IEEE 1394 interface
Year created:	1995
Created by:	Apple
Width:	1 bit
Number of devices:	63
Capacity	400 Mbit/s, 800 Mbit/s, 1600 Mbit/s
Style:	Serial
Hotplugging?	Yes
External?	Yes

The IEEE 1394 interface (although the 1394 standard also defines a backplane interface) is a serial bus interface standard, for high-speed communications and isochronous real-time data transfer, frequently used in a personal computer (and digital audio and digital video). Apple Inc, ( formerly Apple Computer Inc, is an American Multinational corporation with a focus on designing and manufacturing Consumer electronics A bit is a binary digit, taking a value of either 0 or 1 Binary digits are a basic unit of Information storage and communication A megabit is a unit of Information or computer storage abbreviated Mbit (or Mb) A megabit is a unit of Information or computer storage abbreviated Mbit (or Mb) In Telecommunication and Computer science, serial communication is the process of sending data one Bit at one time sequentially over a Communication Ethernet is a family of frame -based Computer networking technologies for Local area networks (LANs The Institute of Electrical and Electronics Engineers or IEEE (read eye-triple-e) is an international Non-profit, professional organization A backplane (or "backplane system" is a circuit board (usually a Printed circuit board) that connects several connectors in parallel to each other so In Telecommunication and Computer science, serial communication is the process of sending data one Bit at one time sequentially over a Communication In Telecommunications an interface standard is a standard that describes one or more functional characteristics (such as Code conversion, line Isochronous: From Greek iso, equal + Chronos, time It literally means to occur at the same time or at equal time intervals A personal computer ( PC) is any Computer whose original sales price size and capabilities make it useful for individuals and which is intended to be operated Digital audio uses Digital signals for Sound reproduction. This includes analog-to-digital conversion, digital-to-analog conversion, storage Digital video is a type of Video recording system that works by using a Digital rather than an analog video signal The interface is also known by the brand names of FireWire (Apple's name) and i. Apple Inc, ( formerly Apple Computer Inc, is an American Multinational corporation with a focus on designing and manufacturing Consumer electronics LINK (Sony's name). is a multinational conglomerate corporation headquartered in Minato Tokyo, Japan, and one of the world's largest Media conglomerates with

FireWire has replaced Parallel SCSI in many applications, due to lower implementation costs and a simplified, more adaptable cabling system. Implementation is the realization of an application or execution of a Plan, idea Model, Design, Specification, standard, Algorithm A cable is one or more Wires or Optical fibers bound together typically in a common protective jacket or sheath IEEE 1394 has been adopted as the High Definition Audio-Video Network Alliance (HANA) standard connection interface for A/V (audio/visual) component communication and control^[1]. High Definition Audio-Video Network Alliance, or HANA, is a media industry group of leading companies established to create a design guideline for secure high-definition FireWire is also available in wireless, fiber optic, and coaxial versions using the isochronous protocols.

Almost all modern digital camcorders have included this connection since 1995, as do the vast majority of high end professional audio interfaces. A camcorder is a portable Consumer electronics device for recording Video and audio using a built-in recorder unit Since 2003 many computers intended for home or professional audio/video use have built-in FireWire/i. LINK ports, including all Sony computers, all but one of Apple's computers (the new MacBook Air), many of its older iPods, and most Dell and HP models currently produced. is a multinational conglomerate corporation headquartered in Minato Tokyo, Japan, and one of the world's largest Media conglomerates with Apple Inc, ( formerly Apple Computer Inc, is an American Multinational corporation with a focus on designing and manufacturing Consumer electronics The MacBook Air is a thin lightweight Macintosh Notebook computer designed by Apple. iPod is a popular brand of Portable media players designed and marketed by Apple Inc The multinational technology company Dell Inc develops manufactures sells and supports Personal computers and other computer-related products It is also available on many retail motherboards.

