Informatics Practices · Ch 1 — Computer System
Evolution of Computer
Evolution of Computer
The road from a simple calculating aid to the modern data processor was travelled in a remarkably short span of time. Two threads run through this story: machines became programmable — able to store and follow instructions — and their electronics became relentlessly smaller and denser. The key inventions are laid out as a timeline (Figure 1.5).
The timeline of key inventions
| Period | Invention | What it contributed |
|---|---|---|
| about 500 BC (almost 3000 years ago) | Abacus | Computing is attributed to its invention — a mechanical device capable of simple arithmetic calculations only. |
| 1642 | Pascaline | Blaise Pascal's mechanical calculator, which could add and subtract two numbers directly, and multiply and divide through repeated addition or subtraction. |
| 1834 | Analytical Engine | Charles Babbage's mechanical computing device for inputting, processing, storing and displaying output — considered to form the basis of modern computers. |
| 1890 | Tabulating Machine | Herman Hollerith's machine for summarising data stored on punched cards — considered the first step towards programming. |
| 1937 | Turing Machine | A general purpose programmable machine concept, capable of solving any problem by executing a program stored on punched cards. |
| 1945 | EDVAC / ENIAC | John Von Neumann introduced the stored program computer, holding data as well as the program in memory; EDVAC and then ENIAC were developed on this concept. |
| 1947 | Transistor | Developed at Bell Labs from semiconductor materials, transistors replaced vacuum tubes. |
| 1970 | Integrated Circuit | A silicon chip carrying an entire electronic circuit on a very small area — ICs drastically reduced the size of the computer. |
A punched card, the storage medium behind Hollerith's machine and the Turing machine concept, is a piece of stiff paper that stores digital data in the form of holes at predefined positions.
The Von Neumann architecture
The design that still underlies computers is the Von Neumann architecture (Figure 1.4). It consists of a Central Processing Unit (CPU) for processing arithmetic and logical instructions, a memory that stores both data and programs, input and output devices, and communication channels to send and receive the output data. Storing the program itself in memory, alongside the data, is the idea that made the general-purpose computer possible. The Electronic Numerical Integrator And Computer (ENIAC) was the first binary programmable computer based on this architecture.
Shrinking circuits: LSI, VLSI and SLSI
Once circuits moved onto chips, the race was to pack more onto less:
- 1970s — Large Scale Integration (LSI): integration of electronic circuits advanced far enough to place a complete CPU on a single chip, called the microprocessor.
- Moore's Law predicted exponential growth in the number of transistors that could be assembled on a single microchip — and the following decades bore it out.
- 1980s — Very Large Scale Integration (VLSI): around 3 million components were integrated on a small-sized chip, and the processing power of computers grew exponentially.
- Super Large Scale Integration (SLSI): further advancement made it feasible to fabricate transistors and other components at very high density — approximately 10⁶ (one million) components — on a single IC (Figure 1.6).
The personal computer era
Computing then stepped out of the laboratory and into the home:
- 1981 — IBM introduced its first personal computer (PC) for the home user.
- 1984 — Apple introduced the Macintosh machines.
- The PC's popularity surged with the arrival of Graphical User Interface (GUI) based operating systems from Microsoft and others, replacing computers that offered only a command line interface, such as UNIX or DOS.
- Around the 1990s, the growth of the World Wide Web (WWW) accelerated mass usage further, and computers became an indispensable part of everyday life.
Portable, personal, and everywhere …
The figure is a minimal block diagram of the Von Neumann architecture, the design on which virtually every modern computer is built. On the left sits an oval labelled Input, from which an arrow points into a large shaded rectangle that represents the machine itself. Inside this rectangle are two boxes stacked one above the other: the Central Processing Unit on top and Memory below it, joined to each other by a double-headed arrow. A single arrow then leaves the rectangle on the right and ends at an oval labelled Output.
Every visual element carries a precise meaning. The ovals outside the rectangle stand for the devices through which the computer talks to the outside world: input devices feed raw data and instructions in, and output devices carry the results back out. The arrows entering and leaving the rectangle are the communication channels along which this data travels. …
The figure lays out the history of computing as a horizontal timeline. Milestone dots sit along a central line, and each dot is connected by a short vertical stem to a year label and an annotated text block — the invention's name in italics followed by a one-line description. The blocks alternate above and below the line, so the eye sweeps left to right through roughly 2,500 years of progress at a glance.
The earliest marker, at 500 BC, is the Abacus — a purely mechanical device, invented almost 3,000 years ago, that could carry out only simple arithmetic calculations. The next dot, at 1642, marks the Pascaline, the mechanical calculator of Blaise Pascal: it could add and subtract two numbers directly, and managed multiplication and division indirectly, through repeated addition or subtraction.
At 1834 comes Charles Babbage's Analytical Engine, a mechanical computing device capable of inputting, processing, storing and displaying output — the reason it is regarded as the conceptual ancestor of the modern computer. The 1890 dot marks Herman Hollerith's Tabulating Machine, which summarised data stored on punched cards (stiff paper cards holding digital data as holes punched at predefined positions); this is considered the first step towards programming. …
The figure is a growth chart that turns Moore's Law into a single picture. The vertical axis is labelled Number of Transistors per Integrated Circuit and climbs in powers of ten — 1, 10, 100, 1,000 and so on, all the way up to 10,000,000,000. Because each step of the axis multiplies the previous value by ten rather than adding to it, this is a logarithmic scale. The horizontal axis runs across the years from 1940 to 2020.
Near the bottom left of the chart, a marker labelled Invention of the Transistor sits at roughly 1947, close to the value 1 — the starting point of the story. From there a dashed trend line rises steadily to the upper right, passing through a series of white dots. Each dot is a real Intel processor, identified by name: 4004, 8086, 286, 386, 486, Pentium, Pentium II, Pentium III, Pentium IV, Core 2 DUO and Core i7. A legend box titled Intel Microprocessors identifies the dots, and an annotation on the trend line states the rule they follow: Doubles every 2 years. …