Encyclopedia of Computer Science and Technology

BIOS 49interest in biometrics. For example, a pilot program in theUnited Kingdom has used iris scanning to replace the PIN(personal identification number) as a means of verifyingATM users.The general advantage of biometrics is that it does notrely on cards or other artifacts that can be stolen or otherwisetransferred from one person to another, and in turn,a person needing to identify him or herself doesn’t haveto worry about forgetting or losing a card. However, whileworkers at high-security installations can simply be requiredto submit to biometric scans, citizens and consumers havemore choice about whether to accept techniques they mayview as uncomfortable, intrusive, or threatening to privacy.Recent heightened concern about the stealing of personalidentification and financial information (see identitytheft) may promote greater acceptance of biometric techniques.For example, a built-in fingerprint reader (alreadyprovided on some laptop computers) could be used tosecure access to the hard drive or transmitted to authenticatean online banking customer.Of course every security measure has the potential forcircumvention or misuse. Concerns about the stealing andcriminal use of biometric data (particularly online) mightbe addressed by a system created by Emin Martinian of theMitsubishi Electric Research Laboratories in Cambridge,Massachusetts. The algorithm creates a unique code basedon a person’s fingerprint data. The data itself is not stored,and the code cannot be used to re-create it, but only tomatch against the actual finger.The growing use of biometrics by government agencies(such as in passports and border crossings) is of concernto privacy advocates and civil libertarians. When combinedwith surveillance cameras and central databases, biometrics(such as face analysis and recognition) could aidpolice in catching criminals or terrorists, but could alsobe used to strip the anonymity from political protesters.The technology is thus double-edged, with the potentialboth to enhance the security of personal information and toincrease the effectiveness of surveillance.Further ReadingAshborn, Julian D. M. Biometrics: Advanced Identity Verification,the Complete Guide. New York: Springer-Verlag, 2000.“Biometrics Overview.” Available online. URL: http://www.biometricgroup.com/a_bio1/_technology/research_a_technology.htm.Accessed April 20, 2007.Biometrics Research Homepage at Michigan State University. Availableonline. URL: http://biometrics.cse.msu.edu/. AccessedApril 24, 2007.“Biometrics: Who’s Watching You?” Electronic Frontier Foundation.Available online. URL: http://www.eff.org/Privacy/Surveillance/biometrics/.Accessed April 24, 2007.Harreld, Heather. “Biometrics Points to Greater Security.” FederalComputer Week, July 22, 1999. Available online. URL:http://www.cnn.com/TECH/computing/9907/22/biometrics.idg/index.html.Jain, Anil, Ruud Bolle, and Sharath Pankanti. Biometrics: PersonalIdentification in Networked Society. Norwell, Mass.: KluwerAcademic Publishers, 1999.Woodward, John D., Nicholas M. Orlans, and Peter T. Higgins.Biometrics: Identity Assurance in the Information Age. NewYork: McGraw-Hill, 2002.BIOS (Basic Input-Output System)With any computer system a fundamental design problemis how to provide for the basic communication between theprocessor (see cpu) and the devices used to obtain or displaydata, such as the video screen, keyboard, and paralleland serial ports.In personal computers, the BIOS (Basic Input-OutputSystem) solves this problem by providing a set of routinesfor direct control of key system hardware such as diskdrives, the keyboard, video interface, and serial and parallelports. In PCs based on the IBM PC architecture, theBIOS is divided into two components. The fixed code isstored on a PROM (programmable read-only memory) chipcommonly called the “ROM BIOS” or “BIOS chip.” Thiscode handles interrupts (requests for attention) from theperipheral devices (which can include their own specializedBIOS chips). During the boot sequence the BIOS coderuns the POST (power-on self test) and queries variousdevices to make sure they are functional. (At this time thePC’s screen will display a message giving the BIOS manufacturer,model, and other information.) Once DOS is running,routines in the operating system kernel can accessthe hardware by making calls to the BIOS routines. In turn,application programs can call the operating system, whichpasses requests on to the BIOS routines.The BIOS scheme has some flexibility in that part ofthe BIOS is stored in system files (in IBM PCs, IO.SYS andIBMIO.COM). Since this code is stored in files, it can beupgraded with each new version of DOS. In addition, separatedevice drivers can be loaded from files during systemstartup as directed by DEVICE commands in CONFIG.SYS,a text file containing various system settings.For further flexibility in dealing with evolving devicecapabilities, PCs also began to include CMOS (complementarymetal oxide semiconductor) chips that allow for thestorage of additional parameters, such as for the configurationof memory and disk drive layouts.In modern PCs the BIOS setup screen also allows usersto specify the order of devices to be used for loading systemstartup code. This, for example, might allow a potentiallycorrupted hard drive to be bypassed in favor of a bootableCD or DVD with disk repair tools. Another scenario wouldallow users to boot from a USB memory stick (see flashdrive) and use a preferred operating system and workingfiles without disturbing the PC’s main setup.The data on these chips is maintained by a small onboardbattery so settings are not lost when the main systempower is turned off.Additionally, modern PC BIOS chips use “flash memory”(EEPROM or “electrically erasable programmable read-onlymemory”) to store the code. These chips can be “flashed” orreprogrammed with newer versions of the BIOS, enabling thesupport of newer devices without having to replace any chips.Beyond the BiosWhile the BIOS scheme was adequate for the earliest PCs,it suffered from a lack of flexibility and extensibility. Theroutines were generic and thus could not support all thefunctions of newer devices. Because BIOS routines for