EDVAC was one of the earliest electronic computers. Unlike its predecessor the ENIAC, it was binary rather than decimal, was designed to be a stored-program computer. ENIAC inventors John Mauchly and J. Presper Eckert proposed the EDVAC's construction in August 1944. A contract to build the new computer was signed in April 1946 with an initial budget of US$100,000. EDVAC was delivered to the Ballistics Research Laboratory in 1949; the Ballistic Research Laboratory became a part of the US Army Research Laboratory in 1942. Functionally, EDVAC was a binary serial computer with automatic addition, multiplication, programmed division and automatic checking with an ultrasonic serial memory capacity of 1,000 34-bit words. EDVAC's average addition time was 864 microseconds and its average multiplication time was 2,900 microseconds. ENIAC inventors John Mauchly and J. Presper Eckert proposed EDVAC's construction in August 1944, design work for EDVAC commenced before ENIAC was operational; the design would implement a number of important architectural and logical improvements conceived during the ENIAC's construction and would incorporate a high-speed serial-access memory.
Like the ENIAC, the EDVAC was built for the U. S. Army's Ballistics Research Laboratory at the Aberdeen Proving Ground by the University of Pennsylvania's Moore School of Electrical Engineering. Eckert and Mauchly and the other ENIAC designers were joined by John von Neumann in a consulting role. A contract to build the new computer was signed in April 1946 with an initial budget of US$100,000; the contract named the device the Electronic Discrete Variable Automatic Calculator. The final cost of EDVAC, was similar to the ENIAC's, at just under $500,000; the EDVAC was a binary serial computer with automatic addition, multiplication, programmed division and automatic checking with an ultrasonic serial memory capacity of 1,000 44-bit words. Physically, the computer comprised the following components: a magnetic tape reader-recorder a control unit with an oscilloscope a dispatcher unit to receive instructions from the control and memory and direct them to other units a computational unit to perform arithmetic operations on a pair of numbers at a time and send the result to memory after checking on a duplicate unit a timer a dual memory unit consisting of two sets of 64 mercury acoustic delay lines of eight words capacity on each line three temporary tanks each holding a single wordEDVAC's average addition time was 864 microseconds and its average multiplication time was 2,900 microseconds.
Time for an operation depended on memory access time, which varied depending on the memory address and the current point in the serial memory's recirculation cycle. The computer had 6,000 vacuum tubes and 12,000 diodes, consumed 56 kW of power, it weighed 17,300 pounds. The full complement of operating personnel was thirty people per eight-hour shift. John Von Neumann's famous EDVAC monograph, First Draft of a Report on the EDVAC, proposed the main enhancement to its design that embodied the principle "stored-program" concept that we now call the Von Neumann architecture; this was the storing of the program in the same memory as the data. The British computers EDSAC at Cambridge and the Manchester Baby were the first working computers that followed this design, and it has been followed by the great majority of all computers made since. Having the program and data in different memories is now called the Harvard architecture to distinguish it. EDVAC was delivered to the Ballistics Research Laboratory in 1949.
After a number of problems had been discovered and solved, the computer began operation in 1951 although only on a limited basis. In 1952 it was running over 7 hours a day. By 1957 EDVAC was running over 20 hours a day with error-free run time averaging 8 hours. EDVAC received a number of upgrades including punch-card I/O in 1954, extra memory in slower magnetic drum form in 1955, a floating-point arithmetic unit in 1958. EDVAC ran until 1962 when it was replaced by BRLESC. List of vacuum tube computers Moore School of Electrical Engineering. A Functional Description of the EDVAC: A Report of Development Work under Contract W36-034-ORD-7593 with the Ordnance Department, Department of the Army. Philadelphia: University of Pennsylvania. A complete technical description of EDVAC's original structure and operation in 1949. Viewable online. Oral history interview with J. Presper Eckert, Charles Babbage Institute, University of Minnesota. Oral history interview with Carl Chambers, Charles Babbage Institute, University of Minnesota.
