DLTTape Drive 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

DLTtape
Digital linear tape is an adaptation of the early generation reel-to-reel magnetic tape recording method.
Developed by Digital Equipment and originally used in support of its own computer systems, half-inch
DLTtape drives were introduced to the client/server and network-attached PC market several years ago.
Quantum Corporation now owns the DLTtape trademark, having acquired the technology from Digital in
1994. In October of 1998, Quantum and Tandberg Data entered into a strategic manufacturing and

distribution agreement that made Tandberg Data an independent second source for DLTtape drives under
the Tandberg Data brand name, though the specifications remain the same. In October of 2001,
Tandberg Data extended its manufacturing and distribution agreement with Quantum Corporation. The
new agreement allows Tandberg to sell DLTtape and Super DLTtape technology to distributors and
OEMs that are headquartered in Europe, Asia/Pacific and Japan only while U.S. and Latin American
markets would be left to Quantum.
DLTtape products use a single-reel design whereby the tape cartridge contains the supply reel and the
corresponding take-up reel is located in the tape drive. Loading the tape is accomplished by attaching a
leader strip to the end of the tape and using that to pull the tape out of the cartridge, around the head
guide assembly, past a stationary read/write head and onto the take-up reel. This is in contrast to helical-
scan designs, which have two reels per cartridge and rotating read/write heads. The head guide assembly
is shaped like a boomerang and features six rollers that guide the tape along the tape path, working from
the back of the tape so that they never touch the recorded side of the media.
One disadvantage affecting some of the DLTtape drives is the result of the leader mechanism designed to
pull the tape out of the cartridge and wrap it around the take-up reel. Under certain conditions, the leader
can disengage, leaving the tape drawn partway out of the cartridge but not successfully engaged in the
drive. This renders the drive unusable and the tape (with all its data) not repairable. Quantum addressed
this intermittent problem in a revision to its DLT 8000 product by expanding the leader latch to allow more
room for airflow; however, previous models (DLT 4000 and DLT 7000) were not refitted. Both the DLT
4000 and the DLT 7000 have been marked for end-of-life by Quantum. The phaseout for the DLT 4000
was completed at the end of the third quarter of 2001. Quantum, however, has opted to continue selling
the DLT 7000 on a limited basis.
Quantum and Benchmark Tape Systems have engaged in a partnership that allows Quantum to focus its
development initiatives on SuperDLT enhancements, while Benchmark focuses its efforts on improving
and extending the life of DLTtape. Through a technology licensing agreement with Quantum, Benchmark
has developed what is essentially a next-generation DLT 4000, called the DLT1. The DLT1 is replacing
the DLT 4000 and DLT 7000 in the market. DLT1 actually surpasses both products in native capacity with
40GB (the DLT 4000 supports up to 20GB, and the DLT 7000 supports up to 35GB) and in fact actually
matches the DLT 8000. The DLT1 falls in between the DLT 4000 and the DLT 7000 in data transfer rate
at 3 MB/sec native data transfer rate vs. 1.5 MB/sec for the DLT 4000 and 5 MB/sec for the DLT 7000.
DLT1 is read-compatible with the DLT 4000 and utilizes DLTtape IV media. Quantum's Super DLTtape
drive will also read media written by Benchmark's DLT1 tape drive. Benchmark's ValuSmart Tape 80 is a
repackaged DLT1 drive in a half-high form factor. All capacity, performance, format, reliability and
compatibility specifications are identical with the DLT1.
In June 2002, Benchmark announced its next-generation drive in the ValuSmart family, the ValuSmart
Tape 160. The new drive, which is expected to become generally available by year-end 2002, will offer an
80GB native (160GB compressed) capacity and an 8 MB/sec native (16 MB/sec compressed) data
transfer rate, and will be backward read compatible with the DLT1 and ValuSmart 80.