A storage system comprising: a cartridge, said cartridge including an upright having mounted on one side a plurality of guide blocks; a plurality of first drawer information means; and a plurality of latch mechanisms, said system further comprising a plurality of drawers, each said drawer including at least one compartment open at the top of the drawer; guide block engaging means extending in a depth direction of the drawer for mounting a first side of the drawer adjacent a respective guide block, the guide block engaging means comprising upper rail-engaging means for engaging an upper rail of the guide block and lower rail-engaging means for engaging a lower rail of the guide block, said upper and lower rail-engaging means extending in a depth direction of the drawer for mounting the first side of the drawer adjacent a holding apparatus; second drawer information means disposed adjacent the first drawer information means, said first and second information means for providing information on at least one of position and movement of said drawer; and at least one stop on the first side of the drawer for engaging with a said latch mechanism, wherein the latch mechanisms are electronically controllable for regulating access to the drawers, and the ratio of the depth of each guide block to the depth of the corresponding drawer is in the range 0.1 to 0.5. a cartridge, said cartridge including an upright having mounted on one side a plurality of guide blocks; a plurality of first drawer information means; and a plurality of latch mechanisms, a plurality of guide blocks; a plurality of first drawer information means; and a plurality of latch mechanisms, said system further comprising a plurality of drawers, each said drawer including at least one compartment open at the top of the drawer; guide block engaging means extending in a depth direction of the drawer for mounting a first side of the drawer adjacent a respective guide block, the guide block engaging means comprising upper rail-engaging means for engaging an upper rail of the guide block and lower rail-engaging means for engaging a lower rail of the guide block, said upper and lower rail-engaging means extending in a depth direction of the drawer for mounting the first side of the drawer adjacent a holding apparatus; second drawer information means disposed adjacent the first drawer information means, said first and second information means for providing information on at least one of position and movement of said drawer; and at least one stop on the first side of the drawer for engaging with a said latch mechanism, at least one compartment open at the top of the drawer; guide block engaging means extending in a depth direction of the drawer for mounting a first side of the drawer adjacent a respective guide block, the guide block engaging means comprising upper rail-engaging means for engaging an upper rail of the guide block and lower rail-engaging means for engaging a lower rail of the guide block, said upper and lower rail-engaging means extending in a depth direction of the drawer for mounting the first side of the drawer adjacent a holding apparatus; second drawer information means disposed adjacent the first drawer information means, said first and second information means for providing information on at least one of position and movement of said drawer; and at least one stop on the first side of the drawer for engaging with a said latch mechanism, wherein the latch mechanisms are electronically controllable for regulating access to the drawers, and the ratio of the depth of each guide block to the depth of the corresponding drawer is in the range 0.1 to 0.5.