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 directory. 

­−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)

Plan 9  —  June 29, 2000