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Thread: Flash RAM vs a Hard Drive
09-17-2007, 09:38 AM #1Flash RAM vs a Hard Drive
The allure of Flash RAM has many facets. For starters, reading from Flash is faster than from a hard drive. The Classic can occasionally be forced to stutter if you start playing music and then immediately zip through menus or quickly pan through album artwork in Coverflow. That's because the display and music playback are both scrambling to read from the hard drive at once. This is not really a serious performance problem on the Classic, because once a song has played for a few seconds, it will read ahead enough music to prevent skipping. However, it signals one reason why Apple is leaning toward Flash.
Second, Flash is much more energy efficient. To operate from a hard drive, iPods have always incorporated a small amount of RAM, 34MB to 64MB. This allows it to read a large chunk of music from the disk and copy it into RAM for playback. This not only makes for smooth, skip-free playback, but also allows it to turn the drive off and coast along in low power mode until it needs more music from the disk. Without this aggressive disk caching, the iPod's battery wouldn't last nearly as long. Playing video or games makes the iPod's disk work harder, and therefore helps to shorten battery life.
As Apple migrates the iPod line toward iPhone-like functions, using a hard drive for storage becomes unworkable due to its power draw. A hard drive based iPhone or iPod Touch would perform more like a laptop, requiring a much larger battery to deliver more than a couple hours of runtime. It would make it much larger and heavier.
The obvious advantage of a hard drive is much more cost effective storage. One of the most expensive components in the iPhone is its 8GB of Flash, which is roughly the same price in quantity component orders as an 80GB 1.8-inch hard drive like the one in the iPod Classic. Combining the two for a pocket mobile device with ten times the storage sounds tantalizing until the reality of battery life, battery size, and additional hard drive volume all add up to create a box the size of a small book, or alternatively a mobile device that can't run for more than two hours without a recharge. Additionally, the hybrid device would be slower and hesitate every time it had to spin up the disk.
On top of all that, 2.5-inch laptop hard drives are already rated for lighter duty and have shorter lifespans than full size 3.5-inch hard drives in desktop computers. A micro-mobile iPod device constantly reading from an even smaller iPod sized 1.8-inch drive to run a full-blown operating system with complex applications like the OS X environment of the iPhone or the iPod Touch would be even more fragile and likely to fail at inopportune times.
That's why Apple doesn't recommend using the iPod Classic in disk mode as a boot device; it simply isn't rated for full-time use. Apple also pulled all references on its website about using hard drive-based iPods during exercise or running due to the risk of mechanical failure associated with operating hard drives in such extreme conditions. It only offers the Nike+ for use with the Flash-based Nano. The Classic is the most vulnerable of all iPods.
That means the hard drive-based iPod Classic is likely to soon be a dead end on the iPod road map. As the price of Flash RAM components rapidly fall as production technology increases, the entire line of iPods is likely to eventually move permanently to Flash. At some point, they will likely be followed by laptops, too. Depending on the demand that remains for large capacity iPods, the Classic line may retire as early as a year or two from now.