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The Task Manager
RISC OS incorporates a comprehensive means of allowing the user to keep track of all the various programs or Tasks that are running and the memory they are using. All of this information is displayed in the Task Manager window.
This is more than just a display of what's going on, you can also use it to make alterations to some items.
 Click the MENU button with the mouse pointer over the rightmost icon on the icon bar (shown left) and the menu shown will appear. For standard RISC OS Six this icon will be in the form of the RISC OS Six 'Cog', for earlier versions of RISC OS the icon may be different but it will always be the icon at the extreme right hand end of the icon bar.
- Info - If you slide off this item to the right a window will open giving you more information about the version of RISC OS that you are using. You will find that most RISC OS programs have a similar 'Info' window available from their icon bar menu.
- System info - This opens a window showing graphical representations of memory allocation at the time the menu was clicked.
- New task - You will probably never need to use this. It is simply a method of executing an OS or 'star' command without either leaving the desktop or opening a Task Window.
- Task Display - We'll come to this soon.
- *Commands - This is equivalent to pressing F12 as previously described at the end of Chapter 1.
- Task Window - As you might expect this will open a Task Window equivalent to pressing Ctrl-F12.
- Configure - This will open the RISC OS configuration system, in a similar way to double clicking on !Boot.
- Stand by - If your machine supports power saving then this will put the computer into power saving mode.
- Shutdown - This will shut down the computer, the same as pressing Shift-Ctrl-F12
System info
The System information window uses the RISC OS 6 DrawChart feature to display memory usage in graphical pie charts. This helps you see at a glance where memory has been used.
The charts show a snap-shot of the usage at the time the display was opened.
The Task Display
You can open the Task Display window by selecting that option from the menu or by clicking on the Task Manager icon with SELECT. This will open a window similar to the one below.
Upon initial opening of the Task display window, its size will default to the top section only. This top section shows a summary of memory usage across the different memory areas of the system. The information is shown both in figures and graphically by the coloured sliders.
Red sliders may be changed by dragging them with the mouse left or right to decrease or increase the allocated memory. The solid colour part of the sliders shows the current usage, whereas the white area indicates the maximum possible allocation of memory to that area.
Of those areas which are user draggable, the most likely ones you will change are:
- Font cache
- RAM disc
- Next slot
These are described in more detail below.
The dark green bars show information about used memory in the different areas. These will change as memory allocation changes, but are not user draggable.
At the top of the list of memory areas is an area that shows the System heap memory usage, that is, the memory used by all the various components of RISC OS itself. Although this is user draggable, it is unlikely you will need to modify this. RISC OS will increase the memory allocated as and when it needs to, although you may find that you can sometimes recover memory back to the free pool by dragging this slider left if you've been working with lots of resources and then later tidied up by closing programs and files afterwards. If you're unsure what you are doing, do not modify this.
Font cache is the amount of memory reserved for caching or 'remembering' fonts. If this is too small and you are viewing something like a DTP document that uses a large number of different fonts RISC OS won't be able to cache all the fonts and so will have to keep loading them from disc. This is very much slower than loading the fonts from a font cache held in memory, so viewing the document will be slow and jerky. If this happens then try dragging the Font cache slider to the right to allocate more memory.
System sprites is an area not normally used by modern RISC OS programs, so it would normally be set to zero by default. However, some very old programs may need some memory to be allocated in this area. There are ways that a program can do this itself, but if you get an error message saying something like 'Not enough room in System sprites area' when you run an old program you could try dragging this slider out to allocate some memory.
The RAM disc
A RAM disc is something that looks and behaves like a small hard disc but is actually located in the computer's memory instead of on some type of physical media. The big advantage of this is that it is very fast. The big disadvantage is that because all the data is held in memory any data on the RAM disc will be lost as soon as you switch off the computer or if it crashes for any reason.
A RAM disc is therefore an ideal repository for temporary or transient files.
To create a RAM disc drag the slider next to RAM disc in the Memory allocation section of the Task Manager window. You can make it as big or as small as you like, and you can alter its size later if you wish, or even reduce its size to zero to remove it completely, but you can only change its size when there are no files stored on it. The size you make it will depend on what you intend to use it for and how much memory is installed in your computer, but around 4 Mb would probably be enough for most purposes.
When you drag the RAM disc slider to the right this creates a RAM disc. You will see that a new icon has appeared on the icon bar to the left of the Apps icon. This is the RAM disc icon, and you can click on it to open a filer window onto the RAM disc just as you can with any other drive.
If you have some files stored on a RAM disc when you shut the computer down then you will be warned and given the option of aborting the shutdown in case some of the files are wanted. Don't forget that any files left on a RAM disc when you shut down will be lost forever.
Module area (sometimes called RMA) is a special area of memory in which Relocatable Modules are loaded and executed. This area can grow as required, but it can only shrink if the free space within it is at the end of the area. For this reason, Module area also keeps track of the blocks of free space within and tries to use these efficiently when new modules are loaded.
The dark green Free and Largest block sliders indicate how fragmented the RMA is. If the Free slider is large, it is quite possible that some of the free space in the RMA is at the end of the area and it may be possible to recover some memory back to the Free pool by dragging the slider for Module area to the left.
The Applications slider shows how much of the computer's memory is in use by all the running applications. More detail about the applications that are running is available in the Tasks section of the window.
Next slot is the amount of RAM that will be allocated by default to the next task that starts up. Usually when a program starts it tells RISC OS how much RAM it needs and that is the amount that will be allocated, but not all programs do this. If a program doesn't ask for a specific amount of RAM then the amount set in Next slot will be given to it.
Dynamic areas shows the total memory in use by all dynamic areas. These are listed individually in the last section of the task display window.
Free pool gives the total amound of unallocated memory that is free for allocation to any of the other areas and is therefore shown in a different colour to illustrate that it is unallocated.
The next section of the window is Tasks.The size of this section changes according to how many tasks are running. The picture below shows some of the tasks that were running on the computer used to write this guide.
The Tasks section shows all the running tasks in the system and whether they're running from ROM, or are using either application memory or RMA memory. Tasks using application memory will have a slider displaying how much memory they are using, in addition to the memory in figures.
Note that Tasks are now listed in alphabetical order rather than in the order they were started. More tasks would be visible if this example window were to be scrolled or enlarged.
To see how the Tasks display works, with the Task Manager window open press Ctrl-F12 to open a Task Window. This may open over the Task Manager window so drag it out of the way and you will see that a new Task has appeared on the list called TaskWindow using the amount of RAM that is set in the red Next slot entry in the Memory allocation section at the top of the window. Close the Task Window. You will find that if you click and hold down SELECT with the mouse pointer near the right hand end of the Next slot slider you can drag this slider to the left or right, increasing or decreasing the amount of memory that will be allocated to the next task. Once you have altered the amount press Ctrl-F12 again and you will see that the amount of memory allocated this time has changed to whatever you altered Next to.
If you had watched the Free pool slider previously when pressing Ctrl-F12 you would have seen that each time you opened a Task Window the amount of free memory decreased by the amount of memory specified by Next slot.
At the bottom of the Task Manager window is a section labelled Dynamic areas. This is mainly for information only. A dynamic area is a part of the computer's memory used by a program to store data. These are created, extended and removed by programs as they are required. There is not normally anything that a user can or would need to do about these.
Killing tasks
If you click MENU over one of the task names in the Task Manager window the menu shown will open with the name of the task in the forth position from the top.
This menu has a sub-menu with just one item, Quit .
Almost all normal programs have a Quit item on their icon bar menu, but not all programs install on the icon bar. This is the way of killing those that don't. Just click on Quit and the task should die.
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