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Data structure

In computer science, a data structure is a data organization, and storage format that is usually chosen for efficient access to data. More precisely, a data structure is a collection of data values, the relationships among them, and the functions or operations that can be applied to the data, i.e., it is an algebraic structure about data.

Usage
Data structures serve as the basis for abstract data types (ADT). The ADT defines the logical form of the data type. The data structure implements the physical form of the data type.

Different types of data structures are suited to different kinds of applications, and some are highly specialized to specific tasks. For example, relational databases commonly use B-tree indexes for data retrieval, while compiler implementations usually use hash tables to look up identifiers.

Data structures provide a means to manage large amounts of data efficiently for uses such as large databases and internet indexing services. Usually, efficient data structures are key to designing efficient algorithms. Some formal design methods and programming languages emphasize data structures, rather than algorithms, as the key organizing factor in software design. Data structures can be used to organize the storage and retrieval of information stored in both main memory and secondary memory.

Implementation
Data structures can be implemented using a variety of programming languages and techniques, but they all share the common goal of efficiently organizing and storing data. Data structures are generally based on the ability of a computer to fetch and store data at any place in its memory, specified by a pointer—a bit string, representing a memory address, that can be itself stored in memory and manipulated by the program. Thus, the array and record data structures are based on computing the addresses of data items with arithmetic operations, while the linked data structures are based on storing addresses of data items within the structure itself. This approach to data structuring has profound implications for the efficiency and scalability of algorithms. For instance, the contiguous memory allocation in arrays facilitates rapid access and modification operations, leading to optimized performance in sequential data processing scenarios.

The implementation of a data structure usually requires writing a set of procedures that create and manipulate instances of that structure. The efficiency of a data structure cannot be analyzed separately from those operations. This observation motivates the theoretical concept of an abstract data type, a data structure that is defined indirectly by the operations that may be performed on it, and the mathematical properties of those operations (including their space and time cost).

Examples
There are numerous types of data structures, generally built upon simpler primitive data types. Well known examples are:
 * An array is a number of elements in a specific order, typically all of the same type (depending on the language, individual elements may either all be forced to be the same type, or may be of almost any type). Elements are accessed using an integer index to specify which element is required. Typical implementations allocate contiguous memory words for the elements of arrays (but this is not always a necessity). Arrays may be fixed-length or resizable.
 * A linked list (also just called list) is a linear collection of data elements of any type, called nodes, where each node has itself a value, and points to the next node in the linked list. The principal advantage of a linked list over an array is that values can always be efficiently inserted and removed without relocating the rest of the list. Certain other operations, such as random access to a certain element, are however slower on lists than on arrays.
 * A record (also called tuple or struct) is an aggregate data structure. A record is a value that contains other values, typically in fixed number and sequence and typically indexed by names. The elements of records are usually called fields or members. In the context of object-oriented programming, records are known as plain old data structures to distinguish them from objects.
 * Hash tables, also known as hash maps, are data structures that provide fast retrieval of values based on keys. They use a hashing function to map keys to indexes in an array, allowing for constant-time access in the average case. Hash tables are commonly used in dictionaries, caches, and database indexing. However, hash collisions can occur, which can impact their performance. Techniques like chaining and open addressing are employed to handle collisions.
 * Graphs are collections of nodes connected by edges, representing relationships between entities. Graphs can be used to model social networks, computer networks, and transportation networks, among other things. They consist of vertices (nodes) and edges (connections between nodes). Graphs can be directed or undirected, and they can have cycles or be acyclic. Graph traversal algorithms include breadth-first search and depth-first search.
 * Stacks and queues are abstract data types that can be implemented using arrays or linked lists. A stack has two primary operations: push (adds an element to the top of the stack) and pop (removes the topmost element from the stack), that follow the Last In, First Out (LIFO) principle. Queues have two main operations: enqueue (adds an element to the rear of the queue) and dequeue (removes an element from the front of the queue) that follow the First In, First Out (FIFO) principle.
 * Trees represent a hierarchical organization of elements. A tree consists of nodes connected by edges, with one node being the root and all other nodes forming subtrees. Trees are widely used in various algorithms and data storage scenarios. Binary trees (particularly heaps), AVL trees, and B-trees are some popular types of trees. They enable efficient and optimal searching, sorting, and hierarchical representation of data.

A trie, or prefix tree, is a special type of tree used to efficiently retrieve strings. In a trie, each node represents a character of a string, and the edges between nodes represent the characters that connect them. This structure is especially useful for tasks like autocomplete, spell-checking, and creating dictionaries. Tries allow for quick searches and operations based on string prefixes.

Language support
Most assembly languages and some low-level languages, such as BCPL (Basic Combined Programming Language), lack built-in support for data structures. On the other hand, many high-level programming languages and some higher-level assembly languages, such as MASM, have special syntax or other built-in support for certain data structures, such as records and arrays. For example, the C (a direct descendant of BCPL) and Pascal languages support structs and records, respectively, in addition to vectors (one-dimensional arrays) and multi-dimensional arrays.

Most programming languages feature some sort of library mechanism that allows data structure implementations to be reused by different programs. Modern languages usually come with standard libraries that implement the most common data structures. Examples are the C++ Standard Template Library, the Java Collections Framework, and the Microsoft .NET Framework.

Modern languages also generally support modular programming, the separation between the interface of a library module and its implementation. Some provide opaque data types that allow clients to hide implementation details. Object-oriented programming languages, such as C++, Java, and Smalltalk, typically use classes for this purpose.

Many known data structures have concurrent versions which allow multiple computing threads to access a single concrete instance of a data structure simultaneously.

title: Data structure


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Dmitri Shostakovich

Dmitri Dmitriyevich Shostakovich (25 September 1906 – 9 August 1975) was a Soviet-era Russian composer and pianist who became internationally known after the premiere of his First Symphony in 1926 and thereafter was regarded as a major composer.

Shostakovich achieved early fame in the Soviet Union, but had a complex relationship with its government. His 1934 opera Lady Macbeth of Mtsensk was initially a success but later condemned by the Soviet government, putting his career at risk. In 1948 his work was denounced under the Zhdanov Doctrine, with professional consequences lasting several years. Even after his censure was rescinded in 1956, performances of his music were occasionally subject to state interventions, as with his Thirteenth Symphony (1962). Nevertheless, Shostakovich was a member of the Supreme Soviet of the RSFSR (1947) and the Supreme Soviet of the Soviet Union (from 1962 until his death), as well as chairman of the RSFSR Union of Composers (1960–1968). Over the course of his career, he earned several important awards, including the Order of Lenin, from the Soviet government.

Shostakovich combined a variety of different musical techniques in his works. His music is characterized by sharp contrasts, elements of the grotesque, and ambivalent tonality; he was also heavily influenced by neoclassicism and by the late Romanticism of Gustav Mahler. His orchestral works include 15 symphonies and six concerti (two each for piano, violin, and cello). His chamber works include 15 string quartets, a piano quintet, and two piano trios. His solo piano works include two sonatas, an early set of 24 preludes, and a later set of 24 preludes and fugues. Stage works include three completed operas and three ballets. Shostakovich also wrote several song cycles, and a substantial quantity of music for theatre and film.

Shostakovich's reputation has continued to grow after his death. Scholarly interest has increased significantly since the late 20th century, including considerable debate about the relationship between his music and his attitudes toward the Soviet government.

Youth
Born into a Russian family that lived on Podolskaya Street in Saint Petersburg, Russian Empire, Shostakovich was the second of three children of Dmitri Boleslavovich Shostakovich and Sofiya Vasilievna Kokoulina. Shostakovich's immediate forebears came from Siberia, but his paternal grandfather, Bolesław Szostakowicz, was of Polish Roman Catholic descent, tracing his family roots to the region of the town of Vileyka in today's Belarus. A Polish revolutionary in the January Uprising of 1863–64, Szostakowicz was exiled to Narym in 1866 in the crackdown that followed Dmitry Karakozov's assassination attempt on Tsar Alexander II. When his term of exile ended, Szostakowicz decided to remain in Siberia. He eventually became a successful banker in Irkutsk and raised a large family. His son Dmitri Boleslavovich Shostakovich, the composer's father, was born in exile in Narym in 1875 and studied physics and mathematics at Saint Petersburg University, graduating in 1899. He then went to work as an engineer under Dmitri Mendeleev at the Bureau of Weights and Measures in Saint Petersburg. In 1903, he married another Siberian immigrant to the capital, Sofiya Vasilievna Kokoulina, one of six children born to a Siberian Russian.

Their son, Dmitri Dmitriyevich Shostakovich, displayed musical talent after he began piano lessons with his mother at the age of nine. On several occasions, he displayed a remarkable ability to remember what his mother had played at the previous lesson, and would get "caught in the act" of playing the previous lesson's music while pretending to read different music placed in front of him. In 1918, he wrote a funeral march in memory of two leaders of the Kadet party murdered by Bolshevik sailors.

In 1919, at age 13, Shostakovich was admitted to the Petrograd Conservatory, then headed by Alexander Glazunov, who monitored his progress closely and promoted him. Shostakovich studied piano with Leonid Nikolayev and Elena Rozanova, composition with Maximilian Steinberg, and counterpoint and fugue with Nikolay Sokolov, who became his friend. He also attended Alexander Ossovsky's music history classes. In 1925, he enrolled in the conducting classes of Nikolai Malko, where he conducted the conservatory orchestra in a private performance of Beethoven's First Symphony. According to the recollections of the composer's classmate, Valerian Bogdanov-Berezhovsky:

"Shostakovich stood at the podium, played with his hair and jacket cuffs, looked around at the hushed teenagers with instruments at the ready and raised the baton. ... He neither stopped the orchestra, nor made any remarks; he focused his entire attention on aspects of tempi and dynamics, which were very clearly displayed in his gestures. The contrasts between the 'Adagio molto' of the introduction and 'Allegro con brio' first theme were quite striking, as were those between the percussive accents of the chords (woodwinds, French horns, pizzicato strings) and the momentarily extended piano in the introduction following them. In the character given to the pattern of the first theme, I recall, there was both vigorous striving and lightness; in the bass part there was an emphasized pliancy of tenderly threaded articulation.... Moments of these sorts... were discoveries of an improvised order, born from an intuitively refined understanding of the character of a piece and the elements of musical imagery embedded in it. And the players enjoyed it."

