On Tuesday 14 March 2006 15:34, Jeremy C. Reed wrote:
> What are the issues with using NetBSD's FFS with flash memory?
>
> Are there any recommended flash memory hardware that works best with FFS?
>
> What are some workarounds? I assume noatime or nodevmtime (which I have
> never used) or only mounting read-write when really needed to write.
>
> What are the alternative file systems for use with flash memory?
>
>  Jeremy C. Reed

The issue is that flash memory has a limited life for writing. Newer flash 
implements wear levelling to mitigate this.

I mount flash read-only and use MFS for volatile data. When I must write to 
it, I mount rw,noatime. I also purchase flash cards/module larger than 
required.

I use flash memory in a number of embedded devices. Most use socketed flash 
cards; for these I prefer the one from Lexar media because they have a faster 
write time. I also use som M-System 2.5" flash disks and have some 3.5" ones 
currently on order for a project.

Flash cards are rather slow. The flash disk modules are available with 
difference interfaces. The SATA ones are quite fast (and expensive).

The program I'm working one is using flash modules as you might use rotating 
media with a DOS filesystem. The engineers swear that this is OK with modern 
devices.

Here's an article on flash life:

http://www.vmebus-systems.com/articles/id/?784

-- 
John R. Shannon, CISSP
john@johnrshannon.com
jshannon@dsci-usa.com
john.r.shannon@us.army.mil
shannonjr@NetBSD.org