«625»
«Audio Producer»
«CET»|
Data storage systems for TV Rates of development high-end corporate IT-systems recently have got avalanche character. Cost of memory, hard disks, processors, and, hence, of the highly reliable servers, clusters and systems of data storage is constantly decreased. Now information decisions, of which only large banks and the industrial companies earlier might take advantage, are accessible to TV companies by the most different level. The purpose of this review is to acquaint with technologies of data storage which were tested at the large enterprises and may be applied for preparation of TV programs in telecasting. Introduction of similar systems considerably simplifies the preparation process of programs, reduces load to the personnel, improves quality of materials, and, that is the most important, makes the creation process of a TV broadcasting more transparent and reliable. From the technical point of view, the modern TV is a complex production, which basic criteria of efficiency are operability, reliability and the maximal quality at the minimal capital investments. Improvement of these activities was promoted by wide introduction of technologies of nonlinear editing which initially assumes the work with video and audio materials in a digital format. The following step in development of TV technologies is the use of systems of data storage. For today the systems of data storage of three topology are existed: SAS/DAS, NAS, SAN. In this article we shall tell about the basic distinctions, hardware which is applied at their introduction, and variants of practical application in TV. SAS/DASSAS (Server Attached Storage) or DAS (Direct Attached Storage) ate the systems of data storage attached directly to a server. In them the traditional method of connection of system of data storage to the high-speed interface of a server, as a rule, to parallel interface SCSI is used. Terms SAS and DAS define the same concept, simply various manufacturers from marketing reasons use different names because of what there is a mess. Therefore in this article these systems of data storage are incorporated under general name SAS/DAS. The basic advantage of system of the data storage connected to a server, before other variants is their low cost and high speed (at the rate of one system of data storage for one server). Such topology is optimum at use of one server through which the access to data files is organized. But, as in this case a row of problems all the same remains, designers were compelled to search for other variants of the organization of access to systems of data storage.
On TV the SAS/DAS systems may be used for creation of system of data storage for cluster, mobile system of data storage of the big volume and as disk files for design of NAS, SAN. Clustered systems with SAS/DAS are applied for the organization of a highly reliable output of the mounted material in an air, high-speed data processing, for construction of archive system and archiving, i. e. at those stages of production which are characterized by the increased criticality to speed and failure-resistance. The SAS/DAS-system most involved in telecasting is host-independent data files Raidtec FlexArray HI 12 which is a highly reliable system of storage with two-channel controller and Ultra160 SCSI RAID-array. Its characteristics are given below.
FlexArray HI 12 is provided by excellent features of reliability/failure-resistance and high function rate with the data streams. It is successfully used on many TV studios all over the world, but, unfortunately, is expensive a little, that limits its application in broadcasting companies of Russia and CIS countries. As inexpensive system SAS/DAS of an initial level it is possible to recommend the production of AXUS company. This system concerns to lower price range that is caused by application of disks ATA/SATA which, certainly, are less reliable, than disks SCSI. Though in due time we have offered rather simple method, allowing to bypass this restriction: we take two disk files Brownie, mount them in parallel and we receive the failure-safe device which under the price may compete with FlexArray HI 12.
According to information received from AXUS distributors, these devices have successfully passed the tests and today are applied on channel “ORT”. Systems of data storage SCSI-to-SCSI, Fibre-to-ATA from Brownie which cost cheaper than other similar products are offered also. NASNAS (Network Attached Storage) — the system of data storage connected to a network. Such version of the access organization has appeared rather recently, and its main advantage is convenient integration of additional system of data storage in existing networks though in architecture of systems of data storage the radical changes it does not introduce. Actually NAS in many respects reminds a pure file server, and today it is possible to meet many new realizations of systems of data storage such as NAS on the basis of technology Thin Server. Important difference NAS from a file server consists in that in the latter the traditional operational system (UNIX, Windows) which has the increased multi functionality is used. The file server may be applied for the organization of post-, web- and other servers; it has no specialization and may carry out many functions which are redundant at record/reading, conduct to essential decrease of the system reliability and to increasing of delays at data processing. OS for NAS is developed so that to ensure maximum fast and reliable work with the data, frequently for this purpose use OS Linux or Windows with appropriate tuning. Such OS in does not additionally need to be arranged under a network, as a rule, to establish IP-address enough, and NAS it is ready to work. It allows to avoid errors of the manager on adjustment, conducts to standardization of system of data storage and allows to reduce maintenance to very simple operations.
