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Prevent WIN95 from SafeMode ?

Posted on 1997-08-27
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Last Modified: 2013-12-16
Hi,
When Win95 boots and the reset key is pressed it comes up with a boot menu the next time the computer is started. From there, one can access everything and bypass any security software. My question:

How can I prevent Win95 from switching to this bootmenu after an interrupted boot-up?
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Question by:novowi
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by:j2
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Short story:

Open msdos.sys in an editor and add
BootKeys=0


Long story:
MSDOS.SYS: Special Startup Values

Windows 95 Setup creates a hidden, read-only system file named MSDOS.SYS in the root of the computer's boot drive. This file contains important paths used to locate other Windows files, including the Registry. MSDOS.SYS also supports an [Options] section, which you can add to tailor the startup process.

The following example shows a typical file with default values:




[Options]
BootGUI=1

[Paths]
WinDir=C:\WINDOWS
WinBootDir=C:\WINDOWS
HostWinBootDrv=C


Most values in the [Options] section are Boolean — that is, the value can be 1 (enabled) or 0 (disabled). The following table describes entries in MSDOS.SYS, using the typical default values.



MSDOS.SYS Values



Entry



Description



[Paths] section:





HostWinBootDrv=c



Defines the location of the boot drive root directory.



WinBootDir=



Defines the location of the necessary startup files. The default is the directory specified during Setup; for example, C:\WINDOWS.



WinDir=



Defines the location of the Windows 95 directory as specified during Setup.



[Options] section:





BootDelay=n



Sets the initial startup delay to n seconds. The default is 2. BootKeys=0 disables the delay. The only purpose of the delay is to give the user sufficient time to press F8 after the Starting Windows message appears.



BootFailSafe=



Enables Safe Mode for system startup. The default is 0. (This setting is enabled typically by equipment manufacturers for installation.)



BootGUI=



Enables automatic graphical startup into Windows 95. The default is 1.



BootKeys=



Enables the startup option keys (that is, F5, F6, and F8). The default is 1. Setting this value to 0 overrides the value of BootDelay=n and prevents any startup keys from functioning. This setting allows system administrators to configure more secure systems. (These startup keys are described in Chapter 35, "General Troubleshooting.")



BootMenu=



Enables automatic display of the Windows 95 Startup menu, so that the user must press F8 to see the menu. The default is 0. Setting this value to 1 eliminates the need to press F8 to see the menu.



BootMenuDefault=#



Sets the default menu item on the Windows Startup menu; the default is 3 for a computer with no networking components, and 4 for a networked computer.



BootMenuDelay=#



Sets the number of seconds to display the Windows Startup menu before running the default menu item. The default is 30.



BootMulti=



Enables dual-boot capabilities. The default is 0. Setting this value to 1 enables the ability to start MS-DOS by pressing F4 or by pressing F8 to use the Windows Startup menu.



BootWarn=



Enables the Safe Mode startup warning. The default is 1.



BootWin=



Enables Windows 95 as the default operating system. Setting this value to 0 disables Windows 95 as the default; this is useful only with MS-DOS version 5 or 6.x on the computer. The default is 1.



DblSpace=



Enables automatic loading of DBLSPACE.BIN. The default is 1.



DoubleBuffer=



Enables loading of a double-buffering driver for a SCSI controller. The default is 0. Setting this value to 1 enables double-buffering, if required by the SCSI controller.



DrvSpace=



Enables automatic loading of DRVSPACE.BIN. The default is 1.



LoadTop=



Enables loading of COMMAND.COM or DRVSPACE.BIN at the top of 640K memory. The default is 1. Set this value to 0 with Novell® NetWare® or any software that makes assumptions about what is used in specific memory areas.



Logo=



Enables display of the animated logo. The default is 1. Setting this value to 0 also avoids hooking a variety of interrupts that can create incompatibilities with certain memory managers from other vendors.



Network=



Enables Safe Mode With Networking as a menu option. The default is 1 for computers with networking installed. This value should be 0 if network software components are not installed.




Tip for Starting an Earlier Version of MS-DOS

If you installed Windows 95 in its own directory, the earlier version of MS-DOS is preserved on your hard disk. If you set BootMulti=1 in the [Options] section in the Windows 95 version of MSDOS.SYS, you can start the earlier version of MS-DOS by pressing F4 when the Starting Windows message appears during system startup.
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by:novowi
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Hi j2,

This is all what I know myself. The problem is:

- Reboot your computer.
- When the win95 logo appears, wait a second or two and then reboot the computer again.
- Now, you will have the whole boot-up menu despite having set Bootkey=0 in the MSDOS.SYS.

I tried it all. Sorry, but this answer is not correct to my question.