Oral history interview with Irven A. Travis, Charles Babbage Institute, University of Minnesota. Oral history interview with S. Reid Warren, Charles Babbage Institute, University of Minnesota. Oral history interview with Frances E. Holberton, Charles Babbage Institute, University of Minnesota
The People's Commissariat for Internal Affairs, abbreviated NKVD, was the interior ministry of the Soviet Union. Established in 1917 as NKVD of Russian SFSR, the agency was tasked with conducting regular police work and overseeing the country's prisons and labor camps, it was disbanded in 1930, with its functions being dispersed among other agencies, only to be reinstated as an all-union ministry in 1934. The functions of the OGPU were transferred to the NKVD in 1934, giving it a monopoly over law enforcement activities that lasted until the end of World War II. During this period, the NKVD included both ordinary public order activities, as well as secret police activities; the NKVD is known for its role in political repression and for carrying out the Great Purge under Joseph Stalin. It was led by Nikolai Yezhov and Lavrentiy Beria; the NKVD undertook mass extrajudicial executions of untold numbers of citizens, conceived and administered the Gulag system of forced labour camps. Their agents were responsible for the repression of the wealthier peasantry, as well as the mass deportations of entire nationalities to uninhabited regions of the country.
They oversaw the protection of Soviet borders and espionage, enforced Soviet policy in communist movements and puppet governments in other countries, most notably the repression and massacres in Poland. In March 1946 all People's Commissariats were renamed to Ministries, the NKVD became the Ministry of Internal Affairs. After the Russian February Revolution of 1917, the Provisional Government dissolved the Tsarist police and set up the People's Militsiya; the subsequent Russian October Revolution of 1917 saw a seizure of state power led by Lenin and the Bolsheviks, who established a new Bolshevik regime, the Russian Soviet Federative Socialist Republic. The Provisional Government's Ministry of Internal Affairs under Georgy Lvov and under Nikolai Avksentiev and Alexei Nikitin, turned into NKVD under a People's Commissar. However, the NKVD apparatus was overwhelmed by duties inherited from MVD, such as the supervision of the local governments and firefighting, the Workers' and Peasants' Militsiya staffed by proletarians was inexperienced and unqualified.
Realizing that it was left with no capable security force, the Council of People's Commissars of the RSFSR established a secret political police, the Cheka, led by Felix Dzerzhinsky. It gained the right to undertake quick non-judicial trials and executions, if, deemed necessary in order to "protect the Russian Socialist-Communist revolution"; the Cheka was reorganized in 1922 as the State Political Directorate, or GPU, of the NKVD of the RSFSR. In 1922 the USSR formed, with the RSFSR as its largest member; the GPU became the OGPU, under the Council of People's Commissars of the USSR. The NKVD of the RSFSR retained control of the militsiya, various other responsibilities. In 1934 the NKVD of the RSFSR was transformed into an all-union security force, the NKVD, the OGPU was incorporated into the NKVD as the Main Directorate for State Security; as a result, the NKVD took over control of all detention facilities as well as the regular police. At various times, the NKVD had the following Chief Directorates, abbreviated as "ГУ"– Главное управление, Glavnoye upravleniye.
ГУГБ – государственной безопасности, of State Security ГУРКМ– рабоче-крестьянской милиции, of Workers and Peasants Militsiya ГУПВО– пограничной и внутренней охраны, of Border and Internal Guards ГУПО– пожарной охраны, of Firefighting Services ГУШосДор– шоссейных дорог, of Highways ГУЖД– железных дорог, of Railways ГУЛаг– Главное управление исправительно-трудовых лагерей и колоний, ГЭУ – экономическое, of Economics ГТУ – транспортное, of Transport ГУВПИ – военнопленных и интернированных, of POWs and interned persons Until the reorganization begun by Nikolai Yezhov with a purge of the regional political police in the autumn of 1936 and formalized by a May 1939 directive of the All-Union NKVD by which all appointments to the local political police were controlled from the center, there was frequent tension between centralized control of local units and the collusion of those units with local and regional party elements resulting in the thwarting of Moscow's plans. Following its establishment in 1934, the NKVD underwent many organizational changes.
