The Connections: Small And Hot-Pluggable
The wide connector on the left reflects the prototype status of the hard disk. The actual Serial ATA connection is next to this. At the bottom left, the data connector (seven-pin); at the bottom right, the redesigned power connector (15-pin).
The number of contacts on the power connector seems remarkably high at first glance. One of the reasons for this is that there is now the option of a third voltage as well as 5 V and 12 V; Serial ATA drives will now accept 3.3 V . 3.3 V is not normally available directly from the power supply. It will normally be supplied by the motherboard, which has to provide 3.3 V to a range of other components anyway.
Three contacts per voltage (positive, negative and ground) still leaves us with six free contacts out of the 15. These are needed for the hot-plugging capability - two per voltage.
Hot-plugging is something new for ATA. It means that devices can be connected or disconnected without first powering the computer down. This is not something you would normally do with the sytem disk, of course, but installing additional Serial ATA hard disks is now possible without having to switch off the computer. The disk will automatically be recognized by more recent Windows systems (from 98SE on). The procedure for formatting disks and creating partitions remains the same.