Resource Allocation. Part I

It is necessary to allocate the resources of a motherboard for normal operation of various devices: interruption (IRQ), channels of direct memory access (DMA), input/output addresses or accessed memory scopes. Most versions of BIOS have special section “PnP/PCI Configurations” which contains resource settings.


If you set these values by default, the system will automatically allocate all resources according to Plug and Play standard. Manual setting may be required to connect some non-standard or outdated devices. The necessity of manual resource setting is very rare so the section “PnP/PCI Configurations” is considerably reduced in modern motherboards and it may have two or three particularly important parameters.

Plug and Play OS (PnP OS Installed)

This parameter defines what will allocate the resources – BIOS or operating system.

Possible values:

  • Yes – BIOS configures those devices which are necessary for booting while operating system sets the rest ones but it must support Plug and Play;
  • No – all devices are set and all resources are allocated by BIOS.

Modern versions of BIOS control the devices using the function “ACPI”. If BIOS complies with this standard, operating system will configure them even with a value No.