Contents 1 History and development 2 Technical specifications 2.1 Operating system support 2.2 Cable system support 2.3 Node hierarchy 3 Standards and versions 3.1 FireWire 400 (IEEE 1394-1995) 3.2 Enhancements (IEEE 1394a-2000) 3.3 FireWire 800 (IEEE 1394b-2002) 3.3.1 FireWire S1600 and S3200 3.4 FireWire S800T (IEEE 1394c-2006) 3.5 Future enhancements 4 Comparison to USB 5 Alternative uses for IEEE 1394 5.1 Aircraft 5.2 Automobiles 5.3 Networking over FireWire 5.4 IIDC 5.5 DV 6 Security issues 7 See also 8 References 9 Other sources 10 External links

History and development

FireWire is Apple Inc.'s name for the IEEE 1394 High Speed Serial Bus. An expansion card (also expansion board, adapter card or accessory card) in Computing is a Printed circuit board that can be inserted Apple Inc, ( formerly Apple Computer Inc, is an American Multinational corporation with a focus on designing and manufacturing Consumer electronics It was initiated by Apple and developed by the IEEE P1394 Working Group, largely driven by contributions from Apple, although major contributions were also made by engineers from Texas Instruments, Sony, Digital Equipment Corporation, IBM, and INMOS/SGS Thomson (now STMicroelectronics). Texas Instruments ( better known in the electronics industry (and popularly as TI, is an American company based in Dallas, Texas, USA is a multinational conglomerate corporation headquartered in Minato Tokyo, Japan, and one of the world's largest Media conglomerates with Digital Equipment Corporation was a pioneering American company in the Computer industry International Business Machines Corporation abbreviated IBM and nicknamed "Big Blue", is a multinational Computer Technology INMOS Ltd was a British semiconductor company founded by Iann Barron, based in Bristol and incorporated in November 1978 Thomson SA (,) formerly known as Thomson Multimedia is an international provider of solutions for the creation management delivery and access of video for the STMicroelectronics (,)is an franco-italian Electronics and Semiconductor manufacturer headquartered in in Geneva, Switzerland.

Apple intended FireWire to be a serial replacement for the parallel SCSI (Small Computer System Interface) bus while also providing connectivity for digital audio and video equipment. Apple's development began in the late 1980's, later presented to the IEEE, and was completed in 1995. The Institute of Electrical and Electronics Engineers or IEEE (read eye-triple-e) is an international Non-profit, professional organization As of 2007, IEEE 1394 is a composite of four documents: the original IEEE Std. 1394-1995, the IEEE Std. 1394a-2000 amendment, the IEEE Std. 1394b-2002 amendment, and the IEEE Std. 1394c-2006 amendment. Work is underway to incorporate all four of those documents into a new revision of the 1394 standard.

Sony's implementation of the system is known as "i. LINK" (fully incorporated in 1394a-2000), and uses only the four signal pins, omitting the two pins which provide power to the device in favor of a separate power connector on Sony's i. LINK products. The ports are sometimes labeled "S100" or "S400" to indicated speed in Mbit/s.

The system is commonly used for connection of data storage devices and DV (digital video) cameras, but is also popular in industrial systems for machine vision and professional audio systems. A data storage device is a device for recording (storing information (data Digital Video (DV is a Digital video format created by Sony JVC Panasonic and other video camera procuers and launched in 1995 and in its smaller tape Form factor Machine vision (MV System is the application of Computer vision to industry and manufacturing It is preferred over the more common USB for its greater effective speed and power distribution capabilities, and because it does not need a computer host. Perhaps more importantly, FireWire makes full use of all SCSI capabilities and has high sustained data transfer rates, a feature especially important for audio and video editors. Benchmarks show that the sustained data transfer rates are higher for FireWire than for USB 2.0, especially on Apple Mac OS X with more varied results on Microsoft Windows. Mac OS X (mæk oʊ ɛs tɛn is a line of computer Operating systems developed marketed and sold by Apple Inc, the latest of which is pre-loaded on all currently Microsoft Windows is a series of Software Operating systems and Graphical user interfaces produced by Microsoft. ^[2][3]

However, the royalty which Apple Inc. and other patent holders initially demanded from users of FireWire (US$0. Apple Inc, ( formerly Apple Computer Inc, is an American Multinational corporation with a focus on designing and manufacturing Consumer electronics A patent is a set of Exclusive rights granted by a State to an inventor or his assignee for a fixed period of time in exchange for a disclosure of an 25 per end-user system) and the more expensive hardware needed to implement it (US$1–$2), both of which have since been dropped, have prevented FireWire from displacing USB in low-end mass-market computer peripherals, where product cost is a major constraint. Economics and Commerce define an end-user as the person who uses a product. ^[4]

