[LAU] Advice on hardwware components

[Joshua Boyd]

On Mon, May 21, 2007 at 08:56:08PM -1000, david wrote:
> Alexandre DENIS wrote:
> >On Monday 21 May 2007, david wrote:
> >>Michael Nelson wrote:
> >>>I'm interested in using a CompactFlash-to-SATA adapter, and booting
> >>>from a CF card. Does anyone know what the speed/reliability would
> >>>be like?
> >>I think it would be pretty slow - my CF cards seem to give only
> >>5-6MB/sec transfer. Even my slowest hard drives run a LOT faster than
> >>that.
> >
> >The new Samsung NSSD achieve much better performance: read=53MB/s, 
> >write=30MB/s with 0.24ms access time.
> ><http://www.samsung.com/Products/Semiconductor/FlashSSD/ModuleType.htm>
> 
> Yes, SD is faster than CF.

That new Samsun FlashSSD isn't SD though.  It is NAND chips with a
microcontroller pretending to be IDE.  That basically describes a modern
CF card.  While CF originally used NOR flash, it switched to
cheaper/faster NAND flash some time ago.  Since CF cards had to have an
adapter chip to emulate IDE anyway, they can use whatever they want for
flash on the other side.
 
> >>Plus - CF has a limited lifespan when it comes to writing to the
> >>card.
> >
> >Modern SSD all use Wear Leveling to improve the lifespan, to get 
> >actually better results than hard disks now.
> 
> At least that's the claim. We'll see! In my relatively short (5 years) 
> use of assorted solid state memory - I've had one CF card fail and one 
> hard drive fail. The hard drive was about 8 years of old and had been 
> very heavily used during its lifetime. The CF card wasn't even a year 
> old ...

I've been using CF cards for boot disks on linux for more than two years
without issue.  The systems are tuned to minimize writes to the CF, but
they are still mostly normal Ubuntu server installs.

Further CF continues to improve.  The new stuff good for 50,000,000
writes to each block isn't that old yet.  And like harddrives, video
cards, sound cards, etc, it is always possible for CF to fail before it
is actually worn out.