TIME WAITS FOR NO MAN ......
AND REAL WORLD SIGNALS DO NOT WAIT FOR COMPUTERS.
In the world of Instrumentation Recorders the
"Value" of the signals to be collected may be impossible to calculate.
Avalon’s recorders have between them millions of hours of successful error
free recordings.
The 'target' may represent an unrepeatable event with a
single opportunity of capture. The recorder may be recording these events on an
aircraft costing hundreds of thousands of dollars to fly whilst putting the crew
in harms way, or maybe be installed in a black tube away for months at a time
with a deployment costing millions of dollars. More than once Avalon’s
recorders have continued to record the data when other equipment had failed all
around it, bringing home priceless information.
On one occasion, around 15 years ago, the Sonar Suite on
a Submarine failed at the start of the mission. The operators continued to
record and change the VHS tapes in the Avalon Recorder in the hope of recovering
data from the mission. On return to base, three months later, they were
delighted to find that the failure had not involved the recorder and that the
entire missions data could be retrieved. This particular recorder is still in
front line service today, and it is planned to continue its deployment for a
further 10 years.
How many times have you requested your computer to do
something only to be presented with the "Hour Glass" or the "Blue
Screen of Death"? Over time we have all learned to live with the
unreliability of computers, saving our files on a regular basis, and most
importantly, have a duplicate copy of our data stored on a separate machine. To
provide additional security Avalon’s recorders have three additional data
protection features.
The fundamental principles of Computer based technology
is that of a collection of devices which take in a specific amount of data,
processes it and returns the answer. The task is usually processed at a time and
a speed convenient to the Operating System, and allows for other non-mainstream
activities to interrupt the process as they see fit.
The fundamental principles of an Instrumentation
Recording system is to faithfully record and reproduce the signal attached to
its input socket, NO MATTER WHAT ELSE IS HAPPENING AROUND IT.
These two principles are clearly diametrically opposed.
If the input data rate is slow enough so that the process can take place
sequentially or that the process can be spread out over a large number of
parallel paths then a Computer based architecture may provide a solution.
However, the owner is then at the mercy of commercial parts and software
which tend to be obsolete within 12 months. It also means that the data is
dependant on more components than is really necessary and this increases the
probability of failure.
AVALON’S MISSION, SINCE ITS INCEPTION NEARLY 25 YEARS
AGO, IS TO TAKE STORAGE TECHNOLOGIES, DESIGNED FOR OTHER PURPOSES, AND TO
INTEGRATE THEM INTO AN ENVIRONMENT WHERE THEY PROVIDE A RELIABLE AND DURABLE
RECORDING SYSTEM, WHERE, WHEN THE RECORD BUTTON IS PRESSED THERE IS A 99.99%
PROBABILITY OF CAPTURING THE SIGNAL.
Designing
for Reliability and Longevity
The first task is to identify suitable primary storage
devices from dependable suppliers with a good history of reliable products and
who are willing to cooperate in investigating why their product fails to operate
as they might have expected, based on their data sheet claims. These storage
devices are then stripped of all unnecessary functions and driven by Avalon
purpose designed, dedicated hardware which will enable the device to operate
continuously at maximum efficiency. The task is not to take "Off the
Shelf" components and link them with software since these devices were
designed for an entirely different operating environment.
ALL HARD DRIVES ARE EQUAL, BUT SOME ARE MORE EQUAL
THAN OTHERS
As part of our engineering investigations we found a
great deal of variation in the performance of Hard Disk Drives from one
manufacturer to another and from model to model from the same manufacturer. In
an operating environment where time to the nearest millisecond is not of
significance all drives perform a reasonable task. However with real world
signals, time is of the essence. After years of investigation we have approved
only two manufacturers, and as an indication of the close cooperation which has
developed, each of these ask Avalon to be one of the first users to evaluate new
products as they recognise that our operating environment is THE most demanding
of all applications in the world.
Part of this qualification process is to monitor the
drive's performance whist subject to vibration, large displacement shocks, and
temperature variations - the type of thing that happens to recording systems
when deployed in the real world. Whilst most disks will recover from these
events, given time, as we said before time waits for no man, so the drive must
perform perfectly whilst subject to these variations.
ONLY HARD DRIVES WHICH PASS OUR STRINGENT EVALUATION
PROCEDURES WILL BE INCORPORATED INTO AVALON’S PRODUCTS.
Avalon is the only company able to offer with confidence
and experience an unconditional 3 year Product Warranty and a 5 year Hard Drive
Warranty.
Detailed descriptions of the tests and evaluations are
available to qualified customers on conclusion of a Non-Disclosure Agreement.
Disk based Instrumentation Recording typically involves
the use of computer Hard Drives operating in parallel to accomplish data
recording rate hitherto undreamed of. Unfortunately some of the terminology
associated with the low cost end of the computer market has been used to try to
describe the deployed technology.
RAID IS AN IMPLIED ADMISSION OF THE
PROBABILITY OF FAILURE
The acronym RAID stands for Redundant Array of
Inexpensive Disks. It implies that the most important feature is their cost, and
that they are configured in anticipation of failure.
JBOD IMPLIES THAT ANY DISK WILL DO
The acronym JBOD stands for Just a Bunch Of Disks. It
implies that there is no significance in the quality or origin of the disks used
to provide the recording engine.
PRIDE IS THE ACRONYM OF THE ENLIGHTENED
Precision Recording Instrumentation Disk Environment
(PRIDE is a trademark of Avalon Electronics)
The disks are the vital heart of any disk recording
system. Whilst most hard drives perform to a satisfactory level under an
operating system environment, there true performance is only evaluated when
tested with continuous real world signals.
Avalon’s engineers have a long history of working with
magnetic recording, including working on Computer Compatible Tape Recorders in
1968, the first Hard Disk drives imported into the UK in 1972, and Exchangeable
Hard Disks in the 1990s.
Avalon has three criteria for selecting hard drives,
Quality, Reliability, and Repeatability. Cost is of no importance. The quality
of manufacture is just the start. The quality of the handling by the distributor
and shipping organization prior to their inclusion to our products is vital.
Avalon has imposed strict handling and packing requirements on the
manufacturer's distributors to ensure that the product is received in perfect
condition.
If Hard drives are damaged in transit, and are operated in a Windows
Environment, the user will be completely unaware of any minor damage that the
unit has sustained.
Damage can be inflicted on a Hard Drive very easily if it is not handled
correctly. By standing a drive on its edge and allowing it to topple over on to
its back exceeds the maximum shock specifications recommended by the
manufacturers. When recording real world signals using a damaged disk the
performance is likely to be intermittent. One day it will work another is may
fail.
Avalon’s Electronics monitor the performance of the
Hard Drives and reports if there is any likelihood of damage, allowing the disks
to be replaced prior to a critical failure whist recording or replaying vital
data
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