Devices: The Basics

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This chapter presents an overview of issues related to Windows 95 support for both Plug and Play-compliant and legacy devices. It also provides specific details for installing and configuring devices, including PCMCIA cards, display adapters, the mouse, and communications ports.

These key features (and related benefits) result from the Windows 95 system design changes (as described in Chapter 18, "Introduction to System Configuration"):

  • Automatic installation for new Plug and Play-compliant devices, allowing the user to start working without configuring or, usually, without restarting the computer.

  • Centralized places in the Registry and Device Manager to configure legacy devices and set preference for resources.

  • Enhanced support for PCMCIA adapters, portable computers, and docking stations.

Windows 95 includes several tools to help install, configure, and manage hardware devices:

  • The Add New Hardware option in Control Panel is a wizard that guides you through the steps required to install and configure drivers for legacy devices. For information, see the summary later in this section, plus "Installing New Devices" later in this chapter.

  • You can view the hierarchy of devices in the system and print various reports on system settings using Device Manager in the System option in Control Panel. For information, see the summary later in this section, plus "Changing Settings with Device Manager" later in this chapter.

  • You can use the Display and Mouse options in Control Panel to install and configure all device driver and user preference settings related to the display and pointing devices. For information, see the summary later in this section, plus "Configuring the Display" later in this chapter and "Configuring the Mouse" later in this chapter.

For other devices, Windows 95 provides installation and configuration wizards. For example, you use wizards to install modems, faxes, printers, multimedia, and sound devices. For information about using these specific tools, see related chapters in this book.

This section summarizes improvements in support for these device types:

  • Display adapters and monitors

  • Mouse pointers and other pointing devices

  • Communications ports

Improved display adapter and monitor support.

Windows 95 Setup automatically detects the display adapter and installs the appropriate display driver. The Windows 95 display drivers are stringently tested to ensure greater reliability and stability than drivers for Windows 3.1.

Also, Windows 95 includes mechanisms to ensure that bad or incompatible display drivers cannot keep you from starting and using the system. If a display driver fails to load or initialize when Windows 95 is started, Windows 95 uses the generic VGA display driver. Benefits of the new display driver support in Windows 95 include the following:

  • More stable and reliable display adapter drivers using the mini-driver architecture, with support for many more display adapters

  • Support for new features, including the ability to change display resolution without needing to restart Windows 95

  • Display driver support for mobile computing, providing functionality to switch automatically between display adapters in a portable computer and a docking station

  • Consolidated installation and configuration of display drivers and display properties such as colors, wallpaper patterns, and screen savers in a single Control Panel icon

  • Image Color Matching (ICM) support for device-independent color usage (offered through an agreement between Microsoft and Kodak)

  • Support for a new generation of hardware and device functionality, such as Energy Star Monitors conforming to the VESA Display Power Management Signaling (DPMS) specification, and detection of monitor properties such as maximum resolution supported when used in conjunction with monitors that support the VESA Display Data Channel (DDC) specification

Windows 95 includes drivers for nearly all popular graphics accelerators, and has been shown to run faster than Windows 3.1 on the following models and chip sets:

ATI Technologies Inc.


Tseng Labs

Cirrus Logic


Western Digital

Chips & Technologies

Matrox MGA


The graphics accelerators in the preceding list are installed on numerous computers and retail graphics adapters and sold under many different make and model names. Before purchasing a new computer or graphics accelerator card, we recommend that you know what graphics accelerator it uses and whether it is supported by Windows 95 drivers developed by Microsoft or another manufacturer. Other accelerator and adapter manufacturers not included in this list will have drivers available.

Improved mouse and pointing device support.

As with other device drivers, the mini-driver architecture of Windows 95 simplifies mouse driver development and improves virtualization in a protected-mode mouse driver to better support MS-DOS – based applications in the Windows environment. Windows 95 includes the following improvements to mouse support over Windows 3.1:

  • Smooth, reliable input support through the use of protected-mode drivers

  • Easy installation for mouse and pointing devices, including Plug and Play support

  • A single mouse driver, eliminating the need to use separate mouse drivers for MS-DOS and Windows, which increases robustness and saves conventional memory

  • Support for connecting a mouse after Windows 95 has started — to assist mobile computer users who forget to connect a mouse before turning on the computer

  • Consolidated mouse configuration and customization support in a single Control Panel option

  • Improved device support to allow the use of serial ports COM1 through COM4 for connecting a mouse or other pointing device

Improved communications hardware support.

Windows 95 provides improved communications device and hardware support over Windows 3.1. A few areas of improvement include the following:

  • 16550A UART FIFO support. Windows 95 provides robust, high-quality performance at high speeds for MS-DOS -based and Windows-based communications applications using local serial ports with 16550A compatible UARTs. Communications support in Windows 95 alleviates the need for communications driver replacements to improve performance.

  • More ports supported. The Windows 95 communication APIs support the same number of logical ports as MS-DOS: 128 serial ports and 128 parallel ports. This enhanced limit allows use of multiport serial devices. The actual limitation on the number of ports usable is still based on the physical number of ports available to the computer.

  • Support for parallel port modems. Additionally, Windows 95 provides support for enhanced capabilities port (ECP) printers and future ECP-based high-speed parallel devices.

Improved power management support.

Microsoft worked with Intel to develop an industry standard for Advanced Power Management (APM). Now most major computer manufacturers of both portable and desktop computers widely support the APM specification. Windows 95 includes an APM driver that sends messages to the computer's BIOS to manage such things as conserving power during idle periods, reducing monitor power consumption, and processing suspend and resume requests on computers with such features. For information about enabling APM if it was disabled during Setup, see "Troubleshooting Device Configuration" later in this chapter.

Devices: The Issues

For information related to the specific devices you are responsible for administering, check the lists of supported hardware in the Add New Hardware wizard and the README.TXT file provided with Windows 95.

If you try to install device drivers that were created to run in 32-bit mode in Windows 3.x, you can damage your Windows 95 configuration, because these particular drivers add VxD information to the SYSTEM.INI file. If the device is supported under Windows 95, the best way to recover and install the device is to do the following.

To recover from faulty installation of a Windows 3.x driver

  1. Restart the computer. Press F8 when the Starting Windows 95 message appears, and then choose the Safe Mode option.

  2. Remove all entries added to SYSTEM.INI by the Windows 3.x driver installation program.

  3. Remove the device in Device Manager, as described in "Changing Settings with Device Manager" later in this chapter.

  4. Restart Windows 95.

  5. In Control Panel, double-click the Add New Hardware icon to reinstall the device using real-mode drivers. To install real-mode drivers, you must choose to manually select the hardware you want to install, and then provide the path name to the real-mode drivers. The device will function correctly, but will not be operating in 32-bit mode.

    Also, contact the device manufacturer to determine when drivers compatible with Windows 95 will be available.

Devices Overview

In Windows 95, how you install a device depends on whether the device and the computer are Plug and Play compliant. To take full advantage of Plug and Play technology, a computer needs the following:

  • Plug and Play operating system (Windows 95)

  • Plug and Play BIOS

  • Plug and Play-compliant hardware devices with drivers

The Plug and Play components perform the following tasks:

  • Identify the installed devices

  • Determine the device resource requirements

  • Create a nonconflicting system configuration

  • Program the devices

  • Load the device drivers

  • Notify the system of a configuration change

Windows 95 handles the installation and configuration of Plug and Play-compliant devices automatically, and it provides a wizard to detect and configure legacy devices. Microsoft recommends that, whenever possible, you choose new Plug and Play-compliant devices, even for a legacy computer which does not have a Plug and Play BIOS.

