On two occasions, parades across the Republic of Ireland have been canceled from taking place on St Patrick´s Day, with both years involving health and safety reasons. In 2001, as a precaution to the foot-and-mouth outbreak, St Patrick´s Day celebrations were postponed to May
Mac OS X was originally presented as the tenth major version of Apple's operating system for Macintosh computers; current versions of macOS retain the major version number "10". Previous Macintosh operating systems (versions of the classic Mac OS) were named using Arabic numerals, as with Mac OS 8 and Mac OS 9. The letter "X" in Mac OS X's name refers to the number 10, a Roman numeral, and Apple has stated that it should be pronounced "ten" in this context. However, it is also commonly pronounced like the letter "X".
The consumer version of Mac OS X was launched in 2001 with Mac OS X 10.0. Reviews were variable, with extensive praise for its sophisticated, glossy Aqua interface, but criticizing it for sluggish performance. With Apple's popularity at a low, the makers of several classic Mac applications such as FrameMaker and PageMaker declined to develop new versions of their software for Mac OS X. Ars Technica columnist John Siracusa, who reviewed every major OS X release up to 10.10, described the early releases in retrospect as 'dog-slow, feature-poor' and Aqua as 'unbearably slow and a huge resource hog'.
At the World Championship Trials for the 2001 World Aquatics Championships, on March 30, Phelps broke the world record in the 200-meter butterfly to become, at 15 years and 9 months, the youngest male ever to set a world record in swimming.