General Dynamics Itronix GoBook MR-1 Manual page 84

GoBook MR-1
collect route history information. Assuming your disk inactivity timeout is set to 1 minute, logging your
GPS coordinates every five minutes will allow the HDD to spin down periodically. This ratio allows the
system to not exceed the recommended 20% duty cycle between HDD power-on hours and
read/write/seek operations.
In Itronix standard factory software load, we pre-configure the Windows "Turn off hard disks" power setting to
"After 1 min". We recommend you keep this setting to ensure maximum HDD service life.
24x7 Operations
Some customers have deployed GoBook® computers in a "24x7" operation environment, taking advantage of the
product's ruggedness and ability to withstand harsh environments. In these applications, users are often trained to
leave the computer running at all times – never going into standby or shutting down.
Remember that the 20,000 hour / 5-year service life estimate of the HDD is based on the average usage pattern of a
notebook with power management (power-on hours < 333/month, "spin time" < 20%). Operating a notebook HDD
in a "24x7" operation without power management will greatly accelerate wear, and may require repair or
replacement of the HDD in as little as 2 years.
Future Hard Disk Technologies
Most Itronix customers experience excellent reliability using today's notebook HDD technology – as they do using
the same technology in their standard non-rugged notebooks. Problems like "constant spinning" are serious but rare.
The good news is that several future technologies promise to improve the reliability, power management, and
service life characteristics of notebook HDDs.
Solid State Disks (SSDs)
Solid state hard disks have been available for several years. SSDs typically use NAND Flash memory to store
information instead of rotating media. They offer extreme resistance to shock, vibration, and temperature – with no
rotating media to wear out.
The downsides of deploying SSDs in notebooks are their limited storage capacity (typically 32 GB or less) and
much higher costs – by several orders of magnitude. This has narrowed the use of SSDs to niche critical
applications where ultimate reliability is required "whatever it costs".
New higher capacity NAND Flash manufacturing processes are bringing the cost of SSDs down each year. While
not yet approaching the capacity/cost advantage of rotating media, the new generation of solid state devices will
allow them to be used in more applications.
Hybrid Hard Disks (HHDs)
Hybrid hard disks combine rotating media with a solid state flash buffer. The rotating media provides the large
storage capacity of conventional hard disks, while the flash buffer is used to cache frequent accesses and reduce the
amount of time the rotating media is needed to spin. A minimal amount of flash buffer is required, so HHDs are
expected to be priced at a modest premium above conventional disks.
Microsoft's forthcoming Windows Vista™ operating system features ReadyDrive technology, which provides native
support for HHD usage transparent to application software. Hardware vendors such as Intel and Samsung have
announced plans to integrate flash buffer technology on motherboard designs – in effect creating a HHD in
combination with standard conventional hard disks.
Hybrid hard disk technology advantages include:
Access to the rotating media is reduced, making "constant spinning" problems much less likely to occur
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