Persistent storage and secondary memory
Secondary memory (a.k.a. secondary or auxiliary storage) is a relatively slow memory that may be written to but is also non-volatile. What’s more, secondary memory has a relatively high capacity to hold data compared to the primary memory.
When the computer stars-up the RAM is empty. Instructions and data need to be copied from secondary memory into the RAM in order for the computer system to run. This is very important since if secondary memory did not exist a computer system would be unable to store instructions and data persistently.
There are numbers of different secondary memory storage devices:
> Hard drive (hard disk)
> CD-RW, DVD-RW
> USB Flash drive
> SD (secure digital) or CF (compact flash) card
> zip disk
> Floppy disk
> Magnetic tape
As secondary memory is obviously crucial to computer systems, it becomes apparent that advances in the technology surrounding secondary memory are beneficial to computer system as a whole. New technologies and existing ones strive to become more efficient, robust, and faster, as well as to hold more data than before.
Cili7@blog.com 