Hard Drive BBS priorities – How to use them

There are so many acronyms when it comes to computing that sometimes it can all get a bit confusing, some of them are easy enough to figure out like HDD (hard disk drive) Some are a little bit harder like BBS…

BBS stands for BIOS Boot Specification. It is a standardized boot process that directs the BIOS to identify and prioritize the initial program load (IPL) of the devices in the computer. Usually allowing the selection of a specific drive to boot from.  

In this article, we will explore the functions of BBS priority and its advantages as well as its differences to other BIOS menu selections like Boot Priority List…

hard drive bbs priorities


First things first, what does booting mean?

When you press the power button on a computer it runs through a lot of processes before you are welcomed with the home screen. These processes are what we refer to when we talk about booting up a computer. It probably takes a full term of computer science at Harvard to understand every part of the process but we can easily summarize it here for the sake of understanding a bit more about BBS priorities and how to use them.

The first step in starting up a computer is to press the power button. This sends power to the motherboard and devices attached to the system that runs a process known as POST (Power On Self Test) Which makes sure everything is functioning at the hardware level.

The Motherboard then uses BIOS or EFI (this is essentially a very simple operating system that controls the motherboard) to go through the attached drives searching for a boot sector. The boot sector is program data stored on a storage device that can be used to load the operating system.

Once it has worked its way through the priorities and found the first drive with a boot sector it uses that drive to initiate the operating system by loading it into the memory, from there the operating system takes over and you finally get your home screen.

What are Hard Drive BBS Priorities?

As mentioned above, BBS stands for BIOS Boot Specification. But let’s get a little more specific.

1. B is for BIOS – This is the software stored on your motherboard that initiates the POST sequence when booting up your computer.

2. B is for Boot –  Booting is the entire process from pressing the power button to seeing the home screen.

3. S is for Specification – Here we are talking about the specific hard drive you want to use to boot up the computer so that the BIOS can choose the right sector once the POST sequence has finished.

So, essentially BBS gives us a chance to choose which disks to prioritize and in what order so that we can boot to different operating systems stored on different hard drives. It is worth noting that as the name suggests BBS is hard drive specific. Often BBS is a subset menu of the Boot Priority Order that gives you preferential choices for your hard drives which are selected as a coverall by the Boot Priority Order.

How to set BBS priorities.

The ability to set the BBS priorities is dependent on the Bios that your computer uses. To check if you have the option simply restart your computer and press the required keyboard key when prompted. This can happen quickly so it can often pay off to have a quick internet search of how to access the bios for your particular computer before restarting so you can hit that key while the computer powers up to access BIOs before the computer boots.

Once in Bios, you will need to navigate to the ‘BOOT’ tab if you have that option available. From there you can choose the ‘Boot Order Priorities’ in order to select where on the list of priorities your bios should look for a bootable partition. Usually, the hard disk option would be first.

Below that (BIOS dependant) you should see the option for Hard disk BBS. If you navigate to that menu and open it you will be able to configure the order that the BIOS searches through the disk to search for bootable partition.

This is basically a sub-priority list so that the ‘Hard Disk’ selection in the previous ‘Boot Order Priorities’ knows what disk to check first when it is called upon.

You may also see menu options for ‘Network Drive BBS Priorities’ and ‘USB Key BBS Priorities’ These do the exact same thing for that type of media.

Hard drive BBS vs Boot Priority List.

I have seen often people asking the question of BBS vs Boot Priority List, but in actuality, the two are one and the same. Simply BBS is a subset of the boot priority list that gives you more control over the order that devices are scanned in the initial boot-up stages.

It can be a bit confusing to get your head around initially but I have found a good analogy is this. Imagine you are stood in front of a magical locked door that can open to different places depending on what key you use to open it. You have a bunch of different keys that are categorized on individual key rings by the type of key. All of the keys have the potential to unlock the door but each one will take you to a different place and you know where you want to go and you know which key will take you there. So first you prioritize by type of key and then you prioritize by individual key so that you select the right one each time.

