RE: RAM or "empty"?

[Learner <ruxyz@yahoo.com>]

Hi,

Reply Inline 

--- Ankit Jain <ankitjain1580@yahoo.com> wrote:

> well it is really unique. actually i could not
> understand in this what is this reseved address
> space.
> 
> 
> rest reply inline
> 
> 
>  --- Learner <ruxyz@yahoo.com> wrote: 
> > Hi ,
> > 
> > Reply Inline .
> > 
> > --- "Thekkedath, Gopakumar"
> > <Gopakumar.Thekkedath@fci.com> wrote:
> > 
> > > 
> > > 
> > > 
> > > 
> > > >Is there a way to find the PHYSICAL ADDRESSES
> of
> > > all
> > > >the devices used in a Computer ? 
> > > 
> > >    does cat /proc/iomem serves the purpose ?
> > > 
> > 
> > Well , if /proc/iomem gives the PHYSICAL address
> > range of devices , then why is the  System RAM 
> > split into 3 different address ranges as seen
> below 
> > (marked by arrows ) ? Is it bcoz the Motherboard
> is
> > designed in this manner ? 
> > 
> > ~> cat /proc/iomem
> > 00000000-0009fbff : System RAM  <--- 1
> 
> basically this hex range represents 2^32
> 
> how much memory area can be accessed by this and
> what
> about rest. 1 mopre ques. suppose i have 1Mb of RAM
> for that how many address lines i need

The Hex range is 2^32 since the output is taken 
on a 32-bit processor based computer , where in 
you can address 0 - 4 GB addresses ( i.e. 0 - 2^32 ) .

> 
> > 0009fc00-0009ffff : reserved
> 
> whats this reserve says and why and for what it is
> reserved?
>

Not sure about this , maybe Intel manual docs will 
help you on this .
 
> > 000a0000-000bffff : Video RAM area
> > 000c0000-000c7fff : Video ROM
> 
> why do we need to seprate all these areas?
> 

Becoz Video RAM area is read + write capabable area,
but Video ROM is a read only area.


> > 000e0000-000effff : Extension ROM
> > 000f0000-000fffff : System ROM
> > 00100000-1fecffff : System RAM  <---- 2
> >   00100000-0028dadf : Kernel code
> >   0028dae0-00324f63 : Kernel data
> > 1fed0000-1feeffff : ACPI Non-volatile Storage
> > 1fef0000-1fefffff : System RAM  <---- 3
> > 40000000-40000fff : Intel Corp. 82801BA/BAM/CA/CAM
> > Ethernet Controller
> >   40000000-40000fff : eepro100
> > 40300000-4037ffff : Intel Corp. 82815 CGC [Chipset
> > Graphics Controller]
> > 44000000-47ffffff : Intel Corp. 82815 CGC [Chipset
> > Graphics Controller]
> > feea0000-ffffffff : reserved
> > 
> > Are these memory address ranges dynamically 
> > determined ? Which kernel code file does this ?
> > 
> > Also , does  /proc/ioports represent IO-mapped 
> > PHYSICAL memory addresses ,
> > similar to the  the Memory-mapped PHYSICAL memory 
> > addresses in /proc/iomem ?
> > 
> > ~> cat /proc/ioports
> > 0000-001f : dma1
> > 0020-003f : pic1
> > 0040-005f : timer
> > 0060-006f : keyboard
> > 0070-007f : rtc
> > 0080-008f : dma page reg
> > 00a0-00bf : pic2
> > 00c0-00df : dma2
> > 00f0-00ff : fpu
> > 0170-0177 : ide1
> > 01f0-01f7 : ide0
> > 02f8-02ff : serial(auto)
> > 0376-0376 : ide1
> > 03c0-03df : vga+
> > 03f6-03f6 : ide0
> > 03f8-03ff : serial(auto)
> > 0cf8-0cff : PCI conf1
> > 1000-103f : Intel Corp. 82801BA/BAM/CA/CAM
> Ethernet
> > Controller
> >   1000-103f : eepro100
> > 2000-20ff : Intel Corp. 82801BA/BAM AC'97 Audio
> >   2000-20ff : Intel 82801BA-ICH2 - AC'97
> > 2400-243f : Intel Corp. 82801BA/BAM AC'97 Audio
> >   2400-243f : Intel 82801BA-ICH2 - Controller
> > 2440-245f : Intel Corp. 82801BA/BAM USB (Hub #2)
> >   2440-245f : usb-uhci
> > 2460-246f : Intel Corp. 82801BA IDE U100
> >   2460-2467 : ide0
> >   2468-246f : ide1
> > 
> > > >Also , does the VM in linux translate the
> memory 
> > > >address of programs into actual Physical
> > addresses 
> > > >of RAM , or is it that Hardware does the actual
> > > >translation to Physical addresses  ( since the
> > RAM 
> > > >addresses would differ across different
> Computers
> > 
> > > >depending on the amount of RAM & also the
> > > Motherboard
> > > >design ) .
> 
> does it really depend on motherboard? or does it
> depend on the hardwares stuffs we have on system?
> 

I think motherboard , since the point to add
additional
H/W is fixed .  

Cheers !

> thanks
> 
> ankit
> 
>
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