Number 307 - December 2008

Solid State Drives
by John Lansdale, MCP, CDP, Danbury Area Computer Society,
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 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.
Number 307 - December 2008