Linear Tape Open-LTO Technology

Quarter-Inch Cartridge (QIC) | O-MaSS | Minicartridge | DLTtape | Super DTLtape (SDLT) | Linear Tape-Open (LTO) | Half-Inch Cartridge | StorageTek 9840/T9840B/T9940 | Helical-Scan Technologies | 4-mm Helical Scan Digital Audio Tape/Digital Data Storage (DAT/DDS) | 8-mm Helical Scan Mammoth Technology | VXA Technology | Advanced Intelligent Tape (AIT) Technology | S-AIT

Linear Tape-Open (LTO)
Linear Tape-Open (LTO) is an open tape architecture that was developed jointly by a consortium of three
vendors-IBM, Hewlett-Packard and Seagate. It is made up of two specifications, LTO Ultrium, which was
targeted for capacity-intensive applications, and LTO Accelis, which was designed for access-intensive
applications. Since no manufacturer committed to develop a first-generation Accelis-based product,
however, second-generation licenses were not released, essentially shelving the Accelis specification.

In contrast, the Ultrium specification was pursued by each of the three vendors, all of which currently offer
drives based on first-generation specification. First-generation LTO Ultrium drives support a native
capacity of 100GB (200GB compressed with a 2:1 data compression ratio) and native sustained transfer
rates up to 20 MB/sec (40 MB/sec compressed). Ultrium uses half-inch-wide, Metal Particle (MP) tape, a
multichannel and bidirectional format using a linear serpentine recording method, and Magneto-Resistive
(MR) head and servo technology. Other features common to all first-generation LTO Ultrium drives are:
o
Recording Format-LTO Ultrium tapes have 384 tracks recorded in four bands (96 tracks each)
across the half-inch tape. Five servo tracks are prerecorded onto the media to act as guides for the
heads during reading and writing functions. In addition, the LTO media has horizontal servo tracks
that travel down the length of the tape to maintain and control the positioning of the read/write heads
on the data track. First-generation Ultrium tape drives feature eight read/write channels.
o
LTO Cartridge Memory (LTO-CM)-All Ultrium tape drives come with LTO Cartridge Memory (LTO-
CM), a radio frequency (RF)-based feature that allows certain kinds of data to be stored on a chip
rather than in the first region of the tape. As a result, the information is accessible as soon as the
cartridge is loaded into the drive rather than when the tape is actually threaded past the head and
read. The types of data that can be stored in LTO-CM include information on the tape contents (such
as file location data), information from the tape manufacturer (such as serial number, manufacturer ID
number and maximum tape speed) and information from the tape drive manufacturer (such as
predictive failure analysis data and information on drive/media health). In all cases, the chip is located
in the rear of the Ultrium data or cleaning cartridge where it can be easily read through an RF
interface by either a stand-alone drive or a reader located on the robotics of a tape library. Data in the
LTO-CM is protected with parity and CRC.
o
Interchangeability of Media-Because of the open specification, all Ultrium drives support any
Ultrium-certified media cartridge regardless of manufacturer. In April 2002, the three LTO technology
provider companies (HP, IBM and Seagate) announced that a "universal" cleaning cartridge for
Generation 1 LTO drives is now available from various suppliers allowing end-users to purchase a
single cleaning cartridge for use with all Generation 1 Ultrium drives regardless of the manufacturer.
The LTO Ultrium format was developed from scratch, with no requirements for backward compatibility.
But while the specification was designed to ensure interoperability, it did not mandate such things as drive
form factor, drive interface, power consumption, reliability standards or specific tape path designs. Each
drive/media manufacturer was therefore able to determine how to meet the specification requirements on
its own, thus allowing for design ingenuity and competitive differentiation.
In April 2002, licenses for the second-generation Ultrium format were made available. This initiates the
product development cycle for next-generation Ultrium drives which will support a native capacity up to
200GB using a new second-generation data cartridge. Performance will also improve with native data
transfer rates up to 40 MB/sec. The Generation 2 Ultrium specification also calls for an increase in the
number of tracks, a faster average tape speed, and a more efficient recording method. Ultrium Generation
2 drives will be able to read from and write to a Generation 1 cartridge in Generation 1 format, as well as
Generation 2 cartridges in Generation 2 format. Availability of the second-generation Ultrium drives from
all vendors is expected in early 2003.
The LTO consortium's roadmap includes four generations of Ultrium products that double in both capacity
and data transfer rate with each successive generation. By the fourth generation, Ultrium products are
expected to offer 800GB of native formatted storage capacity and a 160 MB/sec native data transfer rate.
For more information on LTO Technology, see LTO Tape Technology Overview.