[GTALUG] two or three tricks for installing Linux as a second OS on a Windows box

[D. Hugh Redelmeier]

Most computers come with Microsoft Windows.  If you insist on buying a 
computer without Windows, you have less choice and may have to pay more.  
Besides, once in a blue moon Windows is useful.

To install Linux, you can either blow away Windows (easy!) or your can 
install Linux beside Windows.

If you want to install Linux beside Windows, you usually have to get 
Windows to relinquish some disk space.  (Alternatively you might be able 
to add another disk.)

Windows has a way of reducing the size of a volume but it is unwilling to 
relocate a structure that is in the middle of the volume.  So it is only 
willing to give up slightly less than half of the volume.

I use gparted (ntfresize is underneath) to shrink a Windows NTFS volume, 
because I always want to shrink in to less than 50% of its original size.
I do this from a live Linux flash drive.

Here are the tricks that are not so obvious:

- if Windows is using bitlocker, you need to turn that off in Windows.
  Otherwise gparted cannot do anything with the partition.

  Our newest computer came with bitlocker enabled (with no password).
  That's probably a good idea but not for us.

  After bitlocker is turned off, gparted can operate.

  Perhaps you can turn it on again after resizing.  I don't know.

  (On Windows: Settings: Privacy & Security: Device Encryption)

- By default, Windows assumes that it can leave the filesystem in an 
  inconsistent state when it shuts down.  It assumes that you'll boot
  Windows again when you power the system up.  Apparently this speeds 
  things up a little bit.

  This is very unhealthy if you are going to boot Linux next,
  especially if you are going to run gparted to muck with the NTFS 
  filesystem.

  You can fix this by going to Windows' Control Panel (which is something 
  different from Settings), Power Settings, and untick "turn on fast 
  startup (recommended)".  It is slightly tricky because you have to click 
  some option to allow you to change the fast startup option.  Sheesh.

- (old advice; may be obsolete; I don't wish to find out the hard way that 
  it is still needed.)
  After you have resized the NTFS partition, reboot to Windows.  Don't do 
  anything else with the disk in Linux first.
  Why: it used to be the case that gparted got something slightly wrong in
  the NTFS partition, something that a Windows boot fixed silently.
  After booting Windows, you can reboot to a Linux install medium safely.