On 20 March 1925, Shostakovich's music was played in Moscow for the first time, in a program which also included works by his friend Vissarion Shebalin. To the composer's disappointment, the critics and public there received his music coolly. During his visit to Moscow, Mikhail Kvadri introduced him to Mikhail Tukhachevsky, who helped the composer find accommodation and work there, and sent a driver to take him to a concert in "a very stylish automobile".

Shostakovich's musical breakthrough was the First Symphony, written as his graduation piece at the age of 19. Initially, Shostakovich aspired only to perform it privately with the conservatory orchestra and prepared to conduct the scherzo himself. By late 1925, Malko agreed to conduct its premiere with the Leningrad Philharmonic Orchestra after Steinberg and Shostakovich's friend Boleslav Yavorsky brought the symphony to his attention. On 12 May 1926, Malko led the premiere of the symphony; the audience received it enthusiastically, demanding an encore of the scherzo. Thereafter, Shostakovich regularly celebrated the date of his symphonic debut.

Early career
After graduation, Shostakovich embarked on a dual career as concert pianist and composer, but his dry keyboard style was often criticized. Shostakovich maintained a heavy performance schedule until 1930; after 1933, he performed only his own compositions. Along with Yuri Bryushkov, Grigory Ginzburg, Lev Oborin, and Josif Shvarts, he was among the Soviet contestants in the inaugural I International Chopin Piano Competition in Warsaw in 1927. Bogdanov-Berezhovsky later remembered:

"The self-discipline with which the young Shostakovich prepared for the 1927 [Chopin] Competition was astonishing. For three weeks, he locked himself away at home, practicing for hours at a time, having postponed his composing, and given up trips to the theatre and visits with friends. Even more startling was the result of this seclusion. Of course, prior to this time, he had played superbly and occasioned Glazunov's now famous glowing reports. But during those days, his pianism, sharply idiosyncratic and rhythmically impulsive, multi-timbered yet graphically defined, emerged in its concentrated form."

Natan Perelman, who heard Shostakovich play his Chopin programs before he went to Warsaw, said that his "anti-sentimental" playing, which eschewed rubato and extreme dynamic contrasts, was unlike anything he had ever heard. Arnold Alschwang called Shostakovich's playing "profound and lacking any salon-like mannerisms."

Shostakovich was stricken with appendicitis on the opening day of the competition, but his condition improved by the time of his first performance on 27 January 1927. (He had his appendix removed on 25 April.) According to Shostakovich, his playing found favor with the audience. He persisted into the final round of the competition but ultimately earned only a diploma, no prize; Oborin was declared the winner. Shostakovich was upset about the result but for a time resolved to continue a career as performer. While recovering from his appendectomy in April 1927, Shostakovich said he was beginning to reassess those plans:

"When I was well, I practiced the piano every day. I wanted to carry on like that until autumn and then decide. If I saw that I had not improved, I would quit the whole business. To be a pianist who is worse than Szpinalski, Etkin, Ginzburg, and Bryushkov (it is commonly thought that I am worse than them) is not worth it."

After the competition, Shostakovich and Oborin spent a week in Berlin. There he met the conductor Bruno Walter, who was so impressed by Shostakovich's First Symphony that he conducted its first performance outside Russia later that year. Leopold Stokowski led the American premiere the next year in Philadelphia and also made the work's first recording.

In 1927, Shostakovich wrote his Second Symphony (subtitled To October), a patriotic piece with a pro-Soviet choral finale. Owing to its modernism, it did not meet with the same enthusiasm as his First. This year also marked the beginning of Shostakovich's close friendship with musicologist and theatre critic Ivan Sollertinsky, whom he had first met in 1921 through their mutual friends Lev Arnshtam and Lydia Zhukova. Shostakovich later said that Sollertinsky "taught [him] to understand and love such great masters as Brahms, Mahler, and Bruckner" and that he instilled in him "an interest in music ... from Bach to Offenbach."

While writing the Second Symphony, Shostakovich also began work on his satirical opera The Nose, based on the story by Nikolai Gogol. In June 1929, against the composer's wishes, the opera was given a concert performance; it was ferociously attacked by the Russian Association of Proletarian Musicians (RAPM). Its stage premiere on 18 January 1930 opened to generally poor reviews and widespread incomprehension among musicians. In the late 1920s and early 1930s, Shostakovich worked at TRAM, a proletarian youth theatre. Although he did little work in this post, it shielded him from ideological attack. Much of this period was spent writing his opera Lady Macbeth of Mtsensk, which was first performed in 1934. It was initially immediately successful, on both popular and official levels. It was described as "the result of the general success of Socialist construction, of the correct policy of the Party", and as an opera that "could have been written only by a Soviet composer brought up in the best tradition of Soviet culture".

Shostakovich married his first wife, Nina Varzar, in 1932. Difficulties led to a divorce in 1935, but the couple soon remarried when Nina became pregnant with their first child, Galina.

First denunciation
On 17 January 1936, Joseph Stalin paid a rare visit to the opera for a performance of a new work, Quiet Flows the Don, based on the novel by Mikhail Sholokhov, by the little-known composer Ivan Dzerzhinsky, who was called to Stalin's box at the end of the performance and told that his work had "considerable ideological-political value". On 26 January, Stalin revisited the opera, accompanied by Vyacheslav Molotov, Andrei Zhdanov and Anastas Mikoyan, to hear Lady Macbeth of the Mtsensk District. He and his entourage left without speaking to anyone. Shostakovich had been forewarned by a friend that he should postpone a planned concert tour in Arkhangelsk in order to be present at that particular performance. Eyewitness accounts testify that Shostakovich was "white as a sheet" when he went to take his bow after the third act.

The next day, Shostakovich left for Arkhangelsk, where he heard on 28 January that Pravda had published an editorial titled "Muddle Instead of Music", complaining that the opera was a "deliberately dissonant, muddled stream of sounds ...[that] quacks, hoots, pants and gasps." Shostakovich continued his performance tour as scheduled, with no disruptions. From Arkhangelsk, he instructed Isaac Glikman to subscribe to a clipping service. The editorial was the signal for a nationwide campaign, during which even Soviet music critics who had praised the opera were forced to recant in print, saying they "failed to detect the shortcomings of Lady Macbeth as pointed out by Pravda". There was resistance from those who admired Shostakovich, including Sollertinsky, who turned up at a composers' meeting in Leningrad called to denounce the opera and praised it instead. Two other speakers supported him. When Shostakovich returned to Leningrad, he had a telephone call from the commander of the Leningrad Military District, who had been asked by Marshal Mikhail Tukhachevsky to make sure that he was all right. When the writer Isaac Babel was under arrest four years later, he told his interrogators that "it was common ground for us to proclaim the genius of the slighted Shostakovich."

On 6 February, Shostakovich was again attacked in Pravda, this time for his light comic ballet The Limpid Stream, which was denounced because "it jangles and expresses nothing" and did not give an accurate picture of peasant life on a collective farm. Fearful that he was about to be arrested, Shostakovich secured an appointment with the Chairman of the USSR State Committee on Culture, Platon Kerzhentsev, who reported to Stalin and Molotov that he had instructed the composer to "reject formalist errors and in his art attain something that could be understood by the broad masses", and that Shostakovich had admitted being in the wrong and had asked for a meeting with Stalin, which was not granted.

The Pravda campaign against Shostakovich caused his commissions and concert appearances, and performances of his music, to decline markedly. His monthly earnings dropped from an average of as much as 12,000 rubles to as little as 2,000.

1936 marked the beginning of the Great Terror, in which many of Shostakovich's friends and relatives were imprisoned or killed. These included Tukhachevsky, executed 12 June 1937; his brother-in-law Vsevolod Frederiks, who was eventually released but died before he returned home; his close friend Nikolai Zhilyayev, a musicologist who had taught Tukhachevsky, was executed; his mother-in-law, the astronomer Sofiya Mikhaylovna Varzar, who was sent to a camp in Karaganda and later released; his friend the Marxist writer Galina Serebryakova, who spent 20 years in the gulag; his uncle Maxim Kostrykin (died); and his colleagues Boris Kornilov (executed) and Adrian Piotrovsky (executed).

Shostakovich's daughter Galina was born during this period in 1936; his son Maxim was born two years later.

Withdrawal of the Fourth Symphony The publication of the Pravda editorials coincided with the composition of Shostakovich's Fourth Symphony. The work continued a shift in his style, influenced by the music of Mahler, and gave him problems as he attempted to reform his style. Despite the Pravda articles, he continued to compose the symphony and planned a premiere at the end of 1936. Rehearsals began that December, but according to Isaac Glikman, who had attended the rehearsals with the composer, the manager of the Leningrad Philharmonic persuaded Shostakovich to withdraw the symphony. Shostakovich did not repudiate the work and retained its designation as his Fourth Symphony. (A reduction for two pianos was performed and published in 1946, and the work was finally premiered in 1961.)

In the months between the withdrawal of the Fourth Symphony and the completion of the Fifth on 20 July 1937, the only concert work Shostakovich composed was the Four Romances on Texts by Pushkin.

Fifth Symphony and return to favor

The composer's response to his denunciation was the Fifth Symphony of 1937, which was musically more conservative than his recent works. Premiered on 21 November 1937 in Leningrad, it was a phenomenal success. The Fifth brought many to tears and welling emotions. Later, Shostakovich's purported memoir, Testimony, stated: "I'll never believe that a man who understood nothing could feel the Fifth Symphony. Of course they understood, they understood what was happening around them and they understood what the Fifth was about."

