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Tape Drive (streamer) - read-only memory on the principle of magnetic recording to tape, with a consistent data access, according to the principle of operation is similar to domestic tape recorder.
There are areas where it is still great feel "old" tape, whose history can be traced since 1972 - the advent of the tape cassette format QIC (Quarter-Inch tape Cartridge - quarter-cassette). Since then, no other type of media could not surpass the tape on a combination. Tape drives are widely used in intelligence, security systems, communications, navigation and a dozen other areas where it is necessary to continuously record huge amounts of data with absolute ensuring storage reliability.
The main purpose of recording and playback of information, archiving and data backup. With this method, data is recorded on the recording tape in the form of several parallel tracks. The tape has to move in both directions. The read magnetic head while reading stationary, as well as the recording during recording. Upon reaching the end of the tape read / write head moves to the next track, and the tape begins to move in the opposite direction. Technology, in fact, similar to the domestic audio recorders. Perhaps the use of multiple heads that work with multiple tracks simultaneously (multi-track tape drive). In modern devices, this method dominates.
The first magnetic tape was used to record computer data in 1951 on a computer UNIVAC I. As the carrier used a thin metal strip width of 12.65 mm, consisting of nickel-plated bronze. The recording density was 128 characters per inch (198 micrometers / symbol) on eight tracks.
In computers, produced before the advent and widespread hard disks, tape drives, tape drives similar, was used as the main long-term storage medium. Later in the mainframe have been used in the hierarchical control carriers for storing infrequently used data systems. For some time, they are widely used as a removable storage when transferring large amounts of information. Currently, the market is dominated by tape drives, LTO standards relevant line (Linear Tape-Open). Introduced by IBM LTO-5 tape drive TS2350 is equipped with, in addition to two SAS interfaces and an Ethernet interface.
Magnetic tape was first used to record computer data in 1951, the company Eckert-Mauchly Computer Corporation on a computer UNIVAC I. As the carrier used a thin metal strip width of 12.65 mm, consisting of nickel-plated bronze (called Vicalloy). The recording density was 128 characters per inch (198 micrometers / symbol) on eight tracks.
In computers, produced before the advent and widespread hard drive | hard drives, tape drives (POC), similar to those tape drives, used as the main long-term storage medium. Later in the mainframe POC have been used in the hierarchical management of storage media for infrequently used data systems. For some time, they are widely used as a removable storage when transferring large amounts of information.
Widespread tape was associated with larger computers and, in particular, mainframes IBM. Since introduced in 1964 at the family IBM System / 360, IBM, in a standard 9-track tape was passed at a linear recording, which later spread also in the systems of other manufacturers and is widely used until the 1980s. In the USSR, the standard tape completely dominated, by the use of tape-EU family of computers, including computers as a part of other architectures.
In home personal computers of the 1970s and early 1980s (until the mid-1990s) as the primary external storage device often used ordinary household tape or, occasionally, special devices based on it with automatic control. This technology was not sufficiently adapted to the needs of the computer, but it was very cheap and available to the home user (since he audio tape, many of them already had). For industrial PCs used streamers, such as TEAC MT-2ST c tapes CT-500H, CT-600H 50 and 60 MB respectively.
The DDS Technology
Storage DDS data format was developed in 1989, Hewlett-Packard and Sony based on the DAT (Digital Audio Tape) format, developed by Sony and Philips in the mid-1980s. In appearance it resembles a smaller double cassette tape, because it is a chetyrёhmillimetrovuyu tape enclosed in a protective plastic case the size of 73 mm × 54 mm × 10.5 mm. As its name suggests, a tape recording made digitally, not analog way, using the 16-bit pulse-code modulation (PCM) uncompressed, like a CD, a sampling rate can be greater than that of CD (44 , 1 kHz) and smaller, namely, 48, 44.1 or 32 kHz. This means that the recording is made without any loss of quality of the original signal, in contrast to the later formats DCC and MD. DDS drives use a recording technique similar to that used in the DAT-based audio recorders and how to move the vehicle in the horizontal direction, and read-write head - in the vertical direction.