On the majority of parameters the NAS ideally approaches for the organization of work on TV and provides joint access to files. Any user of a network may reach the file necessary to him and make necessary operations from any place of network, thus cost of its possession rather low. High level NAS even allows to make the video editing without copying on a workstation of the user, the truth, in this case there are the restrictions connected to throughput of a local network. Use of the NAS systems in TV complexes opens the big opportunities for teamwork, allows to organize the transparent work for all creative team with step-by-step algorithm when everyone knows what and when he will need to prepare and to insert into an end-product (the sound, the text of the announcer, special effects etc.). It is necessary to note, that two circuits of the NAS organization are existed: the systems which are connected to SAS/DAS and the single-cabinet full-function module with disks. NAS module translates the block record SAS/DAS in file reports, and the user sees only full-function file system. Obligatory condition for the TV used systems is a high speed of work with the stream data. From all NASs, offered by HP, such speed provides only the systems of the high-end class. HP systems of average and the lowest classes are focused on fast and reliable processing of short transactions, as determines their cost.
Raitec Company offers the full-function one-cabinet NAS modules with disks.
Raidtec E0 (the truth, a little bit distinct from what is given in the table), and also FlexArray HI 12 and FlexArray 12 JBOD are used on Byelorussian TV channel STV. This rather inexpensive decision has allowed to create system for teamwork over video and considerably to reduce time spent on preparation of a video air. Now Ustar Company began to produce its own NAS systems of an industrial complete set under the trade mark uNAS. Models of an initial level are intended for application in structure of small and average working groups. And uNAS average and high level can be successfully used for work with video and audio and cost much cheaper than their foreign analogues. In a base of the software uNAS are the traditional NFS and the Samba 3.0, which is the fastest realization of SMB/CIFS with Active Directory. uNAS supports LVM, ACL, DHCP.
SANSAN (Storage Area Network) is the network of data storage. Similar networks intensively began to develop and to introduce only since 1999. Basement of SAN is the network separate from LAN/WAN and which serves for the organization of access to the data of servers and the workstations engaged in their direct processing. Such network is created on the basis of the Fibre Channel standard that in systems of data storage allows to realize the advantages of LAN/WAN technology and the opportunities on the organization of standard platforms for systems with high readiness and intensity of queries. Almost the single disadvantage of SAN in present is relatively high price of components though the total cost of possession for the corporate systems made by the using of technology of network of data storage will be enough low. It is necessary to note, that SAN technology is still rather new and in the near future it should undergo to many improvements in the field of standardization of control and methods of the SAN sub-networks interaction. To advantages of SAN it is possible to attribute practically all its features, but the disadvantage is a high cost.
Application of SAN on TV is justified only when a network is distributed to all process of preparation of TV programs and a TV air. Otherwise or at the limited financial opportunities it is better to use the NAS (the only distinction will be in work rate with the data). At whole the big advantages in function rate of the SAN system are provided by the absence of the conflict to traffic LAN/WAN. As successful example of realization SAN on TV may serve Fibre Channel SAN on telechannel M1. It was made on the basis of two host-independent arrays FibreArray HI 12, optical concentrators FC Switch Vixel V7100 and controllers FC HBA QLA2200F which provide the rate of duplex data transmission 1 Gbit/sec per port. This system was designed in a research department of the Ustar Company. Introduction of systems of data storage on TV is not any fashion tribute, but it is a natural process. Application of systems of data storage NAS or SAN is considerably simplified a processing of end material, is provided the nonlinear access to video and audioarchives for members of a creative command, is allowed to put on the air directly from data files. Work with a film is limited only by initial transmission of the shot material in system, and everything else is already made in system of data storage. And such labour-intensive and responsible work as putting of the programs on the air, is brought to compositing of an off-the-air sheet, that it is not much more complex, than similar process in WinAmp. Thus all traditional film off-the-air studios problems are excluded. If you began to provoke, that for search of one frame a video engineer camera controller should rewind the film forward and back for a long time, it is meant that the time has come to think about systems of data storage. Due to such system the working command can concentrate on creative activity, will receive the reliable and friendly tool of preparation of programs and an air, besides it will be possible to save on various tape decks. |
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Magazine:
For advertising please contact: reclama at 625-net.ru.
All the questions and offers please mail to: magazine at 625-net.ru.
Editorial board: magazine at 625-net.ru, ph./fax: +7 691 7724, 695 9588.
Electronic Mass Media registration certificate El # 77-2794.
© 2003—2009 Publishers 625. All rights reserved.