Flash Memory

Flash memory is non-volatile, meaning that it can retain its data, even when not supplied with power. It is used mainly for transfer of data between various digital products and your computer. Examples of products that use this technology...

• Digital Cameras
• Video Recorders
• USB Flash Drives
• Cell Phones and PDA's
• MP3 Players

The list goes on, but you get the idea. It is very widely used because of its low cost to produce and ease of use. It is also extremely durable. When packaged as a memory card, it can withstand intense pressure, extreme temperatures, and even being submersed in water. I have personally washed and dried a USB drive and it is still working perfectly.

Flash memory does have some limitations. There is a maximum number of writes that can be done. Currently that number is around 1,000,000. This has been somewhat offset by what is called wear leveling. Built in software will control what is written where to spread the writes around. It will also track how many times a location has been written to. Normally, you will most likely not reach this limit however, as it usually extends beyond the life of the product.

There are 4 main flash memory types in use. We'll take a look at each...

1. USB Drives
2. CompactFlash Memory
3. SD Memory Cards
4. Solid State Drives

USB Flash Memory Drive

USB flash drives come in many different shapes and sizes and are known by a few different names. USB flash memory stick, USB pen drives, flash memory drive. They all mean the same thing though, a portable data storage device that is universal to most computers. USB flash memory currently ranges in size from 32MB up to 32GB, and they are currently working on a 64GB version.

USB drives are a huge improvement over other portable media types such as floppy disks, zip drives, and even CD/DVD. First off, they do not need any "media player" to read the data. They don't need a DVD drive or floppy drive to be used. All you need is a USB port, and almost every computer in use today has one. Second, they are solid state. They don't have any moving parts, so cannot break down, as a zip drive might. USB drives do not need an external power source. They draw all the power they need directly from the USB port.

Flash drives can be used in many ways...

• Personal data transport - This is the most common use of flash drives. You can store documents, email, pictures and video on flash drives and carry it wherever you go.
• Operating System - Flash drives have a high enough capacity now that you can install an operating system and boot directly from the flash drive. I wouldn't recommend this as a permanent operating system for your home computer, but it's nice for a portable operating system.
• Computer Repair - Some flash drives have a switch you can flip to not allow the drive to be written to. These are great for computer repair, as you can run virus scans without having to worry about your drive getting infected. You can also keep other repair applications on the drive.
• Window Vista Ready Boost - Ready Boost is a new technology included with Vista that has a goal of making the computer more responsive and load applications more quickly.
• Application Carrier - You can install applications on a flash drive. A new technology called U3 is gaining popularity. U3 allows you to install applications on the flash drive, and then use those applications on any PC you can plug into.

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Compact Flash Memory Cards

Compact Flash memory cards have been around for some time now, and are widely used in the digital camera industry. It is however gaining popularity as a portable means of storing data. Compact flash capacity has grown over the years, and is keeping up with USB flash drives in size.

Many laptops and even desktop computers will come now with a card reader that you can use to read and write to the compact flash card. You will see the speed of the card measured in the same way as you would for DVD players. You will see 8x, 20x, 133x etc. If you multiply that number by 150KB's, you will get the speed. So, for a 20x, you would have 3.0MB/s, for 133x, you get about 20MB/s.

Compact flash memory cards are also extremely durable. They can withstand temperature ranges of -45C to 85C. Most are waterproof and can be submersed in water, and they are able to withstand intense pressures. About the only real downside is its size. For cameras they work great. But for slim devices, such as cell phones and PDA's, the size is just too big.

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SD Flash Memory Cards

SD Flash Memory Cards are smaller than compact flash cards, so are widely used in PDA's, cell phones, GPS and even video game consoles. The Secure in Secure Digital came from the card's origin. SD cards were originally designed by Toshiba, who added encryption hardware to try and prevent the piracy of music. In theory, this was supposed to allow for enforcement of Digital Rights Management (DRM) of digital music. We see where that got them...

Read and write speeds of SD flash memory cards are similar to compact flash memory cards. They range from 1MB/s up to 30MB/s on the high end cards.

Also included in the SD family are micro SD cards. These are very small memory chips that are used mostly in cell phones and PDA's. These are usually installed near the battery under the back cover, and are used to provide storage for music or photos. Micro SD cards need an adapter to be used in a PC. This adapter looks just like a regular SD card with a place to insert the micro SD card.

Uses for SD flash memory cards include...

• Cell Phones - When used in a cell phone they are normally used to store photos, music, and sometimes video.
• PDA's - SD cards are used in PDA's for all kinds of data storage.
• Nintendo WII - The Nintendo WII and other video game consoles use SD memory to hold save game files and other multimedia.
• Car Stereos - Some car stereo's now include a slot for SD memory that allows you to play MP3, WMA and other formats.
• Digital Cameras and Camcorders - Used in digital cameras and camcorders to record still photos and video clips.

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Solid State Drives

Solid state drives are just starting to gain popularity, and are still quite expensive. A solid state drive is basically a hard drive that uses flash memory. Being that they are solid state, they have no moving parts. This makes them faster than a regular hard drive.

There are 3 main advantages to using solid state drives over conventional hard drives.

• Less power usage - With no moving parts, solid state drives use less power.
• Faster data access - Again, with no platters to spin up, and reader arms to move around, data access is much faster.
• Higher reliability - No moving parts means no mechanical pieces to break. They can withstand being dropped much more than conventional hard drives, plus they are able to withstand greater temperature extremes.
  

There are some disadvantages as well.

• Price - As of the time of this writing, a 64GB solid state drive will cost you around $1200, compared to a 64GB conventional hard drive at around $30.
• Capacity - The top capacity of a solid state drive is currently 128Gb, and that will cost you over $3000. Compared to conventional hard drives which have a capacity of 1TB (Terabyte).
• Higher vulnerability to certain conditions - SSD's are more vulnerable to magnetic fields and electric/static discharges than conventional hard drives.

Solid state drives will continue to come down in price as the technology matures. It is something to keep your eye on for the future. However, unless you have a very large budget, the price makes their use very restrictive. One option however would be to purchase a smaller drive, say 16GB. These can be found for around $250. You could use this drive specifically for the operating system only, and help speed up your system.

 

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