This is our seminar about plug and play service in computer systems which was played a dominant role in facilitating the usage of input and output device and indeed computers at all .

1. ‫الرحيم‬ ‫الرحمن‬ ‫الة‬ ‫بسم‬
Mashrq university
Faculty of engineering
Electronics engineering dept
Seminar under title:
Prepared by : supervised by :
Rashid Mohammed Othman eng :BABIEKER abd alrhman
Al-amin Hassan
Hassan ahmed Hassan
Mohammed Duke
Mohammed abd Elwhab madani
yassin ali awad aljeed

2. Introuction:
• its a hardware and software standard for automatically informing
software (device drivers) where it can find various pieces of
hardware (devices) such as modems, network cards, video cards,
etc.
• 1993 leading companies of PCs invented PnP process .
• Plug-and-Play didn’t really hit the mainstream until 1995
with the release of Windows 95 and PC hardware designed
to work with it.
PnP services:
1.The device is completely configurable by software.
2.The device can uniquely identify itself to any inquiring software.
3.The device able to reporting the system with resources it need.

3. What is resource its requires:
Every terminal device need to access RAM & MPU:
• Interrupt requests (IRQ) - An IRQ, also known as a
hardware interrupt, is used by the various parts of a
computer to get the attention of the CPU.
• Direct memory access (DMA) - access system
memory without consulting the CPU first.
• Memory addresses - assign a section of system
memory for exclusive use.
• (I/O)address defines the ports used by the device
for receiving and sending information.

4. PnP requirement :
• PnP BIOS: reads Extended System Configuration
Data (ESCD) , which is a file that contains
information about installed PnP.
• Peripheral Hardware: The devices that you are
adding into the system must themselves be PnP
compatible(almost all devices these days are like
that).
• The System BIOS: The system BIOS plays a key role
in making Plug and Play work.
• The Operating System: Finally, the operating system
must be designed to work with the BIOS

5. PnP operation:
the steps that the BIOS follows at boot time when managing a PCI-based Plug and Play system:
 Create a resource table of the available IRQs, DMA channels and I/O
addresses.
 Search for and identify PnP and non-PnP devices on the PCI and ISA
buses.
 Load the last known system configuration from the ESCD area .
 Compare the current configuration to the last known configuration.
 If the configuration is new, begin system reconfiguration.
 Check the BIOS settings to and eliminate any of these from the resource
table
 Assign resources to PnP cards from the resources remaining in the
resource table,
 Update the ESCD area and show message "Updating ESCD ... Successful".
 Continue with the boot.

6. USB case and hot swap :
When you add a new USB device to your computer system.
• The function driver notifies the PnP Manager that a new device has been
added to the system.
• The PnP Manager queries the USB bus to locate the drivers for the device.
• When the USB bus completes the IRP, it is sent back through the device
stack to the Plug and Play Manager, which determines whether a new
device has been added or removed.
• The PnP Manager obtains information about device and begins to
configure it.
• The PnP Manager searches through the registry to determine whether the
device has been previously installed on the system.
• If the device has not been attached , the PnP Manager updates the
registry .
• The Plug and Play Manager finds and loads the drivers for the device if
they are present.
• The Plug and Play Manager assigns the necessary system resources to the
device.
• The Plug and Play Manager sends an IRP to start the device.