A few days ago Samsung unveiled new type of Flash Memory ( NAND Flash ) with capacity of 16 GB and the size not bigger than a finger nail.
They suggested that it could be used to replace HDDs in Laptops and maybe in Desktop computers. But I don’t think it will be effective or useful for many reasons that I will show in my explanation.
One limitation of flash memory is that while it can be read or programmed a byte or a word at a time in a random access fashion, it must be erased a “block” at a time. Starting with a freshly erased block, any byte within that block can be programmed. However, once a byte has been programmed, it cannot be changed again until the entire block is erased. In other words, flash memory (specifically NOR flash) offers random-access read and programming operations, but cannot offer random-access rewrite or erase operations. When compared to a hard disk drive, a further limitation is the fact that flash memory has a finite number of erase-write cycles, so that care has to be taken when moving hard-drive based applications, such as operating systems, to flash-memory based devices such as CompactFlash. This effect is partially offset by some chip firmware or filesystem drivers by counting the writes and dynamically remapping the blocks in order to spread the write operations between the sectors, or by write verification and remapping to spare sectors in case of write failure.
The cost per byte of flash memory remains significantly higher than the corresponding cost of a hard disk drive, and that (on top of finite number of erase-write cycles previously mentioned) has prevented flash from becoming a solid state replacement for the hard disk drive on normal desktop and laptop computers.
So the Hard Disk Drives wins in the matter of cost and efficiency while the Flash Memory wins in the matter of size.
Author: Hasan Bazerbashi