the-french-artist/wikipedia_20220301.simple_sentence_split huggingface dataset:
Compression is a two-way process: a compression algorithm can be used to make a data package smaller, but it can also be run the other way, to decompress the package into its original form.
Data compression is useful in computing to save disk space, or to reduce the bandwidth used when sending data (e.g., over the internet).
Lossless compression
Lossless compression packs data in such a way that the compressed package can be decompressed, and the data can be pulled out exactly the same as it went in.
This is very important for computer programs and archives, since even a very small change in a computer program will make it unusable.
This type of compression works by reducing how much waste space is in a piece of data.
For example, if you receive a data package which contains "AAAAABBBB", you could compress that into "5A4B", which has the same meaning but takes up less space.
This type of compression is called "run-length encoding", because you define how long the "run" of a character is.
In the above example, there are two runs: a run of 5 A's, and another of 4 B's.
The problem with run-length encoding is that it only works on long pieces of the same value of data.
If you receive a package with "ABBAABAAB" inside, that can be compressed into "1A2B2A1B2A1B"; but that's longer than the original!
In this case, there's another method that can be used: checking how often a particular value comes up in the whole data package.
This is often called frequency compression.
The most common kind of frequency compression is called Huffman coding, after the scientist who came up with the idea.
The basic plan is to give each distinct value in a piece of data a code:- values that crop up all the time get shorter codes, and values that only show up once or twice get longer codes.
Examples of lossless compression
Archiving formats: Zip, GZip, bZip2, 7-Zip, etc.
Images/diagrams: GIF, PNG, PCX
Audio: FLAC, WavPack
Video: FFV1, H.264/MPEG-4 AVC High Predictive Profile
Program compressors: UPX
For some types of data, lossy compression can go much further; this is most often the case with media files, like music and images.
Lossy compression loses some of the data so that there's less to store.
Depending on what information is lost, people do not notice it is missing.
As a result, it can simply be removed from the data.
Examples of lossy compression
Images: JPEG
Audio: MP3, Windows Media
Video: MPEG, DivX, Windows Video
A compiler is a computer program that translates computer code written in one programming language into another programming language.
The first language is called the source language, and the code is called source code.
The second language is called the target and can usually be understood by computers.
In that case, the instructions become machine code.
If a compiler can convert the same instruction text into machine code for different computers (like smartphones or video game machines), it is a 'cross-compiler'.
If the compiler can make instruction text that is easier for people to read, it is a 'de-compiler'.
People who write these instructions are called programmers.
Some even made programs that can translate the instructions that describe how a compiler should work, into a compiler.
That kind of program is called a compiler-compiler.
A compiler usually has three steps.
It reads the text and makes notes about how the instructions go together.
If the instructions don't make sense, it will try to tell the programmer.
Then it will use what it knows about the target language to make the instructions fit better.
It then writes down the instructions in the target language.
If the source instructions are on different pages, it may have to compile several before it can write everything down.
Compiling the language
The first piece, a lexical analyzer, reads a page of instruction text and splits it into words and sentences.
It also marks the type for each word.
For example, a word may be number, a variable, a verb, a math sign, or an adjective.
The output of a lexical analyzer is a list of tokens.
int x = 5 + y;
(type, int) (unknown word, x) (math sign, =) (number, 5) (math sign, +) (word already seen, y)
A parser reads in the output of the lexical analyzer, and verifies the syntax of the language.
If the input program is syntactically incorrect or has a type error, it generates errors and warnings.
This is called semantic analysis.
For example, the parser might complain about the example above, if it had not already seen y with its type adjective.
The parser uses all the information to make a structure typically called an Abstract Syntax Tree (AST).
( write value to unknown
`( unknown
`( type, int ),
`( name, x ) ,
`( value
(add
`( number, 5 ),
`( seen
`( name, y ),
`( value, 0 )
The next piece, an optimizer rearranges the tree structure so the target language is optimized. '
Optimized' includes using fewer instructions to perform the same work.
This could be important if the final program needs to check a lot of data. (
Like seeing how many people, in the whole country, are fifty years old and buy medicine.)
An 'optimized' result might also mean breaking long instructions into smaller ones.
Unused and unaccessible code will be removed at this step.
A programmer usually tries to write instructions in small, related groups.
That way, they can keep track of fewer changes in the program.
But, that means the code may go on several pages.
When a compiler sees that the target program uses several pages to explain the whole recipe, it may use a linker.
The linker will put instructions that say where to find the code that's next.
Finally, the compiler writes down the instructions in the target language.
# instruction, spot, spot, target
Programmers who write compiler code try to make it as perfect as possible.
If the programmer writes incorrect code, the compiler informs of them an error, but if the compiler code itself contains errors, it may be hard to tell where exactly the problem lies.
At the end of each compilation step the partial finished product could be stored and then only processed later on.
A language like Java uses this successfully, where they lack the final translation step to instructions the processor understands.
They only do the final translation step once the Java program is running on a computer.
This is either called "interpreting" or "JIT"ting, depending on the technique used.
For example, the source code might contain an equation, such as "x = 5*10 ".
The lexical analyzer would separate each number and symbol (such as "*" or "+") into separate tokens.
The parser would note the pattern of tokens, as being an equation.
The intermediate-code generator would write a form of coding which defines a storage variable named "x" and assigns the numerical product of 5*10 plus 6 and 1.
