Copyright Goodheart-Willcox Co., Inc. 48 Computer Service and Repair the system. Confi guration information is stored in the config.sys fi le of DOS sys- tems. Th e config.sys fi le is still used in newer operating systems, but it is included only to support legacy software applications. Early Windows systems stored confi guration information in the win.ini and system.ini fi les. Software applications also stored confi guration setting in .ini fi les. Th ese confi guration fi les are replaced by the Windows registry settings for the Windows 95 and later operating systems. Many computer systems still contain .ini fi les to maintain a downward compatibility with some software programs. Th e OS confi guration fi le found in the Windows operating systems is called a registry. Th e registry is essentially a database that stores confi guration information. Th e major sections of the registry are listed as follows with their purposes: ■ HKEY_CLASSES_ROOT: Object linking and embedding (OLE) information and how fi les are associated with each other ■ HKEY_CURRENT_USERS: Information for the current user of this workstation ■ HKEY_LOCAL_MACHINE: Information specifi c to the local computer ■ HKEY_USERS: Information for each user of this workstation ■ HKEY_CURRENT_CONFIG: Display and printer settings Th e registry is accessed by entering regedit in the Run dialog box found in the Start menu or by entering regedit at the command prompt. Figure 2-9 shows the Windows 10 Registry Editor. Th ere are two main registry fi les: system.dat and user.dat. Th e system.dat fi le contains information about the computer settings. Th e user.dat fi le contains information about individuals who use the computer. Registry fi les can be copied to disk, installed on another computer, backed up, and modifi ed. Th e registry is re- paired through the System Restore utility. Rarely does a technician need to access the registry fi les directly. When a technician does access the registry fi les, it is usually as part of repair steps outlined by Microsoft on its TechNet website. Direct modifi cation of the registry should be a last resort eff ort. Microsoft Windows Operating System Th e most widely used desktop operating system is Microsoft Windows. On servers you will fi nd a mix of Windows, Linux and legacy Unix versions. You will encounter 1002: 1.1, 1.2 TECH TIP Changes in the registry can completely disable your computer operating system. Do not experiment with reg- istry settings unless you fully understand the change or are under the supervision of your instructor. Goodheart-Willcox Publisher Figure 2-9 The registry is accessed by entering regedit in the Run box or the command prompt. Users should not experiment with registry settings unless they fully understand the change.