How It Works

When Windows 95 is booted the system checks to see if the start-up logo should be displayed. It does this by consulting the file MSDOS.SYS. This is a text file that allows various boot options to be specified. There are two entries in this file that determine whether the start-up logo is displayed. First, the entry 'BootGUI=1' tells the system to start the GUI interface. If this value is 0 only the command line interface (DOS) is started. Secondly, the entry 'Logo=1' tells the system to display a start-up graphic. Since this is the default, the entry doesn't have to be written in MSDOS.SYS! If the value is 0 then the GUI is booted without displaying the start-up logo.

If the system determines that a start-up logo is to be displayed it attempts to display the file C:\LOGO.SYS. If this file is not found then a default start-up graphic that is embedded in IO.SYS is displayed. The purpose of C:\LOGO.SYS appears to be to allow for local customizations, language or otherwise. This is most visible to those users who have installed the Plus! Pack. During the installation of the Plus! Pack, a new C:\LOGO.SYS is written which contains the Plus! logo.

When Windows 95 is shut down, it displays two logos. The first tells the user to wait whilst the system completes all necessary housekeeping, such as writing any necessary information to disk. This logo is contained in the file LOGOW.SYS. The second logo tells the user that it is safe to switch off the computer. This logo is contained in the file LOGOS.SYS. Both these files are stored in the same directory as the Windows 95 installation. For the majority of users this will be C:\WINDOWS.

It is a fundamental requirement that the three files LOGO.SYS, LOGOW.SYS, and LOGOS.SYS all have the following properties:

1. The file is stored as a Windows Bitmap. Despite the '.SYS' extension, the file is really a '.BMP' in disguise.

2. The size of the logo is 320 pixels wide by 400 pixels high.

3. The color depth is 8 bits per pixel. In other words, it's a 256 color bitmap.

4. The file size is exactly 129,078 bytes.

How to create a custom graphic using Microsoft tools

What you need:

Using Non-Microsoft Tools

Since there are numerous browsers and graphics editing tools it is impossible to give instructions to cover all. The instructions given for the Microsoft tools should serve as a good starting point. The important thing is to aim to create a 320x400 256-color Windows bitmap. If you get stuck, consult the help section for assistance or use the Microsoft tools (these are known to work).

Limitations

1. The size and format of a logo cannot be changed.

2. Depending upon the original graphic and the tools used. When you resize a 640x480 graphic down to 320x400, some bits get 'chopped' out and the result can appear quite fuzzy or block-like when stretched to full-screen. The best results tend to come from those files that are 320x400 to begin with.

3. Some start-up graphics may appear with a white border.

4. The progress indicator (whirly bar at the bottom of the image), present on the Microsoft start-up logo will be missing. Do not immediately assume that the system is not responding.

1. I can't find the file C:\LOGO.SYS

• Don't worry. Many installations of Windows 95 don't get this file by default. It is only a customization file.

2. I can't find any of the logo files.

• If you are using Explorer to locate the files it is quite likely that they are being ignored. By default Explorer ignores many file types, including those with the '.SYS' extension. Select the 'View/Options' menu in Explorer to open the dialog which allows you to change the file types that Explorer reports.

3. My new logo doesn't work! I still get the old one!

• Double check that you copied/renamed your bitmap correctly.

4. My new logo doesn't work! I get nothing or a garbled screen.

• The format of the new logo is wrong. Either you did not save the file as a Windows Bitmap, the size is not 320x400 pixels, or you are not using 256 colors.

5. How can I tell if the format of the file is wrong?

• The logo will not be displayed, or will be displayed as garbage. For more information see the answer to question 7.

6. I've checked the file using MS-Paint. It's 320x400 pixels and uses color. I still won't display. What's wrong?

• MS-Paint doesn't tell you how many colors can be used in the bitmap. You can either use a package that will tell you the color depth of the bitmap, which must be 8-bit (256 colors), or you can see the answer to the next question.

7. Can I examine the file directly to see if it's correct?

• If you're feeling up to it you can examine the file header. You will need a hex editor to do this, of which there are numerous, or you can use the DEBUG utility that is supplied with Windows 95. The instructions below show you how to use DEBUG:
  • a. Open an MS-DOS session

    b. Enter "DEBUG <file>", where <file> is the name of your bitmap graphic. You may need to specify the exact path to this file.

    c. At the "-" prompt, type "d". You should see the following. The xxxx:yyyy values are unimportant.

    xxxx:yyyy 42 4d 36 F8 01 00 00 00-00 00 36 04 00 00 28 00

    xxxx:yyyy 00 00 40 01 00 00 90 01-00 00 01 00 08 00

    The values are broken down as follows:

    42 4d = "BM", This supposedly identifies the file as a bitmap.

    36 F8 01 00 is the size of the file. The numbers are re-arranged to 00 01 f8 36 to reveal the size 129,078 bytes!

    [ The next 10 digit-pairs, to the end of the first line, mean nothing to us ]

    00 00 40 01 is the width of the bitmap, re-arranged to 00 00 01 40 gives the value 320 pixels.

    00 00 90 01 is the height of the bitmap, re-arranged to 00 00 01 90 gives the value 400 pixels.

    00 00 01 00 is the number of planes and must not be different

    08 00 is the number of colors, in bits-per-pixel, re-arranged to 00 08 gives 8 bits-per-pixel, or 256 colors.

    d. Enter 'q' to quit debug.

8. Can I change the default start-up graphic that is embedded in the file IO.SYS?

• Absolutely NOT. It is technically possible to do but the risk of rendering your system un-bootable is extremely high. Customize C:\LOGO.SYS, that's whats it's there for.

9. I didn't make backup copies of the Microsoft logos. How can I get them back?