Thunderbolt

The Thunderbolt interface was developed by Intel in collaboration with Apple . The Thunderbolt trademark was registered by Apple, but was later transferred to Intel. Full rights belong to Intel. The first device to use this interface was Apple’s MacBook Pro , which was announced on February 24, 2011 ^[2] .

Thunderbolt was originally designed to connect mobile devices, laptops, and desktops using fewer cables. The standard has been proposed universal connector for displays and external storage devices. The power transmitted by the Thunderbolt 1 and 2 is 10 watts - more than 4.5-5 watts in standard USB 3.0 .

The Thunderbolt interface combines the PCI Express (PCIe) and DisplayPort (DP) protocols into one serial signal and provides constant voltage over the same cable. Thunderbolt controllers multiplex one or more data channels from their connected PCIe or DisplayPort devices for transmission over a single Thunderbolt duplex channel, then demultiplex them for use by PCIe or DP devices at the other end ^[3] . One Thunderbolt port supports up to six Thunderbolt devices connected via hubs (hubs) or daisy chains .

Several devices can be used as monitors , but their number cannot exceed the number of DP signal sources ^[5] .

A monitor that uses this MDP connector can be connected to the end of the Thunderbolt chain, since Thunderbolt is compatible with devices that support DP 1.1a. When a DP-compatible device is connected to the Thunderbolt port, a DP signal with 4 lines (lane) and a maximum speed of 5.4 Gbit / s per Thunderbolt line is provided. When connected to a Thunderbolt device, the data transfer rate for each line is 10 Gb / s, 4 Thunderbolt lines are configured as 2 full-duplex 10 Gb / s channels, each consisting of a receive line and a transmit line ^[3] .

The Thunderbolt interface can be implemented on PCIe video cards that have access to the DP connector and connection via the PCIe bus, or on the motherboard of new computers with integrated video, such as MacBook Air ^{[5] [6] [7]} .

The interface was originally designed to work with optical cables developed by Intel partners and at Intel's Silicon Photonics laboratory. At this time, the technology was known as Light Peak ^[8] . In 2011, the technology was renamed to Silicon Photonics Link ^[8] . However, it was found that a regular copper wire connection could provide the required bandwidth of 10 Gbit / s per line at a lower price. Thunderbolt optical cables were announced in mid-April 2012 by Sumitomo Electric Industries ^[9] .

Cable

Structurally, the Thunderbolt interface versions 1 and 2 use the same connector as the Mini DisplayPort (MDP). The MDP is electrically compatible with a full-sized DisplayPort, but uses a smaller connector that does not have a latch.

Thunderbolt active cables contain special integrated circuits inside the connector housing. The cable has five wires: one for control and two unidirectional pairs, one for incoming and one for outgoing traffic.

In the Thunderbolt interface of the 3rd version, a USB Type-C connector is used.

Introduction

Intel introduced the Light Peak technology at the Intel Developer Forum (IDF) in 2009 using a prototype of a Mac Pro computer motherboard from which two video streams with a resolution of 1080p, Ethernet and an external storage device were connected via a 30-meter optical cable ^[10] . The interface used modified USB connectors, the controller was implemented on a PCI Express card with two optical modules, providing a signal for four ports ^[11] .

At the exhibition, Intel said that systems equipped with Light Peak may appear as early as 2010 ^[12] . A video published by Intel on YouTube showed the interaction of the Light Peak interface with HD cameras, laptops, docking stations and HD monitors. Jason Ziller, head of the Intel Optical I / O Program Office , also demonstrated the internal components of the technology under a microscope and the process of transferring data on an oscilloscope ^[13] .

On May 4, 2010 in Brussels, Intel demonstrated a laptop with a Light Peak connector, indicating that the controller can be made small for embedding in compact devices. The simultaneous sending of two HD video streams from this laptop was demonstrated, from which it can be concluded that at least some of the software / firmware and protocols were functional. At the same demonstration, Intel representatives said that the production of controllers could begin at the end of 2010 ^[14] .

In September 2010, some early commercial prototypes from manufacturers were demonstrated at the Intel Developer Forum 2010 ^[15] .

Copper or optics

Initially, the technology was conceived as optical, but Intel switched to electrical connections to reduce costs and provide up to 10 watts of power for connected devices ^[16] .

In 2009, Intel representatives said that the company “is working on combining fiber and copper wires so that Light Peak can be used to power devices connected to a PC” ^[17] .

