Dual-Booting

For General Users

The idea of having both Windows and Linux installed on a computer and being able to select one at boot time appeals to many who are trying, or migrating to, Linux. Outcome is very dependent on version of Windows

Windows 10

Should not be attempted by General Users

• searches of online forums produce zero reports of suitable procedures
• high probability that Windows 10 would cease booting

The only viable alternative appears to be using a live Linux distribution see Evaluation

Windows 8.x

The better known Linux distributions will set this up automatically, during installation to a single hard disk drive in the computer

• generally works reliably

Windows < 8

Although this installation is reliable, as per Windows 8.x above, 'It is likely to cease functioning following the next update of Windows and restoring dual-boot requires Getting Technical

Getting Technical

Upgrades to Windows 10

if existing Windows 7

and firmware is BIOS

and partition table(s) are MBR(DOS)

Then it is reported that an upgrade to Windows 10 can dual-boot. Examples include:

Desktop running separate HDD for Linux and Windows.

• BIOS normally boots to the LInux HDD, which is running OpenSUSE Leap42.1
  • and from which Windows 10 can be booted via GRUB 2
• During Windows upgrades, disconnect Linux HDD and set BIOS to boot to Windows HDD.

Although not tested, it seems likely that the above would also work with the Linux (only) HDD partitioned GPT

Laptops & netbooks running Ubuntu 16.4 (YMMV with derivatives)

• Basic setup is for BIOS to boot to the Windows bootloader.
  • GRUB 2, must be installed in the partition containing Linux. (most installers will do that)
• A free utility called EasyBCD is required to modify the Windows bootloader to include entries for other operating systems
  • this utility must be rerun following every Windows upgrade.

One of the many videos on this subject is https://www.youtube.com/watch?v=9dwwSSg-kJM

Upgrades to Windows #> 8.1

to be advised

Issues can often be minimised by having additional hard disk(s) in the computer. This is not an expensive option, given current HDD prices.

Upgrades to Windows 7

There is one known issue when Windows is on either a separate HDD or same HDD. This also prevents Linux from booting before the Win 10 upgrade. Different workarounds are given in the link:

http://answers.microsoft.com/en-us/windows/forum/all/kb3033929-does-not-install-multi-boot-win7-linux/8f35f8f8-c0b2-461a-a8aa-4bbf16c49920?auth=1

USB Drive

Pros

• easily added
• no change to internal HDD

Cons

• Linux relies on the absolute order of storage devices detected by the computer's firmware
  • plugging in (say) a uSB memory drive, may upset the booting
  • contermporary Linux avert this by allocating a unique UUID to the drive and booting/mounting via that ID

Internal HDD

• ensures permanent order of drives

Installation

• mainstream Linux will allow installation to a second hDD
• the bootloader must also be installed to the second HDD, in this technique
  • can require "drilling down" the installation options

Selecting Boot Device

The selection of "drive" and hence OS is done at POST stage and depends on type of firmware in the computer

see Booting from Removable Media