Technical specifications

See also: Coding system of FireWire

FireWire can connect up to 63 peripherals in a tree topology (as opposed to Parallel SCSI's Electrical bus topology). FireWire, also known as IEEE 1394 iLINK (Sony or DV (Panasonic is a Serial bus architecture for high-speed data transfer For an account of the words periphery and peripheral as they are used in biology sociology politics computer hardware and other fields see the An electrical bus (sometimes spelled incorrectly as buss) is a physical electrical interface where many devices share the same electric connection It allows peer-to-peer device communication — such as communication between a scanner and a printer — to take place without using system memory or the CPU. For other uses of the term see Peer-to-peer (disambiguation For peer-to-peer networks used for file sharing see File sharing Historical precedent Scanners can be considered the successors of early telephotography input devices consisting of a rotating drum with a single Photodetector at FireWire also supports multiple hosts per bus. A server is a Computer dedicated to providing one or more services over a computer network typically through a request-response routine It is designed to support Plug-and-play and hot swapping. Plug-and-play is a computer feature that allows the addition of a new device normally a Peripheral, without requiring reconfiguration or manual installation of Device Hot swapping and hot plugging are terms used to separately describe the functions of replacing system components hot swapping describes changing components like fans and Its six-wire cable is more flexible than most Parallel SCSI cables and can supply up to 45 watts of power per port at up to 30 volts, allowing moderate-consumption devices to operate without a separate power supply. The watt (symbol W) is the SI derived unit of power, equal to one Joule of energy per Second. (As noted earlier, the Sony-branded i. LINK usually omits the power wiring of the cables and uses a 4-pin connector. Devices have to get their power by other means. )

FireWire devices implement the ISO/IEC 13213 "configuration ROM" model for device configuration and identification, to provide plug-and-play capability. Plug-and-play is a computer feature that allows the addition of a new device normally a Peripheral, without requiring reconfiguration or manual installation of Device All FireWire devices are identified by an IEEE EUI-64 unique identifier (an extension of the 48-bit Ethernet MAC address format) in addition to well-known codes indicating the type of device and the protocols it supports. In Computer networking a Media Access Control address ( MAC address) or Ethernet Hardware Address ( EHA) hardware address Ethernet is a family of frame -based Computer networking technologies for Local area networks (LANs In Computer networking a Media Access Control address ( MAC address) or Ethernet Hardware Address ( EHA) hardware address In computing, a protocol is a convention or standard that controls or enables the connection Communication, and Data transfer between two computing

Operating system support

Full support for IEEE 1394a and 1394b is available for FreeBSD, Linux^[5], Apple Mac OS 8.6 through to Mac OS 9^[6], and Mac OS X as well as NetBSD and Haiku. FreeBSD is a Unix-like free Operating system descended from AT&T UNIX via the Berkeley Software Distribution (BSD branch through Linux (commonly pronounced ˈlɪnəks Mac OS 8 is an Operating system released by Apple Computer on July 26 1997. Mac OS 9 is the final major release of Apple's "Classic" Mac OS. Mac OS X (mæk oʊ ɛs tɛn is a line of computer Operating systems developed marketed and sold by Apple Inc, the latest of which is pre-loaded on all currently NetBSD is a freely redistributable Open source version of the Unix -derivative Berkeley Software Distribution (BSD Computer Operating Haiku, formerly known as OpenBeOS, is a free and Open source software project dedicated to the re-creation and continuation of BeOS on Microsoft Windows XP supports both, but as of Service Pack 2, each FireWire device will run at S100 (100 megabits per second) speed. Microsoft Corporation is an American multinational Computer technology Corporation, which rose to dominate the Home computer Windows XP is a family of 32-bit and 64-bit Operating systems produced by Microsoft for use on Personal computers including home and A megabit is a unit of Information or computer storage abbreviated Mbit (or Mb) A download is available from Microsoft which enables devices rated at S400 or S800 speeds to operate at their rated speed. ^[7] Some FireWire hardware manufacturers also provide custom device drivers which replace the Microsoft OHCI host adapter driver stack, enabling S800-capable devices to run at full 800 Mbit/s transfer rates. At the time of its release, Microsoft Windows Vista supported only 1394a, with assurances that 1394b support would come in the next service pack. Windows Vista (ˈvɪstə is a line of Operating systems developed by Microsoft for use on Personal computers including home and business desktops ^[8] Service Pack 1 for Microsoft Windows Vista has since been released, however the addition of 1394b support is not mentioned anywhere in the release documentation. Windows Vista (ˈvɪstə is a line of Operating systems developed by Microsoft for use on Personal computers including home and business desktops ^[9][10][11]