The success put Shostakovich in good standing once again. Music critics and the authorities alike, including those who had earlier accused him of formalism, claimed that he had learned from his mistakes and become a true Soviet artist. In a newspaper article published under Shostakovich's name, the Fifth was characterized as "A Soviet artist's creative response to just criticism." The composer Dmitry Kabalevsky, who had been among those who disassociated themselves from Shostakovich when the Pravda article was published, praised the Fifth and congratulated Shostakovich for "not having given in to the seductive temptations of his previous 'erroneous' ways."

It was also at this time that Shostakovich composed the first of his string quartets. In September 1937, he began to teach composition at the Leningrad Conservatory, which provided some financial security.

Second World War
In 1939, before Soviet forces attempted to invade Finland, the Party Secretary of Leningrad Andrei Zhdanov commissioned a celebratory piece from Shostakovich, the Suite on Finnish Themes, to be performed as the marching bands of the Red Army paraded through Helsinki. The Winter War was a bitter experience for the Red Army, the parade never happened, and Shostakovich never laid claim to the authorship of this work. It was not performed until 2001. After the outbreak of war between the Soviet Union and Germany in 1941, Shostakovich initially remained in Leningrad. He tried to enlist in the military but was turned away because of his poor eyesight. To compensate, he became a volunteer for the Leningrad Conservatory's firefighter brigade and delivered a radio broadcast to the Soviet people.  The photograph for which he posed was published in newspapers throughout the country.

Shostakovich's most famous wartime contribution was the Seventh Symphony. The composer wrote the first three movements in Leningrad while it was under siege; he completed the work in Kuybyshev (now Samara), where he and his family had been evacuated. According to a radio address he made on 17 September 1941, he continued work on the symphony in order to show his fellow citizens that everyone had a "soldier's duty" to ensure life went on. In another article written on 8 October, he wrote that the Seventh was a "symphony about our age, our people, our sacred war, and our victory." Shostakovich finished his Seventh Symphony on 27 December. The symphony was premiered by the Bolshoi Theatre Orchestra in Kuibyshev on 29 March and soon performed in London and the United States, where several conductors vied to conduct its first American performance. It was subsequently performed in Leningrad while the city was still under siege. The city's remaining orchestra only had 14 musicians left, which led conductor Karl Eliasberg to reinforce it by recruiting anyone who could play an instrument.

The Shostakovich family moved to Moscow in spring 1943, by which time the Red Army was on the offensive. As a result, Soviet authorities and the international public were puzzled by the tragic tone of the Eighth Symphony, which in the Western press had briefly acquired the nickname "Stalingrad Symphony". The symphony was received tepidly in the Soviet Union and the West. Olin Downes expressed his disappointment in the piece, but Carlos Chávez, who had conducted the symphony's Mexican premiere, praised it highly.

Shostakovich had expressed as early as 1943 his intention to cap his wartime trilogy of symphonies with a grandiose Ninth. On 16 January 1945, he announced to his students that he had begun work on its first movement the day before. In April, his friend Isaac Glikman heard an extensive portion of the first movement, noting that it was "majestic in scale, in pathos, in its breathtaking motion". Shortly thereafter, Shostakovich ceased work on this version of the Ninth, which remained lost until musicologist Olga Digonskaya rediscovered it in December 2003. Shostakovich began to compose his actual, unrelated Ninth Symphony in late July 1945; he completed it on 30 August. It was shorter and lighter in texture than its predecessors. Gavriil Popov wrote that it was "splendid in its joie de vivre, gaiety, brilliance, and pungency!" By 1946 it was the subject of official criticism. Israel Nestyev asked whether it was the right time for "a light and amusing interlude between Shostakovich's significant creations, a temporary rejection of great, serious problems for the sake of playful, filigree-trimmed trifles." The New York World-Telegram of 27 July 1946 was similarly dismissive: "The Russian composer should not have expressed his feelings about the defeat of Nazism in such a childish manner". Shostakovich continued to compose chamber music, notably his Second Piano Trio, dedicated to the memory of Sollertinsky, with a Jewish-inspired finale.

In 1947, Shostakovich was made a deputy to the Supreme Soviet of the RSFSR.

Second denunciation
In 1948, Shostakovich, along with many other composers, was again denounced for formalism in the Zhdanov decree. Andrei Zhdanov, Chairman of the Supreme Soviet of the RSFSR, accused the composers (including Sergei Prokofiev and Aram Khachaturian) of writing inappropriate and formalist music. This was part of an ongoing anti-formalism campaign intended to root out all Western compositional influence as well as any perceived "non-Russian" output. The conference resulted in the publication of the Central Committee's Decree "On V. Muradeli's opera The Great Friendship", which targeted all Soviet composers and demanded that they write only "proletarian" music, or music for the masses. The accused composers, including Shostakovich, were summoned to make public apologies in front of the committee. Most of Shostakovich's works were banned, and his family had privileges withdrawn. Yuri Lyubimov says that at this time "he waited for his arrest at night out on the landing by the lift, so that at least his family wouldn't be disturbed."

The decree's consequences for composers were harsh. Shostakovich was among those dismissed from the Conservatory altogether. For him, the loss of money was perhaps the heaviest blow. Others still in the Conservatory experienced an atmosphere thick with suspicion. No one wanted his work to be understood as formalist, so many resorted to accusing their colleagues of writing or performing anti-proletarian music.

During the next few years, Shostakovich composed three categories of work: film music to pay the rent, official works aimed at securing official rehabilitation, and serious works "for the desk drawer". The last included the Violin Concerto No. 1 and the song cycle From Jewish Folk Poetry. The cycle was written at a time when the postwar anti-Semitic campaign was already under way, with widespread arrests, including that of Dobrushin and Yiditsky, the compilers of the book from which Shostakovich took his texts.

The restrictions on Shostakovich's music and living arrangements were eased in 1949, when Stalin decided that the Soviets needed to send artistic representatives to the Cultural and Scientific Congress for World Peace in New York City, and that Shostakovich should be among them. For Shostakovich, it was a humiliating experience, culminating in a New York press conference where he was expected to read a prepared speech. Nicolas Nabokov, who was present in the audience, witnessed Shostakovich starting to read "in a nervous and shaky voice" before he had to break off "and the speech was continued in English by a suave radio baritone". Fully aware that Shostakovich was not free to speak his mind, Nabokov publicly asked him whether he supported the then recent denunciation of Stravinsky's music in the Soviet Union. A great admirer of Stravinsky who had been influenced by his music, Shostakovich had no alternative but to answer in the affirmative. Nabokov did not hesitate to write that this demonstrated that Shostakovich was "not a free man, but an obedient tool of his government." Shostakovich never forgave Nabokov for this public humiliation. That same year, he composed the cantata Song of the Forests, which praised Stalin as the "great gardener".

Stalin's death in 1953 was the biggest step toward Shostakovich's rehabilitation as a creative artist, which was marked by his Tenth Symphony. It features a number of musical quotations and codes (notably the DSCH and Elmira motifs, Elmira Nazirova being a pianist and composer who had studied under Shostakovich in the year before his dismissal from the Moscow Conservatory), the meaning of which is still debated, while the savage second movement, according to Testimony, is intended as a musical portrait of Stalin. The Tenth ranks alongside the Fifth and Seventh as one of Shostakovich's most popular works. 1953 also saw a stream of premieres of the "desk drawer" works.

During the 1940s and 1950s, Shostakovich had close relationships with two of his pupils, Galina Ustvolskaya and Elmira Nazirova. In the background to all this remained Shostakovich's first, open marriage to Nina Varzar until her death in 1954. He taught Ustvolskaya from 1939 to 1941 and then from 1947 to 1948. The nature of their relationship is far from clear: Mstislav Rostropovich described it as "tender". Ustvolskaya rejected a proposal of marriage from him after Nina's death. Shostakovich's daughter, Galina, recalled her father consulting her and Maxim about the possibility of Ustvolskaya becoming their stepmother. Ustvolskaya's friend Viktor Suslin said that she had been "deeply disappointed by [Shostakovich's] conspicuous silence" when her music faced criticism after her graduation from the Leningrad Conservatory. The relationship with Nazirova seems to have been one-sided, expressed largely in his letters to her, and can be dated to around 1953 to 1956. He married his second wife, Komsomol activist Margarita Kainova, in 1956; the couple proved ill-matched, and divorced five years later.

In 1954, Shostakovich wrote the Festive Overture, opus 96; it was used as the theme music for the 1980 Summer Olympics. (His '"Theme from the film Pirogov, Opus 76a: Finale" was played as the cauldron was lit at the 2004 Summer Olympics in Athens, Greece.)

In 1959, Shostakovich appeared on stage in Moscow at the end of a concert performance of his Fifth Symphony, congratulating Leonard Bernstein and the New York Philharmonic Orchestra for their performance (part of a concert tour of the Soviet Union). Later that year, Bernstein and the Philharmonic recorded the symphony in Boston for Columbia Records.

Joining the Party
The year 1960 marked another turning point in Shostakovich's life: he joined the Communist Party. The government wanted to appoint him Chairman of the RSFSR Union of Composers, but to hold that position he was required to obtain Party membership. It was understood that Nikita Khrushchev, the First Secretary of the Communist Party from 1953 to 1964, was looking for support from the intelligentsia's leading ranks in an effort to create a better relationship with the Soviet Union's artists. This event has variously been interpreted as a show of commitment, a mark of cowardice, the result of political pressure, and his free decision. On the one hand, the apparat was less repressive than it had been before Stalin's death. On the other, his son recalled that the event reduced Shostakovich to tears, and that he later told his wife Irina that he had been blackmailed. Lev Lebedinsky has said that the composer was suicidal. In 1960, he was appointed Chairman of the RSFSR Union of Composers; from 1962 until his death, he also served as a delegate in the Supreme Soviet of the USSR. By joining the party, Shostakovich also committed himself to finally writing the homage to Lenin that he had promised before. His Twelfth Symphony, which portrays the Bolshevik Revolution and was completed in 1961, was dedicated to Lenin and called "The Year 1917".

