Encyclopedia of Computer Science and Technology

198 flash and smart mobs(or even programs) are being run at the same time, the situationgets even more complicated and a semaphore that canbe controlled by one process at a time is more appropriate(see concurrent programming). However, a main programthat sets a flag to indicate the program mode and doesnot allow the flag to be changed by routines within the programis relatively safe.Flags can also have more than two valid conditions,such as for specifying a number of possible states for a fileor device. This usage is found mostly in operating systems.Further Reading“C++ I/O Flags.” Available online: URL: http://www-control.eng.cam.ac.uk/~pcr20/www.cppreference.com/cppio_flags.html.Accessed August 4, 2007.“Class Flags” [Java]. Available online. URL: http://java.sun.com/j2ee/sdk_1.3/techdocs/api/javax/mail/Flags.html. AccessedAugust 4, 2007.Myers, Gene. “Becoming Bit Wise.” C-Scene Issue 09. Availableonline. URL: http://www.gmonline.demon.co.uk/cscene/cs9/cs9-02.html. Accessed April 28, 2008.Vincent, Alan. “Flag Variables, Validation and Function Control.”Available online. URL: http://wsabstract.com/javatutors/valid1.shtml. Accessed February 4, 2008.flash and smart mobsA flash mob is a spontaneously organized public gatheringfacilitated by ubiquitous mobile communications (see especiallytexting and instant messaging). The earliest flashmobs were a mixture of whimsy and social experiment. Thefirst reported example, coordinated by Bill Wasik, senioreditor of Harper’s Magazine, occurred in June 2003 whena hundred people suddenly showed up on the ninth floorof Macy’s in New York City, claiming to be shopping for a“love rug.”Smart MobsSmart mobs are similar in organization to flash mobs buttend to be more purposeful and enduring forms of socialorganization. The phenomenon was first described by HowardRheingold in his book Smart Mobs: The Next SocialRevolution (see Rheingold, Howard). Rheingold describesseveral examples of smart mobs, including teenage “thumbtribes” in Tokyo and Helsinki, Finland (named for their useof tiny thumb-operated keyboards on cell phones). Theirtypical activities included organizing impromptu raves orconverging on rock stars or other celebrities.Smart mobs took on a more political bent in 1999 withspontaneously organized, fast-moving antiglobalizationprotests in Seattle. Police had considerable difficulty containingthe protests, their communications and coordinationcapabilities not being equal to the task.Another political smart mob occurred in 2001 whenprotesters in the Philippines used text messaging to organizedemonstrations against the government of PresidentJoseph Estrada. The protests grew rapidly, and Estrada wassoon forced from office (see political activism and theInternet). Smart mob techniques were also used startingin 2003 to coordinate protests against the Iraq War. Aswireless communication continues to become ubiquitous,aspects of smart mob organization can be expected to turnup in future mass movements.Even as the term has faded from public use, flash mobshave continued to flourish, appealing to a desire to have funwhile striking out against an overly regimented consumersociety. The term urban playground movement has also beenused for the promotion of such gatherings.Further ReadingBerton Justin. “Flash Mob 2.0: Urban Playground MovementInvites Participation.” San Francisco Chronicle, November 10,2007. Available online. URL: http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2007/11/10/MNMVT8UM9.DTL. AccessedApril 23, 2008.“Howard Rheingold: Smart Mobs.” Edge, July 16, 2002. Availableonline. URL: http://www.edge.org/3rd_culture/rheingold/rheingold_print.html. Accessed September 21, 2007.Packer, George. “Smart-Mobbing the War.” New York Times, March9, 2003. Available online. URL: http://query.nytimes.com/gst/fullpage.html?res=9D02E5D61F3CF93AA35750C0A9659C8B63. Accessed September 21, 2007.Rheingold, Howard. Smart Mobs: The Next Social Revolution. Cambridge,Mass.: Basic Books, 2002.———. Smart Mobs Web site. Available online. URL: http.://www.smartmobs.com/. Accessed September 21, 2007.Schwartz, John. “New Economy: In the Tech Meccas, Massesof People, or ‘Smart Mobs,’ are Keeping in Touch throughWireless Devices.” New York Times, July 22, 2002. Availableonline. URL: http://query.nytimes.com/gst/fullpage.html?sec=technology&res=98 02E5D61638F931A15754C0A9649C8B63. Accessed March 28, 2008.flash driveA flash or “thumb” drive is a small data storage device thatuses semiconductor flash memory rather than a disk drive.It is connected to a digital device using the universal serialbus (see usb). Because most computers, digital cameras,and other digital devices have USB ports, a flash drive is aconvenient way to provide up to 16 GB (as of 2007) of lowpower, rewritable memory. Flash drives first appeared inlate 2000.Flash drives can use a separate USB cable (useful whenseveral devices need to be connected to closely spaced USBports) or simply have a connector that plugs directly intothe port. Many people who regularly work with severalcomputers carry their backup data or even a complete operatingsystem (such as Linux) on a flash drive, perhaps connectedto their keyring.In Windows Vista some recent flash drives can be usedto provide an additional system memory cache through afeature called ReadyBoost.Flash drives can also be built into portable devices,including video and audio players. A competing technology(particularly found in digital cameras and PDAs) is theSecure Digital (SD) memory card developed by Matsushita,SanDisk, and Toshiba, which offers comparable capacitybut is proprietary and requires a special interface.For high-security applications, flash drives can includebuilt-in encryption or fingerprint readers (see biometrics).However, as with other readily portable media, unsecured