Windows 95 uses a large number of subsystems to control various classes of devices that identify logical device types such as the display, keyboard, and network. Each subsystem uses a different driver architecture and offers different user options and compatibility constraints, so different installation mechanisms are required for each class. For many devices, you must use Device Manager in the System option in Control Panel for configuration if you need to make manual changes.

The following table lists the default classes and shows where you can find the installation tools for changing the device driver.

Class and device types

Where to configure this device

Disk class:
Disk drives and adapters


Properties for specific devices displayed under related disk controllers in Device Manager.

Display class:
Display adapters


Display option in Control Panel. See "Configuring the Display" later in this chapter.

Keyboard class:
Keyboard devices


Keyboard option in Control Panel. See online Help.

Modem class:
Data and fax modems


Modem option in Control Panel. See Chapter 25, "Modems and Communications Tools."

Mouse class:
Mouse devices


Mouse option in Control Panel. See online Help. See also "Configuring the Mouse" later in this chapter.

Multimedia class:
Multimedia devices


Multimedia option in Control Panel. See the related media devices in Device Manager for game ports; see also Chapter 21, "Multimedia."

Network class:
Network adapters


Properties for the network adapter under the Network option in Control Panel. See Chapter 12, "Network Technical Discussion."

PCMCIA class:
PC Card sockets


Specific device's properties in Device Manager. See "Enabling PCMCIA Cards" later in this chapter.

Ports class:


Ports properties in Device Manager. See "Configuring Communications Ports and Printer Ports" later in this chapter.

Printer class:


Printers Folder (no class installer). See Chapter 23, "Printing and Fonts."

System class:
System devices


Installation handled by the system. Configure using the device's properties in Device Manager.

Unknown class:
Detected devices with no driver for Windows 95


Add New Hardware icon in Control Panel. See "Installing New Devices" later in this chapter.

How Windows 95 Installs a New Device: An Overview

Windows 95 Setup performs an inventory of all devices on the computer and records the information about those devices in the Registry. Setup gets configuration information from device INF files. To maintain compatibility, Setup also checks entries in WINI.INI, SYSTEM.INI, and CONFIG.SYS.

When a new device is installed, Windows 95 uses the device ID to search Windows 95 INF files for an entry for that device. Windows 95 uses this information or a default driver to create an entry for the device under the Hkey_Local_Machine branch in the Registry, and it copies the drivers needed. Then the Registry entries are copied from the INF file to the driver's Registry entry, including the DevLoader= and DriverDesc= values for the Driver entry, and the Driver= and ConfigFlags= values for the Enum entry.

Tip If you use custom setup scripts to install Windows 95, you can include the setting devicepath=1 in the [Setup] section to specify that Windows 95 should check a source installation path to find INF files, rather than looking only in the Windows INF directory when installing devices. When you use this parameter in setup scripts, you can later add INF files to a single network source location to ensure that up-to-date drivers are used any time a new device is installed on computers running Windows 95. For information, see Appendix D, "MSBATCH.INF Parameters."

Installing New Devices

When you need to install a new device, you should first rely on Windows 95 to detect and configure it. For Plug and Play-compliant devices, this means inserting the device into the computer. For legacy devices, this means running the Add New Hardware wizard.

Note: Before you install a new device, check the Modems section in the Windows 95 README.TXT file for possible information.

To install a new Plug and Play-compliant device

  1. Insert the device.

    Whether you need to turn off the power before inserting the device depends on the type of device. Check the documentation for your new device.

  2. Windows 95 notifies you that it has identified a new card. If no driver is provided on the system, it asks you to insert a disk that contains a driver that was developed for Windows 95.

  3. For PCMCIA cards, after Windows 95 identifies and loads the appropriate driver, the computer emits a beeps when the new device is configured.

    You can begin working with the device immediately. Windows 95 notifies other drivers and applications that the device is available.

If your computer uses PCMCIA cards or other Plug and Play cards and if a driver is not available for the new device, Windows 95 prompts you for a driver file to install. If Windows 95 detects the presence of a new device—either during Setup, device installation, or startup—but does not have a driver, it automatically asks for a disk that can be used to install and configure a driver.

To install a legacy device

  1. In Control Panel, double-click the Add New Hardware option.


  2. In the Add New Hardware wizard, click Next, and then click the option named Automatically Detect Installed Hardware.


  3. Continue to follow the instructions on the screen to install drivers and to configure the device driver.

If Windows 95 does not have a driver for the device, you can install the driver from a disk by using the Add New Hardware wizard.

To install a legacy device from a disk by using the Add New Hardware wizard

  1. In the Add New Hardware wizard, click Next, and then click Install Specific Hardware.

  2. In the list of hardware devices, click a device class, and then click Next.

  3. In the next Add New Hardware dialog box, specify the manufacturer and model of the device, and then click Have Disk.

  4. In the Install From Disk dialog box, type the path name to the driver files, and then click OK.

Changing Settings with Device Manager

For Plug and Play-compliant devices, there are no true default settings. Instead, Windows 95 identifies devices and their resource requests, and then arbitrates requests among them. If no other device requests the same resources as another device, its settings should not change. If another device requests its resources, the settings might change to accommodate the request. Consequently, you should never change resource settings for a Plug and Play-compliant device unless absolutely necessary. Doing so will fix its settings, making it impossible for Windows 95 to grant another device's request to use that resource.

All legacy devices have fixed resource settings, which are defined either during Windows Setup from a previous configuration, or afterward in the Add New Hardware wizard in Control Panel.

Certain circumstances might require users to change resource settings after they have been configured. For example, Windows 95 might not be able to configure one device without creating conflicts with another device. In such a case, a message usually appears to explain what is happening and what you can do about the problem — turn off a device to make room for the new device, disable the new device, or reconfigure a legacy device to make room for the new device.

The best place for resolving any conflicts that might occur is the Hardware Conflict Troubleshooter in Windows 95 online Help. For more information, see "Troubleshooting Device Configuration" later in this chapter.

When you must manually change a device's configuration, you can use Device Manager in the System option in Control Panel. Using Device Manager helps you avoid the errors that can occur if you attempt to edit Registry entries directly.

If you need or want to resolve device conflicts manually, you can use Device Manager and try the following strategies:

  • Identify a free resource, and assign the device to use that resource.

  • Disable a conflicting Plug and Play-compliant device to free its resources.

  • Disable a legacy device by removing the legacy device card and not loading the device drivers.

  • Rearrange resources used by another device or other devices to free resources needed by the device with a conflict.

  • Change jumpers on your hardware to match the new settings.

Caution: Changing default settings using either Device Manager or Registry Editor can cause conflicts that make one or more devices unavailable on the system.

Device Manager and Registry Editor are provided as configuration tools for advanced users who understand configuration parameters and the ramifications of changing settings.

To use Device Manager


  1. In the System option in Control Panel, click the Device Manager tab.

    – Or –

    Right-click My Computer, click Properties from the context menu, and then click the Device Manager tab.


  2. Double-click the device type in the list to display the specific devices of that type on your computer.

  3. Double-click the device you want to configure. Or select the device, and then click the Properties button to view or change its settings.

To change the device driver using Device Manager

  1. In Device Manager, double-click the related device type.

  2. Double-click your current device to display its properties.

  3. Click the Driver tab.

    The Driver properties dialog box shows the driver files and current resource setup for that device.


  4. Click the Change Driver button.


  5. In the Select Device dialog box, the Show Compatible Devices option is checked to show you a list of drivers that Windows 95 has identified as compatible for your device.

    – Or –

    Click Show All Devices to see a list of all the drivers available in Windows 95.

