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Disk Terminology

 

Tracks
the concentric circles on the disk
Cylinders
identical tracks on multiple platters
Sector
part of a track, like a system of arcs.  Generally hold 512bytes.  usually the block size of a file system maps to a multiple of 512.  The smallest physical storage unit on the disk. 
Logical Block Addressing (LBA)
has replaced track/sector/cylinder addressing for a flat address space.  The disk drive controller maintains the map.  Spare sectors can be reserved for bad sector remapping without the OS being involved. 
Stripe Size the unit of data that is written and access from a disk in a RAID system.  This is configurable by the SAN folks.  Smaller stripe sizes allow data to be distributed to more disks and increases I/O parallelism.  64KB (a sql server extent) is the lower limit.  64KB or 256 KB should work for most sql server workloads according to MS.  256 allows for more efficient read-ahead. 
Short Stroking
Limits a drive's capacity by only formatting the outer tracks of the disk.  This reduces seek times and increases media transfer rates.  Disk throughput is higher on the outside tracks of a disk.  More here.  Tiered Storage
Zoned Bit Recording allows more sectors/track as the radius increases, hence, near the outside of the platter.  This is also facilitated using LBA.  Zone 0 will be near the edge of the platters.  The tranfer rates will be much higher here. 
Rotational Latency avg amount of time to wait for a random I/O and is calculated as the time it takes for a platter to complete 1/2 revolution. 
 

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