During Yezhov's time in office, the Great Purge reached its height from the years 1937 and 1938 alone, at least 1.3 million were arrested and 681,692 were executed for'crimes against the state'. The Gulag population swelled by 685,201 under Yezhov, nearly tripling in size in just two years, with
ENIAC was the first electronic general-purpose computer. It was Turing-complete and able to solve "a large class of numerical problems" through reprogramming. Although ENIAC was designed and used to calculate artillery firing tables for the United States Army's Ballistic Research Laboratory, its first program was a study of the feasibility of the thermonuclear weapon. ENIAC was completed in 1945 and first put to work for practical purposes on December 10, 1945. ENIAC was formally dedicated at the University of Pennsylvania on February 15, 1946 and was heralded as a "Giant Brain" by the press, it had a speed on the order of one thousand times faster than that of electro-mechanical machines. The combination of speed and programmability allowed for thousands more calculations for problems, as ENIAC calculated a trajectory in 30 seconds that took a human 20 hours; the completed machine was announced to the public the evening of February 14, 1946 and formally dedicated the next day at the University of Pennsylvania, having cost $500,000.
It was formally accepted by the U. S. Army Ordnance Corps in July 1946. ENIAC was shut down on November 9, 1946 for a refurbishment and a memory upgrade, was transferred to Aberdeen Proving Ground, Maryland in 1947. There, on July 29, 1947, it was turned on and was in continuous operation until 11:45 p.m. on October 2, 1955. ENIAC's design and construction was financed by the United States Army, Ordnance Corps and Development Command, led by Major General Gladeon M. Barnes; the total cost was about $487,000, equivalent to $7,051,000 in 2018. The construction contract was signed on June 5, 1943. Herman H. Goldstine persuaded the Army to fund the project, which put him in charge to oversee it for them. ENIAC was designed by John Mauchly and J. Presper Eckert of the University of Pennsylvania, U. S; the team of design engineers assisting the development included Robert F. Shaw, Jeffrey Chuan Chu, Thomas Kite Sharpless, Frank Mural, Arthur Burks, Harry Huskey and Jack Davis. In 1946, the researchers resigned from the University of Pennsylvania and formed the Eckert-Mauchly Computer Corporation.
ENIAC was a modular computer, composed of individual panels to perform different functions. Twenty of these modules were accumulators that could not only add and subtract, but hold a ten-digit decimal number in memory. Numbers were passed between these units across several general-purpose buses. In order to achieve its high speed, the panels had to send and receive numbers, save the answer and trigger the next operation, all without any moving parts. Key to its versatility was the ability to branch. By the end of its operation in 1956, ENIAC contained 20,000 vacuum tubes, it weighed more than 30 short tons, was 2.4 m × 0.9 m × 30 m in size, occupied 167 m2 and consumed 150 kW of electricity. This power requirement led to the rumor that whenever the computer was switched on, lights in Philadelphia dimmed. Input was possible from an IBM card reader and an IBM card punch was used for output; these cards could be used to produce printed output offline using an IBM accounting machine, such as the IBM 405.
While ENIAC had no system to store memory in its inception, these punch cards could be used for external memory storage. In 1953, a 100-word magnetic-core memory built by the Burroughs Corporation was added to ENIAC. ENIAC used ten-position ring counters to store digits. Arithmetic was performed by "counting" pulses with the ring counters and generating carry pulses if the counter "wrapped around", the idea being to electronically emulate the operation of the digit wheels of a mechanical adding machine. ENIAC had 20 ten-digit signed accumulators, which used ten's complement representation and could perform 5,000 simple addition or subtraction operations between any of them and a source per second, it was possible to connect several accumulators to run so the peak speed of operation was much higher, due to parallel operation. It was possible to wire the carry of one accumulator into another accumulator to perform double precision arithmetic, but the accumulator carry circuit timing prevented the wiring of three or more for higher precision.
ENIAC used four of the accumulators to perform up to 385 multiplication operations per second. The other nine units in ENIAC were the initiating unit, the cycling unit, the master programmer, the reader, the printer, the constant transmitter, a
Eckert–Mauchly Computer Corporation
The Eckert–Mauchly Computer Corporation was founded by J. Presper Eckert and John Mauchly, it was incorporated on December 22, 1947. After building the ENIAC at the University of Pennsylvania and Mauchly formed EMCC to build new computer designs for commercial and military applications; the company was called the Electronic Control Company, changing its name to Eckert–Mauchly Computer Corporation when it was incorporated. In 1950, the company was sold to Remington Rand, which merged with Sperry Corporation to become Sperry Rand, survives today as Unisys. Before founding Eckert-Mauchly Computer Corporation, Mauchly researched the computing needs of potential clients. Over a period of six months in 1944 he kept detailed notes of his conversations. For instance, Mauchly met with United States Census Bureau official William Madow to discuss the computing equipment they desired; the Census Bureau was keen on reducing the number of punch cards it had to manage with each census. This meeting led to Madow making a trip to see ENIAC in person.
