What is secondary boot order

sumanch · 05-24-2010, 04:08 AM

Hi,
This is a general question. I know that we can set boot order in BIOS setting and the system boots up according to that. But recently I have come across the term "secondary boot order"? What I gathered so far is that using secondary storage device for booting. Is my understanding correct? Also please elaborate. Thanks in advance.

business_kid · 05-24-2010, 04:50 AM

This certainly won't help you. It depends on where you found the term.
In your bios, you set up the devices you want to boot from in order. Second & subsequent options are the secondary boot order
In bootloader literature, in can mean your other configured boot options in the boot loader
In other places, It can mean anything you boot off except the primary hard disk.
Give it to Groucho Marx, and I am sure he could add a twist to it

ajeetsinghraina · 05-24-2010, 04:53 AM

(1st Stage Bootloader) Primary bootloader generally means "MBR" while Secondary Bootloader(2nd Stage Bootloader) means "GRUB or LILO" which lets you to select Operating system.

Also,we have 1.5 stage bootloader which I let you to explore for homework

onebuck · 05-24-2010, 07:38 AM

Hi,

It would be nice to know where the OP got the term(s)?

Initial Program Loader (IPL) or Secondary Program Loader (SPL) are the proper terms. But 'Boot loader showdown: Getting to know LILO and GRUB' would be one good reference the OP should read.

Quote:

excerpt 'Boot loader showdown: Getting to know LILO and GRUB'
What is a boot loader?

Most simply, a boot loader loads the operating system. When your machine loads its operating system, the BIOS reads the first 512 bytes of your bootable media (which is known as the master boot record, or MBR). You can store the boot record of only one operating system in a single MBR, so a problem becomes apparent when you require multiple operating systems. Hence the need for more flexible boot loaders.

The master boot record itself holds two things -- either some of or all of the boot loader program and the partition table (which holds information regarding how the rest of the media is split up into partitions). When the BIOS loads, it looks for data stored in the first sector of the hard drive, the MBR; using the data stored in the MBR, the BIOS activates the boot loader.

Due to the very small amount of data the BIOS can access, most boot loaders load in two stages. In the first stage of the boot, the BIOS loads a part of the boot loader known as the initial program loader, or IPL. The IPL interrogates the partition table and subsequently is able to load data wherever it may exist on the various media. This action is used initially to locate the second stage boot loader, which holds the remainder of the loader.

The second stage boot loader is the real meat of the boot loader; many consider it the only real part of the boot loader. This contains the more disk-intensive parts of the loader, such as user interfaces and kernel loaders. These user interfaces can range from a simple command line to the all-singing, all-dancing GUIs.

Boot loaders are usually configured in one of two ways: either as a primary boot loader or as a secondary boot loader. Primary boot loaders are where the first stage of the boot loader is installed on the MBR (per the previous description). Secondary boot loaders are where the first stage of the boot loader is installed onto a bootable partition. A separate boot loader must then be installed into the MBR and configured to pass control to the secondary boot loader.

Quote:

Originally Posted by ajeetsinghraina

(1st Stage Bootloader) Primary bootloader generally means "MBR" while Secondary Bootloader(2nd Stage Bootloader) means "GRUB or LILO" which lets you to select Operating system.

Also,we have 1.5 stage bootloader which I let you to explore for homework

If you look at the above explanation for boot loader then your definition is not quite right. Either 'Lilo' or 'Grub' could have a bootloader at the 'MBR' with a secondary on the partition of choice. Of course the BIOS does recognize the hardware initially but the passing to the 'IPL' on the 'MBR' is the general means we use today to initialize our systems.