| slovo | definícia |
sector map
(foldoc) | sector interleave
interleave
interleaving
sector interleaving
sector map
(Or sector map) The mapping from logical to physical sector
numbers on a magnetic disk designed to optimise sequential
reads and writes. Data is usually transferred to and from the
disk in blocks or sectors where one sector lies within a
continuous range of rotational angle of the disk. If logical
sectors are assigned sequentially to physical sectors
(0,1,2,...) then by the time one sector has been read and
processed (e.g. writen to main memory) the start of the next
logical sector will have passed the read/write head and will
not be accessible until the disk's rotation brings it back
under the head.
Staggering the physical sectors (e.g. 0,3,6,1,4,7,2,5,8) aims
to allow just enough time deal with one sector before the next
is accessible. This obviously depends on the relative speed
of the rotation of the disk, sector size, sectors per track
and the speed of transfer of sectors to main memory.
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| | podobné slovo | definícia |
sector mapping
(foldoc) | sector mapping
In this scheme the memory and cache are divided into blocks
of 2^m bytes (the cache line size). A sector consists of
2^n consecutive blocks.
When a block is cached, it is read into the correct position
in any sector of the cache, given by discarding the bottom m
address bits and taking the next n as the block number within
the sector.
That whole sector is then tagged with the remaining upper
address bits and the other blocks in the sector are marked as
invalid. This scheme takes advantage of locality of reference
to consecutive blocks and needs fewer tags thus reducing the
cost of associative access to the tags.
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