The QIC technology
In the 1990s, for backup of personal computers systems were popular standards QIC-40 and QIC-80, use a small physical tape capacity of 40 and 80 MB respectively. It supports hardware data compression. Aggregators of these standards were established in a standard 5-inch drive bay and connected to the interface of the floppy disk controller. In the future, a large number of similar standards under the trademarks QIC and Travan, determining media capacity of up to 10GB.
The DLT technology
DLT technology was presented by the company in the early 1990s based on earlier CompacTape technology for the VAX computer company Digital Equipment Corporation, a tape unit which has acquired Quantum. A further development was the DLT Technology Super DLT (SDLT).
Ruler CompacTape / DLT / SDLT media standard defines the physical capacity from 100 MB to 800 GB.
Since 2007 and the development of standard Quantum SDLT firm discontinued in favor of the LTO, but the equipment and recording media still available.
|1951||Remington Rand||UNISERVO||224 kB||First computer tape drive, used nickel-plated phosphor bronze tape|
|1952||IBM||726||Use of plastic tape (cellulose acetate);
[7-track tape that could store every 6-bit byte plus a parity bit
|1958||IBM||729||Separate read/write heads providing transparent read-after-write verification. As of January 2009, the Computer History Museum in Mountain View, California has working IBM 729 tape drives attached to its working IBM 1401 system.|
|1964||IBM||2400||9-track tape that could store every 8-bit byte plus a parity bit|
|1970's||IBM||3400||Auto-loading tape reels and drives, avoiding manual tape threading
Group code recording for error recovery
|1972||3M||Quarter Inch Cartridge (QIC-11)||20 MB|| Tape cassette (with two reels)
Linear serpentine recording
|1974||IBM||3850||Tape cartridge (with single reel)
First tape library with robotic access
|1977||Commodore International||Commodore Datasette||1978 kB||Use of standard audio cassettes|
|1980||Cipher||(F880)||RAM buffer to mask start-stop delays|
|1984||IBM||3480||200 MB||Internal takeup reel with automatic tape takeup mechanism.
Thin-film magnetoresistive (MR) head
|1984||DEC||K50||94 MB||Digital Linear Tape (DLT) line of products|
|1986||IBM||3480||400 MB||Hardware data compression (IDRC algorithm)|
|1987||Exabyte/Sony||EXB-8200||2.4 GB||First helical digital tape drive
Elimination of the capstan and pinch-roller system
|1993||DEC||Tx87||Tape directory (database with first tapemark nr on each serpentine pass)|
|1995||IBM||3570||Servo tracks - factory-recorded tracks for precise head positioning (Time Based Servoing or TBS)
Tape on unload rewound to the midpoint — halving access time (requires two-reel cassette)
|1996||HP||DDS3||12 GB||Partial Response Maximum Likelihood (PRML) reading method — no fixed thresholds|
|1997||IBM||VTS||Virtual tape — disk cache that emulates tape drive|
|1999||Exabyte||Mammoth-2||60 GB||The small cloth-covered wheel cleaning tape heads
Inactive burnishing heads to prep the tape and deflect any debris or excess lubricant Section of cleaning material at the beginning of each data tape
|2000||Quantum||Super DLT||110 GB||Optical servo precisely positioning the heads|
|2003||Sony||SAIT-1||500 GB||Single-reel cartridge for helical recording|
|2006||StorageTek||T10000||Multiple head assemblies and servos per drive|
|2006||IBM||3592||Encryption capability integrated into the drive|
|2008||IBM||TS1130||GMR heads in a linear tape drive|
|2010||IBM||TS2250 LTO Gen5||Linear Tape File System (LTFS), which allows accessing files on tape in the file system directly (similar to disk filesystems) without an additional tape library database|
|2014||IBM||IBM TS1150||10 TB||Linear Tape File System (LTFS) 360 MB/sec|
Modern streamers are usually connected via high SAS interface that provides data transfer speeds of 3 Gbps or 6 / s. Older IBM models have the ability to connect via FICON interface.
