The invention is directed to an improved abacus and related calculating method. The improved abacus and method are adapted to perform mathematical operations including addition, subtraction, multiplication, division and factoring. Additional mathematical operations are performable using described techniques. The improved abacus has a frame divided into an upper and lower section by a horizontal bar. The abacus includes a plurality of rods in which each rod contains four movable beads on the upper section of each rod and one movable bead on the lower section of each rod. The beads in the upper section have a value of two and the bead in the lower section has a value of one. Beads moved toward the bar are counted while those beads away from the bar are not counted. The improved abacus also includes a unit indicator, mathematical operational signs and positive and negative sliding indicators signs on the frame.

A system for interfacing with a co-processor or input/output device is disclosed. According to one embodiment, the system is configured to receive a command from a host memory controller of a host system and store the command in a command buffer entry. The system determines that the command is complete using a buffer check logic and provides the command to a command buffer. The command buffer comprises a first field that specifies an entry point of the command within the command buffer entry.

An abacus comprising a base, a first post and a second post mounted vertically on the base, and a plurality of rails coupled between the first post and the second post. Each of the plurality of rails is configured to receive a removable token that is slidably mounted on each rail. Each rail has a substantially flat cross-section. The cross-section of the rail is tilted at an angle between a vertical position and a horizontal position to enable gravity to keep a removable token mounted on the rail.

An abacus comprising a base, a first post and a second post mounted vertically on the base, and a plurality of rails coupled between the first post and the second post. Each of the plurality of rails is configured to receive a removable token that is slidably mounted on each rail. Each rail has a substantially flat cross-section. The cross-section of the rail is tilted at an angle between a vertical position and a horizontal position to enable gravity to keep a removable token mounted on the rail.