Regards,

Oliver
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by:edey
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I do not belive that this is possible, and for good reason.  The above, rejected, answer showed, rather clearly and expilcitly, how to prevent the user from accessing the boot menu during a regular startup.  This is generally used on restricted systems. Your problem, though, involves an irregular boot, something that shouldn't happen.  The menu gives, in case of trouble like bad hardware/doftware install, a chance to avoid the startup proceses that cause the problem.  To completely elimanate the menu allows to chance to keep win95 from booting.  In light of this if this menu thing really is a problem, simply disconnect the reset button.  This still leaves the power button to interupt reboots, but the I suppose you could delete command.com giving the user no choice of ui, aside from win95.
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by:edey
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I do not belive that this is possible, and for good reason.  The above, rejected, answer showed, rather clearly and expilcitly, how to prevent the user from accessing the boot menu during a regular startup.  This is generally used on restricted systems. Your problem, though, involves an irregular boot, something that shouldn't happen.  The menu gives, in case of trouble like bad hardware/doftware install, a chance to avoid the startup proceses that cause the problem.  To completely elimanate the menu allows to chance to keep win95 from booting.  In light of this if this menu thing really is a problem, simply disconnect the reset button.  This still leaves the power button to interupt reboots, but the I suppose you could delete command.com giving the user no choice of ui, aside from win95.
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by:j2
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Sorry, you can not get it safer then that.
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by:novowi
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Well, I just had a look at the file io.sys and I am working out a solution myself. I let you know how it will work.

Regards,

Oliver
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by:Ikon
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Install OSR2 this will run scandisk rather than give a menu.
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by:j2
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Ikon: What? It wil only run Scandisk AFTER you have a chance to choose bootmode.
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by:Ikon
Comment Utility
OK (sheepish grin)
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by:jerryd
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novowi,
If Win95 is not shut down properly, there is no way to prevent it from coming up with the boot menu and/or running Scandisk (OSR/2) if the system detects a problem.  Win95 is not desiged to be a secure OS - to get that you'd have to go to NT.

HOWEVER, most systems built in the last few years have BIOS password protection built in.  You would need to enable the BOOT password to prevent prying eyes from getting into your system on a RESET (which should include a power up from OFF - although the system may also have a power on password).  Rumage through your systems BIOS to see if you have the capability.

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Author Comment

by:novowi
Comment Utility
Ok folks,

It does work. Here is the solution:
Take a HEX editor and change the string "WNBOOTNG.STS" in the io.sys file to "________._". That's it.

Explanation:
During the start-up of win95, a file named WNBOOTNG.STS is created by Win95 in the Win-directory. If the start-up is successfull, Win95 erases this file again. If it is not successfull, the file will be still on the HD after the next boot-up and IO.SYS is looking for that. Is the file on the HD, io.sys brings up the boot menu. With my patch, it looks for a file, that anyway never exists.

Please, don't answer this question anymore, since I will reject any answer.

Regards,

Oliver
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Expert Comment

by:magigraf
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to novowi...
Submit a memo to Expert-Exchange, to remove the question, or it will stay on line until you accept an answer!
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by:j2
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when will ppl learn? you CAN remove a question all by yourself.. look around the site people :)

And furthermore... i have already found a workaround for that modified io.sys. it is very easily defeated.
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by:novowi
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To j2,

It's only defeated if you know the patch string. Of course, one can create this filename in the WinDir, but who knows the string?
It, of course, makes only sense, if you have a software running that protects dirs and files on your HD. For the normal user, io.sys is invisible and therefore cannot be read.
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by:j2
Comment Utility
There are quite a few other ways to trigger the Bootmenu on a W95 system... atleast 3 others i know of.
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by:magigraf
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To j2..
When nice ppl tell others how to do it...
To novowi..
You can delete a question yourself.  To do so just pull up the question at Experts Exchange and click on the "Delete
question..." link.  Then click on "Refund."
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by:tadams
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Edit config.sys and putt SHELL=C:\WINDOWS\WIN.COM and delete any command.com found in your directorys.
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Author Comment

by:novowi
Comment Utility
Sorry tadam,

That is not a solution because Win95 jumps into the SafeBoot Menu before even having looked at the config.sys. My solution as mentioned in the question's history is working fine, have a look at it.

Regards,  Oliver
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Accepted Solution

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smeebud earned 100 total points
Comment Utility
novowi,
Please submit a request to have this question removed. it will stay in the active question list if you don't, and clutter things up.
Thank you for your answer. I for one learned from it ;)
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Author Comment

by:novowi
Comment Utility
Ok smeebud,

That was the best comment so far. I give you the points.

Regards,

Oliver
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