    Important: Be very careful in selecting a driver in the Show All Devices list. You should select a driver from the Show All Devices list only when you know that you are selecting a driver that is compatible with the device.

  6. In the Models list, select the driver you want to use, and then click OK.

  7. If requested, follow the instructions on the screen to provide a disk or a path to a directory that contains the display driver.

In Device Manager, you can print reports about system settings, including reports on the following:

  • System summary

  • Selected class or device

  • All devices and system summary

To print a report about system settings

  1. In Device Manager, click Print.

  2. In the Print dialog box, click the type of report you want.

Caution: You should quit all MS-DOS – based applications before printing the report named All Devices And System Summary because the device detection code might cause problems for some MS-DOS – based applications. If you do not do this, some applications might report the system is out of memory.

To change a device's resource settings using Device Manager

  1. In Device Manager, double-click a device class.

    The tree expands to show the devices of that class available on the computer.

  2. Double-click a device to display its properties.

  3. In the device's properties, click the Resources tab.


    Notice that the Conflicting Devices List shows any conflicting values for resources used by other devices.

  4. In the Resource Type list, select the setting you want to change — for example, the Input/Output Range — and then click the Change Setting button.

    Notice that you can select and set the IRQ, I/O, and DMA independently, and that if the option named Use Automatic Settings is checked, you cannot change resource settings.


    The dialog box shows the various settings that the device supports. Notice that in the Edit Input/Output Range box any interrupt marked with an asterisk (*) will conflict with an existing device. Any interrupt marked with a pound sign (#) indicates that the actual configuration has been tested.

    When you clicked the Change Setting button, you might have received an error message saying "This resource setting cannot be modified." If this is the case, you must choose a different basic configuration until you find one that allows you to change resource settings.

  5. Choose a setting that does not conflict with any other devices, and then click OK.

  6. Shut down and restart Windows 95. Then verify that the settings are correct for the device.

Note: Most legacy devices have jumpers or switches that set the IRQ, DMA, and I/O addresses. If you change these settings in Device Manager, you must also change the settings on the device to match them.

Tips for Changing Settings with Registry Editor

You can use Registry Editor to change specific values for devices. Use Registry Editor to change system settings in the following cases:

  • When directed to make specific changes by a product support representative.

  • When you know the correct Registry key, value settings, and editing restrictions for a specific device.

  • When you cannot successfully change the value using Device Manager or other built-in tools.

When you make changes in Registry Editor, always make one change at a time, and then test the system for the results. If you have problems with the system after making a change, restart the computer and press F8 when the Starting Windows 95 message appears, and then choose the Safe Mode option. Then you can change the setting back to its previous value.

You can also use the Connect command in Registry Editor to connect to and view the Registry on a remote computer if that computer has the Microsoft Remote Registry service installed. For information about using Registry Editor, see Chapter 33, "Windows 95 Registry."

Enabling PCMCIA Cards

To enable Windows 95 Plug and Play support for the PCMCIA socket, you must run the PCMCIA wizard. The PCMCIA wizard comments out the real-mode drivers in the AUTOEXEC.BAT and CONFIG.SYS files and enables the PCMCIA socket. In some cases, Windows 95 disables Plug and Play PCMCIA support if there is a risk of incompatibility.

If you must use old drivers, Windows 95 should work well with your previous PCMCIA drivers, although some Plug and Play capabilities such as automatic installation and friendly device names will not be available.

Windows 95 supports many PCMCIA cards including modems, network adapters, SCSI cards, and others. If Windows 95 includes supporting drivers for the PCMCIA card and for the socket, then installation and configuration should be automatic. This section provides some guidelines for enabling Windows 95 enhanced PCMCIA support when automatic detection and configuration aren't available for your card.

If your PCMCIA card is not shown in the list of manufacturers and models in the Add New Hardware wizard, contact the vendor and request a Windows 95-compatible installation disk before enabling the Windows 95 enhanced PCMCIA support. Also, see these Help topics:

  • "Setting Up Other Hardware," if you added a PCMCIA socket after setting up Windows 95

  • "If You Have Trouble Using a PCMCIA Card"

Important: Your PCMCIA socket driver and network driver both must be Plug and Play-compliant drivers (that is, developed for Windows 95 and NDIS 3.1-compliant) or both must be real-mode drivers. If these drivers are of mixed types, the computer might stall or the network might not work.

Windows 95 Setup automatically detects the presence of a PCMCIA socket, but to enable it, you must run the PCMCIA wizard.

To verify that Windows 95 has properly detected your PCMCIA socket

  1. In the System option in Control Panel, click the Device Manager tab.

  2. Look for a PCMCIA Socket listing.


If Windows 95 has not detected a PCMCIA socket, your socket controller might not be supported by Windows 95.

To find out if a PCMCIA socket is supported

  1. In Control Panel, double-click the Add New Hardware icon.

  2. On the first screen in the Add New Hardware wizard, click the Next button, and then click Install Specific Hardware.

  3. In the Hardware Types list, select PCMCIA Socket, and then click the Next button.

  4. Select the manufacturer for your device, and examine the Models list.

    If your socket does not appear in the list, you should contact the manufacturer to see if new drivers are available.

To enable support for PCMCIA by running the PCMCIA wizard

  • In Control Panel, double-click the PCMCIA icon.

    – Or –

    Double-click the PCMCIA controller in the Device Manager.

    – Or –

    Look up the topic named "PCMCIA" and then look up "Enable Support For" in the Windows 95 Help Index.

To find out if Windows 95 has activated enhanced PCMCIA support

  1. In Device Manager, click your PCMCIA controller, and then click the Properties button.

  2. Click the General tab.

    If a hardware profile in the Device Usage box is checked, then PCMCIA support is enabled.

If you have the correct drivers and enhanced PCMCIA support is activated, but the device is still not available, your computer is probably using the wrong memory window for the device. Windows 95 selects a default set of commonly supported settings. Your socket might not support certain interrupt settings, so you might be able to get a PCMCIA socket to work by changing the IRQ. Similarly, your socket might not work on certain memory windows, and changing the memory window might solve your problem.

To change the memory window for a PCMCIA device

  1. In Device Manager, click your PCMCIA socket, and then click the Properties button.

  2. In the PCMCIA controller properties, click the Global Settings tab.

  3. Make sure that the Automatic Selection check box is not checked.

  4. Change the Start address based on information from your hardware manual.

    Typically, selecting a Start value higher than 100000 will work.

  5. Restart Windows 95.

To change the interrupt for a PCMCIA device

  1. In Device Manager, click your PCMCIA socket, and then click the Properties button.

  2. Change the IRQ from its default to a value that doesn't conflict with other IRQ settings used on your computer.

  3. Restart Windows 95.

If Windows 95 still doesn't detect your PCMCIA cards, you should disable the Windows 95 enhanced PCMCIA support.

To disable the enhanced PCMCIA support

  1. In Device Manager, click your PCMCIA controller, and then click the Properties button.

  2. Click the General tab, and in the Device Usage box, click to clear the check beside the hardware profile.

Using Hardware Profiles for Alternate Configurations

Windows 95 uses hardware profiles to determine which drivers to load when the system hardware changes. When you start Windows 95, Windows 95 runs detection to see if any hardware on the computer has changed. If the hardware has changed significantly, Windows 95 creates a new hardware profile and prompts you for a name. If you move the computer to a new site and use a different configuration, Windows 95 notices it when you start the computer and loads the appropriate drivers.

The only time Windows 95 prompts you for the name of a hardware profile is when two profiles are so similar that Windows 95 can't differentiate between them. If this happens, Windows 95 displays a Hardware Profile menu from which you can choose the correct one.