The optimizer would simplify the calculation, of 5*10+6+1, as being just 57.
Hence, the target machine-code generator would set a variable named "x" and put the value 57 into that storage place in the computer's memory, using the instructions of whichever computer chip is being used.
Compiler -Citizendium
The eye is a round organ for sensing light so organisms can see.
It is the first part of the visual system.
About 97 percent of animals have eyes.
Image-resolving eyes are present in cnidaria, molluscs, vertebrates, annelids and arthropods.
In mammals, two kinds of cells, rods and cones, allow sight by sending signals through the optic nerve to the brain.
Some animals can see light that humans cannot see.
They can see ultraviolet or infrared light.
The lens on the front part of the eye acts like a camera lens.
It can be pulled flatter by muscles inside the eye, or allowed to become rounder.
As some people get older, they may not be as able to do this perfectly.
Many people are born with other small problems or get them later in life, and they may need eyeglasses (or contact lenses) to fix the problem.
Like different cameras, different eyes have different abilities.
They may have higher or lower resolution, the ability to detect small details.
They may have different performance in low light; nocturnal animals can see better at night than daytime animals.
They may have different ability to distinguish colours.
Parts of the eye
The human eye is composed of several different parts.
These parts may or may not be the same in other animals.
Cornea: The outermost, transparent layer that protects the iris and pupil.
Pupil: The black circle in the middle of the eye, through which light passes.
Iris: The colorful circle of the eye around the pupil.
It can be brown, blue, green, etc.
Its main function is to regulate the amount of light coming into the eye.
Sclera: The large, white field around the iris that keeps the eyeball in shape.
Lens: Behind the cornea there is a transparent bioconvex lens of very short focal length.
This lens is held in the centre of eye ball with the help of ciliary muscles .
Retina: Has the cells which turn light into nerve impulses.
Optic nerve: The nerve that connects the eye to the brain.
Optical information is taken to the rear of the brain for processing: see cerebral cortex.
Types of eye
Today, ten different types of eyes are known.
Most ways of capturing an image have evolved at least once.
One way to categorize eyes is to look at the number of "chambers".
Simple eyes are made of only one concave chamber, perhaps with a lens.
Compound eyes have many such chambers with their lenses on a convex surface.
Eyes also can be grouped according to how the photoreceptor is made.
Photoreceptors are either cillated, or rhabdomic.
and some annelids possess both.
Simple eyes
Pit eyes
Pit eyes are set in a depression in the skin.
This reduces the angles at which light can enter.
It allows the organism to say where the light is coming from.
Such eyes can be found in about 85% of phyla.
They probably came before the development of more complex eyes.
Pit eyes are small.
They are made of up to about hundred cells, covering about 100 µm.
The directionality can be improved by reducing the size of the opening, and by putting a reflective layer behind the receptor cells.
Pinhole eye
The pinhole eye is an advanced form of pit eye.
It has several bits, most notably a small aperture and deep pit.
Sometimes, the aperture can be changed.
It is only found in the Nautilus.
Without a lens to focus the image, it produces a blurry image.
Consequently, nautiloids can not discriminate between objects with a separation of less than 11°.
Shrinking the aperture would produce a sharper image, but let in less light.
Spherical lensed eye
The resolution of pit eyes can be improved a lot by adding a material to make a lens.
This will reduce the radius of the blurring, and increase the resolution that can be achieved.
The most basic form can still be seen in some gastropods and annelids.
These eyes have a lens of one refractive index.
It is possible to get a better image with materials that have a high refractive index which decreases towards the edges.
This decreases the focal length and allows a sharp image to form on the retina.
This eye creates an image that is sharp enough that motion of the eye can cause significant blurring.
To minimize the effect of eye motion while the animal moves, most such eyes have stabilizing eye muscles.
The ocelli of insects have a simple lens, but their focal point always lies behind the retina.
They can never form a sharp image.
This limits the function of the eye.
Ocelli (pit-type eyes of arthropods) blur the image across the whole retina.
They are very good at responding to rapid changes in light intensity across the whole visual field — this fast response is accelerated even more by the large nerve bundles which rush the information to the brain.
Focusing the image would also cause the sun's image to be focused on a few receptors.
These could possibly be damaged by the intense light; shielding the receptors would block out some light and  reduce their sensitivity.
Refractive cornea
The eyes of most land-living vertebrates (as well as those of some spiders, and insect larvae) contain a fluid that has a higher refractive index than the air.
The cornea is sharply curved and refracts light towards the focus.
The lens need not do all of the refracting.
This lets the lens adjust the focus more easily, for much higher resolution.
Reflector eyes
Instead of using a lens it is also possible to have cells inside the eye that act like mirrors.
The image can then be reflected to focus at a central point.
This design also means that someone looking into such an eye will see the same image as the organism which has them.
Many small organisms such as rotifers, copeopods and platyhelminthes use such this design, but their eyes are too small to produce usable images.
The scallop  Pecten has up to 100 millimeter-scale reflector eyes fringing the edge of its shell.
It detects moving objects as they pass successive lenses.
Compound eyes
Compound eyes are different from simple eyes.
Instead of having one organ that can sense light, they put together many such organs.
Some compound eyes have thousands of them.
The resulting image is put together in the brain, based on the signals of the many eye units.
Each such unit is called ommatidium, several are called ommatidia.
The ommatidia are located on a convex surface, each of them points in a slighly different direction.
Unlike simple eyes, compound eyes have a very large angle of view.
