I’ve just set up a simple NAS (Network-Attached Storage) server using an old PC and the FreeNAS: The Free NAS Server software. This is based on FreeBSD and supports CIFS (samba), FTP, NFS, AFP, RSYNC, iSCSI protocols, S.M.A.R.T., local user authentication, Software RAID (0,1,5) with a Full WEB configuration interface. FreeNAS takes less than 32MB once installed on Compact Flash, hard drive or USB key.
My installation has the system installed onto a Compact Flash card installed in an adapter to make it look like a regular IDE drive. I am also running a cheap RAID card with a pair of disks that are mirrored to give a single drive, although I may change this if/when I get some larger disks to implement another RAID array. The current system has about 190Gb of mirrored storage and initial indications show that this is a lot faster to access than both my current linux based fileserver and a simple standalone network disk enclosure.
The RAID card can support up to 4 drives, the motherboard can have 4, although 1 is used by the CF drive and another by the DVD-ROM drive. It is possible therefore to have 6 drives connected using a combination of hardware and software RAID to provide a lot of storage capacity.
The web interface in easy to use to define the disks, mount points and protocols to use. I am currenly only using the CIFS/SMB to create network drives that can be accessed from windows XP and Vista machines (and also my linux based machines).
One feature I may look at is installing a compatible wireless card and being able to stream files to connected wireless devices.