isamb->file[i].head.first_block = ISAMB_CACHE_ENTRY_SIZE/b_size+1;
isamb->file[i].head.last_block = isamb->file[i].head.first_block;
isamb->file[i].head.block_size = b_size;
isamb->file[i].head.first_block = ISAMB_CACHE_ENTRY_SIZE/b_size+1;
isamb->file[i].head.last_block = isamb->file[i].head.first_block;
isamb->file[i].head.block_size = b_size;