Serial ATA

Serial ATA (SATA, also S-ATA) is mainly a data bus developed for data exchange between processor and non removable disk.

SATA connection on a Main board
lower surface of a Serial ATA non removable disk of Samsung with data and Stromkabel

Serial ATA has itself from the older ATA, also IDE mentioned, standard develops. To favour of the efficiency one decided to change over from a parallel bus Design to a bit serial bus D. h. that the data will serially transfer (bits for bits) and not, as with the old ATA standards, in 16-Bit words.Opposite its predecessor SATA possesses three main advantages: higher data transfer rate, simplified cable run and the ability for the change of data media during operation (Hot Plug). Since the introduction of Serial ATA the past ATA becomes - standard frequently as parallel ATA (P-ATA) marks, around mistakesto avoid. On newer motherboards one finds in addition to the usual P-ATA-card locations two to eight S-ATA-connections for non removable disks. SATA uses point of point a connection on the left Layer layer (cable). Each equipment has thus its own connection. Serial ATA is not limited to non removable disks, meanwhile gives it to z.B. also SATA tape mechanisms, DVD drive assemblies and - burners.

Table of contents

speed

with parallel penalties becomes it with higher data transmission rates ever more with difficulty, thatData flow on all lines to keep synchronous, that with the IDE bus did not specify bus conclusion and the mass-referred signals limits besides the usable cable length strongly. Serial ATA uses the LVDS (Low volume-meets differential signaling) for the signalling, similarly for a long time with SCSI worked LVD - Technology.

The first Serial ATA generation is specified and thus only insignificantly faster with a data rate of 150 megabytes per second than the up-to-date fastest parallel ATA interface (ATA/133). The current version Serial ATA II doubles the throughput on 300 MB/s. For the year 2007 is a Serial ATA version with 600 MB/s intended.

The usable transfer rate is to the material bit rate because of the 8B/10B-Kodierung with only 80% on the cable.

Computation:

<math>

\ begin {matrix}

 1 {,} 5 \, \ mathrm {GBit/s} \ cdot 0 {,} 8 &=& 1 {,} 2 \, \ mathrm {GBit/s} \ \ 1 {,} 2 \, \ mathrm {GBit/s} \ cdot 1 \, \ mathrm {byte} /8 \, \ mathrm {bits} &=& 150 \, \ mathrm {MByte/s}

\ ends {to matrix} </math>

Become only 80% of 1,5GBit/s material used, results in this 1.2 GBit/s, according to an effective data rate of 150 MByte/s.

Technology

data cable

Serial-ATA-1.0-Kabel
SATA-Stecker, links SATA-2 mit Verriegelungsclip
SATA plug, on the left of SOW-SOWING A2 with bolting device tie-clip

from physical view are the used cables the largest change to P-ATA. The data become by means of a light, flexible cable by 7 linestransfer flat 8 millimeters with broad plugs on each side. It can be meters long up to six. Compared with short (45 cm) 40 - or 80-adrigen transmission cable of the parallel ATA is simplified thereby the construction by complete systems, since the air river not by broadCable is obstructed. The concept of master/Slave relations between the devices was abolished. Serial ATA has only one equipment per cable. The plugs are coded, thus it is no longer possible to wrongly attach the cables. A point of criticism of the SATA plugs was their missing bolting device; this became alsoAppear corrected to II by SATA. Independently of SATA I or II can be used the same cables.

Stromkabel

Serial ATA Stromstecker

the standard plans for pure Serial ATA non removable disks in addition other plugs for voltage supply. They are also flat, but broader than the data cable, whereby a mistake betweenboth to be impossible should. Fifteen pins are used, in order to be able to supply three different tensions: 3.3 V, 5 V and 12 V. These plugs are used both for 2 ½ - tariff Notebook - and for 3 ½ - tariff non removable disks.

Versions of the Serial ATA standard

Serial ATA 1,0 (2002)

the ATA Kabeltypen inComparison

Serial ATA is developed by the companies APT , Dell , IBM , Intel , Seagate and Maxtor. The efficiency of SATA/150 is with 150 MB/s. By Serial ATA the connection between drive assemblies and the exchange of components are - among other things in the currentEnterprise - to be simplified. Serial ATA is based on the fact that the data will serially transfer (bits for bits) and not, as with the old ATA standards, in 16-Bit-Worten.

Serial ATA 2,0 (2005)

companies such as Western digital and Hitachi as well as Seagate drive SATA/300-Festplatten out up to a size of500 GB. SATA/300 was introduced at the beginning of of 2005. The achievement throughput of SATA/300 is with maximum 300 MT /s, thus theoretically twice as fast as with the 1. SATA generation.

The features of SATA2:

  • NCQ: Native COMMANDs Queuing. With this standard the administration becomes the writing andReadings optimizes and accelerates. NCQ must be supported by non removable disk and motherboard.
  • eSATA: eXternal SATA for external drive assemblies, maximum cable length: HotPlug designates
  • 2 meters of data rate of 3 Gb/s, frequently also as 300
  • MB/s: Exchange of the drive assembly during operation, without the system are driven downStaggered
  • Spinup must: time-delayed switching on of several drive assemblies on, over for example the power pack not to overloads
  • haven Multiplier: More if than four drive assemblies in a computer or a server are needed, a haven Multiplier can reduce the quantity of the necessary cables. This muster with a cable to the computerthe side to the drive assemblies four or more (up to 15) connections for short cables. The drive assemblies divide the available transmission band width. With for example 50 MByte/s for each already three drive assemblies 1.5 a Gbit/s distance (150 MByte/s) can charge to capacity drive assembly. It will however occur rather rarely,that three drive assemblies with full range transferred want. With an interface with 3 Gbit/s (300 MByte/s) should be present however sufficient range.
  • Haven Selector: With a haven Selector can be switched between two redundant transmission circuits. So one can go around the problem of single POINT OF failure (SPoF): Two computers can upa drive assembly access. The two computers must determine however even who are active (in each case one). This selection/change-over can take place via non-specified mechanisms.
  • xSATA: With xSATA the drive assemblies can further (max. 8 m, as platziert with SAS) of the computer its as with eSATA. In additionneeds one however different cables and plug connectors.

These characteristics do not have to be compellingly all at the same time with a SATA2-Festplatte present. A SATA non removable disk can offer thus 150 MB/s, NCQ and HotPlug and is thereby a SATA2-Festplatte. Up to now only few new Intel support - and Nvidia -nForce -4-Hauptplatinen the characteristics of SATA II, older motherboards comes therefore only on 150 MB/s. This is however not crucial for the efficiency of the plates, since the throughput of a today's non removable disk amounts to due to the mechanics less than 100 MB/s.

Compatibility

in the transition period between paralleland serial ATA there are most diverse adapters for the transformation of the IDE signals for a SATA non removable disk. For the transformation of serially too parallel or turned around a Bridge (bridge) is used. Unite according to tests is the information flow-rate around little per cent to sink. This restriction becomes only thencompletely disappear, if CONTROLLERs and non removable disks support Serial ATA directly (native SATA). First non removable disks with native SATA 2 are for instance since that 2. Quarter 2005 in the trade available, z. B. the max gate dia. moon max 10 and max LINE iii-series.

Around some DOS programs - z. B. Symantec Norton Ghost -direct access to the data on a SATA non removable disk to permit, adjusting of the compatibility mode in the BIOS is necessary - Setup.

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