Encyclopedia of Computer Science and Technology

service-oriented architecture 425Seniors and the InternetAccording to research by the Pew Internet & AmericanLife Project, for seniors who do go online, e-mail is themost popular activity (and something shared with otherage groups). While teens are most prolific at adopting newtechnologies such as instant messaging, content sharing,and social networking, older users are less likely to adoptemerging services, but more likely to bank or make travelreservations online—perhaps reflecting their having moremoney for leisure travel. Older people also tend to be moreavid in pursuing health information. On the other hand,buying things online seems to be equally popular with allage groups.Computer technology can also assist seniors with theactivities of daily life. At the Quality of Life TechnologiesCenter, researchers from Pitt and Carnegie Mellon Universitiesare developing technologies including:• robotic wheelchairs with arms that can manipulateobjects and even assist in cooking meals• systems to help people get out of bed, dress, bathe,and so on• pervasive sensor networks that can monitor personsas they move around• monitoring systems that can detect growing confusionor cognitive impairment and call for help• systems to supervise daily activities and make suremedications are taken on time• “coaching” software that can help maintain memoryand cognitive skills, even in persons with Alzheimer’sdisease(See disabled persons and computing.)Further Reading“Abby & Me.” Available online. URL: http://www.abbyandme.com.Accessed November 14, 2007.Fox, Susannah, and Mary Madden. “Are ‘Wired Seniors’ SittingDucks?” Pew Internet & American Life Project, April 2006.Available online. URL: http://www.pewinternet.org/pdfs/PIP_Wired_Senior_2006_Memo.pdf. Accessed November 14,2007.———. “Generations Online.” Pew Internet & American LifeProject, December 2005. Available online. URL: http://www.pewinternet.org/pdfs/PIP_Generations_Memo.pdf. AccessedNovember 13, 2007.Rolstein, Gary. “Robotic Aids for the Disabled and Elderly.” PittsburghPost-Gazette, November 14, 2007. Available online.URL: http://www.post-gazette.com/pg/07318/833537-114.stm.Accessed November 14, 2007.Stokes, Abby. It’s Never Too Late to Love a Computer: Everything YouNeed to Know to Plug In, Boot Up and Get Online. Revised ed.New York: Workman Publishing, 2005.Stuur, Addo. Internet and E-mail for Seniors with Windows Vista.Visual Steps Publishing, 2006.serial portThere are basically two ways to move data from a computerto or from a peripheral device such as a printer or modem.A byte (8 bits) of data can be moved all at once, with eachbit traveling along its own wire (see parallel port). Alternatively,a single wire can be used to carry the data one bitat a time. Such a connection is called a serial port.The serial port receives data a full byte at a time fromthe computer bus and uses a UART (Universal AsynchronousReceiver-Transmitter) to extract the bits one at a timeand send them through the port. A corresponding circuitat the other end accumulates the incoming bits and reassemblesthem into data bytes.The data bits for each byte are preceded by a start-bit tosignal the beginning of the data and terminated by an stopbit.Depending on the application, an additional bit may beused for parity (see error correction). Devices connectedby a serial port must “negotiate” by requesting a particularconnection speed and parity setting. Failure to agree resultsin gibberish being received.The official standard for serial transmission is called RS-232C. It defines various additional pins to which wires areconnected, such as for synchronization (specifying whenthe device is ready to send or receive data) and ground.Physically, the old-style connectors are called DB-25because they contain 25 pins (many of which are not used).Most newer PCs have DB-9 (i.e. nine pin) connectors. A“gender changer” can be used in cases where two devicesboth have male connectors (with pins) or female connectors(with corresponding sockets).Because they use a single data transmission line andinclude error-correction, serial cables can be longer thanparallel cables (25 feet or more, as opposed to 10–12 feet).Serial transmission is generally slower (at up to 115,200bits/second) than parallel transmission. Serial connectionshave generally been used for such devices as modems(whose speed is already limited by phone line characteristics),keyboards, mice, and some older printers. Today thefaster and more flexible USB (see universal series bus)is replacing serial connections for many devices includingeven keyboards.Further ReadingPeacock, Craig. “Interfacing the Serial / RS232 Port.” Availableonline. URL: http://www.beyondlogic.org/serial/serial.htm.Accessed August 21, 2007.Tyson, Jeff. “How Serial Ports Work.” Available online. URL: http://computer.howstuffworks.com/serial-port.htm. Accessed August21, 2007.service-oriented architecture (SOA)The traditional model for organizing information processing,particularly in large installations, is in terms of installingand maintaining large applications that each providemany functions, and then devising ways for the applicationsto exchange data and otherwise coordinate with each other.As the information environment has become more complex(particularly with regard to databases and Web-relatedservices), this approach has become more cumbersome, lessflexible, and harder to maintain.