What is the structure of IAS and how it operates?
The IAS computer was designed and built at the Institute for Advanced Study in the early 1950s by a team of researchers that included John von Neumann, Herman Goldstine, and J. Robert Oppenheimer. It was one of the first stored-program computers, meaning that both instructions and data could be stored in the same memory.
Three basic parts make up the IAS computer:
- Central Processing Unit, or CPU
- The primary memory device
- Input/output device or I/O device
CPU consists of program control unit and data processing unit. It also contains control unit along with various set of high-speed registers. These registers are meant for temporary storage of instructions and data.
Set of registers (storage in CPU):
Memory Buffer Register (MBR)
Memory Address Register (MAR)
Instruction Register (IR)
Instruction Buffer Register (IBR)
Program Counter (PC)
Accumulator (ACC)
Multiplier Quotient (MQ)
The IAS computer used vacuum tubes and had a clock speed of about 1 MHz, which was fast for its time. It was used for a variety of applications, including scientific calculations, weather forecasting, and military simulations. The IAS computer was also used to develop early programming languages, such as Fortran and COBOL. The IAS machine was a binary computer that stored two instructions of 20 bits each in each of its 40-bit words. The convention for negative numbers was two’s complement. Accumulator (AC) and Multiplier/Quotient were two of its general-purpose registers (MQ). It made use of a few diodes and 1,700 vacuum tubes. Approximately 2,300 RCA Solectron vacuum tubes were intended for the memory’s initial design.
Examples for IAS machines:
- AVIDAC
- IBM 701
- MANIAC
- ORACLE
While the IAS computer is no longer in operation, its impact on computing history cannot be overstated. Its design and innovations paved the way for the development of modern computers and programming languages, and it continues to be studied and celebrated as a landmark achievement in computer science.