Hardware profiles are an especially important feature for portable computers that can be docked. Windows 95 uses one hardware profile to load drivers when the portable is docked, and another profile when the portable is undocked — for example, at a customer site that has a different monitor than at the office.

Note: It is not necessary to use a different hardware profile for a Plug and Play portable computer, because the computer automatically knows when it is docked or undocked.

To create a hardware profile

  1. In the System option in Control Panel, click the Hardware Profiles tab.

  2. Click the name of the hardware profile you want to base the new hardware profile on, and then click Copy.

  3. Type a name for the hardware profile you are creating.

  4. Change which hardware is enabled or disabled in this profile by using the Device Manager, as described in the following procedure.

Tip If you have a hardware profile with the same name as a Windows 95 Startup Menu item, the corresponding menu item will be run automatically when you use that hardware profile for system startup.

To enable or disable hardware in a hardware profile

  1. In Device Manager, click the plus sign next to the hardware type, and then double-click the hardware.

  2. In the Device Usage box, click to place a check mark next to each hardware profile in which you want to enable the hardware, or clear the check box to disable the hardware for that hardware profile.

  3. If you see a message prompting you to restart your computer, click Yes.

To delete or rename a hardware profile

  1. In the System option in Control Panel, click the Hardware Profiles tab.

  2. Click the name of the hardware profile you want to change.

  3. If you want to remove this profile, click Delete.

    – Or –

    If you want to change the name of the profile, click Rename, and then type a new name.

Configurations are created when Windows 95 queries the BIOS for a dock serial ID and then assigns a name for the docked and undocked configuration. Windows 95 then stores the hardware and software associated with this configuration. Applications access and store information for each of the different hardware configurations used by the mobile user. The Registry support enables applications to adapt gracefully to different hardware configurations.

Tip If you are running Multiconfig, you can name a hardware profile the same as a Multiconfig menu option. In this case, Windows 95 detects a hardware profile and automatically runs the corresponding Multiconfig menu option. You can create this by specifying identical names for the Multiconfig menu option and the hardware profile.

Configuring the Display

Windows 95 consolidates display properties in the Display option in Control Panel, so you can easily customize display adapter settings. You can use the Display option in Control Panel to do the following:

  • Change the display type or driver.

  • Change screen resolution and color palette (without restarting the computer when using display drivers that support this functionality).

  • Change color schemes and text styles in all screen elements, including changing fonts used in dialog boxes, menus, and title bars.

  • View changes in colors, text, and other elements of display appearance before the changes are applied.

  • Configure display settings for each hardware profile; for example, docked and undocked configurations.

Tip To set display options quickly, right-click the desktop, and then click Properties. Click the Help icon to get Help for setting display properties.

Display Driver Overview

Windows 95 provides enhanced functionality and easy configuration for display adapters, in addition to resolving many problems inherent in Windows 3.1 display drivers. By using a mini-driver architecture for display drivers, Windows 95 provides better support for a wide range of hardware and provides more stable and reliable drivers.

Windows 95 Setup automatically detects the display adapter in the computer and installs the correct display driver, upgrading to a new driver if a new version is available.

Windows 95 contains a universal display driver called the device independent bitmap (DIB) engine. The DIB engine provides 32-bit graphics code for fast, robust drawing on high-resolution and frame buffer-type display adapters. Windows 95 display mini-drivers use the DIB engine for all in-memory graphics operations and on-screen operations that do not pass to the adapter for hardware acceleration. This architecture makes it easy for hardware developers to write drivers for a new controller type and to add hardware acceleration features incrementally.

To ensure broad support for display adapter devices in Windows 95, Microsoft developed many of the display drivers in cooperation with the major display-controller hardware manufacturers. The Microsoft development team also worked closely with hardware manufacturers to write additional display drivers and assisted in optimizing drivers to enhance display speed for improved graphic performance.

Windows 95 also includes mechanisms to ensure that incompatible display drivers cannot prevent a user from accessing the system. If a display driver fails to load or initialize when Windows 95 is started, Windows 95 automatically uses the generic VGA display driver. This ensures that you can start Windows 95 to fix a display-related problem.

For displays, colors are described in bits per pixel (bpp). The following table lists the bpp-to-colors conversion.

Bits per pixel

Color conversion

1 bpp


4 bpp

16 colors

8 bpp

256 colors

15 bpp

32,768 (32K) colors

16 bpp

65,536 (64K) colors

24 bpp

16.7 million (16.7M) colors

32 bpp

16.7 million colors

Resolutions are described in horizontal number of pixels multiplied by (x) vertical number of pixels — for example, 640x480.

Changing the Display Type and Driver

You can change a display driver by using the Display option in Control Panel or by using Device Manager. For more information about adding or changing a device driver, see online Help.

Caution: Some monitors can be physically damaged by incorrect display settings. Carefully check the manual for your monitor before choosing a new setting.

To change the display driver by using the Display option in Control Panel

  1. In Control Panel, double-click the Display icon.


    – Or –

    Right-click the desktop, and then click Properties from the context menu.

  2. In the Display Properties dialog box, click the Settings tab.

  3. In the Display Settings dialog box, click the Change Display Type button, and then click the Change button.


  4. In the Select Device dialog box, click the Show Compatible Devices option to see a list of drivers that are compatible with the display adapter.


    Click Show All Devices to see a list of all the display drivers available in Windows 95.

    Important: You can safely select any driver in the Show Compatible Devices list in the Select Driver dialog box. Select the Show All Devices option only if you know that you need to select a driver from the Models list that also supports your display. You must be careful to select a driver that you know to be compatible with your display adapter.

  5. In the Models list, click the driver you want to use, and then click OK.

    If prompted, follow the instructions on your screen to provide a disk or path to a directory that contains the display driver.

Tip The [boot] section of the SYSTEM.INI file should contain the following line for any Windows 95 version of a display driver:


The actual display driver is loaded from the Registry. This supports docking computers that have different adapters for the portable computer versus the docking station.

For display drivers that do not appear in the Select Device dialog box (that is, those that are not provided with Windows 95), the Windows Driver Library (WDL) provides support for drivers from other vendors. For information about the WDL, see Appendix J, "Windows 95 Resource Directory."

You can also install Windows 3.x display drivers, if required. However, Microsoft strongly recommends that you upgrade to Windows 95 display drivers so you can take advantage of the Windows 95-specific display drivers that provide new features and functionality. For example, many display adapters and drivers support Plug and Play detection and "on the fly" resolution changes; these features are not supported by Windows 3.1 drivers.

To install Windows 3.1 display drivers

  1. In the Display option in Control Panel, click the Settings tab, and then click Change Display Type.

  2. Click the Change button next to Adapter Type, and then click the Have Disk button.

  3. Specify the path to the disk or directory containing the Windows 3.1 drivers you want to use.

  4. Select the correct driver to use from the list that appears, and then click OK to install.

    When Show All Devices is selected in the Select Device dialog box, old drivers appear in the Select Device dialog under the manufacturer type Windows 3.x Drivers.

Notice that some Windows 3.1 drivers require the screen resolution to be specified in the [boot.description] section of SYSTEM.INI. For example:

display.drv=Acme Inc. 640x480 256 colors

Configuring Display Resolution and Color Palette

You can configure the display resolution and color palette choices for your display or customize the font size used by using the Display option in Control Panel.

After making these kinds of changes, you must shut down and restart the computer unless you are using a Plug and Play-compliant display adapter and driver that support on-the-fly changes.

