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Helical recording format
| Telecommunications Glossary |
A recording format in which the tape is unwrapped around a cylindrical scanning assembly with one or more recording heads.
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Cylindrical, английский
Цилиндрический
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Hfs - hierarchical file system, английский
Used on the macintosh platform for directory structure. the hierarchical directory structure allows a volume to be divided into smaller units known as directories and, in turn, sub-directories. the hierarchical directory structure uses a graphical metaphor of folders containing files or additional folders. macintosh interface elements, like color icons, are embedded with file structure information.
Hdsl - high-bit-rate digital subscriber line, английский
A method of providing high-speed data services over unconditioned copper wires at a top speed of 1.544 mbit/s. vhdsl (for very high-bit-rate digital subscriber line) is double that at 3 mbit/s. the key advantage of hdsl and vhdsl is that they allow telcos to provide services like frame relay, smds, and high-quality compressed video over existing telephone lines which is much less expensive than pulling fiber or installing additional repeaters. vhdsl is based on carrierless amplitude/phase modulation (cap) and has applications beyond hdsl and vhdsl such as a video-on-demand service (being tested by bell atlantic) using cap in which subscribers can interactively request videos, which are then transmitted over high-speed lines.
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