[mdlug] supplemental memory?

[Robert Citek]

On Tue, Mar 23, 2010 at 10:55 AM, Jeff Hanson <jhansonxi at gmail.com> wrote:
> They are memory.  FLASH memory is faster than hard drives and much
> slower than RAM but with a limited write cycle life.

I had always thought that flash would be faster than a hard drive
until I did a write test on a USB stick:

$ wtest () { dd if=/dev/zero of=zeros bs=1M count=$1 ; sync ; } ; sync
; time -p wtest 100
100+0 records in
100+0 records out
104857600 bytes (105 MB) copied, 7.38919 s, 14.2 MB/s
real 20.27
user 0.00
sys 0.63

The write same on my internal harddrive:

$ wtest () { dd if=/dev/zero of=zeros bs=1M count=$1 ; sync ; } ; sync
; time -p wtest 100
100+0 records in
100+0 records out
104857600 bytes (105 MB) copied, 1.68022 s, 62.4 MB/s
real 3.90
user 0.00
sys 0.63

The hard drive is about 5x faster.  Fairly consistent over multiple tests, too.

Regards,
- Robert