Mac RAM Disk
Type the following exactly in the Terminal (the $ represents a bash prompt and is not to be typed):
$ hdid -nomount ram://52428800
$ newfs_hfs /dev/disk1
$ mkdir /tmp/ramdisk1
$ mount -t hfs /dev/disk1 /tmp/ramdisk1to ditch the RAM disk and unmount it, just type
$ hdiutil detach /dev/disk1

