On Arthur 1.2 you can configure RAM for use with the RAM filing system, but the filing system itself is not implemented. RISC OS corrects this oversight with the implementation of a full-feature RAM filing system.
To make use of it, you must first of all configure some RAM. Either use *CONFIGURE or the Task Manager from the Desktop. As an example of the former:
*CONFIGURE RAMFSsize 160K
followed by Ctrl-Break will set aside 160K of RAM for the RAM filing system. The RAM filing system icon will now appear on the Desktop icon bar alongside the floppy and or hard disc icons. Double clicking on this will open up the root directory in the same way as double clicking on any of the other drive icons.
In fact the RAM disc will behave exactly as any floppy or hard disc. You can copy files or directories between it and any other open directory on the Desktop simply by dragging icons across in the normal way. But there are two main differences. First of all, you must remember that the contents of the RAM disc are volatile, and will be lost after a hard reset (Ctrl-Break or Ctrl-Reset or power off). But it is an easy matter to back up the RAM disc at the end of a session by dragging appropriate RAM directories across to a floppy directory on the Desktop. Secondly the RAM disc is exceptionally fast. It takes just 0.05 seconds to save an 80K screen, for example. This is 100 times faster than a floppy under RISC OS (Arthur screen saves are 300 times slower!).
One obvious application for the RAM disc is in cases where speed of loading and saving is important. For example, you could set up the RAM disc to hold eight mode 12 screens, and load them in at a speed fast enough for animation, and without wear and tear on your floppy.
If you are using your machine without the aid of the Desktop, you can again treat the RAM disc just like any other. To make the RAM filing system current, use:
*RAM (*ADFS will reverse the effect)
You can then use *CAT to catalogue the disc, and use all the ordinary commands just as with the ADFS:
LOAD, SAVE, *LOAD, *SAVE, *FREE, *BACK*WIPE, *COPY, *COUNT etc etc.
To refer to the RAM disc when you are currently in the ADFS or Econet, use the prefix "RAM:". Thus to copy the file "MyProg" from $.Bananas on the ADFS (your current filing system) to $.Potatoes on the RAM disc, use:
*COPY $.Bananas.MyProg RAM:$.Potatoes.MyProg
If you have a program which needs to know which is the current filing system, you can use the SYS call given in this month's Hints. It will return the value 23 for the RAM filing system.
Fans of the RISC User ADFS Menu (RISC User Volume 1 issues 1, 2 and 10) will be pleased to hear that it works well with the RAM filing system. Just use *RAM to engage the RFS. The only thing which it gets wrong is the free space display, but this is easily ignored.