A cache system and method for configuring and accessing a cache that enables a binary-sized memory space to be efficiently shared amongst cache and non-cache uses. A storage device is provided having a plurality of blocks where each block is identified with a block address. An access request identifies a target block address. The target block address includes an upper portion and a lower portion. A non-binary divide is performed on the upper portion to produce a quotient and a remainder. The remainder portion is combined with the lower portion to create an index. The index is applied to a tag memory structure to select an entry or set of entries in the tag memory structure. The content of the selected entry is compared to the quotient portion to determine if the target block is represented in the cache.