Shostakovich's musical response to these personal crises was the Eighth String Quartet, composed in only three days. He subtitled the piece "To the victims of fascism and war", ostensibly in memory of the Dresden fire bombing that took place in 1945. Yet like the Tenth Symphony, the quartet incorporates quotations from several of his past works and his musical monogram. Shostakovich confessed to his friend Isaac Glikman, "I started thinking that if some day I die, nobody is likely to write a work in memory of me, so I had better write one myself." Several of Shostakovich's colleagues, including Natalya Vovsi-Mikhoels and the cellist Valentin Berlinsky, were also aware of the Eighth Quartet's biographical intent. Peter J. Rabinowitz has also pointed to covert references to Richard Strauss's Metamorphosen in it.

In 1962, Shostakovich married for the third time, to Irina Supinskaya. In a letter to Glikman, he wrote, "her only defect is that she is 27 years old. In all other respects she is splendid: clever, cheerful, straightforward and very likeable." According to Galina Vishnevskaya, who knew the Shostakoviches well, this marriage was a very happy one: "It was with her that Dmitri Dmitriyevich finally came to know domestic peace... Surely, she prolonged his life by several years." In November, he conducted publicly for the only time in his life, leading a couple of his own works in Gorky; otherwise he declined to conduct, citing nerves and ill health.

That year saw Shostakovich again turn to the subject of anti-Semitism in his Thirteenth Symphony (subtitled Babi Yar). The symphony sets a number of poems by Yevgeny Yevtushenko, the first of which commemorates a massacre of Ukrainian Jews during the Second World War. Opinions are divided as to how great a risk this was: the poem had been published in Soviet media and was not banned, but it remained controversial. After the symphony's premiere, Yevtushenko was forced to add a stanza to his poem that said that Russians and Ukrainians had died alongside the Jews at Babi Yar.

In 1965, Shostakovich raised his voice in defence of poet Joseph Brodsky, who was sentenced to five years of exile and hard labor. Shostakovich co-signed protests with Yevtushenko, fellow Soviet artists Kornei Chukovsky, Anna Akhmatova, Samuil Marshak, and the French philosopher Jean-Paul Sartre. After the protests, the sentence was commuted, and Brodsky returned to Leningrad.

Later life
In 1964, Shostakovich composed the music for the Russian film Hamlet, which was favorably reviewed by The New York Times: "But the lack of this aural stimulation—of Shakespeare's eloquent words—is recompensed in some measure by a splendid and stirring musical score by Dmitri Shostakovich. This has great dignity and depth, and at times an appropriate wildness or becoming levity".

In later life, Shostakovich suffered from chronic ill health, but he resisted giving up cigarettes and vodka. Beginning in 1958, he suffered from a debilitating condition that particularly affected his right hand, eventually forcing him to give up piano playing; in 1965, it was diagnosed as poliomyelitis, but consensus on his diagnosis is unclear. He also suffered heart attacks in 1966, 1970, and 1971, as well as several falls in which he broke both his legs; in 1967, he wrote in a letter: "Target achieved so far: 75% (right leg broken, left leg broken, right hand defective). All I need to do now is wreck the left hand and then 100% of my extremities will be out of order."

A preoccupation with his own mortality permeates Shostakovich's later works, such as the later quartets and the Fourteenth Symphony of 1969 (a song cycle based on a number of poems on the theme of death). This piece also finds Shostakovich at his most extreme with musical language, with 12-tone themes and dense polyphony throughout. He dedicated the Fourteenth to his close friend Benjamin Britten, who conducted its Western premiere at the 1970 Aldeburgh Festival. The Fifteenth Symphony of 1971 is, by contrast, melodic and retrospective in nature, quoting Wagner, Rossini and the composer's own Fourth Symphony.

Death
Despite suffering from motor neurone disease (ALS) or some other neurological ailment from as early as the 1950s, Shostakovich insisted upon writing all his own correspondence and music himself, even when his right hand became virtually unusable. His last work was his Viola Sonata, which was first performed officially on 1 October 1975.

Shostakovich, a smoker since his youth, was forced to give up the habit after having his first heart attack in 1966. He was diagnosed with lung cancer in 1973. His death is variously attributed to lung cancer or heart failure.

Shostakovich died on 9 August 1975 at the Central Clinical Hospital in Moscow. A civic funeral was held; he was interred in Novodevichy Cemetery, Moscow.

Legacy
Shostakovich left behind several recordings of his own piano works; other noted interpreters of his music include Mstislav Rostropovich, Tatiana Nikolayeva, Maria Yudina, David Oistrakh, and members of the Beethoven Quartet.

Shostakovich's influence on later composers outside the former Soviet Union has been relatively slight. His influence can be seen in some Nordic composers, such as Lars-Erik Larsson.

The Shostakovich Peninsula on Alexander Island, Antarctica, is named for him.

Overview
Shostakovich's works are broadly tonal but with elements of atonality and chromaticism. In some of his later works (e.g., the Twelfth Quartet), he made use of tone rows. His output is dominated by his cycles of symphonies and string quartets, each totaling 15. The symphonies are distributed fairly evenly throughout his career, while the quartets are concentrated towards the latter part. Among the most popular are the Fifth and Seventh Symphonies and the Eighth and Fifteenth Quartets. Other works include operas, concertos, chamber music, and a large quantity of theatre and film music.

Shostakovich's music shows the influence of many of the composers he most admired: Bach in his fugues and passacaglias; Beethoven in the late quartets; Mahler in the symphonies; and Berg in his use of musical codes and quotations. Among Russian composers, he particularly admired Modest Mussorgsky, whose operas Boris Godunov and Khovanshchina he reorchestrated; Mussorgsky's influence is most prominent in the wintry scenes of Lady Macbeth and the Eleventh Symphony, as well as in satirical works such as "Rayok". Prokofiev's influence is most apparent in the earlier piano works, such as the first sonata and first concerto. The influence of Russian church and folk music is evident in his works for unaccompanied choir of the 1950s.

Shostakovich's relationship with Stravinsky was profoundly ambivalent; as he wrote to Glikman, "Stravinsky the composer I worship. Stravinsky the thinker I despise." He was particularly enamoured of the Symphony of Psalms, presenting a copy of his own piano version of it to Stravinsky when the latter visited the USSR in 1962. (The meeting of the two composers was not very successful; observers commented on Shostakovich's extreme nervousness and Stravinsky's "cruelty" to him.)

Many commentators have noted the disjunction between the experimental works before the 1936 denunciation and the more conservative ones that followed; the composer told Flora Litvinova, "without 'Party guidance' ... I would have displayed more brilliance, used more sarcasm, I could have revealed my ideas openly instead of having to resort to camouflage." Articles Shostakovich published in 1934 and 1935 cited Berg, Schoenberg, Krenek, Hindemith, "and especially Stravinsky" among his influences. Key works of the earlier period are the First Symphony, which combined the academicism of the conservatory with his progressive inclinations; The Nose ("The most uncompromisingly modernist of all his stage-works"); Lady Macbeth, which precipitated the denunciation; and the Fourth Symphony, described in Grove's Dictionary as "a colossal synthesis of Shostakovich's musical development to date". The Fourth was also the first piece in which Mahler's influence came to the fore, prefiguring the route Shostakovich took to secure his rehabilitation, while he himself admitted that the preceding two were his least successful.

After 1936, Shostakovich's music became more conservative. During this time he also composed more chamber music. While his chamber works were largely tonal, the late chamber works, which Grove's Dictionary calls a "world of purgatorial numbness", included tone rows, although he treated these thematically rather than serially. Vocal works are also a prominent feature of his late output.

Jewish themes
In the 1940s, Shostakovich began to show an interest in Jewish themes. He was intrigued by Jewish music's "ability to build a jolly melody on sad intonations". Examples of works that included Jewish themes are the Fourth String Quartet (1949), the First Violin Concerto (1948), and the Four Monologues on Pushkin Poems (1952), as well as the Piano Trio in E minor (1944). He was further inspired to write with Jewish themes when he examined Moisei Beregovski's 1944 thesis on Jewish folk music.

In 1948, Shostakovich acquired a book of Jewish folk songs, from which he composed the song cycle From Jewish Folk Poetry. He initially wrote eight songs meant to represent the hardships of being Jewish in the Soviet Union. To disguise this, he added three more meant to demonstrate the great life Jews had under the Soviet regime. Despite his efforts to hide the real meaning in the work, the Union of Composers refused to approve his music in 1949 under the pressure of the anti-Semitism that gripped the country. From Jewish Folk Poetry could not be performed until after Stalin's death in March 1953, along with all the other works that were forbidden.

Self-quotations
Throughout his compositions, Shostakovich demonstrated a controlled use of musical quotation. This stylistic choice had been common among earlier composers, but Shostakovich developed it into a defining characteristic of his music. Rather than quoting other composers, Shostakovich preferred to quote himself. Musicologists such as Sofia Moshevich, Ian McDonald, and Stephen Harris have connected his works through their quotations.

One example is the main theme of Katerina's aria, Seryozha, khoroshiy moy, from the fourth act of Lady Macbeth of the Mtsensk District. The aria's beauty comes as a breath of fresh air in the intense, overbearing tone of the scene, in which Katerina visits her lover Sergei in prison. The theme is made tragic when Sergei betrays her and finds a new lover upon blaming Katerina for his incarceration.

More than 25 years later, Shostakovich quoted this theme in his Eighth String Quartet. In the midst of this quartet's oppressive and somber themes, the cello introduces the Seryozha theme "in the 'bright' key of F-sharp major" about three minutes into the fourth movement. This theme emerges once again in his Fourteenth String Quartet. As in the Eighth Quartet, the cello introduces the theme, which here serves as a dedication to the cellist of the Beethoven String Quartet, Sergei Shirinsky.