To configure your display resolution

  1. In the Display option in Control Panel, click the Settings tab.


  2. In Display properties, use the options described in the following table to change your display settings.



    Color Palette

    Select from this list the number of colors you want for your display adapter. The larger the number, the greater the number of colors.

    Desktop Area

    Drag the slider bar to change the visible screen area used by the display. The larger the desktop area, the smaller everything looks on your screen.

    Font Size

    Select from this list one of the font sizes for your display type. Typically, the selections will be Small Fonts and Large Fonts. To set the font used in dialog boxes, see "Configuring Display Appearance" later in this chapter.


    Click to change the size of the text that Windows 95 displays, as described in the following procedure.

    Change Display Type

    Click to display a dialog box for selecting another adapter type or monitor type. Notice that the monitor type setting has no impact on system performance. This setting identifies the characteristics of the monitor in order to define the maximum resolution and power management capabilities that it supports. For information, see "Changing the Display Type and Driver" earlier in this chapter.

Note: Sometimes a larger number of colors requires you to have a smaller desktop area, and vice versa. This is due to a limitation of the display adapter. Extra large sizes might adversely affect the display in some applications.

To customize display of fonts in dialog boxes

  1. In the Display option in Control Panel, click the Settings tab, and then click the Custom button.


  2. Drag the controls until the sample shows the size you want, and then click OK.

    For non-Plug and Play devices, you must shut down and restart Windows 95 for the changes to take effect.

Setting the monitor type in the Display properties sheet does not affect the refresh rate output of your display adapter. To change this, you must run a utility supplied by your display adapter manufacturer or computer manufacturer. Some display utilities must be run in the AUTOEXEC.BAT file; however, on other computers, display type is set in BIOS configuration programs. Some examples of such utilities are described in the following list.


Manufacturer's display utility



Cirrus Logic


Diamond Stealth


Diamond Stealth 64




Tseng Labs


Western Digital


Configuring Display Appearance

You can use the Display option in Control Panel to set the screen saver and the background pattern used on the desktop. (These options replace Desktop options in the Windows 3.x Control Panel.)

You can also use settings in Screen Saver properties to take advantage of Energy Star Monitor support in Windows 95 if your hardware supports this feature. This is similar to the standby mode commonly used in portable computers to save power. Windows 95 can support screen saver power management if both of the following conditions are true for your computer:

  • In the Change Display Type dialog box, the option named Monitor Is Energy Start Compliant is checked.

    This option is checked automatically if, during Setup, hardware detection determined that the monitor supports the VESA DPMS specification. You can also check this option manually.

  • The device driver for this display uses either the Advanced Power Management (APM) 1.1 BIOS interface with support for device "01FF" (which is not supported by every APM 1.1 BIOS), or the VESA BIOS Extensions for Power Management. For information about whether your display adapter supports these BIOS interfaces, see the documentation for your device driver.

The display monitor is typically one of the most "power hungry" components of a computer. Manufacturers of newer display monitors have incorporated energy-saving features into their monitors based on the VESA Display Power Management Signaling (DPMS) specification. Through signals from the display adapter, a software control can place the monitor in standby mode or even turn it off completely, thus reducing the power the monitor uses when inactive. To do this, Windows 95 extends the screen saver capabilities to provide both a time-delay setting that allows the user to put the display monitor in a low-power standby mode, and a delay setting to turn the monitor off completely.

If your computer can use Energy Star power consumption features, additional options appear in Screen Saver properties. To take advantage of these features, both the display adapter and monitor must meet the Energy Star specifications. Also, the display driver must support the extensions needed to control the monitor. Several hardware providers currently manufacture monitors designed to support the Energy Star goals.

To use Energy Star power consumption features

  • In Display properties, click the Screen Saver tab and specify the time intervals for when to use low-power standby and when to shut off power.

For example, you might want to set these options:

  • Display a specific screen saver after 5 minutes of inactivity

  • Set the computer to standby after the screen saver has displayed for 10 minutes

  • Turn off the monitor after 15 minutes of standby

For information about setting up a screen saver, or changing the appearance of display colors, type styles, background pattern, and wallpaper, see online Help.

Configuring the Mouse

Mouse drivers based on the Windows 95 mini-driver architecture are protected-mode drivers that provide better support for MS-DOS – based applications in the Windows 95 environment. Windows 95 makes mouse configuration and customization easier by providing a single Control Panel option for mouse settings.

Windows 95 Setup detects Microsoft, Logitech, and Microsoft-compatible mouse device drivers, and then replaces these with new drivers.

Mouse and Pointing Device Driver Overview

Windows 95 provides the following improvements in mouse and pointing device support:

  • Supports Plug and Play for easy installation of pointing devices. For example, the VMOUSE driver interface supports Plug and Play.

  • Provides smooth, reliable input when using the new protected-mode drivers.

  • Supports multiple simultaneous devices; for example, when using PS/2® and serial devices at the same time.

  • Eliminates the need to use separate MS-DOS – based mouse drivers.

    Windows 3.1 required that an MS-DOS – based mouse driver be loaded before starting Windows to use a mouse in an MS-DOS – based application running in a window or running in a full screen.

The protected-mode Windows 95 VxD mouse driver provides mouse support for Windows-based applications, MS-DOS – based applications running in a window, and MS-DOS – based applications running in a full screen. These improvements result in zero use of conventional memory for mouse support in the Windows 95 environment. (However, most legacy real-mode drivers will run in Windows 95.)

In addition to better mouse services, Windows 95 allows the use of serial ports COM1 through COM4 for connecting a mouse or other pointing device.

To see the improvements in mouse driver support

  1. Be sure the real-mode mouse driver from such entries as MOUSE.COM or MOUSE.SYS has been removed from CONFIG.SYS or AUTOEXEC.BAT.

  2. Restart the computer, and start an MS-DOS – based application that supports the use of a mouse.

    For example, use an application such as Edit, and try the MS-DOS – based application both in a window and in a full screen. Notice that the mouse is available in both modes.

Changing Mouse Drivers

The Mouse option in Control Panel provides customization options, including setting the behavior of the mouse buttons and the mouse pointer. You can use either the Mouse option or Device Manager to change drivers for a pointing device. For information, see online Help.

For pointing device drivers that do not appear in the Select Device dialog box (that is, those that are not provided with Windows 95), the Windows Driver Library (WDL) provides support for additional drivers from other vendors. For information about the WDL, see Appendix J, "Windows 95 Resource Directory."

Configuring Mouse Behavior

You can use the Mouse option in Control Panel to configure buttons, customize mouse cursor appearance, set mouse speed, and other functions. This section briefly describes these functions. Different functions might be available, depending on the pointing device used with your computer.

To specify mouse behavior

  • In the Mouse option in Control Panel, click the tab for the behavior you want to set, as described in the following illustrations. After changing the settings to the ones you want, click the Apply Now button.

    For information about the configuration options, see the online Help.

Click the Buttons tab to specify the primary button and the speed for double clicks.


Configuring Communications Ports and Printer Ports

A communications resource is a physical or logical device that provides a single, asynchronous data stream. Serial ports, parallel ports, and modems are examples of communications resources. In Windows 95, VCOMM is the communications VxD that manages all access to communications devices. Port drivers use VCOMM to register themselves and to manage access to communications devices.

Two types of ports appear in Device Manager:

  • Communications ports, also known as COM ports, serial ports, or RS-232 ports, are used to connect RS-232 – compatible serial devices such as modems and pointing devices to the computer.

  • Printer ports, also known as LPT ports or parallel ports, are used to connect parallel devices such as printers to the computer. For more information about configuring printer ports, see Chapter 23, "Printing and Fonts."

