This service call notifies TaskManager of changes to a module's licence acknowledgements. It is used to allow modules to communicate information about their licences which they are required to state, but would otherwise have no other means of displaying. Primarily it is intended for commercial developers and software built into the OS itself, but may be used by anyone. You should not claim this service.
The code to add messages must be called as :
On entry
R0 = Group identifier of form &GMMM, where G is :
0 = system overview (3QD Developments Ltd only)
1 = system required components (3QD Developments Ltd only)
2 = subsidiary components (3QD Developments Ltd only)
3 = commercial components
4 = freeware components
5 = user components - private use only
The MMM field should be set to 0 and is for future developments.
R1 = pointer to zero terminated component title
R2 = pointer to zero terminated acknowledgement details (see Note 2 below)
On exit
All registers preserved
Note 1 - return with MOV pc,link (ie do not preserve the flags)
Note 2 - Details should be formatted as 60 characters LF terminated strings. Try to include full stops at the ends of sentences. Thus, in BASIC, you might use
"© Fred Bloggs, 1998."+CHR$10+"© Sue Bloggs, 1999."+CHR$0
You should only call the entry point when requested for information by the TaskManager. TaskManager 0.11 and later support this service. Data will be copied so you can build strings in a temporary area if necessary.
In assembler you might use code something like the following to register messages :
svc_acknowledgements
TEQ r2,#0
MOVEQ pc,r14
STMFD r13!,{r0-r3 , r14}
MOV r3,r2
MOV r0,#&5000 ; group id
ADR r1,Title ; pointer to your module title string
ADR r2,CopyrightMessage ; some copyright message
MOV r14,pc
MOV pc,r3
MOV r0,r0
LDMFD r13!,{r0-r3 , pc}
CopyrightMessage
= "This software is based in part on work by Diaxos Holdings", 10
= "Incorporated.", 10
= "Some sections have been provided by Wally Williams.",0
In C you might use code something like the following :
typedef void (*addmessages_func)(unsigned int group,char const *title, char const *message);
#define Service_TaskManagerAcknowledgements 0x42680
void main_service(int service_number, _kernel_swi_regs *r, void *pw)
{(service_number==service_taskmanageracknowledgements) {
addmessages_func func=(addmessages_func)r->r[2];
if (func!=NULL)
{func(0x5000 ,Module_Title,"This software is based in part on the work of the Independent\nJPEG Group.");
}
}
}
On module initialisation and finalisation you should notify the TaskManager of the change to the acknowledgement messages by issuing the service with R2 = 0. In C you might do this as :
/* Let TaskManager know it's changed */
_swix(XOS_ServiceCall,_INR(1,2),Service_TaskManagerAcknowledgements,0);
In assembler, this could be :
; Cause a re-cache of the acknowledgements window
LDR r1,=&42680
MOV r2,#0
SWI XOS_ServiceCall
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