They can detect fast movement, and sometimes the polarization of light.
The evolution of eyes started with simplest light-sensitive patches in unicellular organisms.
These eye-spots do nothing but detect if the surroundings are light or dark.
Most animals have a biochemical 'clock' inside.
These simple eye-spots are used to adjust this daily clock, which is called circadian rhythm.
Some snails, for example, see no image (picture) at all, but they sense light, which helps them stay out of bright sunlight.
More complex eyes have not lost this function.
A special type of cells in the eye senses light for a different purpose than seeing.
These cells are called ganglion cells.
They are located in the retina.
They send their information about light to the brain along a different path (the retinohypothalamic tract).
This information adjusts (synchronizes) the animal's circadian rhythm to nature's light/dark cycle of 24 hours.
The system also works for some blind people who cannot see light at all.
More complex eyes give the full sense of vision, including color, motion, and texture.
These eyes have a round shape that makes light rays focus on the back part of the eye, called the retina.
Good fliers like flies or honey bees, or prey-catching insects like praying mantis or dragonflies, have specialized zones of ommatidia organized into a fovea area which gives sharp vision.
In this zone the eyes are flattened and the facets  are larger.
The flattening allows more ommatidia to receive light from a spot.
This gives a higher resolution.
The body of Ophiocoma wendtii, a type of brittle star, is covered with ommatidia, turning its whole skin into a compound eye.
The same is true of many chitons.
A tongue-twister is a phrase that is hard to say.
They often use alliteration and homophones.
They are commonly employed to help warm up singers and actors
He would chuck as many wood as a woodchuck chucks if a woodchuck could chuck wood.
The sea shells she sells are sea shells for sure.
Six sick hicks nick six slick bricks with picks and sticks.
The lips, the teeth, the tip of the tongue.
AbiWord is a free word processor that can be downloaded for free, it is open source and is much smaller in size than a proprietary alternative, Microsoft Word.
It is available for FreeBSD, Linux, Microsoft Windows, Mac OS X, and QNX.
Its mascot is Abi the ant.
It is much smaller than many other commercial word-processors of its time, only using about 15Mb on a computer's hard drive under Microsoft Windows.
Word processors
Insects are a class in the phylum Arthropoda.
They are small terrestrial invertebrates which have a hard exoskeleton.
Insects are the largest group of animals on Earth by far: about 926,400 different species have been described.
They are more than half of all known living species.
They may be over 90% of animal species on Earth.
New species of insects are continually being found.
Estimates of the total number of species range from 2 million to 30 million.
All adult insects have six legs; and most have wings.
Insects were the first animals capable of flight.
As they develop from eggs, insects undergo metamorphosis.
Insects live all over the planet: almost all are terrestrial (live on land).
Few insects live in the oceans or in very cold places, such as Antarctica.
The most species live in tropical areas.
Some people call all insects "bugs", but this is not correct.
Only some insects are true bugs, which is a particular order of insects.
People who study insects are called entomologists.
Insect bodies
Insects have exoskeletons (skeletons on the outside).
Their skeletons are made out of thin, hard pieces or plates, like armour, made of chitin.
All together, these pieces make a hard layer around the insect's body.
The exoskeleton protects the insect.
The body of an insect has three main parts: a head, a thorax, and an abdomen.
On the head are an insect's compound eyes, its two antennae (they feel and smell things), and its mouth.
On the thorax, insects have wings and legs.
All insects have six legs (three pairs of jointed legs) and usually four wings (two pairs).
The abdomen is the back part of the insect.
Inside the abdomen is the stomach, the heart, and the excretory system where body wastes pass out of the insect.
Bees also have a stinger at the back of the abdomen.
Just like our muscles connect to our bones to make us walk and stand up, the muscles of an insect connect to the exoskeleton to make it walk and move.
Their muscles are on the inside of their skeleton.
Insects are cold-blooded, which means that they cannot control their body temperature.
This means that insects are not good at surviving the cold, at any rate out in the open.
In the winter, many insects go into something called diapause, which is the insect version of hibernation.
Some insects, like cockroaches, cannot go into diapause and they will die if it gets too cold outside.
This is why cockroaches love living in people's warm houses.
Respiratory and circulatory systems
Insect respiration happens without lungs.
There is a system of internal tubes and sacs through which gases diffuse or are actively pumped.
Air is taken in through openings on the sides of the abdomen called spiracles.
Oxygen gets to tissues that need it through their trachea (element 8 in diagram).
Many insect larvae live in water.
Many of those have gills that can extract oxygen dissolved in water.
Others must rise to the water surface to get air which may be held or trapped in special parts of their body.
Adult insects use oxygen at a high rate when they fly.
They need it for the flight muscles, the most active tissue known in biology.
The flight muscles use oxygen at a huge rate: 100 ccs of oxygen for every single cc of tissue per hour.
With this system, the greatest diameter a muscle could have (and still consume oxygen at this rate) is about 0.5 cm.
Even with special extra arrangements, insects cannot get larger than about 11 cm long.
The largest insect bodies are about as big as a mouse.
Some insects also use a molecule called haemocyanin, which does the same job as haemoglobin does in vertebrates (but less efficiently).
The insect circulatory system has no veins or arteries.
The 'blood' is called haemolymph, and moves around in the space called the haemocoel.
The organs sit in the haemocoel and are bathed in the haemolymph.
