man(1) Manual page archive


     MEMFS(4)                                                 MEMFS(4)

     NAME
          memfs - mount a heap based filesystem

     SYNOPSIS
          memfs [-rab] [size] mountpoint

     DESCRIPTION
          Memfs mounts a newly created heap-based filesystem on the
          given mountpoint directory.

          The filesystem is entirely maintained in memory, no external
          storage is used.  Unless specified by size, the maximum
          storage provided by the filesystem is 1 megabyte (1024*1024
          bytes).  File data is allocated in 512 byte blocks.  If a
          maximum size is specified, the actual maximum is rounded
          down to the nearest whole number of blocks:

               actualsize := (size / 512) * 512;

          The root of the new filesystem is created with Read, Write
          and Execute permission for the user only (mode 8r700).  The
          owner is given by the value returned from /dev/user at the
          time of running the command.

          Memfs has the following options:

          -r   The default option.  The old mountpoint directory
               becomes a union directory consisting of just the root
               of the new filesystem.

          -a   Add the root of the new filesystem to the end of the
               union directory represented by the mountpoint direc-
               tory.

          -b   Add the root of the new filesystem to the beginning of
               the union directory represented by the mountpoint
               directory.

     FILES
          /dev/user  read to name the owner of the filesystem
          /dev/time  used to set file creation and modify times

     SOURCE
          /appl/cmd/memfs.b

     SEE ALSO
          memfs(2), ramfile(4)