[1][2][3] The concept is often considered synonymous with that of a distributed operating system,[4][5] but a single image may be presented for more limited purposes, just job scheduling for instance, which may be achieved by means of an additional layer of software over conventional operating system images running on each node.
Different SSI systems may, depending on their intended usage, provide some subset of these features.
This may be achieved by a simple NFS server, shared disk devices or even file replication.
The advantage of a single root view is that processes may be run on any available node and access needed files with no special precautions.
Some SSI systems provide a way of "breaking the illusion", having some node-specific files even in a single root.
Some SSI clusters include special hardware to reduce this slowdown.