Posthumous publications
In 2004, the musicologist Olga Digonskaya discovered a trove of Shostakovich manuscripts at the Glinka State Central Museum of Musical Culture in Moscow. In a cardboard file were some "300 pages of musical sketches, pieces and scores" in Shostakovich's hand. "A composer friend bribed Shostakovich's housemaid to regularly deliver the contents of Shostakovich's office waste bin to him, instead of taking it to the garbage. Some of those cast-offs eventually found their way into the Glinka. ... The Glinka archive 'contained a huge number of pieces and compositions which were completely unknown or could be traced quite indirectly,' Digonskaya said."

Among these were Shostakovich's piano and vocal sketches for a prologue to an opera, Orango (1932). They were orchestrated by the British composer Gerard McBurney and premiered in December 2011 by the Los Angeles Philharmonic conducted by Esa-Pekka Salonen.

Reputation
According to McBurney, opinion is divided on whether Shostakovich's music is "of visionary power and originality, as some maintain, or, as others think, derivative, trashy, empty and second-hand". William Walton, his British contemporary, described him as "the greatest composer of the 20th century". Musicologist David Fanning concludes in Grove's Dictionary that "Amid the conflicting pressures of official requirements, the mass suffering of his fellow countrymen, and his personal ideals of humanitarian and public service, he succeeded in forging a musical language of colossal emotional power."

Some modern composers have been critical. Pierre Boulez dismissed Shostakovich's music as "the second, or even third pressing of Mahler". The Romanian composer and Webern disciple Philip Gershkovich called Shostakovich "a hack in a trance". A related complaint is that Shostakovich's style is vulgar and strident: Stravinsky wrote of Lady Macbeth: "brutally hammering ... and monotonous". English composer and musicologist Robin Holloway described his music as "battleship-grey in melody and harmony, factory-functional in structure; in content all rhetoric and coercion".

In the 1980s, the Finnish conductor and composer Esa-Pekka Salonen was critical of Shostakovich and refused to conduct his music. For instance, he said in 1987:

"Shostakovich is in many ways a polar counter-force for Stravinsky. ... When I have said that the 7th symphony of Shostakovich is a dull and unpleasant composition, people have responded: 'Yes, yes, but think of the background of that symphony.' Such an attitude does no good to anyone."

Salonen has since performed and recorded several of Shostakovich's works, including leading the world premiere of Orango, but has dismissed the Fifth Symphony as "overrated", adding that he was "very suspicious of heroic things in general".

Shostakovich borrows extensively from the material and styles both of earlier composers and of popular music; the vulgarity of "low" music is a notable influence on this "greatest of eclectics". McBurney traces this to the avant-garde artistic circles of the early Soviet period in which Shostakovich moved early in his career, and argues that these borrowings were a deliberate technique to allow him to create "patterns of contrast, repetition, exaggeration" that gave his music large-scale structure.

Personality
Shostakovich was in many ways an obsessive man: according to his daughter he was "obsessed with cleanliness". He synchronised the clocks in his apartment and regularly sent himself cards to test how well the postal service was working. Elizabeth Wilson's Shostakovich: A Life Remembered indexes 26 references to his nervousness. Mikhail Druskin remembers that even as a young man the composer was "fragile and nervously agile". Yuri Lyubimov comments, "The fact that he was more vulnerable and receptive than other people was no doubt an important feature of his genius." In later life, Krzysztof Meyer recalled, "his face was a bag of tics and grimaces."

In Shostakovich's lighter moods, sport was one of his main recreations, although he preferred spectating or umpiring to participating (he was a qualified football referee). His favorite football club was Zenit Leningrad (now Zenit Saint Petersburg), which he would watch regularly. He also enjoyed card games, particularly patience.

Shostakovich was fond of satirical writers such as Gogol, Chekhov and Mikhail Zoshchenko. Zoshchenko's influence in particular is evident in his letters, which include wry parodies of Soviet officialese. Zoshchenko noted the contradictions in the composer's character: "he is ... frail, fragile, withdrawn, an infinitely direct, pure child ... [but also] hard, acid, extremely intelligent, strong perhaps, despotic and not altogether good-natured (although cerebrally good-natured)."

Shostakovich was diffident by nature: Flora Litvinova has said he was "completely incapable of saying 'No' to anybody." This meant he was easily persuaded to sign official statements, including a denunciation of Andrei Sakharov in 1973. His widow later told Helsingin Sanomat that his name was included without his permission. But he was willing to try to help constituents in his capacities as chairman of the Composers' Union and Deputy to the Supreme Soviet. Oleg Prokofiev said, "he tried to help so many people that ... less and less attention was paid to his pleas." When asked if he believed in God, Shostakovich said "No, and I am very sorry about it."

Orthodoxy and revisionism
Shostakovich's response to official criticism and whether he used music as a kind of covert dissidence is a matter of dispute. He outwardly conformed to government policies and positions, reading speeches and putting his name to articles expressing the government line. But it is evident he disliked many aspects of the regime, as confirmed by his family, his letters to Isaac Glikman, and the satirical cantata "Rayok", which ridiculed the "anti-formalist" campaign and was kept hidden until after his death. He was a close friend of Marshal of the Soviet Union Mikhail Tukhachevsky, who was executed in 1937 during the Great Purge.

It is also uncertain to what extent Shostakovich expressed his opposition to the state in his music. The revisionist view was put forth by Solomon Volkov in the 1979 book Testimony, which claimed to be Shostakovich's memoirs dictated to Volkov. The book alleged that many of the composer's works contained coded anti-government messages, placing Shostakovich in a tradition of Russian artists outwitting censorship that goes back at least to Alexander Pushkin. He incorporated many quotations and motifs in his work, most notably his musical signature DSCH. His longtime musical collaborator Yevgeny Mravinsky said, "Shostakovich very often explained his intentions with very specific images and connotations."

The revisionist perspective has subsequently been supported by his children, Maxim and Galina, although Maxim said in 1981 that Volkov's book was not his father's work. Volkov has further argued, both in Testimony and in Shostakovich and Stalin, that Shostakovich adopted the role of the yurodivy or holy fool in his relations with the government.

Maxim Shostakovich has also commented on Testimony and Volkov more favorably since 1991, when the Soviet regime fell. To Allan B. Ho and Dmitry Feofanov, he confirmed that his father had told him about "meeting a young man from Leningrad who knows his music extremely well" and that "Volkov did meet with Shostakovich to work on his reminiscences". Maxim has repeatedly said he is "a supporter both of Testimony and of Volkov." Other prominent revisionists are Ian MacDonald, whose book The New Shostakovich put forward further revisionist interpretations of his music, and Elizabeth Wilson, whose Shostakovich: A Life Remembered provides testimony from many of the composer's acquaintances.

Musicians and scholars including Laurel Fay and Richard Taruskin contested the authenticity and debate the significance of Testimony, alleging that Volkov compiled it from a combination of recycled articles, gossip, and possibly some information directly from the composer. Fay documents these allegations in her 2002 article "Volkov's Testimony reconsidered", showing that the only pages of the original Testimony manuscript that Shostakovich had signed and verified are word-for-word reproductions of earlier interviews he gave, none of which are controversial. Ho and Feofanov have countered that at least two of the signed pages contain controversial material: for instance, "on the first page of chapter 3, where [Shostakovich] notes that the plaque that reads 'In this house lived [Vsevolod] Meyerhold' should also say 'And in this house his wife was brutally murdered'."

Recorded legacy
In May 1958, during a visit to Paris, Shostakovich recorded his two piano concertos with André Cluytens, as well as some short piano works. These were issued on LP by EMI and later reissued on CD. Shostakovich recorded the two concertos in stereo in Moscow for Melodiya. Shostakovich also played the piano solos in recordings of the Cello Sonata, Op. 40 with cellist Daniil Shafran and also with Mstislav Rostropovich; the Violin Sonata, Op. 134, in a private recording made with violinist David Oistrakh; and the Piano Trio, Op. 67 with violinist David Oistrakh and cellist Miloš Sádlo. There is also a short newsreel of Shostakovich as soloist in a 1930s concert performance of the closing moments of his first piano concerto. A color film of Shostakovich supervising the Soviet revival of The Nose in 1974 was also made.

Awards
Soviet Union
 * Hero of Socialist Labour (1966)
 * Order of Lenin (1946, 1956, 1966)
 * Order of the October Revolution (1971)
 * Order of the Red Banner of Labour (1940)
 * People's Artist of the RSFSR (1948)
 * People's Artist of the USSR (1954)
 * International Peace Prize (1954)
 * Lenin Prize (1958 – for the Symphony No. 11 "The Year 1905")
 * Stalin Prize (1941 – for Piano Quintet; 1942 – for the Symphony No. 7; 1946 – for Piano Trio No. 2; 1950 – for Song of the Forests and the score for the film The Fall of Berlin; 1952 – for Ten Poems on Texts by Revolutionary Poets)
 * USSR State Prize (1968 – for the cantata The Execution of Stepan Razin for bass, chorus and orchestra)
 * Glinka State Prize of the RSFSR (1974 – for the String Quartet No. 14 and choral cycle Loyalty)
 * Shevchenko National Prize (1976, posthumous – for the opera Katerina Izmailova)

Academic titles
 * Member of the Royal Academy of Science, Letters and Fine Arts of Belgium (1960)

Other awards
 * Léonie Sonning Music Prize (1973)
 * Wihuri Sibelius Prize (1958)
 * Gold Medal of the Royal Philharmonic Society (1966)

In 1962, he was nominated for an Academy Award for Best Scoring of a Musical Picture for Khovanshchina (1959).

