Subject: Re: JFS
To: None <tech-kern@netbsd.org>
From: Thor Lancelot Simon <tls@rek.tjls.com>
List: tech-kern
Date: 02/20/2003 18:37:07
On Thu, Feb 20, 2003 at 05:15:40PM +0000, David Laight wrote:
> 
> You definitely want to minimise writes to flash, so noatime and nodevmtime
> are a must.  Also all flash memory has quite large physical sectors,
> (they were 128kb on a board I used) so writes have to be large RMW
> cycles - and the erase takes ~1 second (some modern parts may be faster).

It's generally pretty much trivial to arrange to mount the "writable"
partition read-only until you need to write, remount, write, and remount.
This isn't an ideal solution, but on the other hand it does make it _very_
explicit when you're actually writing something, which is helpful because,
for example, it makes it easier to conform to standards like FIPS-140 that
require you to perform a number of other explicit tests before rewriting
any configuration data.

Thor