sector interleave
(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.
Nearby terms:
second normal form « Second-Order Lambda-calculus «
second-system effect « sector interleave »
sector interleaving » sector map » sector mapping
sector interleaving
sector interleave
Nearby terms:
Second-Order Lambda-calculus « second-system effect
« sector interleave « sector interleaving »
sector map » sector mapping » Secure File Transfer
Protocol
sector map
sector interleave
Nearby terms:
second-system effect « sector interleave « sector
interleaving « sector map » sector mapping »
Secure File Transfer Protocol » Secure Hash
Algorithm
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.
Nearby terms:
sector interleave « sector interleaving « sector map
«
sector mapping » Secure File Transfer Protocol »
Secure Hash Algorithm » Secure Multipurpose Internet
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