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[aprssig] APRStt ( change the subject line )

Matti Aarnio oh2mqk at sral.fi
Tue Jun 1 22:14:31 UTC 2010


On Tue, Jun 01, 2010 at 02:23:29PM +0100, Dave Baxter wrote:
> Take care.
> 
> Flash memory of any type (card, stick, in-the-chip etc) should *Never*
> be used for temporary storage where there will be many write cycles.
> It literaly wears out.  Use battery backed CMOS ram for that, if there
> is a need to hold the data from one session to another.

I am routinely building Linux installations that operate from RO flash
"disk" of many types.  The trick is to redirect some directories and/or
reconfigure some system maintenance applications to use RAM based /tmp
filesystem instead of "real disk".

When modifications (like software/configuration update) are necessary,
the "disk" can be remounted RW, modifications done, and remounted back
to RO.  With entirely passive cooling the result is a very robust machine.

It is more a question about how familiar you are with the base operating
system to be able to make it play nice?    It is entirely possible to
"embed" a Debian or Fedora Linux installations even tough packers have
not done it quite completely ready for you.

Just drop all GUI stuff, and your installation memory footprint shrinks
considerably.   I have all development stuff in (emacs, gcc, gdb, libs,
valgrind), and system uses 600 MB of 1000 MB "disk".

  ...

I found my old notes on how to embed Debian 4.x, but the text is in
Finnish, and quite out of date with regard of software installation.
Don't hold you breath, but one of these days I will update that, and
make an English translation of it too.  (http://wiki.ham.fi/OH2RDY)


Single software package doing digipeating and igating on Linux/BSD/Posix:

  USER   PID %CPU %MEM  VSZ   RSS TTY  STAT START   TIME COMMAND
  root  9448  0.0  1.5 3388  1868 ?    Ssl  Jun01   0:00 /usr/sbin/aprx

http://wiki.ham.fi/aprx.en

I have been asked to implement APRStt on this codebase, and so far I see
it as a possibility just because of the Hack that the specification is.
But there is D-PRS being worked at first, then perhaps HF PSK63 APRS.

> Regards.
> Dave G0WBX

73 de Matti, OH2MQK



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