What is the main function of HDD cache?

[ManBearPig]

What is the main function of HDD cache? Will an increase in cache help performance? Thanks

 

[imported_whatever]

yes, an increase in hdd cache will increase hdd performance. it is prefetch iirc - works in similar ways to l1/l2 cache on a cpu.

 

[kcthomas]

im sure they optimize the size of the cache for the best performance. if it gets too big then the hdd has to search through a humungous cache, and it takes a while. do they actually have like a memory stick for the cache or is just a section of the hard drive? i noticed that when i partioned my hdd there was an existing partion of 8MB which let me to believe the cache is just a premade partition.

my guess is its main function is just to store recent instructions so it doesn't have to search 120GB for something.

 

[iwantanewcomputer]

it actually is a memory chip not part of the hard drive platter. it stores recently loaded things and maps the entire drive so the drive knows where to search for data

 

[BZeto]

Originally posted by: kcthomas
i noticed that when i partioned my hdd there was an existing partion of 8MB which let me to believe the cache is just a premade partition.

No the cache is not a partition. I can just imagine the kind of tech support calls, people calling in complaining how their systems seem to have slowed down since repartitioning their hard drives

 

[ManBearPig]

so an extra 8 mb of cache would be = to higher rotational speeds?

 

[PremiumG]

Originally posted by: kcthomas
im sure they optimize the size of the cache for the best performance. if it gets too big then the hdd has to search through a humungous cache, and it takes a while. do they actually have like a memory stick for the cache or is just a section of the hard drive? i noticed that when i partioned my hdd there was an existing partion of 8MB which let me to believe the cache is just a premade partition.

my guess is its main function is just to store recent instructions so it doesn't have to search 120GB for something.

yeah for some reason the Windows XP partitioner always always leaves 8 megs even when you try to partition the whole hard drive. I've gotten around this by using other partitioners first but it is annoying. I wonder why it does that.

 

[Matthias99]

Originally posted by: Heen05
so an extra 8 mb of cache would be = to higher rotational speeds?

Not really, although it could provide similar benefits in some instances (with intelligent prefetch, etc.) Higher rotational speeds lower your access time across the board, and boost your transfer rates as well. Cache will help you with these if you are doing small operations and following relatively predictable access patterns, but it doesn't make the physical disk any faster.

 

[Jeff7]

Originally posted by: kcthomas
im sure they optimize the size of the cache for the best performance. if it gets too big then the hdd has to search through a humungous cache, and it takes a while. do they actually have like a memory stick for the cache or is just a section of the hard drive? i noticed that when i partioned my hdd there was an existing partion of 8MB which let me to believe the cache is just a premade partition.

my guess is its main function is just to store recent instructions so it doesn't have to search 120GB for something.

Still, even a huge cache of data that has an access time measured in nanoseconds is many times faster than a hard drive R/W head with an access time measured in milliseconds.

 

[ManBearPig]

Thanks....i guess this helps on my decision whether to get a raptor or maxline. Appreciate it!