The first shy steps made by SerialATA interface have already been left in the far past. This interface started with SerialATA 1.0 specification and was intended as an alternative to the already outdated parallel ATA version.
On the way to perfection it acquired a plenty of additional features typical also of purely server components. So this year, this interface is ready to go external.
It is true, the decision to standardize SerialATA as a universal port for external and internal drives was natural: the speed characteristics of the interface (even the very first versions provided up to 150MB/sec), noise immunity of the interface cable, simple layout and other parameters had to push the SATA developers to this decision one day. And then the overwhelming popularity of the external drives came, with its eternal competition of USB and FireWire interfaces. Although both of them are negligible if compared to SerialATA. For instance, the latest interface versions ensure the following performance levels: USB 2.0 – 480Mbit/sec and FireWire (IEEE1394b) – up to 800Mbit/sec, while SerialATA 1.0 should theoretically be able to provide 1.5Gbit/sec.
The first presentation of the official standard specifications was supposed to take place at the spring IDF 2004 in San Francisco. Although there shouldn’t be any sensation as the mere idea of external devices support has already been implied during the development of this standard, though it is only now that they finally got down to its implementation. The first working demo samples of the external SerialATA interface were displayed at the IDF Fall 2003 at the booths of Maxtor, Silicon Image and Comax Companies and were based on the draft specs presented by SATA II Working group (SerialATA II Cables and Connectors Volume 2). They used Maxtor DiamondMax SATA HDD, PCI-SATA Sil 3112 SATALink bridge and a prototype of an external screened SATA cable from Comax.
The major details about the external SATA standard are available in the presentation called “Knut Grimsrud - Intel, Serial ATA 3 Gbps and Next Frontier”, which was made on September 18, 2003 during the Intel Developer Forum, or in the book by the same Knut Grimsrud called “Serial ATA Storage Architecture and Applications: Designing High-Performance, Cost-Effective I/O Solutions”, which you can browse through or even purchase in the Internet today. If you take a closer look at one of the slides from the last year’s presentation, you will notice a mention of the external Serial ATA versions and their clear definition:
The first generation of SATA interface marked as Gen1, namely its two existing versions – Gen1i and Gen1m (they actually differ by the signal levels) supports only internal devices, just like the first modification of the second generation Gen2i interface. However, the modifications marked as Gen1x/Gen2x are exactly the external implementations of the SerialATA.