Local cache misses that hit in the server cache avoid expensive disk accesses
--the assumption that a random disk access
will be required for each record identifier for each term, as if inverted lists were stored as a linked list on disk (They should be stored contiguously or at the very least in a linked list of blocks.);
The speed of the individual work stations will play a role, the power of the file server's processor and its clock speed, together with the speed of hard disk access
are all important factors when considering the hardware.
They include: (1) the inability to use disk caching routines such as SmartDrive, which really slows disk access
; (2) much slower disk defragmenting - over an hour to defrag a compacted disk vs.
Running Speed Disk keeps the hard disk access
time from slowing down by correcting the file fragmentation that occurs with use.
DOS keeps track of where everything is located, but one result is to slow disk access
Speeding transmissions and disk access
time, compression creates smaller files, yielding the equivalent of 20 to 50 times more color image storage capacity than with uncompressed image data, according to Nikon.
Ideally, he says, laptop software should only require disk access
when the program loads or when the user saves data.
Then the time elapsed for each activity such as processing, disk access
, etc., is plugged into the formula in order to determine cost per unit of service provided.
CACHING AND OTHER DISK ACCESS
AVOIDANCE TECHNIQUES ON PERSONAL COMPUTERS Disk caching is a technique for keeping the most recently used disk blocks in an associative memory in main storage, with the expectation that those blocks will be used again in the near future.