A system (10, 20, 30, 40, 70, 70', 1100, 1100') comprising: a base chip including: a plurality of attachment slots for attaching dies (200, 200-1, 200-2, 200-3) thereto; a plurality of cross bar switches, each of the plurality of cross bar switches associated with respective ones of the plurality of attachment slots; and a test and configuration block (136, 436, 436', 436", 710, 710') configured to receive and transmit test signals to determine electrically connected signal lines (s1, s2) of one or more attachment slots when one or more dies (200, 200-1, 200-2, 200-3) are attached to the base chip and further configured to receive configuration data to program one or more of the cross bar switches, wherein the plurality of cross bar switches are arranged in a matrix configuration, the plurality of cross bar switches comprising a plurality of input/output channels that form a crossed pattern of interconnecting lines, wherein the plurality of cross bar switches are configured to establish a connection between at least two of the interconnecting lines by closing at least one of the plurality of cross bar switches located at an intersection of at least two of the plurality of input/output channels, the system being characterised in that the plurality of input/output channels are configured to be programmable based on configuration data and alignment data, wherein the alignment data is associated with metal contacts of the base chip and metal contacts (202, 212, 222, 232) of a die (200, 200-1, 200-2, 200-3) attached to the base chip, the metal contacts (202, 212, 222, 232) of the die (200, 200-1, 200-2, 200-3) having a different size or pitch than a size or pitch of the metal contacts of the base chip. a base chip including: a plurality of attachment slots for attaching dies (200, 200-1, 200-2, 200-3) thereto; a plurality of cross bar switches, each of the plurality of cross bar switches associated with respective ones of the plurality of attachment slots; and a test and configuration block (136, 436, 436', 436", 710, 710') configured to receive and transmit test signals to determine electrically connected signal lines (s1, s2) of one or more attachment slots when one or more dies (200, 200-1, 200-2, 200-3) are attached to the base chip and further configured to receive configuration data to program one or more of the cross bar switches, a plurality of attachment slots for attaching dies (200, 200-1, 200-2, 200-3) thereto; a plurality of cross bar switches, each of the plurality of cross bar switches associated with respective ones of the plurality of attachment slots; and a test and configuration block (136, 436, 436', 436", 710, 710') configured to receive and transmit test signals to determine electrically connected signal lines (s1, s2) of one or more attachment slots when one or more dies (200, 200-1, 200-2, 200-3) are attached to the base chip and further configured to receive configuration data to program one or more of the cross bar switches, wherein the plurality of cross bar switches are arranged in a matrix configuration, the plurality of cross bar switches comprising a plurality of input/output channels that form a crossed pattern of interconnecting lines, wherein the plurality of cross bar switches are configured to establish a connection between at least two of the interconnecting lines by closing at least one of the plurality of cross bar switches located at an intersection of at least two of the plurality of input/output channels, the system being characterised in that the plurality of input/output channels are configured to be programmable based on configuration data and alignment data, wherein the alignment data is associated with metal contacts of the base chip and metal contacts (202, 212, 222, 232) of a die (200, 200-1, 200-2, 200-3) attached to the base chip, the metal contacts (202, 212, 222, 232) of the die (200, 200-1, 200-2, 200-3) having a different size or pitch than a size or pitch of the metal contacts of the base chip.