The 'heart' is little more than a single tube which pulses (squeezes).
How insects grow
Insects start life as an egg.
Usually a female (mother) insect lays eggs, but a few species have live birth (the eggs develop inside the mother).
The eggs are small; but they can usually be seen with the naked eye.
Although the adults are larger, they do need a magnifying glass or a binocular microscope to see the details.
A professional entomologist uses a binocular microscope to identify insects, plus a printed reference work.
There are far too many insects for anyone to remember them all, and most entomologists specialise in just one or two orders.
After the eggs hatch, two kinds of development may occur.
Some insects have what is called 'incomplete metamorphosis'.
This means that a small insect, called a nymph comes out of the egg, and the nymph looks almost the same as the adult insect.
As the nymph grows, it does not change the way it looks, but only how big it is.
It goes through a number of stages, called 'instars'.
Grasshoppers grow in this way.
Other insects have complete metamorphosis, which means that the small larva which comes out of the egg looks very different from the adult insect.
Insects that have complete metamorphosis usually come out of the egg as a larva, which usually looks like a worm.
The larva eats food and gets bigger until it turns into a pupa.
Butterfly pupae (plural for pupa) are often inside cocoons.
Inside the cocoon the insect changes the way it looks and often grows wings.
When the cocoon opens, the adult insect comes out.
Many insects have complete metamorphosis, for example beetles, butterflies and moths, and flies.
The adult stage of development is called the imago.
Evolutionary history
Origin of insects
The oldest known insect fossil is the Devonian Rhyniognatha, from the 396 million year old Rhynie chert.
It may have superficially resembled a modern-day silverfish insect.
This species already possessed mandibles of a type associated with winged insects, suggesting that wings may already have evolved at this time.
Thus, anatomical records suggest the first insects may have appeared earlier, in the Silurian period.
Genomic analysis puts their origin even further back in the Ordovician period.
Origin of wings
The origin of insect flight is unclear, since the earliest known winged insects appear to have been capable fliers.
Some extinct insects had an additional pair of winglets attaching to the first segment of the thorax, for a total of three pairs.
It seems the insects were not a particularly successful group of animals before they evolved wings.
Upper Carboniferous and Lower Permian insect orders include both living groups and a number of Palaeozoic groups, now extinct.
During this era, some giant dragonfly-like forms reached wingspans of  making them far larger than any living insect.
This gigantism may have been due to higher atmospheric oxygen levels, which allowed increased respiratory efficiency.
The lack of flying vertebrates could have been another factor.
Many of the early groups became extinct during the PermianTriassic extinction event, the largest mass extinction in the history of the Earth, around 252 million years ago.
Kinds of insects
Different kinds of insects are put into groups called orders.
There are about 29 insect orders.
The biggest insect orders are listed below:
Beetles (order Coleoptera) have the front pair of wings changed into a hard shell to protect the back wings.
Butterflies and moths (order Lepidoptera) have large, often colourful wings.
Flies (order Diptera) have only two wings.
Ants, bees, and wasps (order Hymenoptera) sometimes have stingers and sometimes live in large colonies (like ant hills).
True bugs (order Hemiptera) have a mouth that is long and narrow, like a drinking straw.
This kind of mouth is called a beak.
Grasshoppers (order Orthoptera) can usually jump with their legs.
Eat grass and grain plants.
Odonata, dragonflies and damselflies are top predators of other insects.
Both aquatic nymphs and flying adults are carnivorous.
Phasmatodea, the stick and leaf insects, is an order which is entirely based on camouflage.
It includes the world's longest insect, Chan's megastick.
Spiders, scorpions, and similar animals are not insects; they are arachnids.
Arachnids are arthropods that have four pairs of legs.
Centipedes are also arthropods, but not insects: they are in a subphylum called the Myriapoda.
Archaeognatha (jumping bristletails)
Thysanura (silverfish or bristletails)
Palaeoptera (insects that cannot flex their wings over their abdomen)
Ephemeroptera (Mayflies)
Anisoptera (dragonflies)
Zygoptera (damselflies)
Neoptera (insects that can flex their wings over their abdomen)
Exopterygota sensu stricto
Caloneurodea (extinct)
Titanoptera (extinct)
Protorthoptera (extinct)
Plecoptera (stone flies, about 1700 species)
Embioptera (webspinners, about 300 species)
Orthoptera (grasshoppers, crickets and locusts)
Zoraptera (one genus, about 30 species, resemble termites)
Dermaptera (earwigs)
Notoptera ~tentative~
Grylloblattidae (ice crawlers)
Mantophasmatidae (discovered in 2001, (gladiators)
Phasmatodea (stick insects, about 2500 species) ~tentative~
Blattaria (cockroaches)
Isoptera (termites)
Mantodea (mantids)
Psocoptera (booklice)
Thysanoptera (thrips)
Phthiraptera (lice)
Hemiptera (true bugs, 80.000 species)
Endopterygota or Holometabola (850,000 living species in eleven orders)
Hymenoptera (ants, bees, wasps, sawflies)
Coleoptera (beetles)
Strepsiptera (parasites that mostly live inside other insects)
Raphidioptera (snakeflies)
Neuroptera (net-winged insects, contains antlions for example)
Mecoptera (scorpionflies, may include fleas)
Siphonaptera (fleas)
Diptera (true flies)
Trichoptera (moth-like)
Lepidoptera (moths and butterflies)
Insects and people
Some insects can be pests to people in different ways.
