Dual booting SSD-based desktop/laptop with Windows pre-installed

Part-3 : The dual booting - the preparation and planning

So far, in part 1 and 2 you have tried out, but not modified anything on the laptop. Now you are cmfortable and prepared to take the plunge.

Everything we do can be reversed in this part, so no worries.

Step 2 Shrink the C: drive such that you have at least 64GB of space for Linux.

Now right-click "This computer" on the desktop, then select Manage. You will see a screen with disk volume display, with C:, D:, etc. Right click on the C: volume, then select "Shrink volume". The system usually throws up a scary looking message. If the laptop is fairly new, the warning can be ignored.

Shrink the volume so that about 64 GB space is freed up. If the disk is 64GB total, make free space for 24GB. For this, you can subtract 64 from the disk size (or 24 if the disk is smaller than 128GB). Say the disk is 128GB. The new size of the C: would be 128-64 = 64GB, or approximately 64 followed by 9 zeros. For 64GB SSD, the number is 40GB.

That is the new size of the C:

Select OK, OK, OK, etc. At the end, you should have SSD divided in to 2 volumes (partitions), one is the C:, now suitably reduced in size, and an unnamed volume of free space. This free space will be used for Linux OS later.

Step 2.5 Shrink D: drive if required

If D: drive uses the entire HDD, shrink the D: also; you will need space for user data and other parts of Linux.

Right-click "This computer" on the desktop, then select Manage. You will see a screen with disk volume display, with C:, D:, etc. Right click on the D: volume, then select "Shrink volume". The system usually throws up a scary looking message. If the laptop is fairly new, the warning can be ignored.

Again, give about half to Windows and free up half the disk as unused. Make sure you use the GB count - so if you have 1TB disk, 512 GB should be freed up. If the disk is 512GB, 256 GB should be freed up, etc. You can shoose less or more, depending on your needs.

Now reboot the system. Windows needs to adjust its indexes etc for the disk size changes you have made. For a good measure, reboot a second time (and a third time) so that Windows boots up without any warning.

Step 3 Planing Linux installation

Your SSD should contain the Linux boot programs, application binaries and configuration files. But these are not conveniently laid out. I chose to place /boot and /usr on SSD, which contains bulk of Linux OS and utilities. So I need to make two partitions in the SSD free space, one should be size 8GB (for /boot) and the remaining space for /usr.

a) /boot - 8GB

b) /user - emaining space on SSD (say 56GB)

Apart from these, you need a swap, a root (/) and a home (/home) partitions.

Swap should be abut 2x size of memory, but then again, only if you plan to use the laptop with memory intensive programs, or multiple virtual machines (in which case even 3x the memory may be required. For root (/) partition, we don't need a lot of space - perhaps 32GB is enough, as /usr is now on a separate partition. The remaining HDD space should be allocated to /home. So:

c) swap - 8GB (or 16GB for 8GB main memory)

d) root (/) - 32GB

e) remaining space on HDD for /home

Alternatively, you can keep root (/) on the SSD, and make /home, /tmp, /var and swap on HDD. You need 5 partitions either way.

So now that you know how your Liux OS will be laid out, it is time to boot into bootable Linux USB drive, and install Linux.

Before you proceed, you should try installing Linux in a virtual machine, with the exact same partitions as planned above, so that there are no surprises for you.