08-08-2012, 02:30 PM
LIGHT PEAK
LIGHT PEAK .docx (Size: 123.25 KB / Downloads: 79)
ABSTRACT:
This article compares and contrasts two technologies for delivering broadband wireless Internet access services: “3G” vs. “Wi-Fi”. The former, 3G, refers to the collection of third-generation mobile technologies that are designed to allow mobile operators to offer integrated data and voice services over mobile networks. The latter, Wi-Fi, refers to the 802.11b wireless Ethernet standard that was designed to support wireless LANs. Although the two technologies reflect fundamentally different service, industry, and architectural design goals, origins, and philosophies, each has recently attracted a lot of attention as candidates for the dominant platform for providing broadband wireless access to the Internet. It remains an open question as to the extent to which these two technologies are in competition or, perhaps, may be complementary. If they are viewed as in competition, then the triumph of one at the expense of the other would be likely to have profound implications forth evolution of the wireless Internet and structure of the service-provider industry
Introduction
Intel introduced Light Peak at the 2009 Intel Developer Forum (IDF), using a prototype Mac Pro motherboard to run two 1080p video streams plus LAN and storage devices over a single 30-meter optical cable with modified USB ends.[9] The system was driven by a prototype PCI Express card, with two optical buses powering four ports.[10]
At the show, Intel claimed that Light Peak-equipped systems would begin to appear in 2010.[11] A YouTube video simultaneously published by Intel also showed Light Peak interfacing 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 outputing of data through an oscilloscope.[12]
On 4 May 2010, in Brussels, Intel demonstrated a laptop with a Light Peak connector, indicating that the technology had shrunk small enough to fit inside such a device, and had the laptop send two simultaneous HD video streams down the connection, indicating that at least some fraction of the software/firmware stacks and protocols were functional. At the same demonstration, Intel officials said they expected hardware manufacturing to begin around the end of 2010.[13]
In September 2010, some early commercial prototypes from manufacturers were demonstrated at Intel Developer Forum 2010.
Copper vs. optical
Originally conceived as an optical technology, Thunderbolt switched to electrical connections to reduce costs and to supply up to 10W of power to connected devices.[15]
In 2009, Intel officials said the company was "working on bundling the optical fiber with copper wire so Light Peak can be used to power devices plugged into the PC."[16] In 2010, Intel said the original intent was "to have one single connector technology" that would allow "electrical USB 3.0[…] and piggyback on USB 3.0 or 4.0 DC power."[17]
In January 2011, Intel's David Perlmutter told Computerworld that initial Thunderbolt implementations would be based on copper wires.[18] "The copper came out very good, surprisingly better than what we thought," he said.[19]
Intel and industry partners are still developing optical Thunderbolt hardware and cables.[20] The optical fiber cables are to run "tens of meters" but will not supply power, at least not initially.[21][22][23] They are to have two 62.5-micron-wide fibers to transport an infrared signal up to 100 metres (330 ft).[24] The conversion of electrical signal to optical will be embedded into the cable itself, allowing the current DisplayPort socket to be future compatible, but eventually Intel hopes for a purely optical transceiver assembly embedded in the PC.[23]
Market introduction
Macbook Pro with Thunderbolt interface. The Thunderbolt port is the third port from the right.
It was rumoured that the early-2011 MacBook Pro update would include some sort of new data port, and most of the speculation suggested it would be Light Peak.[25] At the time, there were no details on the physical implementation, and mock-ups appeared showing a system similar to the earlier Intel demos using a combined USB/Light Peak port.[26] Shortly before the release of the new machines, the USB Implementers Forum (USB-IF) announced they would not allow this, stating that USB was not open to modification in this way.
In spite of these comments and speculation, the introduction came as a major surprise when it was revealed that the port was based on Mini DisplayPort, not USB. As the system was described, Intel's solution to the display connection problem became clear: Thunderbolt controllers multiplex data from existing DisplayPort systems with data from the PCI Express port into a single cable. Older displays, using DisplayPort 1.1 or earlier, have to be located at the end of a Thunderbolt device chain, but newer displays can be placed anywhere along the line.[22] Thunderbolt devices can go anywhere on the chain. In this respect, Thunderbolt shares a relationship with the older ACCESS.bus system, which used the display connector to support a low-speed bus.
Apple published[27] technical details explaining that 6 daisy-chained peripherals are supported per Thunderbolt port, and that the display should lie at the end of the chain.
In February 2011, Apple introduced its new line of MacBook Pro laptop computers and announced the technology's commercial name would be Thunderbolt, with these machines being the first to feature the new I/O technology.
In May 2011, Apple announced a new line of iMacs that include the Thunderbolt interface.[28]
The Thunderbolt port on the new Macs is in the same location relative to other ports and maintains the same physical dimensions and pin out as the legacy Mini DisplayPort connector. The primary visual differentiation on Thunderbolt equipped Macs is a Thunderbolt symbol instead of a DisplayPort symbol next to the port opening.[6]
The DisplayPort standard is partially compatible with Thunderbolt, as the two share Apple's physically compatible Mini DisplayPort connector. The Target Display mode on iMacs requires a Thunderbolt cable to accept a video-in signal from another Thunderbolt-capable computer.[29] Mini DisplayPort monitors must be the last (or only) device in a chain of Thunderbolt devices.
Intel announced that a developer kit would be released in the second quarter of 2011,[30] while manufacturers of hardware development equipment have indicated they will add support for the testing and development of Thunderbolt devices.[31] The developer kit was not yet available as of 21 July 2011, with Intel saying that interested parties needed to keep checking later.[32]