Cable system support

Cable TV providers (in the US, with digital systems) must, upon request of a customer, provide a high-definition capable cable box with a functional FireWire interface. A set-top box (STB or set-top unit (STU is a device that connects to a Television and an external source of signal, turning the signal into This applies only to customers leasing high-definition capable cable boxes from said cable provider after April 1, 2004. A set-top box (STB or set-top unit (STU is a device that connects to a Television and an external source of signal, turning the signal into Events 527 - Byzantine Emperor Justin I names his nephew Justinian I as co-ruler and successor to the throne "MMIV" redirects here For the Modest Mouse album see " Baron von Bullshit Rides Again " The relevant law is CFR 76. 640 Section 4 Subsections i and ii. ^[12] The interface can be used to display or record Cable TV, including HDTV programming. ^[13]

Node hierarchy

FireWire devices are organized at the bus in a tree topology. Each device has a unique self-id. One of the nodes is elected root node and always has the highest id. The self-ids are assigned during the self-id process, which happens after each bus reset. The order in which the self-ids are assigned is equivalent to traversing the tree in a depth-first, post-order manner. Depth-first search ( DFS) is an Algorithm for traversing or searching a tree, Tree structure, or graph.

Standards and versions

FireWire 400 (IEEE 1394-1995)

FireWire 400 can transfer data between devices at 100, 200, or 400 Mbit/s half-duplex data rates (the actual transfer rates are 98. In telecommunications Bit rate or Data transfer rate is the average number of Bits characters or blocks per unit time passing between equipment in a data transmission A duplex Communication system is a system composed of two connected parties or devices which can communicate with one another in both directions 304, 196. 608, and 393. 216 Mbit/s, i. In telecommunications Bit rate or Data transfer rate is the average number of Bits characters or blocks per unit time passing between equipment in a data transmission e. 12. 288, 24. 576 and 49. 152 megabytes per second respectively). A megabyte is a unit of Information or Computer storage equal to either 106 (1000000 Bytes or 220 (1048576 bytes depending on These different transfer modes are commonly referred to as S100, S200, and S400.

Cable length is limited to 4. 5 metres (14. 8 ft), although up to 16 cables can be daisy chained using active repeaters, external hubs, or internal hubs often present in FireWire equipment. The S400 standard limits any configuration's maximum cable length to 72 meters. The 6-pin connector is commonly found on desktop computers, and can supply the connected device with power.

The 6-pin powered connector adds power output to support external devices. Typically a device can pull about 7 to 8 watts from the port; however, the voltage varies significantly from different devices. ^[14] Voltage is specified as unregulated and should nominally be about 25 volts (range 24 to 30). Apple's implementation on laptops is typically related to battery power and can be as low as 9 V and more likely about 12 V.

Enhancements (IEEE 1394a-2000)

An amendment IEEE 1394a was released in 2000, which both clarified and enhanced the original specification. It added in support for asynchronous streaming, quicker bus reconfiguration, packet concatenation, and a power saving suspend mode. Streaming multimedia is Multimedia that is constantly received by and normally presented to an end-user while it is being delivered by a streaming provider (the Packet concatenation is a computer networking optimization that coalesces multiple packets under a single header See also Standby power Sleep mode refers to a low power mode for electronic devices such as computers televisions and remote controlled devices

1394a also standardized the 4-pin connector already widely in use. The 4-pin version is used on many consumer devices such as camcorders, laptops, and other small FireWire devices. A camcorder is a portable Consumer electronics device for recording Video and audio using a built-in recorder unit Though fully data compatible with 6-pin interfaces, it lacks power connectors.

FireWire 800 (IEEE 1394b-2002)

FireWire 800 (Apple's name for the 9-pin "S800 bilingual" version of the IEEE 1394b standard) was introduced commercially by Apple in 2003. This newer 1394 specification (1394b) and corresponding products allow a transfer rate of 786. 432 Mbit/s full-duplex via a new encoding scheme termed beta mode. In telecommunications Bit rate or Data transfer rate is the average number of Bits characters or blocks per unit time passing between equipment in a data transmission A duplex Communication system is a system composed of two connected parties or devices which can communicate with one another in both directions It is backwards compatible to the slower rates and 6-pin connectors of FireWire 400. However, while the IEEE 1394a and IEEE 1394b standards are compatible, FireWire 800's connector is different from FireWire 400's connector, making the legacy cables incompatible. A bilingual cable allows the connection of older devices to the newer port.

