Re: [Modularkernel-developer] PhysicalKernelStart, PhysicalManagedStart

[Daniel O. <mus...@go...>]

> Well, only unless you do not want to manage some part of the physical memory,
> which I get is the nonsense :)
>    

Exactly. I am actually working on a reimplemantation of the multitasking 
code (which is not really working at the moment). Perhaps (if i don't 
get too confused^^) i will clean up this nonsense then, too.



>> Its a relict from previous code, where I thought (which was wrong, as I
>> know now) that PHYSICAL memory under 1 MB is needed for DMA, but in fact
>> it is VIRTUAL, so there should be no problem managing all physical
>> memory in the same way :)
>>      
> Interesting, what is your previous code about?
>
> Where did you get this information that memory under 1 MB is not needed for DMA?
> I recall that like the first 16 MB is used for DMA, because some devices
> simply cannot address higher memory for their DMA transfers.
> Does it have to do with IO Ports (and a lot of RAM, like plus 4GB)?
>    

Eh, i can't remember from where exactly i got this wrong information (i 
think i just misunderstood it). The code is quite about the same thing, 
just leaving this 1 MB free to be managed by a later (and nether 
existent) "DMA memory manager"
How DMA will have to be implemented is another thing, about which i 
don't think yet.
But i have some good ressources ( http://www.osdever.net/ )

In fact, it gets time to think about how to implement a "hardware 
abstraction" concerning the devices.
I mean, we must, in some way, manage all devices which are present to 
the system.
We (the kernel) will only be responsible for recognizing that there are 
some devices and to provide some sort of infrastructure, that allows 
only one process (-tree) to use the specific device.
What's done with the device is then up to the driver, which should not 
be part of the kernel and thus exchangeable.

:)