Mauchly met with Lt. Colonel Solomon Kullback, an official at the Army Signal Corps, to discuss codes and ciphers. Kullback said there was a need for many "more flexible" computers at his agency. Mauchly responded by analyzing EDVAC's potential encryption and decryption abilities. Eckert and Mauchly thus believed. By the spring of 1946, Eckert and Mauchly had procured a U. S. Army contract for the University of Pennsylvania and were designing the EDVAC – the successor machine to the ENIAC – at the university's Moore School of Electrical Engineering. However, new university policies that would have forced Eckert and Mauchly to sign over intellectual property rights for their inventions led to their resignation, which caused a lengthy delay in the EDVAC design efforts. After seeking to join IBM and John von Neumann's team at the Institute for Advanced Study in Princeton, New Jersey, they decided to start their own company in Philadelphia, Pennsylvania. Mauchly persuaded the United States Census Bureau to order an "EDVAC II" computer – a model, soon renamed UNIVAC – receiving a contract in 1948 that called for having the machine ready for the 1950 census.
Eckert hired a staff that included a number of the engineers from the Moore School, the company launched an ambitious program to design and manufacture large-scale computing machines. A major achievement was the use of magnetic tape for high-speed storage. During development Mauchly started a software department, they developed applications, starting with the world's first compiler for the language Short Code. EMCC received contracts for one UNIVAC machine each for the Army and Air Force; these contracts were canceled after the company was accused of having hired engineers with "Communistic leanings" during the McCarthy era. The company lost its clearance for government work. Company president and chief salesman Mauchly was banned from the company property, he challenged the accusations, but it took two years before a hearing allowed him to work at his company again. The programming to allow the UNIVAC I to be used in predicting the outcome of the 1952 Presidential election had to be done by Mauchly and University of Pennsylvania statistician Max Woodbury at Mauchly's home in Ambler, Pennsylvania.
Cash flow was poor and the UNIVAC would not be finished for quite some time, so EMCC decided to take on another project that would be done quickly. This was a small computer for the Northrop corporation. Original estimates for the development costs proved to be unrealistic, by the summer of 1948, EMCC had just about run out of money, but it was temporarily saved by Harry L. Straus, vice president of the American Totalisator Company, a Baltimore company that made electromechanical totalisators. Straus felt that EMCC's work, besides being promising in general terms, might have some application in the race track business, invested $500,000 in the company. Straus became chairman of the EMCC board, American Totalisator received 40 percent of the stock; when Straus was killed in an airplane crash in October 1949, American Totalisator's directors withdrew their support. BINAC was delivered in 1949, but Northrop complained that it never worked well for them, it was believed at EMCC that Northrop allowed BINAC to sit, disassembled, in their parking lot for a long time before any effort toward assembly was made.
As had happened with BINAC, EMCC's estimates of delivery dates and costs proved to be optimistic, the company was soon in financial difficulty again. In early 1950, the company was for sale. Remington Rand made the first offer, purchased EMCC on February 15, 1950, whereupon it became the UNIVAC division of Remington Rand; the first UNIVAC was not delivered until March 1951, over a year after EMCC was acquired by Remington Rand, too late to help much for the 1950 census. However, upon acceptance at the company premises, truck load after truck load of punched cards arrived to be recorded on tape for processing by UNIVAC; the US Census Bureau use
Radar is a detection system that uses radio waves to determine the range, angle, or velocity of objects. It can be used to detect aircraft, spacecraft, guided missiles, motor vehicles, weather formations, terrain. A radar system consists of a transmitter producing electromagnetic waves in the radio or microwaves domain, a transmitting antenna, a receiving antenna and a receiver and processor to determine properties of the object. Radio waves from the transmitter reflect off the object and return to the receiver, giving information about the object's location and speed. Radar was developed secretly for military use by several nations in the period before and during World War II. A key development was the cavity magnetron in the UK, which allowed the creation of small systems with sub-meter resolution; the term RADAR was coined in 1940 by the United States Navy as an acronym for RAdio Detection And Ranging The term radar has since entered English and other languages as a common noun, losing all capitalization.
