hi all.. i have been working on char device driver. i need a good document on advance char device driver..?

From: kernelnewbies-request@kernelnewbies.org Subject: Kernelnewbies Digest, Vol 5, Issue 20 To: kernelnewbies@kernelnewbies.org Date: Thu, 14 Apr 2011 12:00:01 -0400

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Today's Topics:

1. Re: Missing 1GB RAM, where is it? (Andrzej Kardas)

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Message: 1 Date: Thu, 14 Apr 2011 17:43:05 +0200 From: Andrzej Kardas <andrzej-kardas@o2.pl> Subject: Re: Missing 1GB RAM, where is it? To: Adrian Cornish <adrianc@cqg.com> Cc: kernelnewbies@kernelnewbies.org Message-ID: <4DA71609.5070800@o2.pl> Content-Type: text/plain; charset="iso-8859-1"

On 14.04.2011 17:09, Adrian Cornish wrote:

...

Just a thought - lower end graphic cards use system RAM as their own dont they You right, devices like graphic card, ethernet cards etc. are mapped into memory, what cause some amount RAM is not available for system use. But as i've wrote before, i'm wondering why addresses in /proc/iomem (where the map of memory is) are not contiguous. I think, there should be info about what region of memory is mapped where (BIOS, PCI bus, for system use etc)*for whole 4GB *(Am I right??) address space (for 32bit OS). Instead of that, there are small "holes" in addresses and the total size of this holes (in my case) is about 400MB. So i wonder where that memory is.