Since May, the demand for SAS wire has soared in the market. Therefore, we have conducted a special investigation. Why

SAS (Serial Attached SCSI) is a Serial Attached SCSI, and its demand continues to grow. After searching for relevant information, Gartner, a market research company, has nearly doubled the sales volume of SAS hard disks with a transmission rate of 6gbit / sec due to the shortage of traditional hard disks. Dataquest research reports that consumers have received this new generation of high-speed hard drives, and SAS now has a speed of 6gbit / sec. The report also predicts that SAS will replace the ultra320 SCSI hard disk by the end of this year and become the standard configuration for high-capacity storage servers. Relevant industry people predict that SAS hard disk will greatly penetrate into the market this year, because it can meet people's demand for large capacity, low power consumption and high-speed hard disk, and it can also be a blade server with more perfect performance. As the successor of parallel SCSI, SAS specification has appeared in people's vision for some time. In the past few years, SAS has been improving its specification. Although the underlying protocol has been retained, there are not many changes, the specification of external interface connector has undergone many changes. This is an adjustment made by SAS to adapt to the market environment. With these continuous improvements, SAS specification has become increasingly mature, The interface connectors of different specifications can be regarded as the witness of SAS development history, and also the potential factor of this surge in demand.

It's so easy to dazzle people with all kinds of SAS cables and connectors... How many have you seen?

At the beginning of the advent of SATA, the situation of cable and connector was relatively simple - after all, SATA did not support port aggregation, one port corresponds to one interface connector, so the cable only had one way connection. SAS is different: it supports four wide links at the beginning, allows up to four narrow links to aggregate into one wide port, and formulates corresponding connector specifications. In this way, there are at least two kinds of SAS interface connectors. In addition to the difference between inside and outside, there are more than 10 types of SAS cable with various feasible combinations. Therefore, it is common that 'although you have SAS cable in your hand, you can't connect the SAS devices at both ends'. Today, let's summarize the common types of SAS interface

1. Basic introduction of SAS cable

First of all, it is necessary to distinguish the concepts of 'port' and 'connector'. The ports of hardware devices are also called interfaces, whose electrical signals are defined by interface specifications, and the number depends on the design of controller IC (also including ROC). But no matter the interface or the port, it must rely on the manifestation of an entity, mainly pins and connectors, to play the role of connection, and then form a data path. Therefore, there are interface connectors, which are always used in pairs: on one side of the hard drive, HbAS, raid cards, or backplane, they 'snap' together with the other side at one end of the cable. As for which side is 'socket connector' and which side is 'plug connector', it depends on the specific connector specification.

The situation of SATA cable and connector is relatively simple, one port corresponds to one interface connector, so the cable has only one way connection. SAS is different: it supports four wide links at the beginning, allows up to four narrow links to aggregate into one wide port, and formulates corresponding connector specifications. In this way, there are at least two kinds of SAS interface connectors. In addition to the difference between inside and outside, there are dozens of SAS cable types due to various feasible combinations. If we consider the changes in the shape of interface connector made by various computer manufacturers in order to meet the needs of wiring, then there will be more types of SAS cables.

2.SFF-8643：Internal Mini SAS HD 4i/8i

Sff-8643 is the latest HD minisas connector design, which is used to realize HD SAS internal interconnection solution.

The sff-8643 is a 36 pin 'high density SAS' connector with a plastic body commonly used for internal connections. A typical application is the internal SAS link between SAS HbAS and SAS drives.

Sff-8643 conforms to the latest SAS 3.0 specification and supports 12gb / s data transmission protocol

The HD minisas external counterpart of sff-8643 is sff-8644, which is also compatible with SAS 3.0 and supports 12gb / s SAS data transmission speed

Both sff-8643 and sff-8644 can support up to 4 Ports (4 channels) of SAS data.

3.SFF-8644：External Mini SAS HD 4x / 8x

Sff-8644 is the latest HD minisas connector design for implementing HD SAS external interconnection solutions.

The sff-8644 is a 36 pin 'high density SAS' connector with a metal enclosure compatible with shielded external connections. A typical application is the SAS link between SAS HbAS and SAS drive subsystems.

