to swap or not on SD card

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1

Hi...

I understand that using flash memory for swap is generally considered
bad, since flash has a limited number of writes for each bit. I see
that some of the notes in the elinux wiki indicate that some apps/GUI
might need flash in order to run on the 128MB versions of the
Beagleboard. What would you recommend for a RevC2 Beagleboard with
256MB of RAM running linux from a SD card? Could I get by without
swap or would I want to have some regardless?

Are the algorithms for swap flash-aware these days? Could the overall
lifetime be improved by using a larger partition for swap (hoping that
writes are distributed) or perhaps by leaving some of the flash
unpartitioned, so that it is available for re-allocation (does it even
work that way)? In case this is application-dependent, I am
interested in running typical desktop/multimedia applications.

Thanks for any comments/insights/suggestions...

-Chris

2

Not only is there a limited # of writes (which is nowadays not that
small by the way, so I would not expect that to be a problem factor,
and if it becomes so in a year, just get yourself a new card).
More problematic is probably the write speed. Try a test where you
want to write 4k blocks to flash randomly and measure the speed.

(btw I am assuming you are not considering using internal flash for
swapping. In that case I would recommend against it.
Whether you need swap or not depends on how you are going to use your
beagle. I haven't come to a point where I needed it (but if you are
going to run large sql databases or want gcc to compile itself, I
guess you will.

Frans