The modern uses of radar are diverse, including air and terrestrial traffic control, radar astronomy, air-defense systems, antimissile systems, marine radars to locate landmarks and other ships, aircraft anticollision systems, ocean surveillance systems, outer space surveillance and rendezvous systems, meteorological precipitation monitoring and flight control systems, guided missile target locating systems, ground-penetrating radar for geological observations, range-controlled radar for public health surveillance. High tech radar systems are associated with digital signal processing, machine learning and are capable of extracting useful information from high noise levels. Radar is a key technology that the self-driving systems are designed to use, along with sonar and other sensors. Other systems similar to radar make use of other parts of the electromagnetic spectrum. One example is "lidar". With the emergence of driverless vehicles, Radar is expected to assist the automated platform to monitor its environment, thus preventing unwanted incidents.
As early as 1886, German physicist Heinrich Hertz showed that radio waves could be reflected from solid objects. In 1895, Alexander Popov, a physics instructor at the Imperial Russian Navy school in Kronstadt, developed an apparatus using a coherer tube for detecting distant lightning strikes; the next year, he added a spark-gap transmitter. In 1897, while testing this equipment for communicating between two ships in the Baltic Sea, he took note of an interference beat caused by the passage of a third vessel. In his report, Popov wrote that this phenomenon might be used for detecting objects, but he did nothing more with this observation; the German inventor Christian Hülsmeyer was the first to use radio waves to detect "the presence of distant metallic objects". In 1904, he demonstrated the feasibility of detecting a ship in dense fog, but not its distance from the transmitter, he obtained a patent for his detection device in April 1904 and a patent for a related amendment for estimating the distance to the ship.
He got a British patent on September 23, 1904 for a full radar system, that he called a telemobiloscope. It operated on a 50 cm wavelength and the pulsed radar signal was created via a spark-gap, his system used the classic antenna setup of horn antenna with parabolic reflector and was presented to German military officials in practical tests in Cologne and Rotterdam harbour but was rejected. In 1915, Robert Watson-Watt used radio technology to provide advance warning to airmen and during the 1920s went on to lead the U. K. research establishment to make many advances using radio techniques, including the probing of the ionosphere and the detection of lightning at long distances. Through his lightning experiments, Watson-Watt became an expert on the use of radio direction finding before turning his inquiry to shortwave transmission. Requiring a suitable receiver for such studies, he told the "new boy" Arnold Frederic Wilkins to conduct an extensive review of available shortwave units. Wilkins would select a General Post Office model after noting its manual's description of a "fading" effect when aircraft flew overhead.
Across the Atlantic in 1922, after placing a transmitter and receiver on opposite sides of the Potomac River, U. S. Navy researchers A. Hoyt Taylor and Leo C. Young discovered that ships passing through the beam path caused the received signal to fade in and out. Taylor submitted a report, suggesting that this phenomenon might be used to detect the presence of ships in low visibility, but the Navy did not continue the work. Eight years Lawrence A. Hyland at the Naval Research Laboratory observed similar fading effects from passing aircraft. Before the Second World War, researchers in the United Kingdom, Germany, Japan, the Netherlands, the Soviet Union, the United States, independently and in great secrecy, developed technologies that led to the modern version of radar. Australia, New Zealand, South Africa followed prewar Great Britain's radar development, Hungary generated its radar technology during the war. In France in 1934, following systematic studies on the split-anode magnetron, the research branch of the Compagnie Générale de Télégraphie Sans Fil headed by Maurice Ponte with Henri Gutton, Sylvain Berline and M. Hugon, began developing an obstacle-locatin
The Venona project was a United States counterintelligence program initiated during World War II by the United States Army's Signal Intelligence Service. It was intended to decrypt messages transmitted by the intelligence agencies of the Soviet Union. Initiated when the Soviet Union was an ally of the US, the program continued during the Cold War, when it was considered an enemy. During the 37-year duration of the Venona project, the Signal Intelligence Service obtained 3,000 Soviet messages; the signals intelligence yield included discovery of the Cambridge Five espionage ring in the UK and Soviet espionage of the Manhattan Project in the U. S.. The espionage was undertaken to support the Soviet atomic bomb project; the Venona project remained secret for more than 15 years. Some of the decoded Soviet messages were not declassified by the United States and published until 1995. During World War II and the early years of the Cold War, the Venona project was a source of information on Soviet intelligence-gathering directed at the Western military powers.