In 2010, Intel announced that their initial goal was to “have one single technology” that would allow us to have “USB 3.0 electrical signals [...] and combined power transfer for USB 3.0 or 4.0” ^[18] . It was stated that the connectors must withstand 7,000 connection cycles, the cables have such a small bending radius that they can literally be tied in a knot, and the fiber has high strength. It was expected that Light Peak cables would be no more expensive than HDMI cables ^[19] .

In January 2011, David Perlmatter from Intel told Computerworld that the initial Thunderbolt implementations would use fiber-free copper cables ^[20] . “Copper technology came out very good, surprisingly better than we thought,” he said. ^[21] One of the important advantages of copper cable is the ability to transfer power. Thunderbolt's final standard defines a permissible load of 10 watts per port.

Intel and its partners are still developing optical cables and Thunderbolt devices ^[22] . Optical fiber will allow you to create cables up to tens of meters in length, but without transferring power ^{[23] [24] [25]} . It is planned to use a pair of fibers with a diameter of 62.5 microns and IR signals with a maximum transmission distance of 100 meters ^[26] . The conversion of electrical signal to optical will be built into the cable itself, so it will be compatible with current connectors in the MDP format, but in the future, Intel hopes to integrate the optical transceiver into a PC ^[25] .

Market

It was rumored that in early 2011, the MacBook Pro update would include some kind of new data port, and most experts suggested that this would be Light Peak (Thunderbolt). At that time, there was no information about the physical implementation; the layouts began to show a system similar to the earlier Intel demonstration examples using the USB / Light Peak combo port. Shortly before the release of the new USB-IF machines, they announced that they could not do this, claiming that USB was not open to modification in this way.

However, in July 2011, Sony launches its Vaio Z21 laptop with a "Power Media Dock" with Thunderbolt on optics to connect to an external video card using a combo port that behaves not only as USB, but also includes an interconnected optical connection, required for thunderbolt. Other implementations of this technology began in 2012 with desktop boards offering an affordable interconnected connection.

Despite these comments and suggestions, the introduction of Apple was a major surprise when it turned out that the port was based on MDP, not USB. As the system was described, the solution to the display problem became clear: Thunderbolt controllers multiplex data from existing DP systems with data from a PCIe port into one cable. Older displays using DP 1.1a or earlier should be located at the end of the Thunderbolt chain of devices, but native displays can be placed anywhere along the line. Thunderbolt devices can move anywhere in the chain. In this case, the Thunderbolt interface shares the relationship with the older ACCESS.bus system, which uses the display connector to support the low-speed bus.

Apple explained that 6 peripherals connected in a series circuit supported by the Thunderbolt port should be at the end of the chain.

In February 2011, Apple introduced its new line of MacBook Pro laptops and announced that Thunderbolt will be the commercial name of the technology and it will be used on these machines for I / O for the first time.

In May 2011, Apple announced a new line of iMac, which included the interface Thunderbolt.

The Thunderbolt port on the new Mac is in the same location relative to the other ports and supports the same physical dimensions as the previous MDP connector. The main visible difference of a Mac equipped with a Thunderbolt is the Thunderbolt symbol next to the port.

The DisplayPort standard is partially compatible with Thunderbolt, since both share a physically compatible Apple MDP connector. The target display mode on the iMac requires the Thunderbolt cable to accept incoming video from another Thunderbolt-enabled computer. DP monitors should be the last (or only) devices in the Thunderbolt device chain.

Intel announced that the development kit will be released in the second quarter of 2011, while hardware manufacturers have indicated that they will add support for testing and developing Thunderbolt devices. The developer kit is available on request only.

Peripherals

While Apple released its first computer with Thunderbolt interface support in early 2011, it took some time to capture the peripheral market.

The manufacturer of storage devices Promise Technology was the first company to release Pegasus R4 (4 drives) and Pegasus R6 RAID storage systems (6 drives), however they were relatively expensive for the average consumer. In addition, after massive flooding in Thailand, where a number of components were produced for a significant proportion of hard drives, their production declined dramatically, so that, in general, along with many products on the market, after the initial release, retail prices also increased, not contributing to the rapid introduction of these devices.

In addition, it took some time for other manufacturers of storage devices to release products with more focus on smaller storage devices, with an emphasis on speed, rather than large-scale data storage needs. Many of these devices were 1 TB in size, some also had SSDs for fast external data access instead of a standard hard drive, mainly aimed at a professional user. Backward compatibility with non-Thunderbolt-equipped computers was also a problem, since most storage devices only had two Thunderbolt ports in order to chain up to six devices together from one port.

