- المجال:
- Number of terms: 20560
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- Company Profile:
Tektronix provides test and measurement instruments, solutions and services for the computer, semiconductor, military/aerospace, consumer electronics and education industries worldwide.
a) Using more than one drive to achieve either higher throughput, security, or both. New technology has made it possible to create EIDE RAID systems that give excellent performance at a very low cost. b) A grouping of standard disk drives together with a RAID controller to create storage that acts as one disk to provide performance beyond that available from individual drives. Primarily designed for operation with computers, RAIDs can offer very high capacities, fast data transfer rates, and much increased security of data. The latter is achieved through disk redundancy so that disk errors or failures can be detected and corrected. A series of RAID configurations is defined by levels and, being designed by computer people, they start counting from zero. Different levels are suited to different applications.
Level 0: No redundancy, benefits only of speed and capacity, generated by combining a number of disks. Also known as "striping".
Level 1: Complete mirror system, two sets of disks both reading and writing the same data. This has the benefits of Level 0 plus the security of full redundancy, but at twice the cost. Some performance advantage can be gained in read because only one copy need be read, so two reads can occur simultaneously.
Level 2: An array of nine disks. Each byte is recorded with one bit on each of eight disks and a parity bit recorded to the ninth. This level is rarely, if ever, used.
Level 3: An array of n+1 disks recording 512 byte sectors on each of the n disks to create n x 512 “super sectors” + 1 x 512 parity sector on the additional disk which is used to check the data. The minimum unit of transfer is a whole superblock. This is most suitable for systems in which large amounts of sequential data are transferred, such as for audio and video. For these, it is the most efficient RAID level since it is never necessary to read/modify/write the parity block. It is less suitable for database types of access in which small amounts of data need to be transferred at random.
Level 4: The same as Level 3 but individual blocks can be transferred. When data is written, it is necessary to read the old data and parity blocks before writing the new data as well as the updated parity block, which reduces performance.
Level 5: The same as Level 4 but the role of the parity disk is rotated for each block. In Level 4, the parity disk receives excessive load for writes and no load for reads. In Level 5 the load is balanced across the disks.
Industry:Software
Special effect in which the lightest and darkest values of a picture are made dark while the middle tones become light. An ADO effect.
Also a photo-optic process.
Industry:Software
The 50% point on the leading edge of the horizontal sync pulse. In an RGB system, the green signal’s horizontal sync pulse is used. In color-difference formats, the Y signal’s horizontal sync pulse is used.
Industry:Software
The noise arising when reproducing an erased tape with the erase and record heads energized as they would be in normal operation, but with zero input signal. This noise is usually 3 to 4 dB higher than the bulk erased noise. The difference between bulk erased and zero modulation noise is sometimes referred to as induced noise.
Industry:Software
The line of push button switches on the control panel which select and indicate the next video that will appear when the DSK fader is pulled (AVC series in flip or flip-flop mode only). The idea behind the name is that this is a bus that allows one to pre-select (or preset) the next video.
Industry:Software
A magnetic material is in this condition when, using the influence of a magnetizing field cycled between equal but opposite values, its successive hysteresis loops coincide.
Industry:Software
Randomly switching from one video signal to another will often result in a jump in the picture upon playback. The problem is compounded when the tape is copied. To avoid this problem, switching is best performed on synchronized signals during the vertical blanking retrace period, known also as the vertical interval. This allows complete replacement of one whole frame by a second whole frame resulting in a very smooth on-screen switch.
Industry:Software
Equalization which is greater at the center frequency than at either side of center.
Industry:Software