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Dmitri Shostakovich


text:
Doom (1993 video game)

Doom is a first-person shooter game developed and published by id Software. Released on December 10, 1993, for DOS, it is the first installment in the Doom franchise. The player assumes the role of a space marine, later unofficially referred to as Doomguy, fighting through hordes of undead humans and invading demons. The game begins on the moons of Mars and finishes in hell, with the player traversing each level to find its exit or defeat its final boss. It is an early example of 3D graphics in video games, and has enemies and objects as 2D images, a technique sometimes referred to as 2.5D graphics.

Doom was the third major independent release by id Software, after Commander Keen (1990–1991) and Wolfenstein 3D (1992). In May 1992, id started developing a darker game focused on fighting demons with technology, using a new 3D game engine from the lead programmer, John Carmack. The designer Tom Hall initially wrote a science fiction plot, but he and most of the story were removed from the project, with the final game featuring an action-heavy design by John Romero and Sandy Petersen. Id published Doom as a set of three episodes under the shareware model, marketing the full game by releasing the first episode free. A retail version with an additional episode was published in 1995 by GT Interactive as The Ultimate Doom.

Doom was a critical and commercial success, earning a reputation as one of the best and most influential video games of all time. It sold an estimated 3.5 million copies by 1999, and up to 20 million people are estimated to have played it within two years of launch. It has been termed the "father" of first-person shooters and is regarded as one of the most important games in the genre. It has been cited by video game historians as shifting the direction and public perception of the medium as a whole, as well as sparking the rise of online games and communities. It led to an array of imitators and clones, as well as a robust modding scene and the birth of speedrunning as a community. Its high level of graphic violence led to controversy from a range of groups. Doom has been ported to a variety of platforms both officially and unofficially and has been followed by several games in the series, including Doom II (1994), Doom 64 (1997), Doom 3 (2004), Doom (2016), Doom Eternal (2020), and Doom: The Dark Ages (2025), as well as the films Doom (2005) and Doom: Annihilation (2019).

Gameplay
Doom is a first-person shooter presented with 3D graphics. While the environment is shown in a 3D perspective, the enemies and objects are instead 2D sprites rendered at fixed angles, a technique sometimes referred to as 2.5D graphics or billboarding. In the single-player campaign mode, the player controls an unnamed space marine—later unofficially termed "Doomguy"—through military bases on the moons of Mars and in hell. To finish a level, the player must traverse through labyrinthine areas to reach a marked exit room. Levels are grouped into named episodes, with the final level of each focusing on a boss fight.

While traversing the levels, the player must fight a variety of enemies, including demons and possessed undead humans. Enemies often appear in large groups. The five difficulty levels adjust the number of enemies and amount of damage they do, with enemies moving and attacking faster than normal on the hardest difficulty setting. The monsters have simple behavior: they move toward their opponent if they see or hear them, and attack by biting, clawing, or using magic abilities such as fireballs.

The player must manage supplies of ammunition, health, and armor while traversing the levels. The player can find weapons and ammunition throughout the levels or can collect them from dead enemies, including a pistol, a chainsaw, a plasma rifle, and the BFG 9000. The player also encounters pits of toxic waste, ceilings that lower and crush objects, and locked doors requiring a collectable keycard or a remote switch. Power-ups include health or armor points, a mapping computer, partial invisibility, a radiation suit against toxic waste, invulnerability, or a super-strong melee berserker status. Cheat codes allow the player to unlock all weapons, walk through walls, or become invulnerable.

Two multiplayer modes are playable over a network: cooperative, in which two to four players team up to complete the main campaign, and deathmatch, in which two to four players compete to kill the other players' characters as many times as possible. Multiplayer was initially only playable over local networks, but a four-player online multiplayer mode was made available one year after launch through the DWANGO service.

Plot
Doom is divided into three episodes, each containing about nine levels: "Knee-Deep in the Dead", "The Shores of Hell", and "Inferno". A fourth episode, "Thy Flesh Consumed", was added in an expanded version, The Ultimate Doom, released two years after Doom. The campaign contains very few plot elements, with a minimal story presented mostly through the instruction manual and text descriptions between episodes.

In the future, an unnamed marine is posted to a dead-end assignment on Mars after assaulting a superior officer who ordered his unit to fire on civilians. The Union Aerospace Corporation, which operates radioactive waste facilities there, allows the military to conduct secret teleportation experiments that turn deadly. A base on Phobos urgently requests military support, while Deimos disappears entirely, and the marine joins a combat force to secure Phobos. He waits at the perimeter as ordered while the entire assault team is wiped out. With no way off the moon, and armed with only a pistol, he enters the base intent on revenge.

In "Knee-Deep in the Dead", the marine fights demons and possessed humans in the military and waste facilities on Phobos. The episode ends with the marine defeating two powerful Barons of Hell guarding a teleporter to the Deimos base. After the battle, the marine passes through the teleporter and is knocked unconscious by a horde of enemies, awakening with only a pistol. In "The Shores of Hell", the marine fights through corrupted research facilities on Deimos, culminating in the defeat of a gigantic cyberdemon. From an overlook, he discovers that the moon is floating above hell and rappels down to the surface. In "Inferno", the marine battles through hell itself and destroys a cybernetic spider-demon that masterminded the invasion of the moons. When a portal to Earth opens, the marine steps through to discover that Earth has been invaded. "Thy Flesh Consumed" follows the marine's initial assault on the Earth invaders, setting the stage for Doom II.

Concept
Id Software released Wolfenstein 3D in May 1992. Later called the "grandfather of 3D shooters", it established the genre's popularity and its reputation for fast action and technological advancement. When most of the studio began work on additional episodes for Wolfenstein, id co-founder and lead programmer John Carmack instead began technical research on a new game. Following the release of Wolfenstein 3D: Spear of Destiny in September 1992, the team began to plan their next game. They were tired of Wolfenstein and wanted to create another 3D game using a new engine Carmack was developing. Co-founder and lead designer Tom Hall proposed a new game in the Commander Keen series, but the team decided that the Keen platforming gameplay was a poor fit for Carmack's fast-paced 3D engines. Additionally, the other co-founders, designer John Romero and lead artist Adrian Carmack (no relation to John Carmack) wanted to create something in a darker style than the Keen games. John Carmack conceived a game about using technology to fight demons, inspired by the Dungeons & Dragons campaigns the team played, combining the styles of Evil Dead II and Aliens. The working title was Green and Pissed, but Carmack renamed it Doom based on a line from the 1986 film The Color of Money: What you got in there?' / 'In here? Doom.

The team agreed to pursue the Doom concept, and development began in November 1992. The initial development team was composed of five people: programmers John Carmack and Romero, artists Adrian Carmack and Kevin Cloud, and designer Hall. They moved operations to a dark office building, naming it "Suite 666" while drawing inspiration from the noises they heard from a neighboring dental practice. They also decided to cut ties with Apogee Software, their previous publisher, and self-publish Doom, as they felt that they were outgrowing the publisher and could make more money by self-publishing.

Design
In November, Hall delivered a design document that he called the "Doom Bible", detailing the project's plot, backstory, and design goals. His design was a science fiction horror concept wherein scientists on the Moon open a portal to an alien invasion. Over a series of levels, the player discovers that the aliens are demons while hell steadily infects the level design. John Carmack not only disliked the proposed story but dismissed the idea of having a story at all: "Story in a game is like story in a porn movie; it's expected to be there, but it's not that important." Rather than a deep story, he wanted to focus on technological innovation, dropping the levels and episodes of Wolfenstein in favor of a fast, continuous world. Hall disliked the idea, but the rest of the team sided with Carmack. Hall spent the next few weeks reworking the Doom Bible to work with Carmack's technological ideas. However, the team then realized that Carmack's vision for a seamless world would be impossible given the hardware limitations, and Hall was forced to rework the design document once again.

At the start of 1993, id put out a press release, touting Hall's story about fighting off demons while "knee-deep in the dead". The press release proclaimed the new 3D engine features that John Carmack had created, as well as aspects including multiplayer, that had not yet even been designed. Early versions were built to match the Doom Bible, and a "pre-alpha" version of the first level included Hall's introductory base scene. Initial versions also retained Wolfensteins arcade-style scoring, but this was later removed as it clashed with Dooms intended tone. The studio also experimented with other game systems before removing them, such as lives, an inventory, a secondary shield, and a complex user interface.

Soon, however, the Doom Bible as a whole was rejected. Romero wanted a game even "more brutal and fast" than Wolfenstein, which did not leave room for the character-driven plot Hall had created. Additionally, the team believed it emphasized realism over entertaining gameplay, and they did not see the need for a design document at all. Some ideas were retained, but the story was dropped and most of the design was removed. By early 1993, Hall created levels that became part of an internal demo. Carmack and Romero, however, rejected the military architecture of Hall's level design. Romero especially believed that the boxy, flat level designs failed to innovate on Wolfenstein, and failed to show off the engine's capabilities. He began to create his own, more abstract levels, which the rest of the team saw as a great improvement.

Hall was upset with the reception of his designs and how little impact he was having as the lead designer. He was also upset with how much he was having to fight with John Carmack to get what he saw as obvious gameplay improvements, such as flying enemies, and began to spend less time at work. The other developers, however, felt that Hall was not in sync with the team's vision and was becoming a problem. In July the other founders of id fired Hall, who went to work for Apogee. He was replaced by Sandy Petersen in September, ten weeks before the game was released. Petersen later recalled that John Carmack and Romero wanted to hire other artists instead, but Cloud and Adrian disagreed, saying that a designer was required to help build a cohesive gameplay experience. The team also added a third programmer, Dave Taylor.

Petersen and Romero designed the rest of Doom levels, with different aims: the team believed that Petersen's designs were more technically interesting and varied, while Romero's were more aesthetically interesting. In late 1993, a month before release, John Carmack began to add multiplayer. After the multiplayer component was coded, the development team began playing four-player games, which Romero termed "deathmatch", and Cloud named the act of killing other players "fragging". According to Romero, the deathmatch mode was inspired by fighting games such as Street Fighter II, Fatal Fury, and Art of Fighting.

