I can only dimly remember planned outages. In my capacity as Customer Services Marketing Manager in Amdahl UK, one of the metrics I had to deal with was MTBUI - Mean Time Between Unscheduled Interruptions. It was essentially downtime with scheduled maintenance factored out - a planned two-hour slot didn't count as downtime unless it overran, and then an MTBUI incident was recognized and the clock started ticking.
But as long ago as 1990 - some might say before - it became quite evident that customers were simply not able to take systems down for scheduled maintenance. A processor, a storage bank, a channel group - maybe. And it wasn't just Amdahl customers - we shared most installations with at least one other supplier and it was the same for them. Indeed, as long ago as 1979, I remember Eternit swapping MVS releases and providing continuous RJE service (and pretty continuous TSO) using shared spool. That's nearly three decades. I can't think of another supplier who has outages like this. My personal systems are set up for automatic virus definition updates, automatic Microsoft patches, etc., and they never fail. I'd love to see someone try to sell a mobile phone with the caveat that it can't be used between 03:00 and 04:00 on Sundays because the network goes down for maintenance. -- Phil Payne http://www.isham-research.co.uk +44 7833 654 800 ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