Some are parasites, such as lice and bed bugs.
Some of these parasite insects spread diseases, for example mosquitoes spread malaria.
Many insects eat agricultural products (plants meant for people to eat).
Locustss are an example of pest insects that eat plants in agriculture.
Some insects are used by us.
The larvae of some moths make silk, which people use to make clothing.
In some parts of the world, people actually eat insects.
Eating insects for food is called entomophagy.
Many bees and flies pollinate plants.
This means the insects help the plants make seeds by moving pollen from one flower to another.
Some good insects eat pest insects, such as lady beetles (or ladybirds or ladybugs) eating aphids.
Many insects eat dead plants and animals.
People often use poisons called insecticides to kill pest insects.
Insecticides do not always work.
Sometimes the pest insects become resistant to the insecticides, which means the insecticides do not hurt them anymore.
Both the Colorado potato beetle and the diamondback moth are insects that are resistant to many insecticides.
Insecticides do not only kill pest insects; sometimes many helpful insects are killed too.
When helpful insects are killed, such as those that eat pest insects, the pest insects may come back in larger numbers than before because they are not being eaten by helpful insects anymore.
Hoell H.V; Doyen J.T. & Purcell A.H. 1998.
Introduction to insect biology and diversity.
2nd ed, Oxford University Press.
Insect -Citizendium
The first operating systems
CTSS (The Compatible TimeShare System, made at MIT by Corbato and others)
Incompatible Timesharing System (The Incompatible Timeshare System, made at MIT)
Multics (project by Bell Labs, GE, and MIT)
Master programme for Leo Computers, Leo III in 1962
THE operating system (by Dijkstra and others)
The first proprietary computer operating systems
Apple Computer (first version was firmware with Integer BASIC; later versions had Microsoft BASIC)
Business Operating System (BOS) - cross platform, text-based
Commodore PET, Commodore 64, and Commodore VIC-20,
First IBM-PC had 3 OSes to start, UCSD P-system, CPM-86, PC-DOS
Flex (by Technical Systems Consultants for Motorola 6800 based computers: SWTPC, Tano, Smoke Signal Broadcasting, Gimix, etc.)
FLEX9 (by TSC for Motorola 6809 based micros)
mini-FLEX (by TSC for 5.25" disks on 6800 based machines)
Sinclair Micro and QX, etc.
TRS-DOS, ROM OS's (largely Microsoft BASIC implementations with file system extensions)
TI99-4
Unix-like and other POSIX-ready systems
AIX (Unix from IBM)
Amoeba (research OS by Andrew S. Tanenbaum)
AtheOS (continued with the Syllable code-fork)
A/UX (Unix Apple OS from start of 1990s)
BSD (Berkeley Software Distribution, a type of Unix)
Cromix (Unix-emulating OS from Cromemco)
Coherent (Unix-emulating OS from Mark Williams Co.)
DNIX
Digital UNIX (later, HP's Tru64 for Digital's AXP 64-bit computers)
FreeBSD (Version of abandoned BSD with free source code)
GNU/Hurd
HP-UX from HP
Idris from Whitesmiths
IRIX from SGI
LainOS (FreeBSD project, a tried version of "Navi" GUI from Serial Experiments Lain)
Linux (free Unix-like kernel)
Minix (educational OS by Andrew S. Tanenbaum in the Netherlands)
NetBSD (post-CSRG open source type of BSD)
NeXTSTEP (foundation for OS X)
OS-9 (not to be confused with Mac OS 9)
OS-9/68k
OS-9000 (OS-9 written in C)
OS/360
OS X from Apple Inc.
OpenBSD (post-CSRG open source type of BSD)
OPENSTEP NeXTSTEP on Intel x86, HP PA-RISC, and different architectures.
Plan 9 (by Bell Labs)
QNX (POSIX, microkernel OS)
SCO UNIX (from SCO, purchased by Caldera)
Solaris from Sun Microsystems
SunOS from Sun Microsystems (became Solaris)
System V (a release of AT&T Unix, 'SVr4' was the 4th minor release)
UNIX (OS developed at Bell Labs in 1970 first by Ken Thompson)
UNIflex (Unix emulating OS by TSC)
Ultrix (DEC's first version of Unix for VAX, PDP-11, MIPS, and Decstation computers)
UniCOS from Cray
Xenix (Microsoft's version of Unix)
z/OS (IBM mainframe OS)
Generic/commodity, non-UNIX, and other
AOS, now called Bluebottle(update to Oberon operating system)
AROS (Amiga Research Operating System)
Bluebottle (see AOS)
BS2000 by Siemens AG
Control Program/Monitor-80 (CPM operating system)
CP/M-86 (by Digital Research)
DESQView (windowing GUI for MS-DOS,1985)
DR-DOS (MS-DOS compatible OS from Digital Research)
FLEX9 (by TSC)
FreeDOS (open source, free MS-DOS alternative)
GEM (GUI for MS-DOS by Digital Research)
MS-DOS (Microsoft purchased from Seattle Computer)
MorphOS (by Genesi)
NetWare (by Novell)
NeXTStep (Foundation for OS X)
PC-DOS (IBM's version of MS-DOS)
Plan 9, Inferno (networked OS by Bell Labs)
Primos by Prime Computer
Mach (kernel by CMU, used in NeXTStep and OS X)
MP/M-80 (by Digital Research)
Oberon operating system (developed at ETH-Zürich by Niklaus Wirth)
OS/2 Windows/MS-DOS compatible operating system made in a Microsoft and IBM project, but later Microsoft stopped when they wanted to work on Windows NT more; which was better than early Windows versions and MS-DOS.
