...lower in capacity than hard disks? Thnx for your quick responseis it why the smaller players use flash memory (upto 4-5 GB max) while the larger players with 20-30GB or above use Hard Disk? Is that an inherent shortcoming of flash memories? Also on a GB to GB comparison is it more expensive than Hard Disk memory?

Yes, it has a much lower capacity. The largest flash memory chip to date is 16-GB while hard drives are into the terabytes (1 terabyte is a thousand gigabytes!!) And also flash memory is MUCH more expensive GB to GB comparison. One Gig of flash memory can be well over $100 while for that you could get quite a large hard drive (like 80 gig probably)