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HashCache is a new method for storing Web content that could make Internet access speedier and more affordable around the world.With the advent of cheap
commodity laptops geared for mass deployments, de-
veloping regions are poised to become major users of
the Internet, and given the high cost of bandwidth in
these parts of the world, they stand to gain signifi-
cantly from network caching. However, current Web
proxies are incapable of providing large storage capac-
ities while using small resource footprints, a requirement
for the integrated multi-purpose servers needed to ef-
fectively support developing-world deployments.
Hash-
Cache presents a radical departure from the conventional
wisdom in network cache design, and uses 6 to 20 times
less memory than current techniques while still provid-
ing comparable or better performance.
Hash Cache gets rid of the index and RAM by transforming the URL of each Web object, which can be an image or a block of text on a web page, into a shorter number using a hash function that correlates with a hard disk memory address. Hash Cache uses a unique hash function because the number that the function produces defines the exact spot on the disk where the corresponding Web object can be found. The hash is used to directly compute the location so the index is not required. Just enough RAM is needed to run the hash function and to retrieve a specific Web object.
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