The LTO Technology
Currently, the market is dominated by tape drives, LTO standards relevant line (Linear Tape-Open).
Introduced by IBM LTO-5 tape drive TS2350 is equipped with, in addition to two SAS interfaces and an Ethernet interface. However, at present (June of 2010), this interface can not be used, it is declared reserved for future versions of firmware ..
The IBM 3592 Technology
IBM is supplying now, in addition to LTO equipment streamers own private standard IBM 3592 (Jaguar), presented by IBM TS1140 model of modern and compatible tape libraries. This equipment is used in servers and mainframes. For IBM 3592 line includes models of streamers actual 3592 (1st generation), TS1120 (2nd generation), TS1130 (3rd Generation) and the TS1140, and tape libraries based on them. Cartridges have a physical capacity of up to 4TB. As, in contrast to the LTO standard, focused not only on the archiving and backup, and random access to the data, the IBM 3592 standard provides a satisfying more stringent requirements on the number of overwriting media. Also in 3592 IBM used a number of solutions to optimize performance in jog mode recording, such as deep data caching and multi-speed movement of the belt (6 or 7 speeds, depending upon the tape drive model). IBM 3592 using the linear recording method..
A distinctive feature of the IBM 3592 standard is built into it the ability to reformat the magnetic media old generation format for newer devices with a corresponding increase in information capacity (in contrast to other contemporary standards, ensuring the compatibility of new equipment with old carriers only in the old format). Generally provides compatibility for 2 generations ahead, specific modes of allowable use of specific media in a particular device are determined by the table below:
|Name||Tape length (m)||Tape drive 3592 J1A||Tape drive TS1120||Tape drive TS1130||Tape drive TS1140|
|Cartridge 3592 JJ/JR||610 m||60 GB||100 GB||128 GB|
|Cartridge 3592 JA/JW||610 m||300 GB||500 GB||640 GB|
|Cartridge 3592 JB/JX||825 m||700 GB||1 TB||1,6 TB|
|Cartridge 3592 JC/JY||4 TB|
|Cartridge 3592 JK (short JC)||500 GB|
At the time, IBM Research companies and FujiFilm presented a technology that allows to record up to 35 terabytes of data on a tape cartridge is comparable in size to the LTO. Openness, however, still remains the issue of providing sufficient bandwidth device connection interface and the device blocks: modern devices LTO-5 focused on the connection to 6 Gb / s SAS interface with the actual bandwidth of 140 MB / s, it would take about 3 days write 35 terabytes of data.
Tape libraries, tape drives called work with several bands simultaneously. The robotic library can contain up to thousands of tapes from which the robot itself gets and sets the desired tape.
From the software point of view, this library looks like a flash drive with a huge capacity and considerable time random access. Cassette in the tape library are identified by special label with a bar code that reads the robot.
Tape Library has significant advantages over disk array in cost and power consumption for large volumes of stored data. For example, in order to maintain constant access archive size of 6.6 petabytes for 5 years, the cost of the disk system (RAID-arrays, controllers, hubs, disks, power, cooling and so on.) Will be US $ 14.7 million (including the cost of electricity - 550 thousand dollars), while the cost of tape library -. less than 700 thousand dollars (including the cost of electricity -. $ 304). The disadvantage of the tape library is a random access to the data, which in normal operation can be up to a few minutes, as well as the drop in performance by orders of magnitude as the number of different concurrent requests a number becoming available read-write devices (when tapes are standing in line for the read / write ).
Advantages and disadvantages of tape drive
- Large capacity;
- Low cost and ample storage conditions of the information carrier;
- Operational stability;
- Low power consumption in a large volume of the tape library.
- Low speed random access to the data because of the sequential access (tape need to scroll to the right place);
- The relatively high cost of recording devices (tape drive)..
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- Wikipedia [Internet source]: Data: 31.11.2016. — Aces: https://ru.wikipedia.org/wiki/Стример.
- Tape drive [Internet source]: Data: 31.11.2016. — Aces: http://www.thg.ru/storage/20040409/.