Although unknown to the public, to Presidents Franklin D. Roosevelt and Harry S. Truman, these programs were of importance concerning crucial events of the early Cold War; these included the Julius and Ethel Rosenberg spying case and the defections of Donald Maclean and Guy Burgess to the Soviet Union. Most decipherable messages were transmitted and intercepted between 1942 and 1945, during World War II, when the Soviet Union was an ally of the US. Sometime in 1945, the existence of the Venona program was revealed to the Soviet Union by cryptologist-analyst Bill Weisband, an NKVD agent in the U. S. Army's SIGINT; these messages were and decrypted beginning in 1946. This effort continued through 1980; the analyst effort assigned to it was moved to more important projects. To what extent the various individuals referred to in the messages were involved with Soviet intelligence is a topic of historical dispute. While a number of academics and historians assert that most of the individuals mentioned in the Venona decrypts were most either clandestine assets and/or contacts of Soviet intelligence agents, others argue that many of those people had no malicious intentions and committed no crimes.
The Venona Project was initiated on February 1, 1943, by Gene Grabeel, an American mathematician and cryptanalyst, under orders from Colonel Carter W. Clarke, Chief of Special Branch of the Military Intelligence Service at that time. Clarke distrusted Joseph Stalin, feared that the Soviet Union would sign a separate peace with Nazi Germany, allowing Germany to focus its military forces against the United Kingdom and the United States. Cryptanalysts of the U. S. Army's Signal Intelligence Service at Arlington Hall analyzed encrypted high-level Soviet diplomatic intelligence messages intercepted in large volumes during and after World War II by American and Australian listening posts; this message traffic, encrypted with a one-time pad system, was stored and analyzed in relative secrecy by hundreds of cryptanalysts over a 40-year period starting in the early 1940s. When used the one-time pad encryption system, used for all the most-secret military and diplomatic communication since the 1930s, is unbreakable.
However, due to a serious blunder on the part of the Soviets, some of this traffic was vulnerable to cryptanalysis. The Soviet company that manufactured the one-time pads produced around 35,000 pages of duplicate key numbers, as a result of pressures brought about by the German advance on Moscow during World War II; the duplication—which undermines the security of a one-time system—was discovered and attempts to lessen its impact were made by sending the duplicates to separated users. Despite this, the reuse was detected by cryptanalysts in the US; the Soviet systems in general used a code to convert words and letters into numbers, to which additive keys were added, encrypting the content. When used so that the plain text is of a length equal to or less than that of a random key, one-time pad encryption is unbreakable. However, cryptanalysis by American code-breakers revealed that some of the one-time pad material had incorrectly been reused by the Soviets, which allowed decryption of a small part of the traffic.
Generating the one-time pads was a slow and labor-intensive process, the outbreak of war with Germany in June 1941 caused a sudden increase in the need for coded messages. It is probable that the Soviet code generators started duplicating cipher pages in order to keep up with demand, it was Arlington Hall's Lieutenant Richard Hallock, working on Soviet "Trade" traffic, who first discovered that the Soviets were reusing pages. Hallock and his colleagues, amongst whom were Genevieve Feinstein, Cecil Phillips, Frank Lewis, Frank Wanat, Lucille Campbell, went on to break into a significant amount of Trade traffic, recovering many one-time pad additive key tables in the process. A young Meredith Gardner used this material to break into what turned out to be NKVD traffic by reconstructing the code used to convert text to numbers. Samuel Chew and Cecil Phillips made valuable contributions. On 20 December 1946, Gardn
Nazi Germany is the common English name for Germany between 1933 and 1945, when Adolf Hitler and his Nazi Party controlled the country through a dictatorship. Under Hitler's rule, Germany was transformed into a totalitarian state that controlled nearly all aspects of life via the Gleichschaltung legal process; the official name of the state was Deutsches Reich until 1943 and Großdeutsches Reich from 1943 to 1945. Nazi Germany is known as the Third Reich, meaning "Third Realm" or "Third Empire", the first two being the Holy Roman Empire and the German Empire; the Nazi regime ended. Hitler was appointed Chancellor of Germany by the President of the Weimar Republic, Paul von Hindenburg, on 30 January 1933; the NSDAP began to eliminate all political opposition and consolidate its power. Hindenburg died on 2 August 1934 and Hitler became dictator of Germany by merging the offices and powers of the Chancellery and Presidency. A national referendum held 19 August 1934 confirmed Hitler as sole Führer of Germany.
