Short answers, pulled from the story.
The abbreviation GULAG stands for Glávnoye upravléniye ispravítel'no-trudovýkh lageréy, which translates to Main Directorate of Correctional Labour Camps. The full official name of the agency changed several times during its existence.
The Gulag was officially established on the 25th of April 1930, as the GULAG by the OGPU order 130/63. It was renamed as the GULAG in November of that year.
A 1993 study of archival Soviet data estimates 1,053,829 people died in the Gulag from 1934 to 1953. The tentative historical consensus is that between 1.6 million and 1.76 million perished as a result of their detention.
One of the Gulag system founders was Naftaly Frenkel, who wrote a letter detailing a productivity improvement proposal known as nourishment scale. This system linked inmates food rations to their rate of production and caused countless casualties.
The Gulag system was officially abolished on the 25th of January 1960 when the remains of its administration were dissolved by Nikita Khrushchev. This occurred six years after Khrushchev was elected First Secretary.