Abstract: A method of addressing mass storage memory in which information is stored in Space Control Pages of physically contiguous disk segments subject to irregularities in the mapping is disclosed. Space Control Pages fall at regular intervals across the address space. An efficient hashing method is disclosed that first hashes record keys across the entire address space to form a hash index. If the hash index falls into one of the Space Control Pages, the key is rehashed across the contiguous hash space following the Space. Control Page utilizing a second hash function. The result of the second hash function is added to the start of the contiguous hash space following the Space Control Page to generate the hash index utilized for those records that initially hashed into a Space Control Page. In all cases the generated hash index is utilized to store and retrieve records in a database or hash file.