"The true sign of inteligence is not knowledge but Imagination."

There are two ways to live your life: either as if nothing is a miracle or as if everything is a miracle."

"The only source of knowledge is experience." (Albert Einstein)

"Those who can imagine any can create the impossible.“  (Alan M. Turing)

"Ideas are easy, execution is everything." (John Doerr)

 

What is a computer?

A computer is an electronic-based device that uses software to process and store data.

A digital computer uses binary code (0 and 1) to process information.

Communication with the computer is done through software, via a programming language.

The computer is at the centre of computer science and is perhaps the most versatile technical invention of all time. As a tool of computer science, the computer - unlike other machines - does not perform any physical or mechanical work. The computer thus occupies a special position among technological innovations.

Few inventions have revolutionised humanity in the same way that the computer has. One could perhaps mention evolutionary phenomena such as language and the upright walk in the same breath.

The list for the use of computers in our time is very long, and it is getting longer and longer, and more and more devices resemble a computer more than their actual form and idea.
In addition, numerous tasks both in the world of work and in people's everyday lives are now being taken over by computer-controlled devices and machines.

The internet has revolutionised the computer and its uses. Online banking and online shopping, social networks, unlimited access to information of all kinds are all possible. The internet enables us to communicate and exchange information in real time with people across the globe, government procedures are made easier by the fact that applications and documents can already be filled out and sent online. There is universal access to the world's potential wealth of knowledge. Anyone can obtain an overview of information on any topic anywhere and at any time, and also contribute to increasing knowledge, with or without a claim to truth. This excerpt of examples is far from reflecting the true influence and immense importance of the computer in the 21st century.

The computer makes people's lives easier: it can now solve countless computing tasks in a matter of seconds, for which a single person would otherwise need days or weeks.

The largest PC makers in 2023 are Lenovo ($72 billion total revenue), HP and Dell, and the largest smartphone makers are Apple ($361 billion total revenue), Samsung ($234 billion total revenue), and Xiaomi.

Computers in their various forms can be found almost everywhere in everyday life these days: in every office, privately as a PC, laptop or smartphone, as a microprocessor in household appliances, entertainment devices, in industry, in transport, in finance or in many vending machines.

Types of computers

  • PC (Personal Computer)
  • Workstation
  • Server (host computer)
  • Mobile computer (notebooks, laptops, tablets, smartphones)
  • Mainframe
  • Supercomputer
  • Microprocessor (embedded system)
  • Single board computer
  • Some machines (e.g. ATM)
  • Game console
  • Smart TV
  • Quantum computer (currently under development)

 

A server is a computer that makes programs, data or services available to all other computers in the network.

A client is a computer that accesses the data on a server and uses its services.

A computer consists of:

  • hardware (unchangeable components of the computer)
  • software (easily modifiable components of the computer)

The hardware of a stationary computer consists of:

  • motherboard
  • CPU (Central Processing Unit)
  • ROM (Read Only Memory)
  • RAM (Random Access Memory)
  • graphic card
  • external storage (hard drive, SSD, CD-ROM/DVD)
  • input and output devices (screen, keyboard, possibly mouse, possibly printer)

Typically hardware components of a smartphone are:

  • the CPU
  • the GPU
  • a display (LCD, touch screen)
  • a keypad
  • a microphone
  • a loudspeaker
  • the SIM card
  • the battery
  • the USB port
  • the antenna
  • the memory unit(RAM,ROM)
  • the camera,
  • CODEC
  • RF part
  • DAC/ADC
  • baseband part (L1/Layer1/physical layer) running on DSP
  • Application/protocol layers running on CPU
  • ON/OFF switch
  • Bluetooth/GPS features

Every computer has a worldwide unique IP address (IP stands for Internet Protocol)

The USB stick is a mobile storage medium for computers.

Software is the entirety of programs for the computer.

 

What is an operating system?

One of most important representants of system software is the operating system (OS).

The OS controls the hardware of the computer and is an essential part of the computer. This is because without the operating system, the user cannot operate the computer and transmit commands to the central processing unit.

The OS appears as the interface between the user and the computer. The OS is also a software, but the OS plays a superior role. The OS and an application software are loaded into the main memory because it communicates with the processor. This ensures faster data processing because the working memory is much faster than the hard disk, for example.

Examples of operating systems:

The Microsoft Windows operating system is mostly used in PCs, laptops and notebooks, Linux is installed on many different types of computers (up to supercomputers), while Android can be found in various smartphones and tablets and iOS has been deve-loped for Apple smartphones and tablets.

Interesting things about computers and software

  • There are 6 billion smartphones in the world, global sales continue to grow. PC sales are declining (340 million units still sold in 2021).
  • The largest computer in the world ("Titan", USA) has the dimensions of a baseball field.
  • The fastest supercomputer in the world ("Frontier", Oak Ridge National Laboratory, USA) manages 1.2 ExaFlops, i.e. 1.2 trillion operations per second.
  • The most expensive smartphone in the world (Falcon SuperNova Pink Diamond iPhone 6) costs $48.5 million.
  • The most expensive PC in the world costs 1 billion dollars because its case is made of 7 kg of gold.
  • Malbolge, an esoteric programming language, is considered the most difficult in the world.
  • The easiest language to learn is considered Python.

