An instrument used for writing with ink, formerly made of a reed, or of the quill of a goose or other bird, but now also of other materials, as of steel, gold, etc. Also, originally, a stylus or other instrument for scratching or graving.
Three basic kinds of pen were used before the 20th century: quill, reed, and metal nib. Most old master drawings with pen are in quill pen, an instrument made from the scraped and cut feathers of birds. Reed pen, made from hollow reed grass, is much less common and produces a shorter, blunter stroke than the more durable and versatile quill. Metal nib pens were not widely used until the 1800s, when advanced techniques for manipulating steel were available.
Most swine are grouped together in pens, whether kept in a shelter or in a fenced open lot. The number of animals penned together may be less than 10 to several hundred, but is normally between 15 and 30.
polyethylene naphthalate: a high performance thermoplastic polyester. The synthesis of PEN is analogous to that of conventional polyester (polyethylene terephthalate or PET). Its modulus is claimed to be five times that of nylon, 2.5 times t
Pen is a load balancer for "simple" TCP-based protocols such as HTTP or SMTP. It allows several servers to appear as one to the outside. It automatically detects servers that are down and distributes clients among the available servers. This gives high availability and scalable performance.