The amount of data is a bit of a difficult topic. The role of the box
will be an embedded message server (email & voice mail). I can compress
both of those quite well to save space, but I think we'd still be looking
at between 20 and 40 MB total. We'd like to be able to leave the email on
the server (i.e. set it up as an IMAP server) which means we'd need enough
space to store "enough" messages (what "enough" is remains to be
determined). The voice mail would only need the ability to be saved for
short periods (maybe a few days).
The concern with the voice mail is wearing out the flash device. I did
some rough calculations though, and found that if I used 20 MB, assuming 2
minutes per message and a compressed data rate of 5 kbps and a flash
lifetime of 300,000 write cycles, the flash would last 800 years even at
500 messages per day. This is less of a concern with email because it
would be written once.
Obviously it would be nice to implement all of this in a RAMdisk (40MB RAM
is quite a bit cheaper than 40MB flash disk), but the concern is that if
there were a power failure or a system crash, the data that was in the
RAMdisk would be lost. Using a disk drive doesn't seem to be a very good
alternative, as we could probably only count on a few years of lifetime.
Regards
Ryan
On Wed, 28 Oct 1998, paulmoody wrote:
> Ryan Bedwell wrote:
>
> > Paul (and everybody)-
> >
> > I read the Embedded Linux mini-HOWTO (very helpful). My question is:
> > if you left the flash disk mounted, would you be risking corruption of
> > the filesystem if there were a power failure? I'm considering a project
> > in which I'd like to leave the flash disk mounted for saving some data
> > that needs to be able to survive a power failure (i.e. can't just throw it
> > in RAMdisk), but I'm wondering if it compromizes the compressed root
> > filesystem on the flash disk.
> >
> > Thanks in advance.
> >
> > Ryan Bedwell <[EMAIL PROTECTED]>
> > TransEra Corp.
> > http://www.transera.com
>
> Hi Ryan,
> How much data are we talking here ?
>
> regards Paul.
>
>
>
