Establishing the Environment If a CONFIG.SYS file is present, it is opened and read by IO.SYS/WINBOOT.SYS. The DEVICE statements are processed first in the order they appear, then INSTALL statements are processed in the order they appear. A SHELL statement is handled next. If no SHELL statement is present, the COMMAND.COM processor is loaded. When COMMAND. COM is loaded, it overwrites the initialization code leftover from IO.SYS (which is now no longer needed. Under Windows 95, COMMAND.COM is loaded only if an AUTOEXEC.BAT file is present to process the AUTOEXEC.BAT statements. Finally, all other statements in CONFIG.SYS are processed, and WINBOOT.SYS also looks for the SYSTEM.DAT registry file. When an AUTOEXEC.BAT file is present, COMMAND.COM (which now has control of the system) will load and execute the batch file. After the batch-file processing is complete, the familiar DOS prompt will appear. If there is no AUTOEXEC.BAT in the root directory, COMMAND.COM will request the current date and time, then show the DOS.