Engine
Doom was written largely in the C programming language, with a few elements in assembly language. The developers used NeXT computers running the NeXTSTEP operating system. The level and graphical data was stored in WAD files, short for "Where's All the Data?", separately from the engine. This allowed for any part of the design to be changed without needing to adjust the engine code. Carmack designed this system so that fans could easily modify the game; he had been impressed by the modifications made by fans of Wolfenstein 3D and wanted to support that by releasing a map editor with an easily swappable file structure.

Unlike Wolfenstein, which has flat levels with walls at right angles, the Doom engine allows for walls and floors at any angle or height but does not allow areas to be stacked vertically. The lighting system is based on adjusting the color palette of surfaces directly. Rather than calculating how light traveled from light sources to surfaces using ray tracing, the game calculates the "light level" of a small area based on the predetermined brightness of said area. It then modifies the color palette of that section's surface textures to mimic how dark it would look. This same system is used to cause far away surfaces to look darker than close ones.

Romero came up with new ways to use Carmack's lighting engine, such as strobe lights. He programmed engine features such as switches and movable stairs and platforms. After Romero's complex level designs started to cause problems with the engine, Carmack began to use binary space partitioning to quickly select the reduced portion of a level that the player could see at a given time. Taylor, along with programming other features, added cheat codes to aid in development and left them in for players.

Art direction
Adrian Carmack was the lead artist for Doom, with Kevin Cloud as an additional artist. They designed the monsters to be "nightmarish", with graphics that were realistic and dark instead of staged or rendered. A mixed media approach was taken to create them. The artists sculpted models of some of the enemies and took pictures of them in stop motion from five to eight different angles so that they could be rotated realistically in-game. The images were then digitized and converted to 2D characters with a program written by John Carmack. Adrian Carmack made clay models for a few demons and had Gregor Punchatz build latex and metal sculptures of the others. The weapons were made from combined parts of children's toys. The developers photographed themselves as well, using Cloud's arm for the marine's arm holding a gun, and Adrian's snakeskin boots and wounded knee for textures. The cover art was created by Don Ivan Punchatz, Gregor Punchatz's father, who worked from a short description of the game rather than detailed references. Romero was the body model used for cover; he posed during a photoshoot to demonstrate to the intended model what the pose should look like, and Punchatz used his photo.

As with Wolfenstein 3D, id hired composer Bobby Prince to create the music and sound effects. Romero directed Prince to make the music in techno and metal styles. Many tracks were directly inspired by songs by metal bands such as Alice in Chains and Pantera. Prince believed that ambient music would be more appropriate and produced numerous tracks in both styles in hope of convincing the team, and Romero incorporated both. Prince did not make music for specific levels, as they were composed before the levels were completed. Instead, Romero assigned each track to each level late in development. Prince created the sound effects based on short descriptions or concept art of a monster or weapon and adjusted them to match the completed animations. The monster sounds were created from animal noises, and Prince designed all the sounds to be distinct on the limited sound hardware of the time, even when many sounds were playing at once. He also designed the sound effects to play on different frequencies from those used for the MIDI music, so they would clearly cut through the music.

Release
Id Software planned to self-publish Doom for DOS-based computers and set up a distribution system leading up to the release. Jay Wilbur, who had been hired as CEO and sole member of the business team, planned the marketing and distribution of Doom. As id would make the most money from copies they sold directly to customers—up to 85% of the planned US$40 price—he decided to leverage the shareware market as much as possible. He believed that the mainstream press was uninterested in the game and bought only a single ad in any gaming magazine. Instead, he gave software retailers the option to sell copies of the first Doom episode at any price, in hopes of motivating customers to buy the full game directly from id.

The team planned to release Doom in the third quarter of 1993 but ultimately needed more time. By December 1993, the team was working non-stop, with several employees sleeping at the office. Taylor said that the work gave him such a rush that he would pass out from the intensity. Id only gave a single press preview, to Computer Gaming World in June, to a glowing response, but had also released development updates to the public continuously throughout development on the nascent internet. Id began receiving calls from people interested in the game or angry that it had missed its planned release date, as anticipation built over the year. At midnight on December 10, 1993, after working for 30 straight hours testing, the development team at id uploaded the first episode to the internet, letting interested players distribute it for them. The team was unable to connect to the FTP server at the University of Wisconsin–Madison where they planned to upload the game, since there were so many users already connected in anticipation of the release. The network administrator was forced to first increase the number of connections, and then kick off all users to make room. When the upload finished 30 minutes later, 10,000 people attempted to download the game at once, crashing the university's network.

Within hours of Doom's release, university networks began banning Doom multiplayer games, as a rush of players overwhelmed their systems. The morning after release, John Carmack quickly released a patch in response to complaints of network congestion from administrators, who still needed to implement Doom-specific rules to keep their networks from crashing from the load.

Ports
In 1995, id created an expanded version of Doom for the retail market with a fourth episode of levels, which was published by GT Interactive as The Ultimate Doom. Doom has also been ported to numerous different platforms, independent from id Software. The first port of Doom was an unofficial port to Linux, released by id programmer Dave Taylor in 1994; it was hosted by id but not supported or made official. Microsoft attempted to hire id to port Doom to Windows in 1995 to promote Windows as a gaming platform, and Microsoft CEO Bill Gates briefly considered buying the company. When id declined, Microsoft made its own licensed port, with a team led by Gabe Newell. One promotional video for Windows 95 had Gates digitally superimposed into the game.

Other official ports of Doom were released for the 32X and Atari Jaguar in 1994, SNES and PlayStation in 1995, 3DO in 1996, Sega Saturn in 1997, Acorn Risc PC in 1998, Game Boy Advance in 2001, Xbox 360 in 2006, iOS in 2009, and Nintendo Switch, Xbox One, PlayStation 4, and Android in 2019. Some of these became bestsellers even many years after the initial release. The ports did not all have the same content, with some having fewer levels, such as the 32X port created by John Carmack, which was released with only two-thirds of the game's levels in order to meet the console's launch date, while the PlayStation port includes The Ultimate Doom and Doom II. The source code for Doom was released under a non-commercial license in 1997, and freely released under the GNU General Public License in 1999. Due to the release of its source code, Doom has been unofficially ported to numerous platforms. These ports include esoteric devices such as smart thermostats, pianos, and Doom itself, which led to variations of a long-running meme, "Can it run Doom?" and "It runs Doom".

Sales
Upon its release in December 1993, Doom became an "overnight phenomenon". It was an immediate financial success for id, making a profit within a day after release. Although the company estimated that only 1% of shareware downloaders bought the full game, this was enough to generate initial daily revenue of US$100,000, selling in one day what Wolfenstein had sold in one month. By May 1994, Wilbur said that the game had sold over 65,000 copies, and estimated that the shareware version had been distributed over 1 million times. In 1995, Wilbur estimated the first-year sales as 140,000, while in 2002 Petersen said it had sold around 200,000 copies in its first year.

By late 1995, Doom was estimated to be installed on more computers worldwide than Microsoft's new operating system, Windows 95. According to PC Data, by April 1998 Doom's shareware edition had yielded 1.36 million units sold and US$8.74 million in revenue in the United States. This led PC Data to declare it the country's 4th-best-selling computer game since 1993. The Ultimate Doom sold over 780,000 units by September 1999, and all versions combined sold 3.5 million copies by the end of 1999. In addition to sales, an estimated six million people played the shareware version by 2002; other sources estimated in 2000 that 10–20 million people played Doom within 24 months of its launch.

Reviews
Doom was highly praised in contemporaneous reviews. In April 1994, a few months after release, PC Gamer UK named it the third-best computer game of all time, claiming "Doom has already done more to establish the PC's arcade clout than any other title in gaming history," and PC Gamer US named it the best computer game of all time that August. It won the Best Action Adventure award at Cybermania '94. GamesRadar UK named Doom Game of the Year in 1993 shortly after release, and Computer Gaming World and PC Gamer UK did the same the year after.

Reviewers heavily praised the single-player gameplay: Electronic Entertainment called it "a skull-banging, palm-sweating, blood-pounding game", while The Age said it was "a technically superb and thrilling 3D adventure". PC Zone called it the best arcade game ever, and it and Computer Gaming World praised the variety of monsters and weapons. Computer Gaming World concluded that it was "a virtuoso performance". Other reviewers, while also praising the gameplay, commented on the lack of complexity: Computer and Video Games found it captivating and praised the variety and complexity of the level design, but called the overall gameplay repetitive, while Dragon similarly praised the fast gameplay and level design, but said that overall it lacked depth. Edge praised the graphics and levels but criticized the straightforward shooting gameplay. The review concluded: "If only you could talk to these creatures, then perhaps you could try and make friends with them, form alliances... Now, that would be interesting." The review attracted mockery and "if only you could talk to these creatures" became a running joke in video game culture. The multiplayer gameplay was praised: Computer Gaming World called it "the most intense gaming experience available", and Dragon called it "the biggest adrenaline rush available on computers". PC Zone named it as the best multiplayer game available, in addition to the best arcade game.

The 3D graphics and art style were praised by reviewers; Computer Gaming World called the graphics remarkable, while Edge said that it "made serious advances in what people will expect of 3D graphics in future", surpassing not only prior games but games that had yet to be released. Compute! and Electronic Games similarly called the graphics excellent and unlike any other game's. PC Zone, Dragon, Computer Gaming World, and Electronic Entertainment all praised the atmosphere and art direction, saying that the level design, lighting effects, and sound effects combined to create a "claustrophobic" and "nightmarish experience". Computer Gaming World also praised the music, as did The Mercury News, which called it as "ominous as the scenario".

Other versions
The Ultimate Doom received mixed reviews upon its release in 1995, as in the review from PC Zone, which gave it a score of 90/100 for new players but 20/100 for anyone who had the original game. The reviewer viewed it as solely a level pack due to the lack of new features and compared it negatively to the hundreds of free fan-made levels available on the internet. Joystick disliked the limited amount of additional content and recommended it only to major fans or those who had not played it. Fusion reviewed the edition positively, praising the difficulty of the new levels, as did GameSpot, which reviewed it from the perspective of introducing the game to new players.