The full IEEE 1394b specification supports data rates up to 3200 Mbit/s over beta-mode or optical connections up to 100 metres in length. In telecommunications Bit rate or Data transfer rate is the average number of Bits characters or blocks per unit time passing between equipment in a data transmission Standard Category 5e unshielded twisted pair supports 100 metres at S100. Category 5 cable, commonly known as Cat 5, is a Twisted pair cable type designed for high signal integrity Twisted pair Cabling is a form of wiring in which two conductors (two halves of a single circuit) are wound together for the purposes of canceling out The original 1394 and 1394a standards used data/strobe (D/S) encoding (called legacy mode) on the signal wires, while 1394b adds a data encoding scheme called 8B10B (also referred to as beta mode). In computing legacy mode is a state in which a computer system component or software application behaves in a way different from its standard operation in order to support older software In Telecommunications 8b/10b is a Line code that maps 8-bit symbols to 10-bit symbols to achieve DC-balance (see

FireWire S1600 and S3200

In December 2007, the 1394 Trade Association announced that products will be available before the end of 2008 using the S1600 and S3200 modes which were already (mostly) defined in 1394b. The 1. 6 Gbit/s and 3. 2 Gbit/s devices will use the same 9-pin connectors as the existing FireWire 800 and will be fully compatible with existing S400 and S800 devices. The future products are intended to compete with the forthcoming USB 3.0. ^[15].

FireWire S800T (IEEE 1394c-2006)

IEEE 1394c-2006 was published on June 8, 2007. Category 5 cable, commonly known as Cat 5, is a Twisted pair cable type designed for high signal integrity Events 68 - The Roman Senate accepts emperor Galba. 536 - St Silverius becomes Pope (probable Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century.

It provides the following improvements

• A new port specification which provides 800 Mbit/s over the same RJ45 connectors with Category 5e cable which is specified in IEEE 802. The 8 Position 8 Contact (8P8C modular plugs and sockets are communications connectors Category 5 cable, commonly known as Cat 5, is a Twisted pair cable type designed for high signal integrity 3 clause 40 (gigabit Ethernet over copper twisted pair)
• An automatic negotiation that allows the same port to connect to either IEEE Std 1394 or IEEE 802.3 (Ethernet) devices. Gigabit Ethernet (GbE or 1 GigE is a term describing various technologies for transmitting Ethernet frames at a rate of a gigabit per second, as defined by the IEEE 8023 is a collection of IEEE standards defining the Physical layer, and the media access control (MAC sublayer of the Data link layer, Ethernet is a family of frame -based Computer networking technologies for Local area networks (LANs
• Various minor updates to IEEE 1394b

Though the potential for a combined Ethernet and FireWire RJ45 port is intriguing, as of December 2007, there are no products or chipsets which include this capability. December 2007 is the twelfth month of that year It began on a Saturday and 31 days later ended on a Monday

Future enhancements

Besides the short term shoring up of S3200 over the beta connector already discussed, future iterations of FireWire should bring a bump in speed to 6. 4 Gbit/s, use of single-mode fiber, and additional connectors such as the small multimedia interface. ^[16]

Comparison to USB

Although high-speed USB 2. 0 runs at a higher signaling rate (480 Mbit/s) than FireWire 400, typical USB PC-hosts rarely exceed sustained transfers of 280 Mbit/s, with 240 Mbit/s being more typical. A megabit is a unit of Information or computer storage abbreviated Mbit (or Mb) This is likely due to USB's reliance on the host-processor to manage low-level USB protocol, whereas FireWire delegates the same tasks to the interface hardware. For example, the FireWire host interface supports memory-mapped devices, which allows high-level protocols to run without loading the host CPU with interrupts and buffer-copy operations. ^[17]

FireWire 800 is substantially faster than Hi-Speed USB. ^[18]

