Information Technology Reference
In-Depth Information
transformrandomwritesintosequential
(motivation:cachesreducereads,butstillneedto
write;bandwidthv.seekgapwideandgrowing)
allowsnapshots
wearleveling(forflash)
additionalgoal:allowatomicmulti-sectorupdate
transactionsandreducecrashrecoverytime;(defer
discussingthisuntilsectionX)
increasinglywidelyused
WAFL,LFS,ZFS,FLASHdevicedrivers
implementation:indexstructures,reads,writes
figurefixedinode-->mobileinode
figure--updatingafile(likeSunslidefigure)
mobilemetadata:solve"noupdateinplace"problem
levelofindirection
better?
morelevelsofindirection...checkpoint/uberblock
snapshots
defragmentation/cleaning
13.2.5
Exercises
QUESTION:linkedlist,tree.Whynothashtable?
QUESTION:spatiallocalityv.temporallocality
13.3
Directories: Naming data
flatfilesystemisastart,butwewantnames
persistence,sharing-->needhuman-sensiblenames
