8mm Mammoth Tape 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

Mammoth Technology
Although based on 8-mm helical-scan recording technology, the first-generation MammothTape drives
(Mammoth-LT and Mammoth) incorporated several significant improvements over the original 8-mm
drives that used camcorder-based mechanisms. With Mammoth, an Exabyte-designed and manufactured
industrial-quality deck design was introduced that eliminated the capstan and pinch-roller system. The
capstanless design removed the part of the drive that places the most pressure on the tape media,
causing unpredictable wear and reducing reliability. A larger scanner was added that completely records
the tape from edge to edge, providing higher capacity and data transfer rates. With the introduction of
Mammoth, Exabyte also added an improved tape transport system that supports Advanced Metal
Evaporated (AME) media-an alternative that is cleaner to use and provides greater capacity than Metal
Particle (MP) tape. In addition, Exabyte changed the tape path design to reduce potential stress points on
the tape. Finally, with Mammoth technology came an innovative approach to extending cleaning intervals
through the use of a cleaning wheel called a Dynamic Head Cleaner that reduces the likelihood of head
contamination by briefly touching the scanner and heads whenever a tape is loaded. The Dynamic Head
Cleaner also automatically performs a cleaning after each 80 minutes of continuous tape motion and can
be invoked by the drive's firmware if needed during extended backups.
The second-generation MammothTape drive, Mammoth-2 (M2), has a native formatted capacity of 60GB
(150GB with a 2.5:1 data compression ratio) and a native sustained data transfer rate of 12 MB/sec (30

MB/sec compressed). It includes a 32MB adaptive buffer that works to compensate for any
inconsistencies in data flow from the host. It also uses an enhanced Partial Response Maximum
Likelihood (PRML) data-encoding scheme and Adaptive Lossless Data Compression (ALDC) as its
compression engine, yielding a compression ratio of 2.5:1 for higher capacity. The M2 features a four-
channel/eight-head scanner in contrast to the Mammoth-1 drive, which had a two-channel/four-head
scanner. The additional read/write heads quadruple the tape drive's transfer rate.
The M2 also adds improvements in the area of tape reliability by using a unique three-pronged approach
to keeping the drive clean. First, it features a Dynamic Head Cleaner, the small cloth-covered wheel
described above. Second, the M2 uses a set of inactive burnishing heads to prep the tape before it
reaches the active read/write heads. These "conditioning heads" are intended to make sure that the tape
is set at the correct air bearing and to remove any contaminants from the tape's surface before it passes
over the read/write heads. Third, the M2 utilizes special AME media, which is equipped with Exabyte's
proprietary "SmartClean" technology. This media design includes a section of cleaning material at the
beginning of each recording tape so that the drive can automatically clean itself when necessary.
The M2 was the first helical-scan drive to offer support for native fibre channel connectivity by attaching
directly to the SAN, eliminating the need for fibre channel-to-SCSI routers. M2's one-Gigabit fibre channel
interface allows throughput of up to 100 MB/sec per path. Along with lowered infrastructure costs, this
type of interface allows the M2 to support serverless backup with the extended copy command that is
embedded into M2 firmware, making continuous, 7x24 backup possible. E-copy is Exabyte's
implementation of the SCSI Extended Copy command within the M2 drive and allows the direct transfer of
data between disk and tape. Data can be transferred across the SAN without the intervention of a server,
eliminating a potential bottleneck in the backup process.
Exabyte announced a new market strategy in April 2002 that redirects the development of its third-
generation MammothTape drive, the Mammoth-3 (M3), which was underway. Now that Exabyte has fully
integrated Ecrix Corporation into its operations, the company will attempt to capitalize on its acquired VXA
technology by integrating it with MammothTape and deliver a new set of products that will provide
improved price/performance and reliability. The new Mammoth-3 will offer a compressed capacity of
625GB and a compressed transfer rate of 60 MB/sec. The drive will be available in two versions, one that
will be backward-read compatible with VXA products, and another with additional backward-read
compatibility with M2.