Several types of communications ports might be listed in Device Manager:

  • Serial ports, also known as RS-232 COM ports, to which external serial devices can be attached. These usually require a 9-pin or 25-pin plug. Serial ports designed for Windows 95 use the 16550A buffered UART, which has a 16-byte FIFO that gives the CPU more time to serve other processes and that can serve multiple characters in a single interrupt routine.

  • An internal modem adapter. In addition to being installed in Device Manager, internal modems should also be installed and configured in the Modems option in Control Panel. For information, see Chapter 25, "Modems and Communications Tools."

  • A PCMCIA modem card, if it is using PCMCIA socket drivers designed for Windows 3.1 instead of Windows 95-compatible PCMCIA drivers. In this situation, a PCMCIA modem card is treated as if it were an internal modem adapter; that is, it must be installed as both a COM port and a modem.

When you install a communications device, Windows 95 automatically assigns COM names to communication ports, internal modem adapters, and PCMCIA modem cards according to their base I/O port addresses as shown in the following list:

  • COM1 at 3F8 (input/output range)

  • COM2 at 2F8

  • COM3 at 3E8

  • COM4 at 2E8

If a device has a nonstandard base address, or if all four standard ports have been assigned to devices, Windows 95 automatically assigns the modem to COM5 port or higher. Some 16-bit Windows 3.1 applications might not be able to access ports higher than COM4. Consequently, in the Systems option in Control Panel, you must adjust the base address in Device Manager or delete other devices to free up a lower COM port.

In addition, if some of the devices installed on a computer are not Plug and Play-compliant, you might have to change resource settings for their communications ports. You can change communications port settings by using Device Manager, as described in "Installing New Devices" earlier in this chapter.

Tip For future reference, you might want to record the settings that appear on the Resources sheet for each communications port.

Real-Mode Drivers and the IOS.INI Safe Driver List

Microsoft strongly recommends that you use 32-bit, protected-mode drivers wherever possible. With protected-mode drivers, configuration information is stored in the Registry rather than in CONFIG.SYS or other files.

The following shows the general guidelines for device entries in CONFIG.SYS, and whether such entries are required or can be removed under Windows 95:

  • When you use only protected-mode drivers, the only configuration information the operating system needs to know for system startup is the location of the Windows 95 system files and the directory for the swap file. You do not need to load drivers in CONFIG.SYS or AUTOEXEC.BAT.

  • Any boot device in your computer that needs real-mode support does not require an entry in CONFIG.SYS. In the unusual case that the CD-ROM is part of system startup, entries for this device must be included in CONFIG.SYS.

  • If your computer requires any real-mode drivers, an entry for loading the driver must be included in CONFIG.SYS and AUTOEXEC.BAT, as was true under earlier versions of MS-DOS.

Windows 95 automatically unloads any real-mode drivers for which it has protected-mode drivers to provide the same functionality. For example, the real-mode DBLSPACE.BIN driver is unloaded and the protected-mode DBLSPACE.VXD driver takes over. However, the protected-mode device driver should take over only when it guarantees similar functionality to the real-mode driver, not merely because it can drive the hardware.

Tip To determine whether a particular driver is running in real mode versus protected mode, click the Performance tab in the System option in Control Panel.

Real-mode drivers that can safely be replaced are identified in the safe driver list, which identifies drivers and TSRs that Windows 95 can replace with corresponding protected-mode drivers. The safe driver list (IOS.INI in the Windows directory) can include the following information:

  • Name of the driver or TSR, using the same name as used in CONFIG.SYS or AUTOEXEC.BAT

  • Driver requirements

  • Whether the driver hooks INT 13

  • Whether the driver monitors INT 13 (regardless of whether I/O is controlled by a protected-mode driver)

  • Whether the driver accesses hardware directly

Windows 95 does not store the version number of the driver or TSR in the list, so the vendor must change the name of the driver if a future version is enhanced so that the driver is safe or unsafe.

By default, the following drivers are considered safe:

  • MS-DOS 5.0-compatible real-mode block device drivers

  • INT 13 driver (provides INT 13 functionality and directly accesses hardware)

  • INT 13 monitors (hooks INT 13 for monitoring I/O but does not access hardware directly or modify the I/O buffer)

  • INT 13 hooker (hooks INT 13 for altering I/O but does not access hardware directly)

  • ASPI Manager (implements the Advanced SCSI Programming Interface for MS-DOS specification)

  • CAM Manager (implements MS-DOS Common Access Method specification)

A real-mode driver is considered unsafe if it implements functionality that is not provided by protected-mode drivers. For example, a real-mode IDE or ESDI driver that uses dynamic encryption is an unsafe driver because Windows 95 does not support encryption. Windows 95 protected-mode drivers do not implement the following functions, so if a real-mode driver uses any of the following functions it is considered unsafe and should not be added to the safe driver list:

  • Data compression (other than DriveSpace-compatible compression)

  • Data encryption

  • Disk mirroring

  • Bad sector mapping

  • Fault tolerance (maintaining ECC correction on a separate disk)

  • IOCTLS defined or extended by the vendor

If Windows 95 provides an appropriate protected-mode driver, you should use only the real-mode driver in these cases:

  • If the real-mode driver is used for a boot device.

  • If an MS-DOS Mode application uses the driver's device, in which case the protected-mode driver must be unloaded in order to load the real-mode driver.

Tip for Using Real-Mode versus Safe Protected-Mode Drivers

If a real-mode driver provides better performance or provides some functions not present in the Windows 95 protected-mode driver, you should remove the real-mode driver from the safe driver list, so that Windows 95 uses real mode to access the driver. Similarly, if a real-mode driver can safely be taken over by a protected-mode driver, add the real-mode driver to the safe driver list.

To determine whether you can use a protected-mode driver, you will have to test the equivalent functionality provided from the protected-mode driver versus your existing real-mode driver.

The following is the syntax of the safe driver list in IOS.INI:

filename, qualifier_string ; comments

The qualifier_string can be one shown in the following list.

Qualifier string



Indicates that it is acceptable to load the protected-mode driver and not use the mapper for this real-mode driver because it doesn't matter whether it sees any I/O requests. This is the default.


Implies that the device driver or TSR is safe, but it has an INT 13 hook that needs to see INT 13 requests. In this case, the protected-mode drivers are loaded, but the system routes the logical requests through the real-mode mapper and then switches back to protected-mode at the end of the INT 13 chain.


Implies that the driver is safe as long as it does not see any INT 13 requests. In this case, the protected-mode drivers are loaded and the real-mode mapper is not used.


Indicates a driver that controls a device that is not a disk, such as Interlnk. IOS issues INT 25 calls to all logical volumes in the system and determines whether the request is mapped to INT 13, ASPI, or CAM. If the request is not mapped, then this is a monolithic driver, as is the case for Interlnk. Adding non_disk prevents IOS from considering Interlnk in its safe-driver processing.


Similar to non_disk. Any driver that is monolithic and safe must have this qualifier set to indicate to IOS that the protected-mode port drivers can be loaded and the driver's entry point can be handled to prevent contention.

IOS.INI also contains an Unsafe CD section in IOS.INI. Adding a driver to this section indicates that this CDFS will not be loaded on the CD drives that this driver controls.

The following is an example of some IOS.INI entries.

386max.sys   ; Qualitas   ; 4DOS shell program   ; Afterdark   ; Afterdark   ; Afterdark
aspi3x90.sys   ; DTC SCSI no PM driver
drd600.sys   ; Acme 60X series CDROM
drd60asp.sys   ; Acme 60X series CDROM
drd60ps.sys   ; Acme 60X series CDROM

Tip for Troubleshooting Protected-Mode Drivers

If you believe that a protected-mode driver should be controlling a device, but the device appears with a real-mode driver in the System option in Control Panel, you can check entries in IOS.LOG. The IOS.LOG file in the Windows directory is created when a protected-mode driver is not available or if the operating system detects that an unknown device driver is controlling a device.

