[maemo-developers] [maemo-developers] Adding swapon/off to Jakub's Load-Plugin applet

[From: David D. Hagood]

Heike C. Zimmerer wrote:

> You're sure?  Maybe I'm not up to date, but I remember figures in the
> order of typically around 100,000 or even as low as 10,000, depending
> of the kind of write cycle (like MLC) for today's standard devices.  A
> pointer to the data of the device actually used by the 770 would be
> much appreciated.
> 
Well, I don't know what the Nokia uses, but the Flash chips I've worked 
with (AMD and others) quoted 100K as a bare minimum with 1M as typical. 
In the "bad old days" when the programming cycle was controlled by the 
computer, and the timing was at best approximate, the chips tended to 
get burned out. Now, that the write cycle is controlled by the chip 
itself, and thus is tuned to the process, the chip does not overstress 
the oxide layer.


> Again, maybe I'm not up to date: isn't wear leveling only effective if
> there's enough room left on your flash which gets freed from time to
> time?  IOW, the more static data there is on a flash (like programs
> and fixed data), the less is gained from any leveling algorithm?
> 
You always do wear leveling, because of the block erase nature of flash 
- you have to keep a certain amount of the flash in reserve so that when 
a write occurs you have a place to put the new data until you have a 
full block.

I've done both low-level flash programming (including the bad-ole-days 
timing with NOPs and JMP $+2's) and flash file systems before.