#!/bin/bash
# ramdisk.sh
# A "ramdisk" is a segment of system RAM memory
#+ that acts as if it were a filesystem.
# Its advantage is very fast access (read/write time).
# Disadvantages: volatility, loss of data on reboot or
powerdown.
# less RAM available to system.
#
# What good is a ramdisk?
# Keeping a large dataset, such as a table or dictionary on
ramdisk
#+ speeds up data lookup, since memory access is much faster than
disk access.
E_NON_ROOT_USER=70 # Must run as root.
ROOTUSER_NAME=root
MOUNTPT=/mnt/ramdisk
SIZE=2000 # 2K blocks (change as appropriate)
BLOCKSIZE=1024 # 1K (1024 byte) block size
DEVICE=/dev/ram0 # First ram device
username=`id -nu`
if [ "$username" != "$ROOTUSER_NAME" ]
then
echo "Must be root to run \"`basename
$0`\"."
exit $E_NON_ROOT_USER
fi
if [ ! -d "$MOUNTPT" ] # Test whether mount point already
there,
then #+ so no error if this script is run
mkdir $MOUNTPT #+ multiple times.
fi
dd if=/dev/zero of=$DEVICE count=$SIZE bs=$BLOCKSIZE # Zero out RAM
device.
mke2fs $DEVICE # Create an ext2 filesystem on it.
mount $DEVICE $MOUNTPT # Mount it.
chmod 777 $MOUNTPT # So ordinary user can access ramdisk.
# However, must be root to unmount it.
echo "\"$MOUNTPT\" now available for use."
# The ramdisk is now accessible for storing files, even by an
ordinary user.
# Caution, the ramdisk is volatile, and its contents will
disappear
#+ on reboot or power loss.
# Copy anything you want saved to a regular directory.
# After reboot, run this script again to set up ramdisk.
# Remounting /mnt/ramdisk without the other steps will not
work.
exit 0
