Windows 95 provides improved support for hardware devices and peripherals including disk devices, display adapters, pointing devices, modems and other communications devices, and printers. This section summarizes the improved device support.
Mini-driver architecture for reliable drivers.
Windows 95 extends the mini-driver architecture for printer drivers used in Windows 3.1 throughout the operating system to the architecture for drivers of other system components, resulting in increased driver stability and forward compatibility. Although it is still possible to write and use monolithic drivers in Windows 95, Microsoft recommends that hardware manufacturers use the mini-driver model.
Improved support through Plug and Play.
Plug and Play is designed so that adding a device, either permanently or dynamically, requires nothing more than taking it out of the box and plugging it in. The computer and operating system seamlessly adjust to the new configuration. When using Plug and Play-compliant hardware, users will no longer be required to manually set jumpers and switches to redirect IRQs, DMA channels, or I/O port addresses. This saves time and expense in service calls related to hardware configurations.
Plug and Play is also a benefit to users who install Plug and Play-compliant devices into older, legacy computers. Information about these devices is stored centrally in the Registry, and devices that cannot be reconfigured dynamically receive first priority when resources are allocated.
The Registry and Device Manager for resource management.
To properly manage resources such as IRQs, I/O addresses, and DMAs, Windows 95 uses the Registry to track devices and resources allocated for both Plug and Play-compliant devices and legacy devices. The Registry provides a centralized, dynamic data store for all Windows settings, with a "current configuration" branch that stores information on a per-configuration basis. For example, the Display option in Control Panel stores per-configuration information about display resolution changes and Print Manager stores per-configuration information about the default printer.
Device Manager — which is available from the System icon in Control Panel — provides a graphical representation of devices configured in Windows 95, and allows properties used by these devices to be viewed and changed, as appropriate. Device Manager also shows resources allocated for the configured devices. Through the resource configuration information maintained in the Registry, Windows 95 is able to automatically identify and resolve device resource conflicts for Plug and Play-compliant devices. For legacy devices, Device Manager helps users quickly identify and resolve resource conflicts with devices in the system.
Virtual device drivers.
Windows 95 uses virtual device drivers (VxDs) where possible to provide improved performance. VxDs replace the real-mode MS-DOS device drivers used in previous versions of Windows for the following:
Windows 95 provides device driver and TSR functionality as protected-mode components that reside in extended memory, avoiding context switches between protected-mode and real-mode when running 32-bit applications. Use of VxDs also improves system stability and reliability over using the MS-DOS device drivers.
PCMCIA support.
Windows 95 delivers power, compatibility, ease of installation, and dynamic card insertion and removal to PCMCIA users. PCMCIA drivers in Windows 95 are robust, 32-bit, dynamically loadable virtual device drivers that use no conventional memory. Windows 95 includes an updated version of Card and Socket services to support PCMCIA.
To install a PCMCIA device, just insert the card in the computer. For example, when you plug in a PCMCIA network adapter, Windows 95 detects the network adapter, loads the network drivers, and establishes a network connection. Then the user interface is updated to show that the mapped network drives are now active. With earlier versions of Windows or other operating systems, you had to shut down and restart the computer to begin using the device.
Hot docking support.
Plug and Play allows "hot docking" (that is, docking with the device powered on) and insertion of devices. This means that when a device is inserted, the operating system recognizes the new device, its capabilities, and its requirements, and loads the appropriate driver without requiring the user to restart the system unless the required resources are not available to the new device. Applications are notified about dynamic events, so they can take advantage of the new functionality or stop attempting to use unavailable devices.
Instead of changing configuration files and restarting the computer, a user working at a docking station can click Eject PC on the Start menu.