Alternative uses for IEEE 1394

Aircraft

IEEE 1394b is used in military aircraft, where weight savings are desired. Developed for use as the data bus on the F-22 Raptor, it is also used on the F-35 Lightning II. WikipediaWikiProject Aircraft. Please see WikipediaWikiProject Aircraft/page content for recommended layout ^[19] NASA's Space Shuttle also uses IEEE 1394b to monitor debris (foam, ice) which may hit the vehicle during launch. NASA 's Space Shuttle, officially called the Space Transportation System ( STS) is the Spacecraft currently used by the United States ^[19] This standard should not be confused with the unrelated MIL-STD-1394B. MIL-STD-1394 and MIL-STD-1394B are Defense Standards, assigned as "PROVISIONS FOR EVALUATING QUALITY OF CAP CROWNS" by the United States Department of Defense

Automobiles

IDB-1394 Customer Convenience Port (CCP) is the automotive version of the 1394 standard. [1]

Networking over FireWire

FireWire can be used for ad-hoc (terminals only, no routers) computer networks. A computer network is a group of interconnected Computers. Networks may be classified according to a wide variety of characteristics Specifically, RFC 2734 specifies how to run IPv4 over the FireWire interface, and RFC 3146 specifies how to run IPv6. Internet Protocol version 4 ( IPv4) is the fourth revision in the development of the Internet Protocol (IP and it is the first version of the protocol to be widely Internet Protocol version 6 ( IPv6) is an Internet Layer protocol for packet -switched internetworks.

Mac OS X, Linux, FreeBSD, Windows ME, Windows 2000, Windows XP, and Windows Server 2003 all include support for networking over FireWire. Mac OS X (mæk oʊ ɛs tɛn is a line of computer Operating systems developed marketed and sold by Apple Inc, the latest of which is pre-loaded on all currently Linux (commonly pronounced ˈlɪnəks FreeBSD is a Unix-like free Operating system descended from AT&T UNIX via the Berkeley Software Distribution (BSD branch through Windows Millennium Edition, or Windows Me (IPA pronunciation, iː is a hybrid 16-bit / 32-bit graphical Operating system released on 14 September Windows 2000 (also referred to as Win2K) is a preemptive, interruptible graphical and business-oriented Operating system designed to work with Windows XP is a family of 32-bit and 64-bit Operating systems produced by Microsoft for use on Personal computers including home and Windows Server 2003 (also referred to as Win2K3 is a server Operating system produced by Microsoft. A network can be set up between two computers using a single standard FireWire cable, or by multiple computers through use of a hub. This is similar to Ethernet networks with the major differences being transfer speed, wire length, and the fact that standard FireWire cables can be used for point-to-point communication. Ethernet is a family of frame -based Computer networking technologies for Local area networks (LANs Point-to-point telecommunications generally refers to a connection restricted to two endpoints usually host computers

On December 4, 2004, Microsoft announced^[20] that it would discontinue support for IP networking over the FireWire interface in all future versions of Microsoft Windows. December 2004: ← - January - February - March - April - May - June - July - August - September Microsoft Corporation is an American multinational Computer technology Corporation, which rose to dominate the Home computer The Internet Protocol Suite (commonly TCP/IP) is the set of Communications protocols used for the Internet and other similar networks Microsoft Windows is a series of Software Operating systems and Graphical user interfaces produced by Microsoft. Subsequently, support for this feature was removed from both Windows Vista and Windows Server 2008. Windows Vista (ˈvɪstə is a line of Operating systems developed by Microsoft for use on Personal computers including home and business desktops Windows Server 2008 is the most recent release of Microsoft Windows ' server line of Operating systems Released to manufacturing on 4 February ^[21][22]

The PlayStation 2 console had an i. LINK-branded 1394 connector. This was used for networking until the release of an Ethernet adapter late in the console's lifespan, but was poorly supported by software.

IIDC

IIDC (Instrumentation & Industrial Digital Camera) is the FireWire data format standard for live video, and what Apple's iSight A/V camera uses. iSight was a Webcam developed and marketed by Apple Inc The iSight was sold retail for US$ 149 as an external unit which connects to a computer via The system was designed for machine vision systems,^[23] but is also used for other computer vision applications and for some webcams. Machine vision (MV System is the application of Computer vision to industry and manufacturing Computer vision is the science and technology of machines that see Webcams ( web cameras) are small cameras (usually though not always Video cameras, whose images can be accessed using the World Wide Web, instant Although they are easily confused since they both run over FireWire, IIDC is different from, and incompatible with, the ordinary DV (Digital Video) camcorder protocol.

