introduction to data tapes
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What are Data Tapes?
“Data storage device that reads and writes data on a magnetic tape”
• Magnetic Tape
– Long and narrow strip of plastic film
– Magnetized undercoating of strip
– Various levels of magnetized data are stored on strip
• Magnetic Tape Data Storage
– Digital recording on magnetic tape to store digital information
– Commonly enclosed in cartridges and cassettes
– Tape Drive performs writing or reading of data
Digitization of Data
• Digital Recording– Digital audio and video are directly recorded on a storage device– Direct encoding of data into the stream of discrete numbers which represents:
• Changes in air pressure for audio and chroma & luminance values for video through time
• Recording Process– Recording– Playback
• Techniques to Record to Commercial Media– Digital Cassettes
• Read/write head moves quickly in order to maintain a high enough speed to keep the bits at a manageable size
– Optical Disc Recording• A laser is used to burn microscopic holes into the dye layer of the
medium• A weaker laser is used to read these signals
• Digital Information– Discrete, discontinuous representations of information or works
History of Data Tapes
• Open Reels– Wound on large (10.5 in/26.67 cm) reels – Standard for large computers
• Univac– First commercial data tape UNIVAC I - 1951. – Used in UNISERVO– Drive’s recording medium:
• A thin metal strip of 0.5 inch wide– Nickel-plated phosphor bronze
• Recording density was 128 characters per inch – Linear speed of 100 in/s
• Eight tracks:– Six data tracks– One parity track– One timing track
• IBM Formats– Used ferrous-oxide coated tape – Magnetic tape dimensions were 0.5 inch– Wound on removable reels up to 10.5 inches in diameter
– Different tape lengths were available• 1200 ft., 2400 ft. • Introduction of half inch tapes
– Tape lengths increased in 1980’s• Started using PET film
– Early half-inch tape had 7 parallel tracks of data along the length – 9 track tapes supported the new 8-bit characters
– Effective recording density increased over time • Common 7-track densities started at 200, then 556, and finally 800 cpi• 9-track tapes had densities of 800, 1600, and 6250 cpi• End of file was designated by a tape mark• End of tape by two tape marks
• DEC Tape I– 0.75in wide tape, having:
• 6 data tracks• 2 mark tracks• 2 clock tracks
– Data recorded at roughly 350 bits per inch– Durable to be used as the main storage medium for a OS – First time used file sharing system– Shoe shining – 1970’s – Slow disk drive
• DEC Tape II– DEC tape II was introduced around 1978 – Same structure but used a much smaller 0.150 in tape– Enclosed in a cartridge– The TU58 DEC tape II drive had an RS232 serial interface
• Allowed it to be used with the ordinary serial ports– Low cost floppy disk technology
• DEC tape II got obsolete
• Cartridges and Cassettes
– Cassette • An enclosure that holds two reels • Single span of magnetic tape
– Cartridge• A single reel of tape in a plastic enclosure
Technical details
• Tape Width
– Half inch
• Recording Method
– Linear
• Linear Serpentine
– Scanning
• Transverse
• Accurate
• Helical
Linear Recording
Linear Serpentine Recording
• Data Blocks
– Data is written on tape in blocks
– Important to keep up with data rate
• Data Buffer
• Modern tapes offer speed matching feature
• Sequential Access to Data
– Tape provides sequential access to data
• Takes 10s to reposition the tape head
– Hard disk performs the action in 10s of milliseconds
• Offers random access to data
• Access Time
– Tape
• Long latency for random accesses
– Alternatives available
• Indexing
• Marking blocks with a tape mark
• Data Compression
– A ratio of 2:1 is typical
– Some enterprise tape drives can encrypt data
Companies Venturing in Data Tapes
• 3M
• DEC
• Sony
• HP
• Quantum
• Storage Tek
• Maxell
• IBM
• Etc
Tape Products Available at ODSI
• 8 MM Tape
• AIT Tape
• Barcode Labels
• Cleaning Cartridges
• DDS Tape
• DLT Tape
• DTF Tape
• Enterprise Tape
• LTO Tape
• T10000 Tape
• Traven Tape
• Tape Storage Cases
• VXA Tape
• Optical Cartridges
• QIC Tape
• RDX Cartridges
• SDLT Tapes
• SLR-MLR Tapes
8MM Tapes
• Magnetic data storage
• Pioneered by Exabyte
• D8 – Abbreviation used by SONY
• Dual reels in cartridge
• First Commercial Helical Scan recording
• Backward compatibility
• 170m length can store up to 170 GB
• Enhance length of 225m length stores 250 GB
• Tape Mediums:
– Metal Particles Tape– Advanced Metal Evaporated Tape (AME)– AME with Smart Clean
Advanced Intelligent Tape (AIT)
• Developed by SONY
• Dual reels in cartridge
• Provides backward and forward compatibility
• Uses helical scanning
• S-AIT is a variant
– Wider tape in larger cartridge
– Single reel
• 25GB to 1040GB
• Technical Features:
– AME (Advanced metal evaporated)
– MIC (Memory in chip)
– R-MIC (Remote memory in cassette)
– WORM (Write once read many)
Barcode Labels
• Barcodes has adhesive backing
• Use for effective management of data tapes
• Alphanumeric coding
Cleaning Cartridges
Digital Data Storage Tapes (DDS)
• Store digital data on DAT Tape
• Tape width is 3.8mm
• Latest formats are 8mm wide
• Helical scan recording method
• Length can be increased
• 2GB to 160GB
• DAT Tape:
– Developed by SONY
– Sequential transmission of data
– Ability to record digital data at:
• Higher lower and equal sampling rate
Digital Linear Tapes (DLT)
• Magnetic tape data storage technology
• Owned by Quantum Corp.
