On Sat, 2009-09-12 at 08:16 -0700, Dave Close wrote: > Flash reads are reasonably fast, I agree. Writes are not in my > experience. And one probably writes to swap at least as often as > one reads from it. > > "Years" sounds like a long time. But many embedded systems are > intended to remain in service for ten years or more. A worn-out > flash memory after eight years (for example) would not be fun.
I find that people tend to underestimate how much actual data would be required to wear out flash. I did a calculation back when I was more involved with the handhelds.org project(s). Major thing at the time was porting the kernel and setting up a distribution for the Compaq IPAQ and other PDA. The first Ipaq has 16 MB of flash. Assuming a modest amount of re-writes for Flash of that era. One would have to write 1.6 TB of data to wear out the flash. And using something like JFFS2 on the flash, the effect amount of written data is easily double that. When people think about the ramifications of writing over a TB of data to handheld PDA, they realize their fears were a bit silly. I'll admit I was worried about wearing out the flash of my IPAQ before I did the math. Even reflashing it a few hundred times, the IPAQ would be obsolete long before I wore out the flash in it. -- Stephen Johnson <[email protected]> _______________________________________________ Discuss mailing list [email protected] http://lopsa.org/cgi-bin/mailman/listinfo/discuss This list provided by the League of Professional System Administrators http://lopsa.org/
