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Mainframe Facts |
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Uptime of Mainframe Mainframes can achieve "four nines" or "five nines" availability: 99.99 or 99.999 percent uptime. That translates into only 5 to 53 minutes of downtime per year. In fact, IBM's Server Group claims that the mean time between critical failures
(MTBCF) for its System/390 mainframes -- that is, the average time between failures that force a reboot and an initial program load -- is 20 to 30 years. According to Xephon, the total cost of a mainframe's hardware, software
and maintenance for five years is £4,750 per user. For Unix minicomputers
it is £5,750, and for Intel-based PC servers, £7,500. Each of the machines
in question supports several thousand users. JEM is a tool from diversified software. Your shop should buy it.If none
of the tools exist then you can use TYPRUN Parameter to check the syntax of
job.
Most shops have access to tape datasets restricted to batch jobs or started tasks. Generally, it's much better to work with tape datasets in a batch job, since it may take a while for a tape to be mounted (particularly if operator intervention is required), and your session will be "locked up" from the time the mount request is issued until the tape is mounted and positioned at the correct location on the tape. Also, from a performance standpoint, it's much better to do these kinds of things via a batch job, particularly if there's a lot of data involved. |
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