How Linux Supports More Devices Than Any Other OS, Ever

[Pedro]

"Greg Kroah-Hartman is a longtime developer of the Linux kernel, known for his work maintaining USB drivers as well as for packaging the SUSE kernel at Novell. O'Reilly Media recently interviewed Greg about his claim that the Linux kernel now supports more devices than any other operating system ever has, as well as why binary-only drivers are illegal, and how the kernel development process works."

-{ Quote: "I've seen quotes from you and I've even heard from you in person that you believe Linux, the kernel, supports more devices than any other operating system ever.

I can back it up by that's true, and it's been independently verified by somebody from Microsoft.

What makes Linux capable of doing this? Is it development process; is it ease of writing drivers; is this sheer stubbornness on parts of people like you? What is it?

I think it's all of those. The ease of writing drivers; Linux drivers are at normally one-third smaller than Windows drivers or other operating system drivers. We have all the examples there, so it's trivial to write a new one if you have new hardware, usually because you can copy the code and go. We maintain them for forever, so the old ones don't disappear and we run on every single processor out there. I mean Linux is 80% of the world's top 500 super computers right now and we're also the number one embedded operating system today. We've got both sides of the market because it's--yeah it's pretty amazing. I don't know why, but we're doing something right.

A lot of people listening to this or reading this are going to say "Now wait a second! I just bought a new computer and plugged in this peripheral and it didn't work. How can you say that you support all this great hardware when I just bought a new piece of hardware and it doesn't work?"

Yeah. The thing about drivers is the vast majority, the number doesn't matter. You only care about what you have so it becomes personal. What you have is a very small number of devices. To be fair, so I originally thought that; we don't have a lot of devices that are supportive. Let's work on that. So I started the Linux Driver Project saying hey we will write any driver for anybody and maintain it for free for you--for companies. I got an underwhelming amount of responses from companies. I got a huge response from developers. I have over 300 people willing to help out with this.
(...)" }-
http://broadcast.oreilly.com/2008/10/how-linux-supports-more-device.html

[Arup]

Linux has no choice since 3rd party drivers are difficult to impelent, what worries me though is that if the Kernel keeps supporting every tom dick and harry hardware on earth, eventually it is bound to get bloated. I do my own custom kernel where I take off support for everything but the hardware I have and it turns out to be a much leaner, faster kernel.

[Kerodo]

Yep, good point Arup, last thing we need is a bloated Linux kernel.... that kinda defeats half the purpose of using Linux....

[Pedro]

Is it really faster? Aren't they just files hanging around, till you change some piece of hardware?

[Alphalutra1]

-{ Quote: "Is it really faster? Aren't they just files hanging around, till you change some piece of hardware?" }-
Although it's written for FreeBSD, all the reasons it gives are valid:

http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/kernelconfig-custom-kernel.html

I'd also just like to add that less code running means less code running that could have bugs, security issues, cause instability, etc. Also, sometimes two drivers both work for a device or think they work for a device which leads to it not functionning as well, I know that this issue happened for slackware in thinkpads since the harddisk was detected by the wrong driver which made it slow

Cheers,

Alphalutra1

[Pedro]

Note that i'm not doubting, but i am trying to understand.
I get the faster boot time, but not the RAM part. Can you give me an example of something being loaded that isn't needed?

TIA :)

[Alphalutra1]

Depends if its compiled into the kernel or as a module. For example, lets say I don't have any wireless cards in my computer, but my kernel has all types of wireless support compiled in. All those bits of code relating to wireless are in the kernel, so that means they are running in my memory even though I'm not using them. Also like the handbook says, the difference in RAM is important for small memory systems (like under 64MB), so you'll save some MB of RAM, but this is inconsequential in a normal desktop and laptop today.

However, if everything is compiled as a module, then all the modules you don't use are sitting on the hardisk, but not loaded into memory. Therefore you can compile all the wireless stuff as modules and just simply not load them then all that code isn't running.

Cheers,

Alphalutra1

[Pedro]

-{ Quote: "
However, if everything is compiled as a module, then all the modules you don't use are sitting on the hardisk, but not loaded into memory. Therefore you can compile all the wireless stuff as modules and just simply not load them then all that code isn't running.
" }-
I guess this is the part i perhaps misunderstood about usual distro kernels. I thought they were mainly using modules for that kind of stuff.

I think i get it now.

[Arup]

My optmized Kernel feels far moren snappier, not only is the memory footprint lesser, it also boots faster, programs open snappier and running whole day, it is more responsive than stock kernel.