OS-9 (Unix emulating OS from Microware)
OS-9/68k (Unix emulating OS from Microware)
OS-9000 (portable Unix emulating OS from Microware)
SSB-DOS (by TSC for Smoke Signal Broadcasting; a variant of FLEX)
TripOS
TUNES
QDOS (made at Seattle Computer Products by Tim Paterson for new Intel 808x CPUs.
Given to Microsoft—soon became MS-DOS)
UCSD P-system (OS by a student project at the University of California, San Diego; directed by Prof Ken Bowles)
VisiOn (first GUI for early PC machines, not successful)
Visopsys (hobby OS for PCs)
VME by International Computers Limited (ICL)
Randolf by United Computer inc,
Vision (first GUI for early PC machines, not successful, by Microware)
ReactOS (an open source OS that runs Windows NT applications natively)
Panalix
RISC OS (was later open sourced under a fully free/open source license)
RISCiX
MultiTOS
MiNT
GS/OS
Macintosh/Mac OS classic
Newton OS
Be Incorporated
BeIA
Digital/Compaq/HP
ITS (for the PDP-6 and PDP-10)
OS-8
RSTS/E (ran on several machines, chiefly PDP-11s)
RSX-11 (multi-user, multitasking OS for PDP-11s)
RT-11 (single user OS for PDP-11)
TENEX (from BBN)
TOPS-10 (for the PDP-10)
TOPS-20 (for the PDP-10)
VMS (by DEC for the VAX mini-computer type; later renamed OpenVMS)
WAITS
AIX (a version of Unix)
ALCS
Basic Operating System (first system released for the System 360, as an interim)
DOS/VSE
MFT (later called OV/VS1)
MVS (latest variant of MVT)
MVT (later called OV/VS2)
OS/360 (first OS planned for the System 360 architecture)
OS/390
OS/400
PC-DOS (IBM's version of DOS)
SVS
VM/CMS
Windows 1.0x (Mostly text interface organised into windows, because graphical hardware was expensive at the time)
Windows 2.X
Windows 3.X
Windows XP (based on code of Windows 2000, was first "non-business" version of Windows NT)
Personal digital assistants (PDAs)
EPOC, today is named Symbian OS
iOS from Apple
Newton OS from Apple, for  Apple Newton MessagePad
Palm OS from Palm Inc
Pocket PC from Microsoft
Windows CE (Windows Compact Edition, from Microsoft)
Microcontroller, embedded
ITRON
OSEK
TRON OS by Ken Sakamura
µCLinux
Fictional operating systems
Lcars - From Star Trek
ALTIMIT OS - From .hack
Digitronix - From The Hacker Files
Hyper OS - From the movie Patlabor
Penix - Pun of Microsoft Xenix with an inappropriate word
Wheatonix - April fool's joke.
GLADOS - Genetic Lifeform and Disk Operating System
Disk operating system
Computer-related lists
Computer jargon means words to do with computers and surrounding topics.
Knowing what these words mean can help people know more about computers.
Most people use these words to discuss computer ideas, but some people use these words to impress others (also known as buzzwords).
Disk - a place to store data.
Data - information stored on a computer.
The amount of data that is stored on a disk is measured with the following terms:
Bit - the smallest data unit, can either be a "0" or a "1."
Nybble - there are 4 bits in a Nybble.
This is the amount of data that can be expressed in one hexadecimal (base 16) character.
Byte - there are 8 bits in a byte.
One byte is enough to hold one single letter or number of text.
Kilobyte - there are 1024 Bytes in a Kilobyte.
Megabyte - there are 1024 Kilobytes in a Megabyte.
Gigabyte - there are 1024 Megabytes in a Gigabyte.
Terabyte - there are 1024 Gigabytes in a Terabyte.
Petabyte - there are 1024 Terabytes in a Petabyte.
Note that some people and some companies use a different version of these numbers, replacing 1024 with 1000 in each of the above numbers.
Upload - to put data on somewhere.
For example, on the internet or a website, "I uploaded my pictures to Facebook."
Download - to copy data from somewhere.
For example, "I downloaded a song from iTunes."
Load - to get data from, or put it on, a disk.
Save - to put data on a disk.
RAM - random access memory.
ROM - read only memory.
This is memory that does not get changed.
Hardware - the solid parts of a computer, like monitors, fans, CPU, etc.
CPU - central processing unit, another name for processor.
GHz - gigahertz.
Used to describe the speed of a processor.
Some processors are capable of doing more than one thing at once, as they have multiple "cores", so a bigger number is not necessarily better.
The bigger the GHz number, the faster it runs and the more energy it uses.
USB - universal serial bus, a method used to plug computer tools into a machine.
Email - electronic mail.
WWW - World Wide Web, part of the Internet.
Broadband - a fast internet connection.
WiFi - wireless fidelity.
A way to connect to a network wirelessly.
Plug & Play - a function from the OS that auto-recognizes any change to the hardware of the computer.
OS - operating system.
The main program that controls all the computer functions, it calls other programs.
Program - set of data that tells the processor what to do and call for in the rest of PC.
Software - another name for program.
Installation - the way a software sets the place for itself in a computer.
