Re: [gentoo-embedded] file system question

[wireless]

Ed W wrote:

> In addition to what everyone else has already noted you really need to
> state your tradeoff between lifetime of the flash cards and minimising
> the risk of loosing data.


Wow, this sounds like a PC programmer's statement and not
how an embedded designer would solve the problem. Granted
the poster has not provided and adequate 'specification' so
my point of view may or may not be precisely applicable.


From what I have gleaned, the developer should first look at
a low power system, with battery backup. If it is an
embedded system designed to run as such, a simple 9V battery
should provide years/decades of reliability to 5 nines of
uptime or more..... This robust research and design approach
will solve power cycling-data loss problems....


Depending on the details of the data collection sensors and
hardware, either redesign as low power, or put them on a
separate power supply. If that, (relatively) hi power supply
is intermittent, you only loose data for those data
collection intervals. You CPU/storage module never looses
power. Some very fast AD devices are power hogs. Other
(slower) AD devices are very power efficient, especially if
they 'sleep' (low or off power mode) when not
actively needed. This is controlled



I could go on and on, but just purchasing a SBC and trying
to turn it into a robust product, is rarely successful in my
experience. USE and SBC of the shelf to get your coders
coding, and get a hardware designer to look at the
specification, and design a low power, minimized design that
has what you need and nothing else.

Then when you ramp up quantity, you'll actually make a
profit as your competition lowers their price, you can still
compete. It's impossible, in my experience, to use off the
shelf SBC and be competitive for very long. Your competition
will under cut you every time....


hth,
James