The Small Brain That Changed the World: The Story of the Birth of the Microprocessor

The smartphones and computers we use every day.
Why have they become so surprisingly small and high-performance?
The answer lies in a groundbreaking technology that was born just about 50 years ago.

That is the "microprocessor."

It is the condensation of computer functions that once filled an entire room into a single chip.
How was this little giant, the microprocessor, born?

In this article, we will introduce the story of the birth of this small brain.

1. The World Before Its Birth and the Technical Background

Palm-sized computers are now taken for granted.
However, until just a short time ago, computers were huge, room-filling machines found only in universities and research institutions.

Before the microprocessor was born, computer calculations and control were created by combining many components like "transistors" and "resistors" as if they were a complex puzzle.

For example, early computers in the 1960s used tens of thousands of transistors, all of which were wired by hand.
As a result, manufacturing took an enormous amount of time and cost, and failures occurred frequently.

The challenge of how to make these huge, complex machines smaller and easier to build was what troubled engineers at the time.

The key to solving this challenge was a technology called the "integrated circuit (IC)."
This is a technology that builds multiple transistors and resistors together on a single small silicon chip.
This paved the way for reducing the number of parts significantly and miniaturizing computers.

However, at this point, there was still no idea of fitting the entire CPU (Central Processing Unit) onto a single chip.

2. Intel's Challenge

The microprocessor began with a chip called the "Intel 4004," developed by the American semiconductor manufacturer Intel in 1971.

This chip was born out of a request from the Japanese calculator manufacturer "Busicom."
Busicom needed to design many types of integrated circuits to develop high-performance calculators.
However, creating dedicated circuits for each calculator was inefficient, costing both time and money.

So, Intel engineers Federico Faggin and Ted Hoff proposed a groundbreaking idea.
"Instead of making separate chips for each calculator function, why not make it possible to perform all basic processing, such as calculations and control, on a single general-purpose chip?"

This idea was truly revolutionary.
They sought to condense a "brain" that could perform various calculations and controls through programming, rather than a chip that could only be used for a specific purpose, into just one chip.

And what was born at the end of this challenge was the world's first general-purpose microprocessor, the "Intel 4004."
This chip held the potential to be used as the brain for various electronic devices, not just calculators.

3. What is a Microprocessor?

3.1 What is a Microprocessor?

A microprocessor is a device that integrates the entire functionality of a computer's CPU (Central Processing Unit) onto a single semiconductor chip.

As the brain of a computer, it performs various calculations, processes data, and controls each component.
When we type characters on a PC or play games on a smartphone, the microprocessor is performing hundreds of millions of calculations in an instant.

3.2 Advantages and Limitations of Microprocessors

(1) Advantages

・Miniaturization and Power Efficiency
By integrating many components onto a single chip, it has become possible to miniaturize devices and significantly reduce power consumption.

・Versatility
By simply rewriting the program, it can be used for various purposes such as calculators, computers, home appliances, and automobiles.
This has significantly reduced development costs and time.

(2) Limitations

Microprocessors also have several constraints.

・Architectural Constraints
Due to factors such as physical wiring limits, there is a limit to what a single chip can do.

・Physical and Technical Constraints
As suggested by "Moore's Law (*)", the integration density of chips is improving year by year, but we are approaching the physical limits of miniaturization at the atomic level. Heat issues and quantum effects are also challenges.

・Application Limitations
For certain specialized calculations (such as AI training), dedicated semiconductors specialized for those calculations (such as GPUs) may be more efficient than microprocessors.

4. Approaches to Overcoming Limitations and the Future

To overcome the limitations of microprocessors, various new technologies are currently being researched.

(1) Multi-core Processing
This is a technology that enables multiple processes to be performed simultaneously by mounting multiple microprocessors (cores) on a single chip. Most current PCs and smartphones adopt this technology.

(2) Heterogeneous Integration
This is an approach to increase efficiency by combining general-purpose microprocessors with semiconductors specialized for specific calculations (such as "NPUs" for AI).

(3) New Computational Methods
Quantum computers that exceed the limits of conventional electronic computing and neuromorphic chips that mimic the workings of the brain are attracting attention as next-generation technologies.

The microprocessor has fundamentally changed our society in just 50 years since its birth.
And its evolution continues even now.

The journey of this little brain will surely continue to open up our future.

Book Introduction

・Essentials of Computer Architecture [2nd Edition] Kindle Edition
By Douglas E. Comer, Translated by Kunio Yoshikawa
Shoeisha; 1st Edition (2020/10/14)
This book is the Japanese translation of
Douglas E. Comer, "Essentials of Computer Architecture, 2nd Edition",
Taylor & Francis Group, LLC. 2017
.
The academic field of "computer architecture" is deep and vast, as it encompasses both computer science and computer engineering.
Mastering all of this vast knowledge is an impossible task, not just for experts, but certainly for so-called IT engineers or beginners standing at the threshold.
Nevertheless, having this knowledge allows you to form a stronger foundation of understanding and move one or two steps ahead as a developer.
From that vast knowledge, this book focuses on the three areas of "processors," "memory," and "input/output (I/O)," providing an easy-to-understand explanation of the parts that serve as effective knowledge weapons for programmers, developers, and beginners, while offering a stepping stone to deeper knowledge.
(* Book descriptions, etc., are generally based on the descriptions on the linked site (Amazon). Please refer to the link for detailed content.)

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・Computer & Technology Anatomy: Visual Edition Kindle Edition
By Ron White, Translated by Top Studio Format: Kindle Edition
SB Creative (2015/9/19)
The ultimate illustrated guide to understanding how computer and IT technologies work, from the operating principles of computers to hardware, software, communications, web services, and printing.
(* Book descriptions, etc., are generally based on the descriptions on the linked site (Amazon). Please refer to the link for detailed content.)
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・Why Do Programs Run? 3rd Edition: Basic Programming Knowledge You Should Know Kindle Edition
By Hisao Yazawa Format: Kindle Edition
Nikkei BP (2021/5/13)
The long-awaited 3rd edition of "Why Do Programs Run?" after 14 years!
Revised to help more readers acquire "the basics that will be useful for the next 10 years."
It explains how programs work inside a computer in a way that anyone can understand. Programs are loaded into memory and interpreted and executed by the CPU. The mechanism is explained in an orderly manner using numerous diagrams.
(* Book descriptions, etc., are generally based on the descriptions on the linked site (Amazon). Please refer to the link for detailed content.)

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・Computer Organization and Design: MIPS Edition 6th Edition Vol. 1 Kindle Edition
By David Patterson, By John Hennessy, Translated by Mitsuaki Narita
Nikkei BP (2021/11/4)
The 6th edition of the classic masterpiece affectionately known as "Pata & Henne." It provides a deep explanation from the basics of computer technology to the latest themes of the mobile/cloud era.
(* Book descriptions, etc., are generally based on the descriptions on the linked site (Amazon). Please refer to the link for detailed content.)

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