How can I procure datasheets for hardware?

[krish240574]

Hello all,
I am an independent developer based in Mumbai, India. I am interested in enhancing Linux by writing device drivers for hardware on it.
How can I procure datasheets/technical documentation for the same? I am interested in SATA and SAS hardware.
Do I need to speak with the company itself? If so, would I , as an independent developer, be able to procure datasheets? (I need to get details of the register set).
Are there any other technical documents I need, for writing a device driver?
PLease advise,

Thanks for any advice, tips.
Highly appreciated.
Regards,
Kumar

[sybvn]

Kumar,

I can answer you only the question

Are there any other technical documents I need, for writing a device driver?

You need your microcontroller's data manual / programming manual, and samething for each external devices. But I suppose you asked a differenrent question, didn't you?

I don't have answer for your other questions but have a similar question.

I am neither an independant developers nor hardware engineer. I am working on embedded software. My hardware colleagues buy hardware components, make hardware, and provide datasheet for me. So I don't know all the fact behind it. And I wonder:

As an independant developer, can one be easy to buy any hardware components they need? I hear rumor that some hardware providers only provide their components at large quantity. Is it real? Is there some technical/business reason for them to do that? And I know the fact that some datasheets are not publicly provided by hardware producers. And the fact that some datasheet contains so many errors and typos (may someone confirm with me this idea?). And that when my company bought components with small quantity, though datasheet was provided, they refused to help on their vague sheets.

I'd like to hear what people know and experience about this problem. Why it is happening like this? The most obvious answer to me now is hardware producers/providers only want to sell at large quantity. Is it right? So do they make vague datasheet purposefully? I am just blind about all. What do you know?