Category Archives: Bus-Interface

Some Specifications

HP EliteBook 820 G3

DisplayPort 1.2
USB 3.0 charging port
USB 3.0 port
USB basic type-C

HP 2013 UltraSlim Docking Station

3 USB 3.0 ports, 1 USB 3.0 charging port
2 DisplayPort 1.1a (DP 1.2 capable)

Dell U2415 Monitor

Native Resolution
1920 x 1200 at 60Hz

2 HDMI(MHL) connector
1 Mini DisplayPort
1 DisplayPort (version 1.2)
1 DisplayPort out (MST)
1 Audio Line out (connect your speakers)
5 USB 3.0 ports – Downstream (5 at the back, 1 with battery charging)
1 USB 3.0 port – Upstream


USB-C (USB Type-c) 一定是USB 3.1吗?

USB Type-C isn’t the same thing as USB 3.1, though. USB Type-C is just a connector shape, and the underlying technology could just be USB 2 or USB 3.0. In fact, Nokia’s N1 Android tablet uses a USB Type-C connector, but underneath it’s all USB 2.0—not even USB 3.0. However, these technologies are closely related. When buying devices, you’ll just need to keep your eye on the details and make sure you’re buying devices (and cables) that support USB 3.1.




SinceUSB 2.0 and USB 3.0 ports may coexist on the same machine and they look similar, the USB 3.0 specification recommends that the Standard-A USB3.0 receptacle have a blue insert (Pantone 300C color).

From: Google




Model Family:     HGST Travelstar 7K1000
Device Model:     HGST HTS721010A9E630
Serial Number:    JG40006PGJL7XC
LU WWN Device Id: 5 000cca 6acc78a77
Firmware Version: JB0OA3B0
User Capacity:    1,000,204,886,016 bytes [1.00 TB]
Sector Sizes:     512 bytes logical, 4096 bytes physical
Rotation Rate:    7200 rpm
Device is:        In smartctl database [for details use: -P show]
ATA Version is:   ATA8-ACS T13/1699-D revision 6
SATA Version is:  SATA 2.6, 6.0 Gb/s (current: 6.0 Gb/s)
Local Time is:    Mon Jan 18 00:01:09 2016 JST
SMART support is: Available - device has SMART capability.
SMART support is: Enabled

The signaling speeds and the sata versions supported are indicated by different bits of the data return by the IDENTIFY DEVICE command. You can see that with smartctl --identify=wb /dev/sdX | grep -i sata.

As you can see, the signal speeds supported are stored in word 76 and the versions are stored in word 222. It’s documented in ACS-3 rev 5, Table 45 — IDENTIFY DEVICE data (

These are the capabilities reported by the drive itself, so don’t mix it up with what is supported by your motherboard, which is CAN BE indicated by “current:” in the smartctl output (and dmesg as told in the other answer from @Jonno)

EDIT: Here is the exact spec file your drive claim to conform with: (ATA8-ACS T13/1699-D revision 6). You can see the two words in Table 29 — IDENTIFY DEVICE data. As you can see, SATA 2.6 and 3.0Gb/s are the latest/maximum defined as of this revision of ACS. So I guess your drive simply doesn’t completely conform with the spec and set the 6.0Gb/s bit, which is defined later, to 1 instead of 0.

What is AHCI ?

From:Crucial Forums

AHCI stand for Advance Host Controller Interface. AHCI is a hardware mechanism that allows software to communicate with Serial ATA (SATA) devices (such as host bus adapters) that are designed to offer features not offered by Parallel ATA (PATA) controllers, such as hot-plugging and native command queuing (NCQ). The specification details a system memory structure for computer hardware vendors in order to transfer data between system memory and the device.

Many SATA controllers can enable AHCI either separately or in conjunction with RAID support. Intel recommends choosing RAID mode on their motherboards (which also enables AHCI) rather than the plain AHCI/SATA mode for maximum flexibility, due to the issues caused when the mode is switched once an operating system has already been installed.

AHCI is fully supported out of the box for Microsoft Windows Vista and the Linux operating system from kernel 2.6.19. NetBSD also supports drivers in AHCI mode out of the box in certain versions. Older operating systems require drivers written by the host bus adapter vendor in order to support AHCI.

Advantage of AHCI

  1. Hot-Plugging (will not cover here as it will not affect computer performance)
  2. Native Command Queuing (might improve computer/system/hard disk responsiveness, espcially in multi-tasking environment

Difference between SATA I, SATA II and SATA III

What is the difference between SATA I, SATA II and SATA III?

SATA I (revision 1.x) interface, formally known as SATA 1.5Gb/s, is the first generation SATA interface running at 1.5 Gb/s. The bandwidth throughput, which is supported by the interface, is up to 150MB/s.

SATA II (revision 2.x) interface, formally known as SATA 3Gb/s, is a second generation SATA interface running at 3.0 Gb/s. The bandwidth throughput, which is supported by the interface, is up to 300MB/s.

SATA III (revision 3.x) interface, formally known as SATA 6Gb/s, is a third generation SATA interface running at 6.0Gb/s. The bandwidth throughput, which is supported by the interface, is up to 600MB/s. This interface is backwards compatible with SATA 3 Gb/s interface.

SATA II specifications provide backward compatibility to function on SATA I ports. SATA III specifications provide backward compatibility to function on SATA I and SATA II ports. However, the maximum speed of the drive will be slower due to the lower speed limitations of the port.

Example: SanDisk Extreme SSD, which supports SATA 6Gb/s interface and when connected to SATA 6Gb/s port, can reach up to 550/520MB/s sequential read and sequential write speed rates respectively. However, when the drive is connected to SATA 3 Gb/s port, it can reach up to 285/275MB/s sequential read and sequential write speed rates respectively.