DV

Main article: DV

Digital Video (DV) is a standard protocol used by nearly all digital camcorders. Digital Video (DV is a Digital video format created by Sony JVC Panasonic and other video camera procuers and launched in 1995 and in its smaller tape Form factor Digital Video (DV is a Digital video format created by Sony JVC Panasonic and other video camera procuers and launched in 1995 and in its smaller tape Form factor In computing, a protocol is a convention or standard that controls or enables the connection Communication, and Data transfer between two computing A camcorder is a portable Consumer electronics device for recording Video and audio using a built-in recorder unit Nearly all DV cameras have a FireWire interface (usually a 4-pin). Labeling of the port varies by manufacturer, with Sony using either its i. LINK trademark or the letters 'DV'. Many digital video recorders have a "DV-input" FireWire connector (usually a 6-pin connector) which can be used to record video from a directly-connected DV camcorder ("computer-free"). A digital video recorder ( DVR) or personal video recorder ( PVR) is a device that records video in a digital format to a Disk drive or other

The protocol also allows remote control (play, rewind, etc. ) of connected devices.

Security issues

Devices on a FireWire bus can communicate by direct memory access, where a device can use hardware to map internal memory to FireWire's "Physical Memory Space". Direct memory access ( DMA) is a feature of modern Computers and Microprocessors that allows certain hardware subsystems within the computer to access system The SBP-2 (Serial Bus Protocol 2) used by FireWire disk drives uses this capability to minimize interrupts and buffer copies. Serial Bus Protocol 2 (SBP-2 standard is a transport protocol within Serial Bus IEEE Std 1394-1995 (also known as FireWire or i In SBP-2, the initiator (controlling device) sends a request by remotely writing a command into a specified area of the target's FireWire address space. This command usually includes buffer addresses in the initiator's FireWire "Physical Address Space", which the target is supposed to use for moving I/O data to and from the initiator. ^[24]

On many implementations, particularly those like PCs and Macs using the popular OHCI, the mapping between the FireWire "Physical Memory Space" and device physical memory is done in hardware, without operating system intervention. A host controller interface (HCI is a register level Interface which allows a Host controller for USB or FireWire to communicate with the While this enables high-speed and low-latency communication between data sources and sinks without unnecessary copying (such as between a video camera and a software video recording application, or between a disk drive and the application buffers), this can also be a security risk if untrustworthy devices are attached to the bus. For this reason, high-security installations will typically either purchase newer machines which map a virtual memory space to the FireWire "Physical Memory Space" (such as a Power Mac G5, or any Sun workstation), disable the OHCI hardware mapping between FireWire and device memory, physically disable the entire FireWire interface, or do not have FireWire at all. Virtual memory is a Computer system technique which gives an application program the impression that it has contiguous working memory while in fact it may be physically A host controller interface (HCI is a register level Interface which allows a Host controller for USB or FireWire to communicate with the

This feature can also be used to debug a machine whose operating system has crashed, and in some systems for remote-console operations. On FreeBSD, the dcons driver provides both, using gdb as debugger. FreeBSD is a Unix-like free Operating system descended from AT&T UNIX via the Berkeley Software Distribution (BSD branch through The GNU Debugger, usually called just GDB, is the standard Debugger for the GNU software system Under Linux, firescope^[25] and fireproxy^[26] exist.

See also

• 1394 Standards Orientation, Introduction.
• High Definition Audio-Video Network Alliance aka HANA
• HAVI, FireWire to control Audio and Video hardware. High Definition Audio-Video Network Alliance, or HANA, is a media industry group of leading companies established to create a design guideline for secure high-definition Home Audio Video Interoperability (HAVi is a connection to control Audio and Video Hardware using FireWire.
• Universal Serial Bus (USB)
• mLAN Yamaha's FireWire-based music networking system
• List of device bandwidths

References

Other sources

External links

• 1394 Trade Association
• High Definition Audio-Video Network Alliance (HANA) Standard using IEEE 1394 FireWire for interconnecting A/V components
• Apple FireWire Technology

This article was originally based on material from the Free On-line Dictionary of Computing, which is licensed under the GFDL. The Free On-line Dictionary of Computing ( FOLDOC) is an online searchable encyclopedic Dictionary of Computing subjects The GNU Free Documentation License ( GNU FDL or simply GFDL) is a Copyleft License for free documentation designed by the Free Software

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