Sff-8644 meets the latest SAS 3.0 specification and supports 12gb / s data transmission protocol

The internal product of HD minisas of sff-8644 is sff-8643, which is also compatible with SAS 3.0 and supports 12gb / s SAS data transmission speed.

Both sff-8644 and sff-8643 can support up to 4 Ports (4 channels) of SAS data.

These new sff-8644 and sff-8643 HD SAS connector interfaces basically replace the old sff-8088 external and sff-8087 internal SAS interfaces.

4.SFF-8087：Internal Mini SAS 4i

Sff-8087 interface is mainly used on mini SAS 4I array card as internal SAS connecting line, which is specially designed for realizing Mini SAS internal interconnection solution.

Sff-8087 is a 36 pin 'mini SAS' connector with plastic locking interface compatible with internal connection. A typical application is the SAS link between SAS HbAS and SAS drive subsystems.

Sff-8087 conforms to the latest 6GB / s Mini SAS 2.0 specification and supports 6GB / s data transmission protocol

Sff-8088 is the mini SAS external counterpart of sff-8087. It is also compatible with mini SAS 2.0 and supports 6GB / s SAS data transmission speed.

Both sff-8087 and sff-8088 can support up to 4 Ports (4 channels) of SAS data.

5.SFF-8088：External Mini SAS 4x

Sff-8088 Mini SAS connector is designed for mini SAS external interconnection solution.

The sff-8088 is a 26 pin 'mini SAS' connector with a metal enclosure compatible with shielded external connections. A typical application is the SAS link between SAS HbAS and SAS drive subsystems.

Sff-8088 conforms to the latest 6GB / s Mini SAS 2.0 specification and supports 6GB / s data transmission protocol.

Sff-8088 is compatible with mini SAS 2.0 and supports 6GB / s SAS data transmission speed.

Both sff-8088 and sff-8087 can support up to 4 Ports (4 channels) of SAS data.

6. Sff-8639 (now known as' U.2 ')

Sff-8639 is the latest connector design for connecting multilink SAS drives or PCI drives (including hard drives and SSD drives). It was recently renamed 'U.2' by the SSD widget group.

Sff-8639 is a revised version of sff-8680, which is a 29 pin 2-channel SAS driver interface. Sff-8639 U.2 is a 68 pin driver interface connector with higher signal quality. It can support 12gb / s SAS and Gen 3x4 PCI or PCI Express nvme.

The sff-8639 / U.2 connector can be integrated into the PCB 'docking board' of multiple drives, or into the 't-card' adapter of a single drive.

Sff-8639 U.2 connector has six high-speed signal paths, but SAS and PCI specifications can only use up to four channels at any time.

It complies with the latest 12gb / s SAS 3.0 specification and X4 gen3 PCI and SSD form factor v 1.0.

7.SFF-8680

Sff-8680 is the latest connector design for connecting SAS drives - SAS hard drives and SAS SSD drives.

The sff-8680 is a 29 pin connector with a plastic body, 15 pins configured to support the power requirements of the driver, and (2) 7 sets of pins used to transmit SAS data signals.

Sff-8680 supports the connection between two SAS ports (channels) and drives.

Sff-8680 can be integrated into a PCB 'docking board' for multiple drives, or into a single drive 't-card' adapter.

Sff-8680 conforms to the latest SAS 3.0 specification and supports 12gb / s data transmission protocol.

The new sff-8680 driver interface connector basically replaces the old sff-8482 driver interface connector.

8.SFF-8482

Sff-8482 is a connector design for connecting SAS drives, SAS hard drives and SAS SSD drives.

Sff-8482 is a 29 pin connector with a plastic body and 15 pins, which can support the power requirements of the driver（ 2) 7 groups of pins, used to transmit SAS data signal.

Sff-8482 supports the connection between two SAS ports (channels) and drives.

Sff-8482 can be integrated into PCB 'docking' backplane of multiple drives and installed on single drive 't-card' adapter.

Sff-8484 interface is mainly used in SAS 4I array card as internal SAS cable. It supports 12gbps bandwidth.