All power was centralised in Hitler's person and his word became the highest law. The government was not a coordinated, co-operating body, but a collection of factions struggling for power and Hitler's favour. In the midst of the Great Depression, the Nazis restored economic stability and ended mass unemployment using heavy military spending and a mixed economy. Extensive public works were undertaken, including the construction of Autobahnen; the return to economic stability boosted the regime's popularity. Racism antisemitism, was a central feature of the regime; the Germanic peoples were considered by the Nazis to be the master race, the purest branch of the Aryan race. Discrimination and persecution against Jews and Romani people began in earnest after the seizure of power; the first concentration camps were established in March 1933. Jews and others deemed undesirable were imprisoned, liberals and communists were killed, imprisoned, or exiled. Christian churches and citizens that opposed Hitler's rule were oppressed, many leaders imprisoned.
Education focused on racial biology, population policy, fitness for military service. Career and educational opportunities for women were curtailed. Recreation and tourism were organised via the Strength Through Joy program, the 1936 Summer Olympics showcased Germany on the international stage. Propaganda Minister Joseph Goebbels made effective use of film, mass rallies, Hitler's hypnotic oratory to influence public opinion; the government controlled artistic expression, promoting specific art forms and banning or discouraging others. The Nazi regime dominated neighbours through military threats in the years leading up to war. Nazi Germany made aggressive territorial demands, threatening war if these were not met, it seized Austria and Czechoslovakia in 1938 and 1939. Germany signed a non-aggression pact with the USSR, invaded Poland on 1 September 1939, launching World War II in Europe. By early 1941, Germany controlled much of Europe. Reichskommissariats took control of conquered areas and a German administration was established in the remainder of Poland.
Germany exploited labour of both its occupied territories and its allies. In the Holocaust, millions of Jews and other peoples deemed undesirable by the state were imprisoned, murdered in Nazi concentration camps and extermination camps, or shot. While the German invasion of the Soviet Union in 1941 was successful, the Soviet resurgence and entry of the US into the war meant the Wehrmacht lost the initiative on the Eastern Front in 1943 and by late 1944 had been pushed back to the pre-1939 border. Large-scale aerial bombing of Germany escalated in 1944 and the Axis powers were driven back in Eastern and Southern Europe. After the Allied invasion of France, Germany was conquered by the Soviet Union from the east and the other Allies from the west, capitulated in May 1945. Hitler's refusal to admit defeat led to massive destruction of German infrastructure and additional war-related deaths in the closing months of the war; the victorious Allies initiated a policy of denazification and put many of the surviving Nazi leadership on trial for war crimes at the Nuremberg trials.
The official name of the state was Deutsches Reich from 1933 to 1943 and Großdeutsches Reich from 1943 to 1945, while common English terms are "Nazi Germany" and "Third Reich". The latter, adopted by Nazi propaganda as Drittes Reich, was first used in Das Dritte Reich, a 1923 book by Arthur Moeller van den Bruck; the book counted the Holy Roman Empire as the German Empire as the second. Germany was known as the Weimar Republic during the years 1919 to 1933, it was a republic with a semi-presidential system. The Weimar Republic faced numerous problems, including hyperinflation, political extremism, contentious relationships with the Allied victors of World War I, a series of failed attempts at coalition government by divided political parties. Severe setbacks to the German economy began after World War I ended because of reparations payments required under the 1919 Treaty of Versailles; the government printed money to make the payments and to repay the country's war debt, but the resulting hyperinflation led to inflated prices for consumer goods, economic chaos, food riots.
When the government defaulted on their reparations payments in January 1923, French troops occupied German industrial areas along the Ruhr and widespread civil unrest followed. The National Socialist German Workers' Party (National