- MS-DOS (/ˌɛmˌɛsˈdɒs/ em-es-DOSS; acronym for Microsoft Disk Operating System, also known as Microsoft DOS) is an operating system for x86-based personal computers mostly developed by Microsoft. Collectively, MS-DOS, its rebranding as IBM PC DOS, and a few operating systems attempting to be compatible with MS-DOS, are sometimes referred to as “DOS” (which is also the generic acronym for disk operating system). MS-DOS was the main operating system for IBM PC compatibles during the 1980s, from which point it was gradually superseded by operating systems offering a graphical user interface (GUI), in various generations of the graphical Microsoft Windows operating system.
- Pyotr Ilyich Tchaikovsky (Wikipedia)
Pyotr Ilyich Tchaikovsky (/tʃaɪˈkɒfski/ chy-KOF-skee; 7 May 1840 – 6 November 1893) was a Russian composer of the Romantic period. He was the first Russian composer whose music would make a lasting impression internationally. Tchaikovsky wrote some of the most popular concert and theatrical music in the current classical repertoire, including the ballets Swan Lake and The Nutcracker, the 1812 Overture, his First Piano Concerto, Violin Concerto, the Romeo and Juliet Overture-Fantasy, several symphonies, and the opera Eugene Onegin.