Two Bus Organization
To overcome the disadvantage of one bus organization another architecture was developed known as two bus organization. In two bus organizations, there are two buses. The general-purpose register can read/write from both the buses. In this case, two operands can be fetched at the same time because of the two buses. One bus fetch operand for ALU and another bus fetch for register. The situation arises when both buses are busy fetching operands, the output can be stored in a temporary register and when the buses are free, the particular output can be dumped on the buses.
There are two versions of two bus organizations, i.e., in-bus and out-bus. From in-bus, the general-purpose register can read data and to the out bus, the general-purpose registers can write data. Here buses get dedicated.
Introduction of ALU and Data Path
Representing and storing numbers were the basic operations of the computers of earlier times. The real go came when computation, manipulating numbers like adding and multiplying came into the picture. These operations are handled by the computer’s arithmetic logic unit (ALU). The ALU is the mathematical brain of a computer. The first ALU (Arithmetic Logic Unit) was indeed the INTEL 74181, which was implemented as part of the 7400 series TTL (Transistor-Transistor Logic) integrated circuits. It was released by Intel in 1970.