CS232 Lecture Notes
7. Programmable Circuits
Fall 2021
Programmable Circuits (IV): The IAS Computer
What is the IAS computer?
-We’ve talked about the programmable circuits. Let’s take a look at the first electronic
computer that could store programs in memory.
-This first electronic computer is called IAS computer, as it’s the first electronic computer built
at the Institute for Advanced Study (ISA) in Princeton.
-IAS computer is also call Von Neumann machine, as the paper describing its design was
edited by John Von Neumann.
-IAS computer is the father of all modern computers, and its primary concept was storing the
program in memory.
-Here is the structure of the IAS computer.
-It contains
•A main memory, which stores both data and instructions
•An ALU capable of operating on binary data (CA: central arithmetical)
•A control unit, which interprets the instructions in the memory and causes them to be
executed (CC: central control)
•I/O equipment operated by the control unit
-IAS computer contains 4096 ( ) memory locations. The memory locations are called,
words.
-Each word is 40-bit long, and could hold one piece of data or two instructions. (binary format)
•Each number is represented by a sign bit and a 39-bit value.
•Each instruction consisting of an 8-bit operation code (opcode) specifying the operation to
be performed and a 12-bit address designating one of the words in memory (numbered
from 0 to 4095)
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