---
title: "Goals of plug and play BIOS"
subject: "Computer Organization and Architecture"
chapter: 7
key: "semester_5/computer_organization_and_architecture:pnp-bios-goals"
source: https://www.bctengineer.com/q/semester_5/computer_organization_and_architecture/pnp-bios-goals
site: BCT Engineering
---

# Goals of plug and play BIOS

Computer Organization and Architecture · Chapter 7: Input-Output Organization

- Asked in: 2068 Baisakh (old course), 8 marks
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_5/computer_organization_and_architecture/pnp-bios-goals
- Whole chapter: https://www.bctengineer.com/md/semester_5/computer_organization_and_architecture/chapter-7

## Question

What are the main goals of the plug and play BIOS specification? Explain.

## Short answer

The main goals are automatic configuration without jumpers, conflict‑free assignment of IRQ/DMA/I/O memory, boot device setup before OS loads, dynamic reconfiguration for hot-plug, a standard OS interface, backward compatibility with legacy hardware, storing settings in non‑volatile memory, and OS independence.

## Answer

The Plug and Play BIOS specification defines how the system BIOS supports automatic configuration of devices. Its main goals are:

1. **Automatic configuration:** configure PnP devices without jumpers, switches or user setup, assigning IRQ, DMA, I/O address and memory to avoid conflicts.
2. **Resource conflict resolution:** allocate non-conflicting resources among PnP cards and legacy (fixed) devices, using the stored configuration (ESCD).
3. **Boot device configuration:** configure the devices that are needed to start the system (display, keyboard, boot disk) before the OS loads.
4. **Dynamic configuration:** support hot insertion/removal and docking or undocking, with the system able to reconfigure without a restart.
5. **Common interface for the OS:** provide a standard set of BIOS functions so that the operating system can find the device nodes, read their resource needs and change settings.
6. **Backward compatibility:** work with existing ISA bus devices and existing software; no changes to the hardware of legacy cards are required.
7. **Non-volatile storage of configuration:** keep the settings in non-volatile memory for faster boot-up next time.
8. **Operating-system independence:** the BIOS does the initial configuration; the OS can take over control of the resource allocation, so the same scheme works with different operating systems.

## Check yourself

The answer's key points as multiple-choice questions, with the correct option and why.

1. What is the goal of automatic configuration in the PnP BIOS specification?
   A. Configure devices without jumpers, switches or user setup, avoiding conflicts
   B. Make users set all IRQs
   C. Remove the ISA bus
   D. Disable all legacy cards
   Answer: A. The BIOS assigns IRQ, DMA, I/O and memory automatically. (Key point: Automatic configuration)

2. Which devices does the BIOS configure before the OS loads?
   A. All printers
   B. Only sound cards
   C. Only network cards
   D. Devices needed to start the system: display, keyboard and boot disk
   Answer: D. Boot device configuration is a stated goal so the system can start. (Key point: Boot devices)

3. What does dynamic configuration support?
   A. Overclocking
   B. Changing the CPU clock
   C. Hot insertion/removal and docking/undocking without restart
   D. Only reboot-time changes
   Answer: C. The system can reconfigure when devices are added or removed. (Key point: Dynamic configuration)

4. What does backward compatibility require?
   A. A new OS only
   B. Work with existing ISA devices and software without changing legacy card hardware
   C. New hardware changes in legacy cards
   D. Removal of ISA
   Answer: B. Legacy cards need no hardware changes. (Key point: Backward compatibility)

## Related in Computer Organization and Architecture

- [Plug and play device configuration](https://www.bctengineer.com/question.md?key=semester_5%2Fcomputer_organization_and_architecture%3Apnp-configure) — Computer Organization and Architecture, chapter 7, asked 2×