Overview: arguments and environment variables of VFS

VFS arguments

• -l <entry in fstab format>

  The -l argument lets you mount the file system.

• -f <path to fstab file>

  The -f argument lets you pass the file containing entries in fstab format for mounting file systems. The ROMFS storage will be searched for the file. If the UMNAP_ROMFS variable is defined, the file system mounted using the ROOTFS variable will be searched for the file.

Example of using the -l and -f arguments

VFS environment variables

• UNMAP_ROMFS

  If the UNMAP_ROMFS variable is defined, the ROMFS storage will be deleted. This helps conserve memory and change behavior when using the -f argument.

• ROOTFS = <entry in fstab format>

  The ROOTFS variable lets you mount a file system to the root directory. In combination with the UNMAP_ROMFS variable and the -f argument, it lets you search for the fstab file in the mounted file system instead of in the ROMFS storage. ROOTFS usage example

• VFS_CLIENT_MAX_THREADS

  The VFS_CLIENT_MAX_THREADS environment variable lets you redefine the SDK configuration parameter VFS_CLIENT_MAX_THREADS during VFS startup.

• _VFS_NETWORK_BACKEND=<backend name>:<name of the IPC channel to VFS>

The _VFS_NETWORK_BACKEND variable defines the backend used for network calls. You can specify the name of a standard backend such as client, server or local, and the name of a custom backend. If the local backend is used, the name of the IPC channel is not specified (_VFS_NETWORK_BACKEND=local:). You can specify two or more IPC channels by separating them with a comma.

• _VFS_FILESYSTEM_BACKEND=<backend name>:<name of the IPC channel to VFS>

  The _VFS_FILESYSTEM_BACKEND variable defines the backend used for file calls. The backend name and name of the IPC channel to VFS are defined the same as way as they were for the _VFS_NETWORK_BACKEND variable.

Default values

For the VfsRamFs executable file:

ROOTFS = ramdisk0,0 / ext4 0

VFS_FILESYSTEM_BACKEND = server:kl.VfsRamFs

For the VfsSdCardFs executable file:

ROOTFS = mmc0,0 / fat32 0

VFS_FILESYSTEM_BACKEND = server:kl.VfsSdCardFs

-l nodev /tmp ramfs 0

-l nodev /var ramfs 0

For the VfsNet executable file:

VFS_NETWORK_BACKEND = server:kl.VfsNet

VFS_FILESYSTEM_BACKEND = server:kl.VfsNet

-l devfs /dev devfs 0