What is the difference between BIOS and firmware?

Question

Could anyone elaborate on the differences between BIOS and firmware please?

Solution 1

As others already stated, BIOS is the specific name for the (motherboard) firmware in older PCs. New computers these days have a technically somewhat different kind of firmware which is called either EFI or UEFI.

Please note that any computer will contain, besides the BIOS (or EFI or UEFI), also other firmware. Network cards, video cards, RAID controllers, hard drives, flash drives, SSDs, sound cards, just to name a few examples, can all have firmware embedded inside the device.

Weirdly enough, the firmware of a video card is often called the video BIOS. This is technically incorrect. BIOS is appropriate only for the startup firmware of the motherboard itself.

Solution 2

So, BIOS is firmware for computers.

As you continue to read about computers, you will get the picture of BIOS, UEFI, EFI and so on.

The BIOS an acronym for Basic Input/Output System and also known as the System BIOS, ROM BIOS or PC BIOS) is a type of firmware used during the booting process (power-on startup) on IBM PC compatible computers.The BIOS firmware is built into PCs, and it is the first software they run when powered on. The name itself originates from the Basic Input/Output System used in the CP/M operating system in 1975.

Firmware is the combination of persistent memory and program code and data stored in it.Typical examples of devices containing firmware are embedded systems (such as traffic lights, consumer appliances, and digital watches), computers, computer peripherals, mobile phones, and digital cameras. The firmware contained in these devices provides the control program for the device.

Solution 3

Firmware is a generic name for all the software that is embedded on non-volatile memory. BIOS is stored in ROM, so it is firmware.

Solution 4

Bios - a specific type of firmware which is responsible for coordinating how your other devices (and firmware) talks to your OS. Bios can also be wielded by the user to dictate what sort of startup options (and the 'behaviour' of certain components, like RAM, CPU, GPU, etc) are run when you turn on the computer's power. Bios starts up first, before anything else, when you power on the computer.

Firmware - this is a more general term referring to the pieces of code that talk to your devices and tell the Operating System how is supposed to function with said devices.

Hopefully this is a decent broad level breakdown for those who are very new to the scene. ;)

Solution 5

The BIOS came about in the early days of LSI (Large Scale Integrated) Chips. It was really a mini operating system and had hooks for system programmers to use. For example outputting a character to some device. Firmware is a generic term for embedded software (and its included data) to run something. System controllers in large computer systems that control power up etc have a mini operating system (typically a mini linux) that's referred to as firmware. These terms are somewhat interchangeable but the firmware downloaded to a computer motherboard is referred as BIOS. Firmware downloaded to a video card can be referenced as BIOS as well.

Hope this helps.

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Comments

[AcePL]

In other words, BIOS is a firmware the same way the square is a rectangle. Kind of the same, but more specialized. Anyway, It would be a good Idea to drop using word BIOS in any case except for pre-UEFI PCs. But we'll see. Language is a very unpredictable beast...

[Koray Tugay]

What else is firmware for example?

[Fiasco Labs]

BIOS is the bootstrap firmware that allows the computer to start up, find all those other interface firmwares, the OS storage (not necessarily a drive) and load the OS. From "pull yourself up by your bootstraps".

[Fiasco Labs]

Any non-volatile memory stored program routines used by any microprocessor or fpga in any motherboard subsystem or peripheral.

[sawdust]

"I think firmware used to exist as something very specific" -- The origin of "firmware" is because it existed between the hardware and software. It has nothing to do with its "Just being, unchanging, firmly". See superuser.com/questions/299442/…

[sawdust]

"BIOS is only appropriate for the startup-firmware of the motherboard itself." -- That's modern usage. On the original IBM PC running MS-DOS or CP/M-86, the BIOS provided the device drivers, as its name indicates, for he basic peripherals. And the video-BIOS provided the driver for the frame buffer. The name was not "technically incorrect" as you assert.

[Louis Waweru]

@sawdust I should have said unmodifiable.

[sawdust]

That's wrong too.

[Louis Waweru]

@sawdust Yes, it is if the original meaning was the middle ground between hard physical logic and software. Thanks for pointing that out, I like it. I really just wanted to point out the fuzzy meaning in the current usage

[Harry Johnston]

Firmware is a kind of software. Whether a piece of software is "firmware" or not can be ambiguous or context-dependent in some cases. The BIOS really isn't one of them, though.

[Koray Tugay]

@HarryJohnston What do you mean "Firmware is a 'kind of' software." ?

[Louis Waweru]

@HarryJohnston not sure if I should take this down, or leave it up and absorb downvotes for the comments about firmware.

[jcbermu]

The OS of a home router or a Blu-Ray Player are good examples of firmware, Even nowadays your TV has firmware.

[Harry Johnston]

It goes off on a tangent rather than answering the question. I would recommend that you delete it, but it's up to you.

[Harry Johnston]

@KorayTugay: I meant what I said. "Firmware" is a sub-category of "software".

[Ismael Miguel]

"Weirdly enough the firmware of a video-card is often called the video-BIOS. This is technically incorrect. " --> In my opinion, a graphic card is basically a second computer. It has it's processor, it's inputs, outputs, power source (most of the time), it's own RAM memory and even has it's own firmware,'operating system' and (yes!) BIOS. Some card even do POST to check it's memory and if it is functioning properly! With this information, it is technically correct to say 'video-BIOS'.

[user]

Actually, while this answer isn't technically incorrect, it would be even more correct to say that the BIOS forms one layer in the CP/M model: BIOS below BDOS below CCP. The IBM PC and SCP's 86-DOS were most likely heavily influenced by the existing systems at the time, including CP/M (a design goal of 86-DOS was CP/M source compatibility after automatic source code translation for 8080 to 8086), and thus both the IBM PC and the prominent DOS for it (86-DOS became PC-DOS, later MS-DOS) adopted a similar architecture.

[Martin Rosenau]

The "video BIOS" is code that is executed by the main CPU (x86), not by the video processor. By the way: Simple on-board graphics still does not contain any processor executing code.

[Martin Rosenau]

"Thats modern usage" - Modern Linux distributions still call BIOS functions when there is no Linux driver for the graphics card available! So calling the BIOS when the OS is running is still done in some cases in modern operating systems.

[Harry Johnston]

Note that nowadays some firmware is located on a hard disk drive, typically in consumer products such as HDD recorders or home network storage.

[SAFX]

@FiascoLabs what about Atari/Nintendo/Sega cartridges, programs on non-volatile storage; do they qualify as firmware?

[Fiasco Labs]

@safx - Well, some memory cards and USB sticks have a write only switch, so is the contents stored on them while the switch is set to ro, firmware? Man, this is getting philosophical (^_^).

[Koray Tugay]

But BIOS is software whereas Firmware is hardware?

[David Richerby]

This seems to be incorrect. BIOS is a kind of firmware but most firmware is not referred to as BIOS.

[Overmind]

I think video BIOS would comply as correct since the video cards today do have (faster) RAM and (more powerful) PUs (than a MB). So the video card is actually a specialized MB.

[DavidPostill]

Please read the question again carefully. Your answer does not answer the original question -- which asks about the difference between BIOS and Firmware.

[lapin]

Hi there, this leads me to some thinking about UEFI definition. Please look at my related question here.

[voices]

@FiascoLabs, I guess so. I mean, if some piece of hardware receives its basic instructions from a read-only, USB-compatible, NAND flash storage device instead of a soldered CMOS EEPROM DIPP (for instance); I think that could be considered firmware.