Short answers, pulled from the story.
The People's Republic of Bulgaria existed from 1946 to 1990. It was formally established after a plebiscite in September 1946 abolished the monarchy, and it ended on the 15th of November 1990 when the Grand National Assembly renamed the country the Republic of Bulgaria.
Todor Zhivkov served as head of the Bulgarian Communist Party from 1954 and was elevated to Head of State under the 1971 constitution, making him the dominant leader for most of the republic's existence. He was removed from office in a party congress on the 10th of November 1989.
Bulgaria earned the nickname because of its involvement in computer construction. Bulgarian engineers developed the country's first computer, the Vitosha, and the Pravetz computer line, and Bulgaria became the only Balkan country to operate a supercomputer, an IBM Blue Gene/P.
Georgi Markov, a Bulgarian dissident writer, was killed in London in 1978 when a stranger drove the tip of an umbrella into his leg, injecting ricin. KGB documents later confirmed that the Bulgarian secret service and the KGB had jointly planned the operation.
In the winter of 1984 the Bulgarian government launched a forced assimilation campaign against the ethnic Turkish minority, banning the Turkish language and requiring Turks to adopt Bulgarian names. The 1989 expulsion of Turks caused a significant drop in agricultural production in southern Bulgaria due to the loss of around 300,000 workers.
According to official 1988 figures, every one of 100 Bulgarian households had a television set, 96 out of 100 had a refrigerator, 95 out of 100 had a radio, and 40 out of 100 had an automobile. Real wages from 1949 to 1989 rose by 195 percent, and the real average monthly pension increased by 868 percent over the same period.