 

History of the computer

Precursors of the digital computer:

Developments from the 20th century:

 

Computer generations

  • The first generation (1946-1959, vacuum tubes)
  • The second generation (1959-1965, transistors)
  • The third generation (1965-1971, integrated circuits)
  • The fourth generation (80s, ULSI microprocessors)
  • The fifth generation (since 2021, VLSI microprocessors)

Development of computer processing power

  • 1 flop              (Z3, 1941)
  • 5000 flops.    (ENIAC, 1946)
  • 21000 flops   (Commodore 64, 1982)
  • 43000 flops.  (Apollo-11 computers)
  • 4 MegaFlops (PC with processor 80386)
  • 6 GigaFlops   (PC mit Pentium-4-Prozessor)
  • 6 GigaFlops   (aktuelles Smartphone)
  • 36 GigaFlops (aktueller PC)
  • 2 ExaFlops     ("Frontier": currently the fastest supercomputer)

FLOPS means Floating Point Operations per Second.

1 flop corresponds to 1 operation per second.

1 MegaFlop equals 1 million operations per second.

1 GigaFlop equals 1 billion operations per second.

1 ExaFlop equals 1 trillion operations per second.

Moore's Law: Every 12 to 24 months, the  computing power or complexity of integrated circuits (of computers) doubles while manufacturing costs remain the same (fits for computer development since 1940 but will encounter limits in the future due to the appearance of quantum effects with further miniaturization).

 

False predictions about computers

● "I think there is a world market for maybe five computers."
(Thomas Watson, chairman of IBM, 1943)

● "The computers of the future will not weigh more than 1.5 tons." (1949, The US Magazine Popular Mechanics)

● "Remote shopping, while entirely feasible, will flop."
(Time Magazine, 1966)

● "There is no reason for any individual to have a computer in his home."
(Ken Olsen, founder of Digital Equipment Corporation, 1977)

● "There's no money in selling computer hardware."
(Ken Olsen, founder of Digital Equipment Corporation, 1977)

● "640 KB ought to be enough for anybody."
(Attributed to Bill Gates, 1981 - though Gates has denied saying this)

● "We will never make a 32-bit operating system."
(Bill Gates, 1989)

● "Windows NT addresses 2 GB of RAM, which is more than any application will ever need."
(Microsoft, 1992)

● "...the idea of a wireless personal communicator in every pocket is a pipe dream driven by greed."
(Andrew Grove, CEO of Intel, 1992)

● "The Internet will soon go spectacularly supernova and in 1996 catastrophically collapse."
(Robert Metcalfe, founder of 3Com, 1995)

● "No online database will replace your daily newspaper."
(Clifford Stoll, 1995)

● "By 2005 or so, it will become clear that the Internet's impact on the economy has been no greater than the fax machine's."
(Paul Krugman, economist, 1998)

● "The mobile phone will never become a serious competitor to the personal computer."
(Tech pundits, early 2000s)

● "Two years from now, spam will be solved."
(Bill Gates, 2004)

● "There’s just not that many videos I want to watch."
(Steve Chen, co-founder of
YouTube, on the initial launch of the platform, 2005)

● "There’s no chance that the iPhone is going to get any significant market share."
(Steve Ballmer, Microsoft CEO, 2007)

● "The iPhone is nothing more than a luxury bauble that will appeal to a few gadget freaks."
(Matthew Lynn, Bloomberg, 2007)

 

What is data?

When information is processed automatically or electronically, we speak of data.

Data contains a sequence of characters together with their meaning for the recipient.

Data are binary coded for processing with the computer, i.e. they can have 2 possible values (0/1). This smallest unit of data representation is called a bit. A byte contains 8 bits. One byte can represent 28=256 different characters.

In practice, the following units are commonly used:

  • KiloByte    (1 KByte=1024 bytes)
  • MegaByte (1 MByte≈106 Bytes bytes or 1 billion bytes)
  • GigaByte   (1 GByte≈109 bytes or 1 trillion bytes)
  • TeraByte   (1 TByte≈1012 bytes or 1 trilliard bytes)

 

What is a file?

A file is a collection of data with an identical structure.

A file is saved under a name on a data carrier.

 

What is an algorithm?

An algorithm is a processing rule consisting of a finite series of steps that can be used to solve a task.

An algorithm has the following properties: finiteness (a finite number of instructions), uniqueness (each instruction is also determined by the next one), general validity (can be used for all tasks of the same type and always leads to the desired result).

A central issue in algorithms is predictability. In order to clarify questions about the algorithmic solvability of problems, it must first be specified what is meant by "algorithmically solvable". Ultimately, this leads to the difficulty of capturing the "essentials" of a method that can be executed by a computer using the most concrete means of description possible.

Alan Turing's Turing machine is a model for the automated execution of algorithmic problem solutions that implements automated processing with the simplest possible means.

Notation forms of algorithms

  • Description with the help of the common language: makes little sense
  • Verbal formalized description
  • Program flow chart (flow chart) : leads to unstructured programming ("spaghetti code")
  • Struktogramm (Nassi-Shneiderman diagramm)
  • Modeling languages ​​(e.g. UML)
  • Program created using a high-level programming language