I keep hearing about this new version of hard drive called SATA and nothing about it seems to jump out at me. So what is so “powerful” about a SATA hard drive that i seem to be missing? From what i’ve read there only seems to be a different power connector and the transfer speed is 150 KB/s (or something like that). But why the fuss about SATA when Ultra SCSI 3 has much faster data rates?
The largest benefit of SATA is its extremely small cable size. When compared to extremely fat SCSI and IDE ribbon cables, the phone-cord-sized SATA cable is very welcome, especially in small form factor PCs. Unlike SCSI and IDE, drives cannot share a SATA channel. This greatly simplifies installation and configuration, as you don’t have to mess with master/slave or SCSI IDs. The fact that you can cram about four SATA connectors onto a motherboard where only one IDE connector fit insures that you’ll be able to connect all the drives you need to.
As for performance, the speed of the interface doesn’t really matter. Even the fastest 15,000RPM SCSI drives can’t approach the 150MB/sec bandwidth of SATA. RAID arrays can meet or exceed that, but since SATA places all drives on seperate channels, the per-channel bandwidth isn’t an issue. When SATA is natively implemented (native support on the HDD, SATA controller integrated into the chipset) it will be a bit faster than IDE, primarily due to slight improvements in the SATA protocol. After the “ooh, it’s new, charge more!” period wears off and we get native SATA implementations, prices should settle down a bit lower than IDE, and DRAMATICALLY lower than SCSI.
The theoretical max bandwidth of SATA is just that - theoretical. It all goes on the PCI bus which has a max bandwidth of 132 MB/s for all devices for 32-bit PCI but is in practice much lower. 64-bit PCI won’t get soaked, but it’s all change anyway as PCI-X is coming in.
For server type systems with multiple drives, I’ll bet on SCSI over SATA any day. But SCSI prices are just plain silly.
A native SATA implementation, such as available on new motherboard chiosets, doesn’t use the PCI bus. Rather, it’s right on the chipset so is directly connected to whatever bus the system uses, either an FSB or HyperTransport link. This pretty much guarantees that bandwidth won’t be an issue in the near future. When HDDs become fast enough to saturate SATA-150, SATA-300 will be available.