Other companies focused on providing interface solutions, allowing older, usually slower, interfaces to be routed through a single Thunderbolt connection, implying that only one Thunderbolt wire should be connected to a computer, rather than many wires for each interface. Similarly, in early July 2011, Apple releases the updated Apple Thunderbolt Display, which supports many older interfaces, including Ethernet , effectively making it the first product to be able to use it as a hub.

From mid-2012, LaCie and Drobo manufacturers began to include USB 3.0 in addition to Thunderbolt for their devices.

Security

Since the Thunderbolt interface extends the PCI Express bus, which is the main expansion bus in existing systems, it allows low-level access to the system. PCI devices must have unrestricted access to memory and may thus jeopardize data storage security. This problem exists with many high-speed expansion buses, including PC Cards , ExpressCard and FireWire .

An attacker could, for example, intentionally set up a device using Thunderbolt. When connected to a computer, the device, having direct and unimpeded access to system memory and other devices, is able to bypass almost all OS security measures and has the ability to read encryption keys or install malicious programs.

Some Intel processors ^[27] , since the introduction of the Nehalem microarchitecture (Core i3, Core i5, Core i7 and later), support hardware I / O virtualization , IOMMU . This allows the operating system to isolate the device in its own virtual memory address space (a similar way to isolate processes from each other using a memory management unit ). Thus, it is possible to prevent access to unauthorized parts of the memory. However, this function is usually not used, except for its initial purpose - to provide access to transfer virtual virtual machines to certain hardware.

Thunderbolt 2

In 2013, the updated Thunderbolt 2 interface was introduced. On the physical level, it is identical to Thunderbolt 1, the same cables and connectors are used, backward compatibility is preserved. At the logical level, the possibility of channel aggregation was added, and now two separate channels of 10 Gbit / s can be combined into one logical channel with a speed of 20 Gbit / s.

Thunderbolt 2 was used in the Apple MacBook Pro Retina of the end of 2013 (submitted October 22, 2013).

Thunderbolt 3

The Intel Thunderbolt 3 controller (codename Alpine Ridge) increases the maximum bandwidth by 2 times, to 40 Gbps (5 GB / s), has lower power consumption and allows you to connect up to two monitors with 4K resolution, or one with 5K resolution (instead of one 4K for earlier versions of the standard). The new controller will support PCIe 3.0 and protocols HDMI 2.0, DisplayPort 1.2 (up to 30 Hz 4K). Thunderbolt 3 is a USB 3.1 compatible port, made with a USB Type-C connector. Compatibility with earlier interface options will be provided with adapters. ^{[28] [29] [30]}

Intel will offer two options for the Thunderbolt 3 controller - one will use PCI Express x4 and provide two ports of Thunderbolt 3, the second uses PCI Express x2 and has only one port of Thunderbolt 3. The first will be used in Mac Pro (2nd generation) and Retina MacBook Pro and the second in cheaper Mac Mini and MacBook Air.

Thunderbolt 3 support is expected in Skylake chipsets. ^{[28] [29] [30]}

Thunderbolt 3 will become part of the USB4 standard, since Intel transferred all rights to it to the USB Implementers Forum .

Apple's first two-meter Thunderbolt cables in the summer of 2011 cost $ 49. In January 2013, Apple lowered the price of its cables to $ 39. Apple also announced the availability of a shorter half-meter cable for $ 29.

In June 2012, Apple began selling Thunderbolt technology for a gigabit Ethernet device for $ 29.

In the third quarter of 2012, other manufacturers began to produce cables of various lengths, including the maximum supported length of 3 meters, while those who manufactured the system units began to include the Thunderbolt cable in the kit.

Thunderbolt controller chips are manufactured by Intel:

These chips are embedded in peripherals and some motherboards.

There are Thunderbolt controllers, made in the form of an expansion card with a PCIe x4 interface, but they require support from the motherboard ^{[32] [33]} .

• Acer , one of the first to launch Thunderbolt, was the first to abandon it in favor of USB 3.0 ^[34] .

• USB
• IEEE 1394

• About Intel Thunderbolt Technology
• About Thunderbolt Technology on the Apple Website (rus.)
• 04.04.2012 :: appleinsider.ru :: Everything you need to know about Thunderbolt
• Light Peak - new data transfer technology from Intel and Apple
• Only one will be left. Light Peak?
• Intel will introduce a 20 Gb / s Thunderbolt chip in 2014 // 3dnews