The piano (Italian pronunciation: [ˈpjaːno]; an abbreviation of pianoforte [pjanoˈfɔrte]) is a musical instrument played using a keyboard. It is widely employed in classical, jazz, traditional and popular music for solo and ensemble performances, accompaniment, and for composing and rehearsal. Although the piano is not portable and often expensive, its versatility and ubiquity have made it one of the world's most familiar musical instruments.
An acoustic piano usually has a protective wooden case surrounding the soundboard and metal strings, and a row of 88 black and white keys (52 white, 36 black). The strings are sounded when the keys are pressed, and silenced when the keys are released. The note can be sustained, even when the keys are released, by the use of pedals.
Pressing a key on the piano's keyboard causes a padded (often with felt) hammer to strike strings. The hammer rebounds, and the strings continue to vibrate at their resonant frequency. These vibrations are transmitted through a bridge to a soundboard that amplifies by more efficiently coupling the acoustic energy to the air. When the key is released, a damper stops the strings' vibration, ending the sound. Although an acoustic piano has strings, it is usually classified as a percussion instrument because the strings are struck rather than plucked (as with a harpsichord or spinet); in the Hornbostel-Sachs system of instrument classification, pianos are considered chordophones. With technological advances, electric, electronic, and digital pianos have also been developed.
In music, dynamics are instructions in musical notation to the performer about hearing the loudness of a note or phrase. More generally, dynamics may also include other aspects of the execution of a given piece.
The two basic dynamic indications in music are:
More subtle degrees of loudness or softness are indicated by:
Beyond f and p, there are also
And so on.
Some pieces contain dynamic designations with more than three f's or p's. In Holst's The Planets, ffff occurs twice in Mars and once in Uranus often punctuated by organ and fff occurs several times throughout the work. It also appears in Heitor Villa-Lobos' Bachianas Brasileiras No. 4 (Prelude), and in Liszt's Fantasy and Fugue on the chorale "Ad nos, ad salutarem undam". The Norman Dello Joio Suite for Piano ends with a crescendo to a ffff, and Tchaikovsky indicated a bassoon solo pppppp in his Pathétique Symphony and ffff in passages of his 1812 Overture and the 2nd movement of his Fifth Symphony.
Piano, also released as Whisper Not, is an album by jazz pianist Wynton Kelly released on the Riverside label featuring performances by Kelly with Kenny Burrell, Paul Chambers, and Philly Joe Jones recorded in 1958.
The Allmusic review by Scott Yanow states "Kelly became a major influence on pianists of the 1960s and 1970s and one can hear the genesis of many other players in these swinging performances".
Environment variables are a set of dynamic named values that can affect the way running processes will behave on a computer.
They are part of the environment in which a process runs. For example, a running process can query the value of the TEMP environment variable to discover a suitable location to store temporary files, or the HOME or USERPROFILE variable to find the directory structure owned by the user running the process.
They were introduced in their modern form in 1979 with Version 7 Unix, so are included in all Unix operating system flavors and variants from that point onward including Linux and OS X. From PC DOS 2.0 in 1982, all succeeding Microsoft operating systems including Microsoft Windows, and OS/2 also have included them as a feature, although with somewhat different syntax, usage and standard variable names.
In all Unix and Unix-like systems, each process has its own separate set of environment variables. By default, when a process is created, it inherits a duplicate environment of its parent process, except for explicit changes made by the parent when it creates the child. At the API level, these changes must be done between running fork
and exec
. Alternatively, from command shells such as bash, a user can change environment variables for a particular command invocation by indirectly invoking it via env
or using the ENVIRONMENT_VARIABLE=VALUE <command>
notation. All Unix operating system flavors, DOS, and Windows have environment variables; however, they do not all use the same variable names. A running program can access the values of environment variables for configuration purposes.
In computing, CLS
(for clear screen) is a command used by the command line interpreters COMMAND.COM and CMD.EXE on DOS, OS/2 and Microsoft Windows operating systems to clear the screen or console window of commands and any output generated by them. It does not clear the user's history of commands, however. The command is also available in the DEC RT-11 operating system. In other environments, such as Linux and Unix, the same functionality is provided by the clear command.
While the ultimate origins of using the three-character string CLS as the command to clear the screen likely predate Microsoft's use, this command was present before its MS-DOS usage, in the embedded ROM BASIC dialects Microsoft wrote for early 8-bit microcomputers (such as TRS-80 Color BASIC), where it served the same purpose. The MS-DOS dialects of BASIC written by Microsoft, BASICA and GW-BASIC, also have the CLS command as a BASIC keyword - as do various non-Microsoft implementations of BASIC such as BBC BASIC found on the BBC Micro computers. The CLS command is also present in BASIC versions for Microsoft Windows, however this generally clears text printed on the form, rather than the whole screen or controls on the form.
CONFIG.SYS is the primary configuration file for the DOS and OS/2 operating systems. It is a special ASCII text file that contains user-accessible setup or configuration directives evaluated by the operating system during boot. CONFIG.SYS was introduced with DOS 2.0.
The directives in this file configure DOS for use with devices and applications in the system. The CONFIG.SYS directives also set up the memory managers in the system. After processing the CONFIG.SYS file, DOS proceeds to load and execute the command shell specified in the SHELL line of CONFIG.SYS, or COMMAND.COM if there is no such line. The command shell in turn is responsible for processing the AUTOEXEC.BAT file.
CONFIG.SYS is composed mostly of name=value directives which look like variable assignments. In fact, these will either define some tunable parameters often resulting in reservation of memory, or load files, mostly device drivers and TSRs, into memory.
In DOS, CONFIG.SYS is located in the root directory of the drive from which the system was booted.