Windows and Linux

In general, a Windows operating system should be installed before installing Linux. Windows and Linux use different bootloaders to start the OS and it’s best to have the Linux bootloader point to Windows. Your Windows installation will usually occupy the entire hard drive in a single partition. If you purchased your computer from a major manufacturer, you may have a recovery or back-up partition as well. An easy solution is to add a second hard drive and dedicate it to Linux. When installed after Windows, all modern Linux distributions will automatically detect your Windows installation on the other hard drive. You will need to make sure that the Linux hard drive has boot priority in your system BIOS. To get to the BIOS, you will need to hit some button, usually F2/DEL/F12, while your computer is booting. When starting with a brand new hard drive, you will still need to partition it for Linux.

To install Linux alongside Windows on the same hard drive, you will need to shrink the Windows partition to make space for a new Linux partition. They cannot exist on the same partition since Windows uses the NTFS filesystem format while Linux uses the ext3/ext4 format. Before beginning the process of installing Linux, you should clean up unnecessary files and defragment your Windows drive. All the repartitioning steps can be done using a Ubuntu Live CD.

Partitioning Your Hard Drive

A Windows partition should be at least 20 Gb (recommended 30 Gb), and a Ubuntu partition should be at least 10 Gb (recommended 20 Gb). Linux also uses a special type of partition called “swap.” Swapping is the process by which a “page” of memory in RAM is copied to the swap space to free up that page of memory. The combined sizes of the physical memory (RAM) and the swap space is the amount of virtual memory available. The result is that when the system requires more memory than is physically available, the kernel swaps out less used pages and gives memory to the current application or process that needs the memory immediately. Most modern systems will have more than enough RAM for Linux and the swap space will be rarely used. You should not run other intensive applications at the same time as RTXI anyway, if you want the best possible real-time performance. A good rule of thumb is to make the swap partition the same size or up to double the size of the amount of physical RAM you have installed.

You might also choose to create another partition that can be accessed from both Windows and Linux e.g. to store your data. This partition should be formatted as NTFS or FAT. Note that the FAT32 format cannot handle files that are larger than 4GB. To read and write a NTFS-formatted partition from Linux, you should install the ntfs-3g package. In Ubuntu, this is just:

$ sudo apt-get install ntfs-3g