File system questions

Thomas Doerfler Thomas.Doerfler at
Thu Sep 16 09:06:03 UTC 2004

Hello Alan,
> 1. It looks like the two supported file system types are IMFS and the 
> FAT file system. Does IMFS require a ram block device to operate, or 
> does it just operate on an area of RAM?

The IMFS gets the memory required from the heap, so you don't 
need a dedicated ramdisk block device.
> 2. Can the FAT file system be used on a RAM disk block device or is it 
> supposed to be used only on physical media such as a hard disk?

For the first tests, the ram disk block device was created. 
Unfortunately there is no "format" function to initialize the 
ram disk, therefore it is currently more or less useless :-(

> 3. Is there an example of how I can create a RAM disk block device, 
> format a DOS FS on top of it, and mount it? How about for an IMFS file 
> system?

For the ramdisk, with DOSFS, no. (see above)

The IMFS is automatically created when you start RTEMS. The only 
thing you must do is to set the configuration define


in your "system.h".

Otherwise you get a stripped down version (mini_IMFS) which does 
not support file creation etc.


> Thanks,
> Alan

IMD Ingenieurbuero fuer Microcomputertechnik
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