Solid State Drives
by John Lansdale
As usual, the news isn�t technology but price. This time
it�s flash memory. It's the stuff inside USB pen drives,
camera cards, cell phones, portable GPS devices, and your computer
BIOS. Solid state drives also use it. They have additional simulated
connections and software to imitate regular hard drives, a little
like cassette tape adapters for your CD player.
�It�s not important to know exactly how flash
RAM works but having a mental model of it at the highest level
can help you understand what these new lower price solid state
drives mean.
With random access memory (RAM), any one piece of information
can be accessed as fast as another, but without power all is
lost. Data persists without power on electro mechanical (hard)
drives but non electronic finding is much slower. Flash memory
is electronic, like RAM, and it retains data when the power is
off. It�s a little slower reading and writing than RAM
because the storage process is time dependent. (There's
a fixed wait for some electrons to get in place. See "How
Flash Memory Works" at (HowStuffWorks.com).
Flash memory is much better than hard drives for reading small
files. The old way of improving performance has been to increase
RAM size and processor speed. Very large blocks of memory are
cached. Start up time is slow but access of cached memory is
fast. The new way is with flash. No cache needed. Less RAM and
slower processors do the same job. This is very good for laptops
because less power means longer battery life.
Flash memory is also lighter and more durable. The only problem
has been its very high price. It is still more expensive. A 64
GB solid state drive will cost around $1000. A high speed 500
GB hard drive is less than $200.
But on the low end, solid state is very affordable. An 8 GB
SD HD card costs $35, 16 GB USB pen drives around $65 and a 4
GB solid state drive $300 (put one in your old laptop to give
it new life). I've included a spreadsheet (PDF)
comparing speeds and prices of several traditional and flash
memory devices. I tried to be accurate and compare apples to
apples but don't trust me 100%. Consider the prices and dates
of the products. Also the two columns you�ll notice I
left out are "write
times" which
are half as fast for flash ROM, and "expected write cycles" which
are finite for flash but I'm not sure how they compare.
The size of Windows and Mac operating systems has grown. Vista
Home requires a minimum of 15 GB and Leopard 9 GB. Both systems
tend to bundle every possible feature there could be along with
extra flashy graphics and multimedia capability. Possibly, they
are trying to appeal to the status conscious consumer who just
wants the best. Linux on the other hand, makes it easy for developers
to create their own variations of operating system (Distro's)
including just what is needed. The Xandros distro on the new
ultra portable Asus Eee and FEDORA on the One Laptop Per Child
XO are less than 2 GB. Even smaller distro's are available.
Prices might drop more, but for now, thanks to SSD, little is
big.
A couple of other things to note are Windows External Memory
Devices which uses flash memory in a USB key drive to extend
regular RAM. There are Hybrid products both RAM/Flash and Flash
Hard Drive (1GB flash built in) which have also been showing
up. The result might mean faster system boots and data retrieval,
even with large databases.
John Lansdale, MCP, CDP
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