Computer Virus - bad software made to mess up a computer or destroy data; nothing good comes from it.
Hacker - people who search flaws in the way computers work.
They can use their knowledge for evil, too.
en:Computer jargon
One million (1,000,000), or one thousand thousand, is the natural number after 999,999 and before 1,000,001.
The name is derived from Italian, where  was 1,000, and 1,000,000 became a "milione", as 'a large thousand'.
In scientific notation, the number is written as 1×106 or just 106.
Physical quantities can also be expressed using the SI prefix  when dealing with SI units.
For example, 1 megawatt equals 1,000,000 watts.
Il Milione is the title of Marco Polo's narration of his travels in China.
The name is supposed to come from Polo's nickname after his tales of riches and multitudes.
A millionaire is someone who owns at least one million units of currency.
In computer science a megabyte is about a million bytes, or 1,048,576 (1,0242).
In measurement there are a million millimeters in a kilometer.
There are a million meters in a megameter. (
A person who travels completely around earth's equator travels 40 megameters).
Also, light travels a million kilometers in around 3 seconds (See: light speed).
A thousand (1000, one thousand or 1,000) is the natural number after 999 and before 1001.
One thousand thousands is known as a million.
Examples of a thousand
The number of grams in a kilogram
The number of millimeters in a meter
The number of years in a millennium
19E03 1000
In economics, gross domestic product (GDP) is how much a place produces in an amount of time.
GDP can be calculated by adding up its output inside the borders of that country.
To find the GDP of a country, one adds up all consumer spending (C), all investment (I), all government spending minus taxes (G), and the value of exports minus imports (X – M).
This is shown by the equation: This measure is often used to find out how healthy a country is; a country with a high value of GDP can be called a large economy.
The United States has the largest GDP in the world.
Germany has the largest in Europe, Nigeria in Africa and China in Asia.
There are different ways to calculate the GDP.
Nominal GDP is the total amount of money spent on all new and final goods in an economy, real GDP (adjusting for changes in prices) tries to correct this number for inflation.
For example, if the prices rise by 2% (meaning, everything costs 2% more) and the nominal GDP grows by 5%, the real GDP growth is only increased by 3%.
GDP per capita is the total income of a country, divided by the number of inhabitants.
It shows how rich people, on average, are.
Nominal GDP
When the gross domestic product is evaluated at the current market prices, it is called the nominal GDP.
It includes changes in prices which makes it different from the real GDP.
These changes can be due to inflation or price fluctuations.
It can be measured in one of three different ways.
The income approach uses the total of all income from businesses and individuals in a single year.
The expenditure approach uses the market value of all goods purchased in a single year.
The production approach is based on the total production in a single year.
Cricket is a sport which is played between two teams of eleven players each.
One team, which is batting, tries to score runs, while the other team is fielding, and tries to prevent this.
Runs are scored by hitting the ball, which is thrown by a player from the fielding team to a player from the batting team, across the boundary, or by the two batting players running back-and-forth between the two wickets.
The wickets are sets of three small, wooden posts that are at each end of a rectangle of short grass called 'the pitch', which is 22 yards long.
The pitch is inside a much larger oval of grass called the 'area of play'.
The area of play is a 30 yard circle inside the cricket ground or stadium.
The fielding team can attempt to get batting players "out" in a number of ways.
When a player is out, a teammate will replace them in the field.
When a team no longer has two "not-out" players left to score, then the other team gets the chance to try to score.
In shorter games of cricket, a team may also have to stop batting when the ball has been thrown to their players a certain number of times.
After both teams have had enough chances to score, the team with the most runs wins.
The game started to gain popularity in England in the 16th century.
The earliest definite reference to the sport is in a court case of 1598.
The Guildford court heard John Derrick, a coroner, that fifty years earlier, "he and diverse of his fellows did run and play [on the common land] at cricket".
Later, the game spread to countries of the British Empire in the 19th and 20th centuries.
Cricket rules
There are two teams: The team bowling has 11 players on the field.
The team batting has two players, one at each end of the pitch (also sometimes called the wicket).
The rest of the batting team are off the field.
Runs are got after a ball is bowled, mostly by hitting the ball and running, or by hitting the ball to or over the boundary.
The bowler is trying to aim the ball at a wicket, which is made up of three sticks (called stumps) stuck into the earth, with two small sticks (called bails) balanced on them.
One of the fielders, called the 'wicket keeper', stands behind the wicket to catch the ball if the bowler misses the wicket.
The other fielders may chase the ball after the batsman has hit it.
He does not throw the ball.
He bowls the ball overarm with a "straight arm" (defined further in the rules and the guidance to umpires).
If he bends his arm, the other teams are given one run and he has to bowl the ball again.
An 'over' is six balls, meaning he bowls six times.
Then another player becomes the bowler for the next over, and bowls from the other end, and so on.
The same bowler cannot bowl two overs one after the other.
The batsman is trying to defend the wicket from getting hit with the ball.
He does this with a bat.
When he hits the ball with his bat, he may run toward the other wicket.
To score a run:
The two batsmen must both run from their wicket to the other wicket before they can be run out.
Being run out is explained below.
The batsmen can run between the wickets as many times as they want, with one run scored each time they do this.
If the ball leaves the field after being hit without bouncing, six runs are scored.
If the ball rolls or bounces out, whether or not the batter hit it, it counts as four runs.
There are different ways that a batsman can get out.