So it isnt so much a case of which system to use it is more a case of using them in conjunction with each other in order to prioritize the right disk at the right time to boot the operating system you need.

What should the boot priority order be?

Dare I say it but this is a very personal question…

With that in mind, this is what I do on my desktop, but I wouldn’t describe myself as an average computer user so take this with a pinch of salt but there may be things here you haven’t considered.

My Boot Priority selection looks like this…

  1. USB key
  2. Hard disk
  3. CD/DVD
  4. Network
  5. USB: Hard Disk
  6. USB: CD/DVD
  7. USB: Floppy

So the most common setup is to put the hard disk as the number 1 spot, this is because most computers use a C: drive and nothing else and just run one operating system. It is worth noting here that the boot priority list can also be used to speed up the boot process. So if you know you are highly unlikely to use a USB key then put Hard Disk 1st to avoid the extra step of looking through any USB keys before going to 2nd on the list.

Never the less I still prefer to put the USB key as number 1. This is so that I can keep a USB key at my desk that has recovery media installed on it. This is so that if I need it I can simply plug in the key and restart the machine without entering BIOS and it will boot from the USB. I also… and this is very nerdy, keep a basic Linux distribution on a separate key so that I can boot up a Linux command if the occasion calls for it.

This means that unless I have a bootable USB key plugged in it will skip over USB and go straight to option 2 which is my hard disks.

I pretty much only ever boot from hard disks or USB keys, so they are the top two and the rest don’t really matter to me. But I put CD drive as 3 and Network as 4 then the rest are variations of USB in the same order.

My hard disk BBS priority looks like this…

  1. SSD 1 (M.2) with Linux installed
  2. SSD 2 (M.2) with Windows installed
  3. other drives…

My motherboard has two M.2 slots so I decided to create a dual boot system that uses an M.2 drive each. On the 1st one, I run POP_OS which is a Linux distribution that I use for daily use. Ont the second drive I have Win10 installed which is where I run all of my professional software from for work.

This order of preference loads the grub2 boot loader from the Linux disk first which allows you to select which operating system to boot meaning you don’t have to enter bios every time you start you want to change the system you simply restart the machine.

You can see here how BBS used in conjunction with the Boot Priority List can be a powerful tool to streamline the startup process of your computer. In my opinion, it is a menu that is often overlooked.

What is Boot Override and how do I use it?

Ther is often an option in BIOS called ‘Boot Override’, this is a powerful tool that can save your bacon without ruining all the hard work and effort you put into setting up that perfect boot priority order.

So let’s say you have perfected your Boot priority order and your PC runs as smooth as butter and boots up like a dream. Then one day there is a strange problem with your machine, there are several tools at your disposal to inspect parts of your computer by isolating them in bootable software. For example, Memtest86, which is a tool to check the status of your RAM. In order to run it, you have to mount the ISO on a disk and boot from it.

But like me, you have opted to put the CD/DVD priority way down on the list so that inserting the disk into the CD/DVD drive will do nothing apart from your usual start-up procedure.

By entering the BIOS on startup and using the Boot Override tool you can force the BIOS to choose the CD/DVD drive or any bootable media you are using as the startup disk for a single instance.

When you save and exit the computer will boot from the selected location if possible and you will be able to do whatever it is you need to do from that location. Then when you are done and you restart the computer everything will proceed as normal without you having to renter the BIOS menus to re-prioritize things.

It’s a powerful tool that seems at first glance like a way to detonate a doomsday device but is actually quite a simple way of using a one-off boot priority.


BBS Priorities are pretty simple once you get your head around the potential they have to offer. Essentially they are a simple way to prioritize how your BIOS chooses where to look for your preferred operating system. There is a myriad of use cases and options to optimize your boot selection process whether you want it as fast as possible or whether you want as many options as possible the BBS priorities and Boot Order List are powerful tools to get your computer starting up just how you like it. 

And as always, remember, BACK UP YOUR HARD DRIVES!!