The first ports of Doom received comparable reviews to the original PC version. VideoGames, GamePro, and Computer and Video Games all gave the Jaguar version high scores, comparing it favorably with the PC version. GamePro and Computer and Video Games also rated the 32X version highly, though they noted that the graphics were worse and the game shorter than the PC or Jaguar versions. The 1995 ports received mixed reviews. The PlayStation version was rated highly by HobbyConsolas, GamePro, and Maximum, which praised the inclusion of Doom II and extra levels, and favorably compared it to other PlayStation shooter games. The SNES version, however, was noted for weaker graphics and unresponsive controls, though reviewers such as Computer and Video Games, GamePro, and Next Generation were split on awarding high or middling scores due to these faults. Later 1990s ports received worse reviews; the 3DO port was panned by GamePro and Maximum for having worse graphics, a smaller screen size, and less intelligent enemies than any previous version, and the Sega Saturn port also met with low reviews for poor graphics and low quality from Mean Machines and Sega Saturn Magazine.

Legacy
Doom has been termed "inarguably the most important" first-person shooter, as well as the "father" of the genre. Although not the first in the genre, it was the game with the greatest impact. Dan Pinchbeck in Doom: Scarydarkfast (2013) noted the direct influence of Doom's design choices on those of first-person and third-person shooter games two decades later, as influenced by the games released in the intervening years.

Doom, and to a lesser extent Wolfenstein 3D, has been characterized as "mark[ing] a turning point" in the perception of video games in popular culture, with Doom and first-person shooters in general becoming the predominant perception of video games in media. Historians such as Tristan Donovan in Replay: The History of Video Games (2010) have termed it as causing a "paradigm shift", prompting the rise in popularity of 3D games, first-person shooters, licensed technology between developers, and support for game modifications. It helped spark the rise of both online multiplayer games and player-driven content generation, and popularized the business model of online distribution. In their book Dungeons & Dreamers: A Story of how Computer Games Created a Global Community in 2014, Brad King and John Borland claimed that Doom was one of the first widespread instances of an "online collective virtual reality", and did more than any other game to create a modern world of "networked games and gamers". PC Gamer proclaimed Doom the most influential game of all time in 2004, and in 2023 said its development was one of the most well-documented in the history of video games.

It has also been used in scholarly research since its release, including for machine learning, video game aesthetics and design, and the effects of video games on aggression, memory, and attention. In 2007 Doom was listed among the ten "game canon" video games selected for preservation by the Library of Congress,  and in 2015 The Strong National Museum of Play inducted Doom to its World Video Game Hall of Fame as part of its initial set of games.

Doom has continued to be included highly in lists of the best video games ever for nearly three decades since its release. In 1995, Next Generation said it was "the most talked about PC game ever". The PC version was ranked the 3rd best video game by Flux in 1995, and in 1996 was ranked fifth best and third most innovative by Computer Gaming World. In 2000, Doom was ranked as the second-best game ever by GameSpot. The following year, it was voted the number one game of all time in a poll among over 100 game developers and journalists conducted by GameSpy, and was ranked the sixth best game by Game Informer. GameTrailers ranked it the most "breakthrough PC game" in 2009 and Game Informer again ranked it the sixth-best game that same year. Doom has also been ranked among the best games of all time by GamesMaster, Hyper, The Independent, Entertainment Weekly, GamesTM, Jeuxvideo.com, Gamereactor, Time, Polygon, and The Times, among others, as recently as 2023.

Clones
The success of Doom led to dozens of new first-person shooter games. In 1998, PC Gamer declared it "probably the most imitated game of all time". These games were often referred to as "Doom clones", with "first-person shooter" only overtaking it as the name of the genre after a few years. As the "first-person shooter" genre label had not yet solidified at the time, Doom was described as a "first person perspective adventure" and "atmospheric 3-D action game".

Doom clones ranged from close imitators to more innovative takes on the genre. Id Software licensed the Doom engine to several other companies, which resulted in several games similar to Doom, including Heretic (1994), Hexen: Beyond Heretic (1995), and Strife: Quest for the Sigil (1996). A Doom-based game called Chex Quest was released in 1996 by Ralston Foods as a promotion to increase cereal sales. Other games were inspired by Doom, if not rumored to be built by reverse engineering the game's engine, including LucasArts's Star Wars: Dark Forces (1995). Several other games termed Doom clones, such as PowerSlave (1996) and Duke Nukem 3D (1996), used the 1995 Build engine, a 2.5D engine inspired by Doom created by Ken Silverman with some consultation with John Carmack.

Sequel and franchise
After completing Doom, id Software began working on a sequel using the same engine, Doom II, which was released to retail on October 10, 1994, ten months after the first game. GT Interactive had approached id before the release of Doom with plans to release a retail version of Doom and Doom II. Id chose to create the sequel as a set of episodes rather than a new game, allowing John Carmack and the other programmers to begin work on id's next game, Quake. Doom II was the United States' highest-selling software product of 1994 and sold more than 1.2 million copies within a year.

Doom II was followed by an expansion pack from id, Master Levels for Doom II (1995), consisting of 21 commissioned levels and over 3000 user-created levels for Doom and Doom II. Two sets of Doom II levels by different amateur map-making teams were released together by id as the standalone game Final Doom (1996). Doom and Doom II were both included, along with previous id games, in the id Anthology compilation (1996). The Doom franchise has continued since the 1990s in several iterations and forms. The video game series includes Doom 3 (2004), Doom (2016), and Doom Eternal (2020), along with other spin-off video games. It additionally includes multiple novels, a comic book, board games, and two films: Doom (2005) and Doom: Annihilation (2019).

Controversies
Doom was notorious for its high levels of graphic violence and satanic imagery, which generated controversy from a broad range of groups. Doom for the 32X was one of the first video games to be given a Mature 17+ rating from the Entertainment Software Rating Board due to its violent gore and nature, while Doom II was the first. In Germany, shortly after its publication, Doom was classified as "harmful to minors" by the Federal Department for Media Harmful to Young Persons and could not be sold to children or displayed where they could see it, which was only rescinded in 2011.

Doom again sparked controversy in the United States when it was found that Eric Harris and Dylan Klebold, who committed the Columbine High School massacre on April 20, 1999, were avid players. While planning for the massacre, Harris said in his journal that the killing would be "like playing Doom". A rumor spread afterward that Harris had designed a custom Doom level that looked like the high school, populated with representations of Harris's classmates and teachers, which he used to practice for the shooting. Although Harris did design several custom Doom levels, which later became known as the "Harris levels", none were based on the school. Doom was dubbed a "mass murder simulator" by critic and Killology Research Group founder David Grossman.

In the earliest release versions, the level E1M4: Command Control contains a swastika-shaped structure, which was put in as a homage to Wolfenstein 3D. The swastika was removed in later versions, out of respect for a military veteran's request, according to Romero.

Community
Doom's popularity and innovations attracted a community that has persisted for decades since. The deathmatch mode was an important factor in its popularity. Doom was the first game to coin the term "deathmatch" and introduced multiplayer shooting battles to a wide audience. This led to a widespread community of players who had never experienced fast-paced multiplayer combat before.

Another popular aspect of Doom was the versatility of its WAD files, enabling user-generated levels and other game modifications. John Carmack and Romero had strongly advocated for mod support, overriding other id employees who were concerned about commercial and legal implications. Although WAD files exposed the game data, id provided no instructions for how they worked. Still, players were able to modify leaked alpha versions of the game, allowing them to release level editors within weeks of the game's release.

On January 26, 1994, university student Brendon Wyber led a group to create the first full level editor, the Doom Editor Utility, leading to the first custom level by Jeff Bird in March. It was followed by "countless" others, including many based on other franchises like Aliens and Star Wars total conversion mods, as well as DeHackEd, a level editor first released in 1994 by Greg Lewis that allowed editing of the game engine. Soon after the first mods appeared, id CEO Wilbur posted legal terms to the company's website, allowing mod authors to charge money without any fees to id, while also absolving the company of responsibility or support.

Doom mods were widely popular, earning favorable comparisons to the official level additions seen in The Ultimate Doom. Thousands of user-created levels were released in the first few years after the release; over 3000 such levels for Doom and Doom II were included in the official retail release Master Levels for Doom II (1995). WizardWorks released multiple collections of mods of Doom and Doom II under the name D!Zone. At least one mod creator, Tim Willits, was later hired at id Software. Mods have continued to be produced, with the community Cacowards awarding the best of each year. In 2016, Romero created two new Doom levels: E1M4b ("Phobos Mission Control") and E1M8b ("Tech Gone Bad"). In 2018, for the 25th anniversary of Doom, Romero announced Sigil, an unofficial fifth episode containing nine levels. It was released on May 22, 2019, for €6.66 with a soundtrack by Buckethead, and then released again for free on May 31 with a soundtrack by James Paddock. A physical release was later produced. A sixth episode, Sigil II, was released on the game's 30th anniversary, December 10, 2023, again for €6.66 for a digital copy with a soundtrack by Valient Thorr, as well as physical editions on floppy disk.

In addition to WAD files, Doom includes a feature that allowed players to record and play back gameplay using files called demos, or game replays. Although the concept of speedrunning a video game existed before Doom, its release coincided with a wave of popularity for speedrunning, amplified by the online communities built on the nascent Internet. Demos were lightweight files that could be shared more easily than video files on internet bulletin board systems at the time. As a result, Doom is credited with creating the video game speedrunning community. The speedrunning community for Doom has continued for decades. As recently as 2019, community members have broken records originally set in 1998. Doom has been termed as having "one of the longest-running speedrunning communities" as well as being "the quintessential speedrunning game".

title: Doom (1993 video game)