The most common ways are:
The batsman misses the ball and the ball hits the wicket: called bowled, or being "bowled out".
The ball hits the batsman's body when it would have hit the wicket otherwise.
Called LBW (leg before wicket).
The way this rule is applied is complicated; this is just the general idea.
A fielder catches the ball after the batsman hits it, and before it bounces or leaves the field: called caught.
While the batsmen are running, a fielder can throw the ball at the wicket.
If the batsmen cannot finish the run in time, and the ball hits the wicket, the batsman nearer to the wicket that is hit is out: this is called run out.
When a batsman is out, another comes onto the field to take his place.
The innings is over when ten wickets are taken (i.e. ten of the eleven batsmen are out).
After this, the team which was the 'fielding' team becomes the 'batting' team.
They now have to score more runs than the other team managed to score.
If they score more runs before ten wickets are taken, they win.
If they do not, the other team wins.
In a one-day game, each side has one innings, and innings are limited to a certain number of overs.
In longer formats each side has two innings, and there is no specific limit to the number of overs in an innings.
Where cricket is played
The countries where cricket is most popular compete in international matches (games between countries) that last up to 5 days, which are called Test matches.
Those countries are England, Australia, West Indies, South Africa, New Zealand, India, Bangladesh, Zimbabwe, Ireland, Afghanistan and Sri Lanka.
The West Indies are a group of Caribbean countries that play together as a team.
Several other countries have more junior status.
The test match idea was invented by teams from England and Australia in the 19th century.
Ireland and Afghanistan are the new teams which can play Test cricket.
The field
A cricket field is where cricket is played.
It is circular or oval-shaped grassy ground.
There are no fixed dimensions for the field.
Its diameter usually varies between 450 feet (137 m) to 500 feet (100 m).
Different forms of cricket
Test matches
Test matches are the top international matches played between countries.
The main point of test cricket is to test young players.
The countries permitted to play test matches are accredited by the ICC: the International Cricket Council.
The ten countries are listed below, with 'West Indies',' England' counting for this purpose as a country.
Tests last for up to five days (This is why many also call it "5 day cricket.")
and can still end in a draw match : it is the longest format of cricket.
Test Playing Nations in order of first dates:
National league systems
Called counties in England, and states in Australia and islands in the West Indies.
These are three or four day matches.
Limited overs cricket
In these games, the length is determined by the number of overs, and each side has one innings only.
A special formula, known as the 'Duckworth–Lewis method' is applied if rain reduces the time for play.
It calculates the target score for the team batting second in a limited overs match interrupted by weather or other circumstance.
One day internationals (ODI50)
ODIs are usually restricted to 50 overs batting for each side and each bowler can bowl up to 10 overs maximum.
The highest team score is England 481-6 against Australia in June 19, 2018.
The highest individual score is 264 off 173 balls by Rohit Sharma for India against Sri Lanka.
Twenty20 cricket (T20 Cricket)
Twenty20 cricket has 20 overs for each side and each bowler can bowl up to 4 overs maximum unlike 10 overs in an ODI match.
The highest team score is 263/5 by Royal Challengers Bangalore (RCB) against Pune Warriors India (PWI) in the 2013 IPL season.
The highest individual score is 175* off 69 balls  by Chris Gayle for RCB in the same match.
A batsman's batting average is the number of runs he has scored in a period (such as a year or his whole career), divided by the number of times he was got out in the same period.
A good batsman has a high batting average.
The highest T20 average for a batsman who has played at least 20 innings is 70.66 by Chris Harris.
A bowler's bowling average is the number of runs that have been scored while he was bowling, in a period, divided by the number of batsmen he has got out in the same period.
A good bowler has a low bowling average.
The lowest T20 bowling average for a bowler who has bowled at least 500 balls is Mushtaq Ahmed with 13.80.
International Cricket Council (ICC)
Cricket statstics and records at ESPNcricinfo
What Is Cricket?
Get to know the sport: a video produced by the International Cricket Council
"Cricket".
Encyclopædia Britannica Online
Track and field is part of the sport of athletics.
Athletics is a collection of sport events that includes running, jumping and throwing.
Track and field events take place in a sports stadium, either on the running track, or on the field inside the running track.
These tracks are generally made up of synthetic rubber – rubber particles bound with latex or polyurethane.
Other athletics events that are not track and field, include cross country running, road running, marathon running, and race-walking - these events take place outside a sports stadium.
Athletics is a very common sporting event over the world.
Athletics is a combination of different sports, generally running, jumping and throwing events.
Running events include marathons, hurdle races, long distance and short distance events.
Some jumping events are high jump, long jump, triple jump and pole vault.
Throwing events involve javelin throw, discus throw, hammer throw and shot put.
There are also events that combine parts of running, jumping, and throwing.
One of these is the decathlon, which includes two short-distance races, a mile run, a hurdles race, javelin, discus, shot-put, high jump and pole vault.
All participants are timed or have a distance measured and this is their end result.
Participants train hard for an event and always aim to better their results.
Athletics is a sport that people take part in all over the world.
It is a sport that is most common between young children up to younger adults.
Athletics can be played for enjoyment, but it can also be a competitive sport.
Athletics is also an event in the Olympic games.
International Association of Athletics Federations website
USA Track & Field website
Results & Statistics for Collegiate, High School, Middle School, and Club teams
Badminton is a sport for two or four( "singles" or "doubles") people.