Chapter 4 MANAGING DEVICES AND PERIPHERALS

Device Manager Provides a graphic view of hardware installed on the computer Helps to manage and trouble shoot the hardware Shows whether hardwire is working properly

Automatic Installation of Hardware Plug-and-Play (PNP) has changed the way we install hardware Manual installation of hardware is a thing of the past All you need to install PNP hardware is  The hardware  The driver  The directions

Automatic Installation of Hardware The Plug and Play (PnP) basic input/output system (BIOS) automatically identifies PnP devices and arbitrates their resource requests. The resource allocation among PnP devices is not permanent. If another PnP device requests a resource that has already been allocated, the BIOS again arbitrates the requests to satisfy all of them.

Automatic Installation of Hardware After startup, Windows XP takes over management of devices and might again change one or more assignments to suit its own requirements

Troubleshooting Installations The best way to avoid problems with the installation of hardware is to follow the manufactures instructions Although you can run into problems with their instructions.

Troubleshooting Installations If you see any of the icons indicating a hardware problem try the following Open the Properties dialog box for the device. The General tab lists the status of the device and lets you launch a device troubleshooter.

Troubleshooting Installations Consult the manufacturer’s instructions to verify that you have performed all necessary steps to configure the device Right-click the device and select Uninstall. Restart Windows, and allow it to detect the device again.

Hardware Resources Hardware resources are used by the hardware to communicate with the operating system They are  Interrupts  Input/Output (I/O) ports  Direct Memory Access (DMA) channels

Hardware Resources Hardware resources are dynamically changed in the PNP process It is important to remember not to change the resources of a PNP device because this can have and effect on the dynamic process

Interrupts Hardware devices must get the processor’s attention to send messages. The microprocessor knows this process as an interrupt request (IRQ) The microprocessor uses this information to determine which device needs its attention and the type of attention that it needs.

Interrupts Modern computers have minimum of 15 interrupts Computers with Advanced Programmable Interrupt Controllers (APICs) can have up to 24 IRQs,

Input/Output (I/O) Ports I/O ports are a section of memory that a hardware device uses to communicate with the operating system. When a microprocessor receives an interrupt request via an IRQ, the operating system checks the I/O port address to retrieve additional information about what the hardware device wants it to do.

Direct Memory Access (DMA) channels DMA channels allow a hardware device, such as a floppy disk drive, to access memory directly, without interrupting the microprocessor. DMA channels speed up access to memory

Direct Memory Access (DMA) channels Modern computers have eight DMA channels, numbered 0 through 7 DMA channels are managed by the motherboard’s chipset or by devices that have their own DMA controller.