fast compression/decompression

Hello,
Does anybody know which algorithm could be a solution for increasing
file transfer speed between two embedded systems:one has 8 Mhz clock,
the other has 14 or 24 Mhz clock.The baudrate is 28800 and can be
upgrade to 57600.Is compression of files that can be compressed by a
factor 2.5 by deflate algorithm convenient even at this baudrate?
thank you very much

Hi,

> Does anybody know which algorithm could be a solution for increasing
> file transfer speed between two embedded systems:one has 8 Mhz clock,
> the other has 14 or 24 Mhz clock.The baudrate is 28800 and can be
> upgrade to 57600.Is compression of files that can be compressed by a
> factor 2.5 by deflate algorithm convenient even at this baudrate?

What kind of data do you expect to transfer? FYI, standard analog
modems already offer an "on the fly" compression.

So long,
Thomas

Thomas Richter <thor@cleopatra.math.tu-berlin.de> wrote in message news:<chp51g$k4i$3@mamen
chi.zrz.TU-Berlin.DE>...
> Hi,
> 
>
> What kind of data do you expect to transfer? FYI, standard analog
> modems already offer an "on the fly" compression.
>
> So long,
> 	Thomas

Data are the code for the systems. I got a good compression rate by
zlib(factor 2.5), but I have not to use modems: I need compression for
a local connection between the two systems, and I don't know if there
is an algorithm that by the total speed(the packets are half,but there
is some loss of time in compressing and decompressing on the fly) is
convenient to use even at 57600 bps. How modems can do
compress/decompress very fastly even having an optimal compression
ratio? (Because it is not a good solution if I have a very fast
compression/decompression but I have not a good compression ratio).

> Does anybody know which algorithm could be a solution for increasing
> file transfer speed between two embedded systems:one has 8 Mhz clock,
> the other has 14 or 24 Mhz clock.The baudrate is 28800 and can be
> upgrade to 57600.

Read <zlib.h>, particularly the description of deflateInit2(),
and try some experiments using low values for compression level
and windowBits.  On the hardware and/or operating system, be sure
that careful attention has been paid to programming the UARTs:
use the silos and/or DMA, minimize the overhead for interrupts, etc.

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