Based on the D-2 tape format (19-mm helical scan
), the system is an outgrowth of Ampex's VPR-300 Digital Video Broadcast Recorder (Figure 3).
Information is recorded on these tapes in a variety of fashions, such as linear tracks, multiple linear tracks, helical scans
and rotary transverse scans.
In order to overcome problems of modulation noise and signal dropout at the very high head-to-tape speeds of helical scan
recording, it is essential that the tape's magnetic base film be exceptionally smooth.
SFF Half-Inch Cartridge/ Other Data Cartridge 22.14% 8mm Helical Scan
4.78% 4mm Helical Scan
50.95% 1/4-Inch Data Cartridge 4.25% Minicartridge 17.89% Figure 1- DDS drives (4mm helical scan
) have maintained their dominant market share (Source: Gartner Dataquest) Note: Table made from pie chart.
As far as capacity futures are concerned DAT/DDS, 8mm, AIT, and VXA helical scan
products have less available total tape area than the linear technology products Travan, SC50, SLR, LTO, and DLT tape formats.
and linear are two popular approaches to storing data on magnetic tape.
One of them is Sony's AIT-1, the helical scan
tape product introduced originally in 1996.
The MSS implemented virtualization by making the physical storage, actually robotically retrieved helical scan
tapes, appear as rotating magnetic disk drives to the operating system.
As another high-capacity format seeking to take market share from the industry leader DLT, Exabyte's Mammoth 2 is currently the highest-capacity helical scan
format available with a native capacity of 60GB and a native transfer rate of 12MB/sec.
Multiple choices in both linear and helical scan
formats offer users more freedom to choose the tape option that best meets their requirements, from small offices to departmental and workgroup environments to multi-terabyte enterprise applications.
Intravenously, 125 mL of 68% iodinated contrast material was administered as a sustained bolus at 4 mL/sec, after which dynamic helical scans
(LightSpeed, GE Healthcare, Chalfont St.