What are the F6 options during installation?

Question

What is the meaning of different options in the F6 context menu of Ubuntu installation dvd ? i.e.

acpi=off
noapic
nolapic
edd=on
nodmraid
nomodeset
Free Software only

How do they affect the installation?

Answer 1

acpi=off: Disables ACPI which is used for power management and actually turning off power after the shutdown. This may help with compatibility with motherboards which misuse ACPI.

noapic: Disables Advanced Programmable Interrupt Controller. This is used to resolve hardware conflicts for interrupts, but may itself cause a conflict. Use of this option may disable some hardware that enters a conflict without an APIC.

nolapic is very similar, but disables a different (newer) kind of APIC called a LAPIC(Local Advanced Programmable Interrupt Controller)

edd=on enables the EDD probe(Enhanced Disk Drive), used by motherboards to provide more functionality to disk drives

nodmraid disables dmraid which is used for RAID purposes but may cause empty disks to appear even if they are fully partitioned, possibly with the wrong size.

nomodeset keeps the video driver from performing modesets which are used to bring the graphics card to an enhanced state, but due to incompatibility, may cause display issues.

Free Software Only is used for legal purposes and will not load restricted drivers or codecs. Use if your jurisdiction disallows the use of restricted software without a license and you do not have one, or if you do not prefer to use closed-source or restricted components or code on your system. Certain codecs or hardware may be unusable.

https://help.ubuntu.com/community/BootOptions#Common_Kernel_Options has a few other options.

Answer 2

acpi=off or noacpi

Disables the "Advanced Configuration and Power Interface" or ACPI which is used for power management in general (Fan speeds, sleep states...). In some cases like running the installer from a Live USB or booting a laptop it is needed for compatibility with the motherboard and how it handles/mishandles ACPI. Just in case you are wondering, the difference between acpi=off and noacpi is that acpi=... can accept more values. For example acpit=force,irq.

noapic

Disables the "Advanced Programmable Interrupt Controllers" which is used to resolve hardware conflicts for interrupts. The effects of using a combination between noacpi and noapic depends on the hardware. In some cases, disabling both will solve booting problems, in others it will create problems. Suggestions are that you try one at a time.

nolapic

Disables the "Local Advanced Programmable Interrupt Controler" which applies to newer CPUs and they are handled. nolapic is commonly used when you are using old hardware. Many times even withnoapic`.

edd=on

Enables the "Enhanced Disk Drive" service which is used by VERY old motherboards to provide support for hard drives, specially ones that go beyond the 32GB barrier, which by todays standards is like the size of a normal flash drive. Anyway, if you have an old motherboard and a HDD bigger than 32GB, then use edd=on.

nodmraid

Disables the "Device Mapper RAID" which is used for everything related to RAIDs. Not recommended if you want to use RAIDs.

nomodeset

Disables the video from using modesets which are used for example for better resolutions and graphics. If you are using an old video card, old monitor or both, then activate this mode.

Free Software Only

Simple eliminates all options to install restricted drivers, codecs or in general any proprietary software. This is all for legal purposes and/or if you want to have a 100% free software environment, but note that you will not be able to listen to MP3 songs, use your Nvidia or Ati card to full potential or watch H264 or Flash videos. You will need to install them afterwards when you finish with the Ubuntu install process.

For more information here are 2 good links about the Kernel parameters:

You can see all Kernel parameters here: http://fxr.watson.org/fxr/source/Documentation/kernel-parameters.txt?v=linux-2.6

Ubuntu used parameters are here: https://help.ubuntu.com/community/BootOptions#Common_Kernel_Options

Answer 3

Option nodmraid only disables the drivers for "FakeRaid" (i.e. Nvidia or intel raid firmware on some SATA controllers). Setting this option may be required if some partitions show up in /dev/mapper/ like nvidia[somehash]. This may also cause some real partitions (/dev/sda1) to disappear if the dmraid driver decides those devices are used in a dm-raid.

So when you are going to use some real hardware raid controller or linux software raid (mdadm) then it is a good idea to disable dmraid.

Answer 4

Newer versions of the "Other options" menu also include Expert mode, which is explained in the InstallMethods wiki:

This causes the installer to ask questions about virtually everything it does. It's supposed to be powerful rather than friendly, so the developers don't pay a lot of attention to UI warts in this mode; however, it should at least work to the point where you can complete an installation. If you like, you can try playing around with non-default answers to the questions it asks, and make sure its responses are appropriate.