?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Adc&rft.relation=http%3A%2F%2Fmiis.maths.ox.ac.uk%2Fmiis%2F167%2F&rft.title=The+Disk+Layout+Problem&rft.creator=Neudauer%2C+Nancy+Ann&rft.subject=None%2FOther&rft.subject=Information+and+communication+technology&rft.description=Imagine+that+we+keep+a+daily+log+of+the+files+that+our+computer+reads+from+its+hard+disk.+For+most+computer+users+the+logs+of+one+day+compared+to+the+next+may+be+very+similar.+For+example%2C+opening+up+a+commonly+used+program+may+require+access+to+the+same+files+in+the+same+order+every+time+that+event+occurs.+We+shall+call+such+a+sequence+of+files+a+trace.%0A%0AThe+essence+of+the+problem+therefore+is%3A+given+a+set+of+traces+that+are+expected+to+be+representative+of+common+use%2C+we+must+rearrange+the+files+on+the+disk+so+that+the+performance+is+optimized.%0A%0APrograms+called+disk+defragmenters+use+these+simple+principles+to+rearrange+data+records+on+a+disk+so+that+each+file+is+contiguous%2C+with+no+holes+or+few+holes+between+data+records.+Some+more+sophisticated+disk+defragmenters+also+try+to+place+related+files+near+each+other%2C+usually+based+on+simple+static+structure+rather+than+a+dynamic+analysis+of+the+accesses.+We+are+interested+in+more+dynamic+defragmentation+procedures.%0A%0AWe+first+consider+a+1D+model+of+the+disk.+We+then+look+at+the+results+from+an+investigation+of+the+2D+disk+model+followed+by+a+discussion+of+caching+strategies.+Finally+we+list+some+of+the+complications+that+may+need+to+be+addressed+in+order+to+make+the+models+more+realistic.&rft.date=2001&rft.type=Study+Group+Report&rft.type=NonPeerReviewed&rft.format=application%2Fpdf&rft.language=en&rft.identifier=http%3A%2F%2Fmiis.maths.ox.ac.uk%2Fmiis%2F167%2F1%2Fhard_disk.pdf&rft.identifier=++Neudauer%2C+Nancy+Ann++(2001)+The+Disk+Layout+Problem.++%5BStudy+Group+Report%5D+++++