Serial ATA looks set to bring about the biggest change in storage technology in the past 10 years. Take a long look at the IDE ribbon cables in your pc because you might not be seeing them for much longer.
Serial ATA is a "serial" architecture as opposed to today"s "parallel" ATA internal disc drive bus. Serial ATA wraps many bits of data into a packet and then at a higher speed (up to 50% higher) than parallel, transfers the packet of data down the wire to or from the host. Today Cyclic Redundancy Checking (CRC) is performed on the data being transmitted back and forth but not on the commands. Serial ATA integrates CRC on the command and data packet level for enhanced bus reliability. Cyclic redundancy code detects all single and double-bit errors and ensures detection of 99.998% of all possible errors.
In English...it goes VERY fast and is more reliable :D
The cabling is neat and slim along the lines of an ethernet cable which should go someway to aleiviate the spaghetti junction inside most of todays cases. The drives themselves are expected to be relatively cheap when they become more readily available next year at around £115 GBP.