In most cases, the first line in IOS.LOG states why the protected-mode driver was not loaded. If the first line mentions MBRINT13.SYS, then the problem most likely is a virus (except if you are using a driver that replaces the master boot record).

Troubleshooting Device Configuration

This section describes specific problems in device configuration and how to correct them. For information about general procedures and Windows 95 tools that can be used in troubleshooting, see Chapter 35, "General Troubleshooting."

Your first and best resource for diagnosing problems due to changing device settings is the Hardware Conflict Troubleshooter in the Windows 95 Help Index.

To use the Hardware Conflict Troubleshooter

  1. In the Help Topics window, click the Contents tab.

    – Or –

    In any Help window, click the Contents button.

  2. Click Troubleshooting, click the option named If You Have A Hardware Conflict, and then follow the instructions on the screen.

Correcting Problems with Display

The display doesn't work correctly.

  1. Restart the computer, and then press F8 when the Starting Windows 95 message appears.

  2. Choose Safe Mode, which uses the standard VGA (640x480x16-color) driver.

    If this resolves the display problem, then the display driver is probably involved. Try replacing the driver with a newer version, or reinstall the driver from the original disks. (See "Correcting Problems with Display" earlier in this chapter.)

Tip Problems can result when Windows 95 incorrectly assumes that a display adapter can support certain functionality. If this occurs, the side effects might be anything from small display irregularities to system lockup.

To determine whether any performance problems might be related to the display adapter, you can progressively disable enhanced display functionality using the System option in Control Panel. On the Performance tab, click the Graphics button, and then use the slider to select new settings. For information, see Chapter 17, "Performance Tuning."

A display error occurs at a specific display resolution.

If your computer has problems with the display, determine whether the problems persist when you use lower screen resolutions and different color palettes with the display driver.

To see if the display error changes with resolution

  1. In the Display option in Control Panel, click the Settings tab.

  2. In the Color Palette box, click the box that displays available resolutions.

  3. If the selection is other than 16-color, select 16-color.

  4. Click the Apply button. Then shut down and restart the computer.

  5. Retest the condition that was causing the display error. If the error does not recur, you might want to temporarily operate at a lower resolution until you can upgrade the display driver to a version that functions without error.

A display driver fails to work.

If the display driver fails (and changing resolutions doesn't resolve it), you should check or replace the current display driver.

To check the display drivers

  1. In Device Manager, click the plus sign next to Display Adapters.

  2. Double-click the specific display adapter shown (for example, Cirrus Logic).

  3. In the properties dialog box, click the Driver tab.

  4. Click each file shown in the Driver Files box. The File Version appears in the File Details box, if available (some vendor's display drivers might not contain version information).

  5. Check displayed file versions for compatibility. Windows 95 display driver files have version numbers starting at 4.00 or higher.

  6. If you have an incompatible driver, you can reinstall the original driver from the Windows 95 disks, or get new drivers from Microsoft TechNet or Support Online at If Microsoft drivers do not support the display adapter, contact the display-adapter vendor for updated drivers.

To check where the driver is loading from

  • To ensure that a Windows 95 version of the display driver is installed, check the [boot] section of SYSTEM.INI for this entry:


If this entry is specified, the display entries in SYSTEM.INI are ignored, and the display drivers are loaded from the Registry. If the entry specifies any driver other than PNPDRVR.DRV, the display drivers are loaded from SYSTEM.INI.

The display adapter is not recognized.

If Windows 95 does not recognize the display adapter, try using the basic VGA drivers (a generic 640x480, 16-color driver). If you have a vendor-supplied driver disk for the display adapter, you can install the OEM drivers. If the drivers do not support Windows 95, some advanced display features are disabled.

Errors occur when initializing the display adapter.

If an error occurs during display adapter initialization, the computer stops responding. To restart the computer, press CTRL+ALT+DEL.

This problem might occur if you are using a video accelerator card and you change the display from the default setting (640x480, 16 colors) to 1024x768, 256 colors in the Display properties dialog box. Although Windows 95 might accept the changes, the error still results. The Super VGA (SVGA) driver (1024x768) included with Windows 95 is designed for nonaccelerated SVGA display adapters only. To correct this problem, change the display driver back to the default VGA setting.

To change your display driver back to VGA

  1. Restart the computer, press F8 when you see the Starting Window 95 message, and then choose Safe Mode.

  2. In the Display option in Control Panel, click the Settings tab.

  3. Click the Change Display Type button, and then click the Change button for the Adapter Type.

  4. Click Show all Devices, click Generic Display Drivers, and then click OK. When asked whether to use the current driver or a new driver, click Current.

If you want to use a high-resolution display driver with Windows 95, consult your display adapter manufacturer for the proper driver to use.

A Windows 3.1 display driver doesn't support advanced features.

Windows 95 cannot support some display features when a Windows 3.1-compatible driver is being used. If you are using a Windows 3.x compatible display driver with Windows 95, some advanced features (such as dynamic resolution changes, font smoothing, and automatic fallback to VGA) will not work.

Some Windows 3.1 drivers require the screen resolution to be specified in the [boot.description] section of the SYSTEM.INI.

Motion is jerky during multimedia playback.

  • Use Add New Hardware in Control Panel to verify that the appropriate display driver is installed for the display adapter you are using.

  • Check to see if MSCDEX is installed. If so, remove it and use Windows 95 CD-ROM File System (CDFS) drivers.

  • If the problem occurs for MS-DOS – based applications, check and maximize available XMS memory in the VM.

Correcting Problems with SCSI Devices

A SCSI device fails to work.

The SCSI and CD-ROM support built into Windows 95 requires that CD-ROM drives provide SCSI parity to function properly. For many drives, this is a configurable option or is active by default. Examples of drives that do not provide or support SCSI parity are the NEC® CDR-36 and CDR-37 drives.

If you have trouble with a SCSI drive, make sure the SCSI bus is set up properly (refer to your hardware documentation for specific details).

In some cases, adding or removing a SCSI adapter might prevent your computer from starting correctly. Check the following:

  • The ends of the SCSI bus must have terminating resistor packs (also called terminators) installed.

    If you have only internal or only external SCSI devices, the ends of the bus are probably the SCSI adapter and the last device on the cable. If you have both internal and external SCSI devices, the adapter is probably in the middle of the bus and should not have terminators installed. If you disconnect a device that has terminators installed (such as an external CD-ROM drive), be sure to install terminators on whatever device then becomes the last one on the bus. One of the devices on the SCSI bus (usually the adapter) should be configured to provide termination power to the bus.

    Windows 95 supports up to seven external SCSI devices in a chain, plus internal connections. In addition to the requirement that the last external and last internal SCSI device must be terminated, some hardware has additional requirements for where it must be placed in the SCSI chain.

  • Removable media must be mounted on the drive before running Setup.

    If you have a SCSI hard disk drive that uses removable media, such as a cartridge drive, make sure the media is mounted on the drive before running Setup. If no media is mounted on the drive, errors might occur during Setup that prevent installation of Windows 95.

A SCSI device works with MS-DOS but not Windows 95.

For many SCSI hardware devices, you can specify command-line parameters when the driver is loaded. By default, the Windows 95 miniport driver runs without parameters (in the same way it does for real-mode drivers). If you want to use a command-line parameter, you can add it to the Settings property for the SCSI controller. For real-mode parameters that the controller supports (and if the device has a Windows 95 .MPD file), you can enter parameters in the Adapter Settings box in the controller's properties.