• Linear serpentine recording
• Half-inch wide tape
• Tape material is metal particle tape (MP/AMP)
• Cartridges contain a single reel
• Reel motors controls tape speed and tension
– No capstan
• DLT includes WORM capability
• 2:1 data compression
• SDLT is a variant
Digital Tape Format (DTF)
• Magnetic tape data storage format
• Developed by Sony
• Uses a 1/2in wide tape
• Cassette with two reels
• Helical scan process
• Two sizes of tape cassettes; "S" and "L”
• Highest capacity DTF 1 media tape is 42 GB
• DTF 2 tape delivers storage capacity of 200 GB
Enterprise Tapes
• Half-inch tape technology
• Few are able to encrypt data
• Leading brands
– Sun
– Imation
– Fuji
– IBM
Linear Tape Open (LTO)
• Magnetic tape data storage
– Open standards
– Part of quantum corp.
– Developed as a replacement for DLT
– Standard form-factor goes by the name Ultrium
• LTO version 6 holds 2.5tb
– 1⁄2-inch wide tape in a single reel cartridge.
• Ultrium drive reads data:
– From a cartridge in its own generation
– From cartridges of at least the two prior generations.
• An Ultrium drive writes data:
– To a cartridge in its own generation
– To a cartridge from the immediate prior generation
Optical Cartridges
• Capable of writing and rewriting data
• Available in 130 mm and 90 mm forms
• The disc consists of a ferromagnetic material
– Sealed beneath a plastic coating
– Reliable and inexpensive medium
– Designed in rewritable and WORM formats
• Leading companies offering magneto optical cartridges:
– Sony, verbatim, IBM, HP, Sony, Philips, Imation, Maxell
Quarter Inch Cartridge (QIC)
• Magnetic tape data storage format
• Enclosed in a package of aluminum and plastic
– Holds two tape reels driven by a single belt
• The tape was originally 1⁄4-inch wide
• Length is 300 to 1,500 feet
– Motorized capstan
• Data is written linearly along the length
• Could also be written in "serpentine”
RDX Cartridges
• Features a removable hard disk cartridge
– A docking station for operating the cartridge
• The highest capacity is 1 TB
• Shock-proof 2.5-inch Serial ATA hard disk drives
SLR-MLR Tape
• Perfect backup for:
– Mid-sized servers
– Small data centers
– Workstations
• Named by Tandberg Data for its line of QIC
• The earliest SLR drive has a capacity of 250 MB
• Latest drive has a capacity of 70 GB
T10000 Tape
• Latest Oracle/Sun Storage Tek tape drive
• Used with large computer system
• Tape cartridges are 1⁄2 in (13 mm) wide
• Storage Capacity:
– T10000A has a native capacity of 500 GB
– T10000B drive support 1 TB
– T10000C tape drive stores 5 TB natively
Travan Tape
• 8 mm magnetic tape cartridge
• Developed by the 3M company
• 750 inch length
• Linear track recording technology
• Travan does not verify data after writing
• The tape is not attached to the hubs
– Wrapped and held by friction
Tape Storage Cases
VAX Tape
• “Packet technology” data format
• Helical scan technology
• 2 read heads for Each stripe
– Each stripe starts with a unique packet ID
– Ends with an ECC packet checksum
• Ensures data integrity
Thank YouTHANK YOU
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Source: Wikipedia
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