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A BIOS provides multiple options for specifying an order/priority to search for boot devices. Is there really much of a purpose now to have to specify more than one possible boot device?

It would seem to me it is only useful when popping in an CD/DVD to install an OS after which the common scenario is to always boot from the hard drive unless something is broken.

I'm curious as to why not simply have 1 option/device to set in the BIOS and expect the user to press a key to do alternate boot instead?

Is there still a scenario for having the BIOS try multiple devices in a configured order?

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2 Answers 2

up vote 1 down vote accepted


Yes, there are indeed practical uses for the boot-priority sequence, even today.

Longer answer

What I have used for years is the following boot priority sequence is:

  1. [cd]
  2. [floppy]
  3. [hard drive].

This allows me to normally boot from the hard-drive, but then to be able to boot into DOS mode to do data-recovery, drive-imaging, or whatever by simply pushing a DOS-formatted floppy that is in the drive all the way in. I can also boot from a DOS-formatted CD or a Windows, Linux, etc. CD/DVD by putting it in the drive. That’s it. I don't have to remember to press any keys, I don't have to press them fast enough, nothing. Simple.

These days, I have replaced the floppy with a small, permanently installed flash-drive, but the rest is the same.

Another common scenario is to have the computer set to automatically boot from the network normally, but if the network connection is down, to fall back to the hard drive.

Moreover, not all motherboards support a boot-device selection key. In this case, it is much easier to set a boot cascade than to have to edit the BIOS.

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You can have more than one hard drive installed (I am currently working on a computer with two installed, and I choose which one to boot from instead of using GRUB or something). You can also boot from a USB stick, the network, CDs... a variety of things. The point of having multiple options is for the people who actually need to use those multiple options.

Other times it is just a preference, as someone who doesn't have a CD drive might disable that device, and make Boot from USB the first choice, then to the HDD. It just depends on how you like things.

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Two nitpicks: (1) Most, if not all BIOSes only let you select one boot device from each class (e.g., one hard-drive, one removable drive, etc.) so you cannot set multiple hard-drive in the priority. (2) The question is about what benefit the boot-priority sequence provides over the boot-menu key. The OP already knows that you can have multiple devices, but the said that you can just press F8, etc. to select whichever one you want. –  Synetech Aug 30 '12 at 2:58

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