SATA (Serial ATA)

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SATA (Serial ATA)

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Definition

History

Serial ATA was developed by Intel in 2000 from the older ATA standard. The decision was made to move from a parallel bus design to a bit-serial point-to-point connection, i.e. the data is transferred serially (bit by bit) and not, as with the old ATA standards, in 16-bit words.

Compared to its predecessor, SATA has three main advantages: higher data transfer rate, simplified cable routing and the ability to hot-plug media. Since the introduction of Serial ATA, the older ATA standard is retronymically referred to as Parallel ATA (PATA) to avoid confusion.

Both connection types were initially found in parallel on the motherboard after the SATA introduction; PATA connections have been increasingly omitted since 2010. In terms of topology, SATA is a point-to-point connection. A SATA connector on the motherboard is therefore intended for only one device. Serial ATA is not limited to hard disks - using the ATAPI protocol, SATA tape drives, DVD drives and burners or memory card readers can also be used. With the external SATA interface, SATA is or was also in competition with USB, FireWire and Thunderbolt.

Versions of the Serial ATA standard

Designations			Net data rate
official		unofficial	Gbit/s	MB/s
Serial ATA	1.5 GBit/s	SATA I, SATA-150	1.20	150
	3.0 Gbit/s, SATA Revision 2.x	SATA II, SATA-300	2.40	300
	6.0 Gbit/s, SATA Revision 3.x	SATA III, SATA-600	4.80	600
SATA Express	8 Gbit/s (PCIe 3.x), SATA Revision 3.2		7.88	985
	16 Gbit/s (PCIe 4.x), SATA Revision 3.2		15.76	1969

Serial ATA 1.5 Gbit/s

This specification is often called SATA I, but this is not a valid name for the interface. Serial ATA was developed in 2002 by the companies APT, Dell, IBM, Intel, Seagate and Maxtor (Serial ATA International Organization). The data throughput of SATA 1.5 Gbit/s is a theoretical 1.2 Gbit/s per direction. Serial ATA is intended to simplify the connection between drives and the exchange of components - among other things during operation.

Serial ATA 3.0 Gbit/s

This specification is usually called SATA II, sometimes also SATA-300, but these are not valid names for the interface. Instead, the Serial ATA International Organization recommends SATA Revision 2.x or SATA 3 Gbit/s. SATA 3.0 Gbit/s was introduced at the beginning of 2005. The data throughput of SATA 3.0 Gbit/s is a theoretical 2.4 Gbit/s, double that of the first generation SATA. Optional capabilities: NCQ (Native Command Queuing).

Serial ATA 6.0 Gbit/s

In August 2008, the SATA IO published the first details of the third version of the SATA protocol, which again provides for a doubling of the transfer rate compared to its predecessor. On 27 May 2009, the completion of the standard was announced. The interface continues to be downward compatible, which is ensured, among other things, by retaining the type of connector used up to now. In addition, new connectors were defined for 1.8″ hard drives (in LIF design) and for new optical drives that are only 7 mm high. Other innovations of the standard include native command queuing extensions for isochronous streaming and the management of pending commands, as well as improved power-saving functions.

SATA Express 8 Gbit/s und 16 Gbit/s

SATA 3.2 introduces the new interface SATA Express with transfer rates of 8 Gbit/s per PCIe lane. SATA Express uses the technology of PCI Express 3.0. This standard is particularly useful when using Solid State Drives, which already use the bandwidth of SATA 6.0 Gbps. SATA Revision 3.2 with SATA Express was released in August 2013. SATA Express has never been able to establish itself on the market and to date no SATA Express drives have appeared on the open market.

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References

1. Wikipedia: Serial ATA

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