For information about the switches that can be used for a particular SCSI device, see the documentation from the device manufacturer. There are no additional parameters added by Microsoft.

For example, if your SCSI adapter has full functionality under MS-DOS, but not under Windows 95, you can add any device parameters previously specified in CONFIG.SYS to the Adapter Settings box. As another example, for Adaptec 7700 SCSI devices, you might specify removable=off to disable support for removable media if you want to load another ASPI removable disk.

Setup does not automatically detect the SCSI CD-ROM drive.

Windows 95 needs exact SCSI ID information for Toshiba 3201, NEC 3x, and Texel 5201 CD-ROM drives. To make this information available to Windows 95, you must run the Add New Hardware wizard in Control Panel and manually choose to install specific hardware rather than running automatic detection of new hardware.

When running MSCDEX real-mode drivers, Windows 95 does not load protected-mode drivers from a SCSI CD-ROM drive.

If you are running MSCDEX.EXE and it loads real-mode drivers, you cannot load protected-mode drivers from a CD-ROM. In this case, you should comment out the lines in the AUTOEXEC.BAT and CONFIG.SYS files that MSCDEX.EXE placed there. For example:

rem device=c:\sbrpo\drv\sbpcd.sys/d:mscd001 /p:220
rem c:\windows\command\mscdex.exe /s /v /d:mscd001

Then you should restart the computer to allow Windows 95 to automatically detect the CD-ROM drive and its protected-mode drivers.

Notice that Windows 95 will automatically comment out these lines if the protected-mode drivers are on the CD-ROM from which you installed the drivers; that is, if you choose automatic detection, Windows 95 detects the hardware and its drivers and automatically comments out the real-mode drivers.

Setup doesn't recognize the correct SCSI CD-ROM drive.

Windows 95 Setup does recognize multiple CD-ROM drives connected to the same SCSI host adapter. Therefore, if it doesn't recognize one of the CD-ROM drives, it is a hardware problem. For example, it could be caused by a legacy adapter with more than one device with the same SCSI ID.

A SCSI tape drive or scanner does not show up in Device Manager.

Windows 95 does not assign drive letters to tape drives and scanners because they have no drive to assign a letter to, that is, they have no official class. Therefore, they appear as Unknown Devices in Device Manager. After you start Windows 95, it asks if you have a driver for these devices. If you have Windows 95 drivers, click Yes. To use existing real-mode drivers, click No, and then type the path to where the drivers are located. Windows 95 will continue to recognize and support these devices even though they are listed as Unknown Devices.

A SCSI drive does not show up in My Computer.

This probably indicates that there is something wrong with the SCSI drivers in CONFIG.SYS and AUTOEXEC.BAT, or that the protected-mode SCSI drivers fail to load. Look for an IOS.LOG file and check its entries, as described in "Real-Mode Drivers and the IOS.INI Safe Driver List" earlier in this chapter.

Running the DIR command on the SCSI drive produces strange characters.

If you type dir and strange characters appear on the screen, the hard disk might be a SCSI drive that requires double buffering which is not loaded. Verify that MSDOS.SYS has DoubleBuffer=1 in the [Options] section. (However, if you start the computer using MS-DOS version 6.0 or higher, double-buffering is provided when SMARTDRV.EXE is loaded in CONFIG.SYS.)

Correcting Problems with Other Devices

The system stalls when accessing CD-ROM.

After you press CTRL+ALT+DEL to shut down and restart the computer, Windows 95 might be unable to find the CD-ROM or stall when trying to access the drive; sometimes, pressing CTRL+ALT+DEL will not reset the computer. This might occur if Windows 95 is relying on real-mode drivers for the Sound Blaster® or Media Vision™ Pro Audio proprietary CD-ROM drive. If this is the case, you cannot access anything on the CD-ROM because its drivers cannot load. If this happens, turn off and then restart the computer. Use the Add New Hardware option in Control Panel to install the protected-mode drivers provided with Windows 95 for the specific CD-ROM device.

CD-ROM performance problems when AutoPlay is enabled.

This problem sometimes occurs with both protected-mode and real-mode (MSCDEX) drivers. To fix it, turn off AutoPlay, which is enabled by default, and then turn it back on again.

.WAV files cannot be played.

If Windows 95 cannot recognize the sound card, you might not be able to play .WAV files.

To verify sound card settings

  1. In Device Manager, click the Sound controller.

  2. Double-click the specific sound card, and then in the card's properties, click the Drivers tab so you can verify the drivers.

  3. Click the Resources tab, and verify IRQ settings.

  4. Check the Conflicting Device List, and verify that no conflicts for the sound card settings appear in the list.

Ports for sound cards with multiple CD-ROM adapters are not detected.

If a sound card has multiple CD-ROM adapters, they often include a program that activates the port to be used. This program must run before Windows 95 runs. If it doesn't, Windows 95 won't detect the port.

An input device fails.

  • Check the physical connection.

  • In Device Manager, check the driver used for the device.

  • Check for conflicts with the I/O and IRQ resources used.

  • Check for conflicting drivers or applications.

The mouse moves erratically or keyboard input fails.

  • In Device Manager, check the mouse and keyboard drivers, replacing them if necessary.

  • In the Mouse option in Control Panel, check Motion configuration for pointer speed.

  • Check the port used for the mouse.

  • Check the physical connection of the mouse and keyboard.

  • Make sure there are no entries for real-mode mouse drivers in CONFIG.SYS, AUTOEXEC.BAT, WIN.INI, and SYSTEM.INI.

  • When the Starting Windows 95 message appears, press F8, and then choose the Logged option. Check the BOOTLOG.TXT file and verify that the mouse driver is loading.

Mouse reports GROWSTUB errors.

If you were using the Microsoft Mouse Manager with Windows 3.1, Windows 95 Setup automatically updates the POINTER.EXE and POINTER.DLL files in the Mouse directory. If these files are not updated correctly, the mouse might stall and report GROWSTUB as a running task in the Close Program dialog box. To fix this problem, remove all references to the mouse in the AUTOEXEC.BAT and CONFIG.SYS files, and make sure the correct POINTER files were copied to the Mouse directory and not just the Windows directory.

Advanced Power Management 1.0 (APM) is not available.

Windows 95 Setup installs APM support automatically if it was installed on the computer previously. You can enable APM support after Setup by using Device Manager.

To enable APM under Windows 95 if it was disabled during Setup.

  1. In Device Manager, click System Devices, click the APM entry, and then click Properties.

  2. In the APM properties, click Settings.

  3. In the Settings dialog box, click Enable Power Management Support if this option is not checked.

    If no APM drivers were installed under previous versions of Windows, no check mark appears. Checking this box enables the drivers.

  4. Click Force APM 1.0 Mode.

    This option forces Windows 95 to use an APM 1.1 BIOS in APM 1.0 mode. In some cases, a BIOS incorrectly handles the new functions provided by APM 1.1 but functions properly when used in 1.0 mode. On some computers, this is checked automatically during Setup.

  5. Click Disable Intel SL Support to disable the SL check.

    In some cases, a BIOS incorrectly handles an unsupported call to the APM interfaces of some SL-type chipsets, causing the computer to stop responding. Disabling this option prevents the system from not responding.

  6. Click Disable Power Status Polling to prevent Windows 95 from calling the APM interface to check current battery level.

    Windows 95 calls the APM interface for this purpose with greater frequency than earlier versions of Windows 3.x, causing some computers to shut down. Disabling this feature prevents this, but also disables the battery meter.