On Mon, 15 Nov 2010 22:57:23 +0000, DoN. Nichols wrote:
On 2010-11-15, Ignoramus25291 wrote:
....
I recently set up a computer that I hope will last over 10 years. It is
based on Intel atom CPU and has NO moving parts: SSD instead of a disk
drive and no fan. I will use it to be a server.

Hmm ... how many write cycles will the SSD survive? I know that
a lot of Compact Flash cards have a limit on the number of writes, which
makes them very poor choices for running a unix/linux/BSD box, since
every time a file is read, the last-accessed time in the inode is
updated -- unless you can mount the disk read-only. I would suggest
frequent backups to some other medium until you know for sure.

Endurance of flash memory chips has increased a lot, so that
SSD lifetime and MTBF is better than some hard drives now.

Per http://www.storagesearch.com/ssdmyths-endurance.html,
endurance of a flash memory cell was typically 10,000 write cycles
in 1994; 100,000 in 1997; millions of cycles now. A few years
ago, "typically 3% of blocks in a flash SSD might only last 100,000
cycles but over 90% would last 1 million cycles." SSD's (solid state
disks) use over-provisioning, bad block testing and management, and
transparent wear leveling for longer equipment life. Due to
wear leveling, for example, even though the logical sector
number of inode doesn't change, the physical sector it is
written in may change from time to time. Example in above
link is a 64GB SSD written continuously with expected lifetime
of 50 years. (A 64GB MZ-5PA064 SSD with 250MB/sec sequential
read and 170MB/sec sequential write speeds is $139 from
samsung.com. If the numbers in example are applied to it,
lifetime is ~ 25 years, due to it being 2 times faster than
in the example.)

Some SSD-specific filesystems are available that avoid
frequent writes, but might or might not be worth pursuing.
Per http://community.spiceworks.com/topic/107081, "The
concept of changing the way that you write to your SSD to
prolong lifespan comes from people using SD and CF cards as
SSDs. These have write lifespans so short that it is a real
issue. Good SSDs like you would use in a normal computer do
not." "Modern SSDs have MTBF so long that using them for
regular swap space is no problem." "An SSD will outlast a
normal HD by orders of magnitude." "When you talk of sparing
the SSD of writes it is like saying that you want to make sure
that it lasts for 40 years instead of 35."

--
jiw