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We thought it might be interesting to see how
Tennessee 811 compared with co-location data
center facilities, and here's what we found out.
The Uptime Institute's tiered classification system is
an industry standard approach to site infrastructure
functionality and addresses common benchmarking
standard needs.
The four tiers, as classified by The Uptime Institute
include the following:
Tier I: composed of a single path for power and cooling distribution, without redundant components, providing 99.671% availability. Tier II: composed of a single path for power and cooling distribution, with redundant components, providing 99.741% availability Tier III: composed of multiple active power and cooling distribution paths, but only one path active, has redundant components, and is concurrently maintainable, providing 99.982% availability Tier IV: composed of multiple active power and cooling distribution paths, has redundant components, and is fault tolerant, providing 99.995% availability. Tier I sites will have computer power distribution and
cooling but may not have raised floors, UPSes, or
engine generators. The critical load on these systems
is up to 100 percent of N. Even with a UPS or
generator, they likely are single-module systems and
have many single points of failure. The infrastructure
should be completely shut down on an annual basis
to perform preventive maintenance and repair work.
Urgent situations may require more frequent
shutdowns. Tier IV data centers have all the bells and
whistles; everything needed to keep them running
without ever shutting down for maintenance, no matter
what happens. [Tier examples courtesy of Processor:
How's & Why's Of Data Center Tiers]
With all of that said. We have discovered that if one
were to use a "check list" of things that comprise
the various Tier levels, Tennessee 811 falls
somewhere between Tier 3 and 4.
The last phase of our Disaster Planning is migrating
redundancy to the Data Center we presently use. This
is a work in progress and will be completed by the
end of Fall 2009, if not sooner.
In a nutshell, what this means is that if we ever lose the actual call center on Elm Hill Pike, we are still in business running our services out of the data center we use for backup and redundancy. |
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Tennessee 811 offers free safety meetings at your
office or work site.
We don't restrict the hours - we can come to you
before your crews go out in the morning, during lunch
or when they come back in the afternoon. We work
around what works for you! We can tailor the time
frame of the presentation to suit your meeting needs
Call or email now and ask for Holly Austin or Scott
Holder and we will set you up.
Holly - haustin@tnonecall.com - 615-367-1110 (x7102) Scott - sholder@tnonecall.com - 615-367-1110 (x7140) "Call Before You Dig" is a great safety topic for any
meeting. Even your inside personnel can benefit.
Remember - there is no cost involved to you, and it's a
service we offer. The better educated your employees
are, the safer they will be.
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We thought it might be interesting to run a series about how GPS works. The content for this series comes directly from the Discovery channel's "How Stuff Works" programs via their website. So, sit back and enjoy the read. This article begins the 3rd topic in the
series.
3-D Trilateration Fundamentally, three-dimensional trilateration isn't
much different from two-dimensional trilateration, but
it's a little trickier to visualize. Imagine the radii from
the previous examples going off in all directions. So
instead of a series of circles, you get a series of
spheres.
If you know you are 10 miles from satellite A in the sky,
you could be anywhere on the surface of a huge,
imaginary sphere with a 10-mile radius. If you also
know you are 15 miles from satellite B, you can
overlap the first sphere with another, larger sphere.
The spheres intersect in a perfect circle. If you know
the distance to a third satellite, you get a third sphere,
which intersects with this circle at two points.
The Earth itself can act as a fourth sphere -- only one
of the two possible points will actually be on the
surface of the planet, so you can eliminate the one in
space. Receivers generally look to four or more
satellites, however, to improve accuracy and provide
precise altitude information.
In order to make this simple calculation, then, the GPS
receiver has to know two things:
?The location of at least three satellites above you
?The distance between you and each of those
satellites
The GPS receiver figures both of these things out by
analyzing high-frequency, low-power radio signals
from the GPS satellites. Better units have multiple
receivers, so they can pick up signals from several
satellites simultaneously.
Radio waves are electromagnetic energy, which
means they travel at the speed of light (about 186,000
miles per second, 300,000 km per second in a
vacuum). The receiver can figure out how far the
signal has traveled by timing how long it took the
signal to arrive. In the next section, we'll see how the
receiver and satellite work together to make this
measurement.
Brain, Marshall, and Tom Harris. "How GPS
Receivers Work." 25 September 2006.
HowStuffWorks.com. Photo courtesy U.S. Department of Defense Artist's concept of the GPS satellite constellation |
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Tennessee 811
email:
tnocs@tnonecall.com
phone:
(615) 367-1110
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