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Article ID: 122051 - Last Review: November 15, 2006 - Revision: 1.1

 
This article was previously published under Q122051

SUMMARY

This article discusses how Windows 95 boots in Safe mode. A Safe-mode boot can be invoked in the following ways:
  • By pressing F5 at the "Starting Windows 95" message.
  • By pressing F8 at the "Starting Windows 95" message, and then choosing Safe Mode from the Windows 95 Startup menu.
  • Automatically, if Windows 95 did not start on the previous attempt.

MORE INFORMATION

How Windows 95 boots in Safe mode:
  1. Windows 95 bypasses the portion of the Registry that loads protected- mode device drivers, and bypasses the Autoexec.bat and Config.sys files.
  2. Himem.sys is loaded with the /testmem:on switch. No other command-line switches are processed. For additional information, please see the following article in the Microsoft Knowledge Base:
    133442  (http://support.microsoft.com/kb/133442/EN-US/ ) Safe Mode Boot Does Not Process Machine Switch for Himem.sys
  3. Ifshlp.sys is loaded. Dblbuff.sys is loaded with the /d+ switch.
  4. Windows 95 obtains path information from the Msdos.sys file.
  5. If Windows 95 files are found, the command "win /d:m" (which enables a Safe-mode boot) is executed and Command.com is skipped.

    If Windows 95 files are not found, Command.com is executed.
  1. When "win /d:m" is executed, Windows 95 looks for a System.cb file in the Windows folder. If this file is not present, a clean System.cb file is loaded from memory.

    A clean System.cb file loads the following virtual device drivers (VxDs):
          mouse=*vmouse
          device=*configmg
          device=*vwin32
          device=*vfbackup
          device=*vshare
          device=*vcomm
          device=*ifsmgr
          device=*ios
          device=*vfat
          device=*vcache
          device=*vcond
          device=*int13
          device=*vxdldr
          device=*vdef
          device=*dynapage
          device=*reboot
          device=*vsd
          device=*parity
          device=*biosxlat
          device=*vmcpd
          device=*vkd
          device=*vdd
          device=*ebios
          device=*vtdapi
          device=*vmpoll
          woafont=dosapp.fon
    						
  2. After these VxDs are loaded, and just before Win.com loads the shell, the System.cb file is discarded and the original System.ini file is restored. If no System.ini file is found to restore, an empty System.ini file is created. The Winstart.bat file is not processed.
  3. Windows 95 now uses the original registry settings and System.ini and Win.ini files.

    This effectively bypasses the [Boot] and [386Enh] sections of the System.ini file and disables all the Windows 95 protected-mode devices listed in Device Manager. Also, Windows 95 does not run programs listed on the "Load=" and "Run=" lines in the [Windows] section of the Win.ini file.

    Note that although the [Boot] section of the System.ini file is bypassed, the "shell=" and "drivers=" lines in the [Boot] section are processed.
  4. The shell resizes the desktop to a resolution of 640 x 480.

APPLIES TO
  • Microsoft Windows 95
Keywords: 
kbenv kbinfo kbui KB122051
Retired KB ArticleRetired KB Content Disclaimer
This article was written about products for which Microsoft no longer offers support. Therefore, this article is offered "as is" and will no longer be updated.
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