IBM 610 workstation computer 3433

On Thu, 02 Mar 06 13:09:27 GMT

No it's not. The most common way of providing delivery of non stop continuous computing services these days is mbuttive redundancy at the machine level rather than redundancy within the machine.

The first setup I worked on with this approach used 20 Motorola 88K based UNIX boxes with a spec requirement that any single machine could fail and be replaced with a new box without interrupting the processing or losing a single bit of data. It took some careful design but that spec was achieved. These days it's considered to be an easy stunt to pull off and systems of several hundred machines in which several machines can die without anyone noticing a glitch are in use.

The thing is that even commodity grade hardware can keep running for several years without failure, so the extra cost of making it capable of being fixed on the fly without stopping which would change years into decades isn't worth it. Especially because by the time three years have past the hardware is obsolete even if still perfectly functional because a new box is ten times faster. Building RAIMs (redundant arrays of inexpensive machines) means that the oldest and slowest box in the room can easily be replaced by a shiny new box that is *way* faster.

-- The computer obeys and wins. A better way to focus the sun You lose and Bill collects. licences available see