CF cards wear out?

[Narvi]

On Fri, 12 Dec 2003, Matthew West wrote:

> On Fri, Dec 12, 2003 at 08:49:05AM -0500, Francisco Reyes wrote:
> > Do CF cards "wear out"? Aren't they like memory?
>
> They are solid-state storage devices; a bit like RAM, except they
> remember what's stored on them even when they're not connected to a
> power source.  :-)
>
> The pros of using CF is that its small, requires only a small amount
> of power to run and has no moving parts (no noise).
>
> The cons of using CF is that its storage capacity is lower than your
> conventional HDDs, and it has a relatively much lower number of writes
> in its lifespan (around 1,000,000 writes I think, it varies from
> product to product).  The number of reads is obviously much higher
> than that though.
>

This is writes to a block (more preceicely, block erases), not writes in
general.

> However, if you're going to be using it to run a router or whatever,
> you're probably only going to write to the thing once or twice to set
> it up, and then set it to mount read-only and leave it there.
>
> What you _don't_ want it doing is churning logfiles every day.  The
> m0n0BSD image mounts /var as a memory file system, so you still get
> your logfiles to watch, but they don't actually get written to the CF
> card.  Of course, you will lose the files when the power is removed...
>

Churning logfiles is an extremely OK thing for a CF, *PROVIDED* you use
a reaosnably sized CF and a CF friendly file system (neither FAT nor UFS
are really). it takes a loong time to overwrite 128MB card 100000 times.

> If you're going to be using a system like the Soekris boards and your
> project requires a media that you can do a lot of writes too, I would
> recommend something like IBM's Microdrives.  You should be able to fit
> these inside the Soekris chassis without a problem.  The NET4801 has a
> Microdrive IDE connector on the board.
>
> --
> mwest at uct.ac.za
>
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