Quote
wallythacker - 2006-03-23 2:41 AM
I thought I read that newer CF cards (2gb and larger) allow more writing before they die. Something on the order of 10x more writing.
Is there any truth to this? Something changed in the technology to extend the card life? I'm hoping so what with my new 2gb CF card.
Or I am thinking about the flash installed in the WM5 units? I'm sure I read that flash is different *and* can take a lot more writing before it dies. It better or there's gonna be a lot of bricks in a couple years.
Flash memory chips are constructed of either NOR or NAND gates. NOR chips function like a computer's main memory, while NAND works like a hard disk. For example, in a digital camera, NOR flash contains the camera's internal software, while NAND flash is used to store the images.
NOR Flash
Developed by Intel in 1988, NOR flash supports one-byte random access and "execute in place"
(XIP
), which means machine instructions can be fetched and executed directly from flash memory without going into main memory
(DRAM
) first as is required with NAND flash.
NOR flash has a lifespan of about 100K write cycles. As with all flash memory, the cells must be erased in large blocks before being written to. Erasing a block of typically 16KB takes several seconds, but reading and writing one byte at a time is very fast.
Let us assume you have an Retail Grade 1 GB CompactFlash of which the operating system takes up 250 MB
(XPembedded, for example
) and the remaining 750 MB is used for data storage. Now, you can write data blocks of 100 KB 7500 times to make up one write cycle
(750 MB/0,1 MB
). This means that you can do 3 million times 7500 writes of 100 KB before the Flash is used up. If you write once every 5 seconds
(24/7
) it will last 3E6 x 7500 x 5 seconds or 3567 years which is surely long enough
(this is based on theory - actual result may vary a lot but even if one divides the time by 100, the period is still long enough for most applications.
)
Bottom line: You should be a-okay....
