Windows 9X boot full secret (below)

Five, COMMAND.COM

COMMAND.COM is the DOS shell (SHELL) in WINDOWS 9X, only some internal commands are added compared to DOS 6.22, no update s things.

IO.SYS has a fundamental change in the processing of COMMAND.COM. When WIN 9X loads the EMM386.EXE driver in CONFIG.SYS to provide UMB, the resident part of COMMAND.COM is loaded into HMA. The resident part is loaded into the UMB (in DOS6.22, COMMAND.COM can only load the resident part into the HMA), which will provide more conventional memory for the DOS program, and does not need to repeatedly restore the temporary part from the disk. , effectively improve system performance. Of course, if EMM386.EXE is not loaded, the system does not provide UMB, and the temporary part of COMMAND.COM can only be placed at the high end of conventional memory like DOS6.22.
Sixth, CONFIG.SYS and AUTOEXEC.BAT

The functions of CONFIG.SYS and AUTOEXEC.BAT in WIN 9X are the same as those of DOS, and are used to assemble all DOS real mode drivers and applications. Or modify the default configuration of IO.SYS. Among them, CONFIG.SYS is mainly used for hardware configuration, AUTOEXEC.BAT is mainly used for software configuration, and its use during startup is described in the IO.SYS section.

After WIN 9X is started, the configuration of these two files is always kept at the bottom of the system as a global setting, which determines all DOS and WIN 16 application environments under WIN 9X. If there is no DOS global setting, the DOS application under the WINDOWS window will use the default settings of WIN 9X, which of course can be configured separately by the user. Note that the PATH, SET and other environment settings required by the DOS software can be set separately in the properties of the respective windows; the environment settings of the PATH, SET, etc. required by the 16-bit WIN 3.X software can only be set in AUTOEXEC.BAT.

WIN 9X has added a lot of configuration commands to make the real-mode DOS environment more convenient to optimize. For each configuration command, please refer to the CONFIG.TXT description in the system directory WINDOWS. WIN 9X manages and uses system software and hardware resources through protected mode drivers such as VXD (virtual device driver) and DLL (dynamic link library). Basically, real-mode program support is not required. Real mode programs are primarily reserved to support some older devices. The existence of real-mode programs makes WIN 9X frequently switch between protected mode and real mode, which greatly reduces system performance and impairs system stability. Therefore, it should be avoided to load real-mode programs at startup.

The default setting of WIN 9X for DOS environment can meet the needs of most DOS software. It is necessary to delete the contents of these two files after completing the WIN 9X installation. Delete the real-mode program, try to achieve the protection mode driver of WIN 9X, and make WIN 9X in the optimal running state of high performance and high stability.

DOS systems without CONFIG.SYS, AUTOEXEC.BAT are almost impossible, and without their WIN 9X performance may be better. In WIN 9X they are mainly reserved to support the original DOS software and ancient equipment. At present, most newspapers suggest to delete these two files completely. This is actually very problematic. For the specific analysis, please refer to the '99 October issue of the computer industry and computer masters'.

VII. WIN.COM

WIN.COM is the GUI startup command of WINDOWS. It can be seen from the file name that this is a pure DOS command, it is also the only COM file in the GUI system. . This command is an interface command of DOS and GUI. It is mainly used to load the protected mode virtual device driver VMM32.VXD (this program is composed of multiple subroutines, so that the CPU runs in protected mode), while processing the GUI boot. Various problems in it, which control the entire transfer process of the system.

The various startup switches provided by WIN.COM are mainly used to determine system failures and reduce system performance: WIN [/D: [F][M][S][V][X]]

/D Used to find fault cause when WINDOWS cannot start normally

:F Turn off 32-bit disk access mode for hard disk that does not support 32-bit access
Equivalent Set in the [386ENH] section of SYSTEM.INI: 32BitDiskAccess=FALSE.

:M Safe mode startup, equivalent to using function key F5 to start

:N with real mode network Supported safe mode startup, equivalent to using function key F6 to start

:S prohibits Windows from using the ROM address space between F000:0000 and 1 MB as a breakpoint equivalent to the SYSTEM.INI [386ENH] Section setting: SystemROMBreakPoint=FALSE.

:V Specifies that the hard disk controller interrupt handled by the ROM routine at startup is equivalent to the setting in the [386ENH] section of SYSTEM.INI: VirtualHDIRQ= FALSE.

:X prohibits WINDOWS from using all high-end memory (from A000-FFFF). Resolving memory conflicts is equivalent to setting in the [386ENH] section of SYSTEM.INI: EMMExclude=A000-FFFF.< Br>