XP 32 bit Memory

In message , Tim Meddick
writes:
Absolutely no need for "3rd-party boot loaders" as Win7 will easily
cope with multi-booting Windows NT-based OSs (although, personally, I
have had some problems getting the NT bootloader to boot MS-DOS-based
Windows...).

==

Cheers, Tim Meddick, Peckham, London. :-)

I wasn't talking about boot loaders, but memory managers. (Which John
says won't happen.)



"John Callaway" wrote in message
.. .
On Mon, 07 Dec 2009 08:34:33 -0400, John John - MVP
wrote:

J. P. Gilliver (John) wrote:
In message , "Ken Blake,
MVP" writes:
[]
All 32-bit client versions of Windows (not just Vista/XP/7) have a 4GB
address space (64-bit versions can use much more). That's the
theoretical upper limit beyond which you can not go.

But you can't use the entire 4GB of address space. Even though you
have a 4GB address space, you can only use *around* 3.1GB of RAM.
That's because some of that space is used by hardware and is not
available to the operating system and applications. The amount you can
use varies, depending on what hardware you have installed, but can
range from as little as 2GB to as much as 3.5GB. It's usually around
3.1GB.

Note that the hardware is using the address *space*, not the actual
RAM itself. If you have a greater amount of RAM, the rest of the RAM
goes unused because there is no address space to map it to.
[]
Since the hardware presumably doesn't need much, presumably the RAM
_beyond_ the hardware address _could_ be used, if someone were to write
a suitable "memory manager" (as used to be done in the early days of DOS
to get round the "640k" limit (and even a little around 1M, IIRR).
Unless the hardware uses incomplete address decoding, that is.

If such a manager were to be written, of course, only software that knew
about it could use it (like DOS software that either knew about being
"loaded high" or didn't), so there probably would be insufficient
usefulness for it to be worth anybody's while, since software houses
would be unlikely to cater for it.

That won't happen on NT operating systems, the kernel will simply not
allow it.

John


Ken Blake,
I do appreciate all the info on this matter. I recently
purchased a Dell laptop with W7 OS. I could not install some older
programs on it, so I tried to install XP 32 bit OS on a partition
that I resized with W7. The CD/DVD drive would not fully load the
install disc. I returned the computer. I have since done some research
and found out that if I have XP 32 Bit OS on the computer and then
load W 7 on it, it seems to go better. So I intend to buy another Dell
with W 7 OS, then resize the partition, making room for XP 32 bit OS
on the other partition. I will then Ghost the W 7 partition using
Norton. I will then load XP 32 bit OS over the W 7 OS providing the
CD/DVD will read the XP install disc. Then Ghost the W 7 OS on the
other partition. I have downloaded EasyBC boot loader utility to have
the option to dual boot to which OS I want on boot up.
Ken, am I on the right track?

John P. Callaway


--
J. P. Gilliver. UMRA: 1960/1985 MB++G.5AL-IS-P--Ch++(p)Ar@T0H+Sh0!:`)DNAf
** http://www.soft255.demon.co.uk/G6JPG-PC/JPGminPC.htm for ludicrously
outdated thoughts on PCs. **

Politicians are much like ships: noisiest when lost in a fog.

J. P. Gilliver (John) wrote:
In message , "Ken Blake,
MVP" writes:
[]
All 32-bit client versions of Windows (not just Vista/XP/7) have a 4GB
address space (64-bit versions can use much more). That's the
theoretical upper limit beyond which you can not go.

But you can't use the entire 4GB of address space. Even though you
have a 4GB address space, you can only use *around* 3.1GB of RAM.
That's because some of that space is used by hardware and is not
available to the operating system and applications. The amount you can
use varies, depending on what hardware you have installed, but can
range from as little as 2GB to as much as 3.5GB. It's usually around
3.1GB.

Note that the hardware is using the address *space*, not the actual
RAM itself. If you have a greater amount of RAM, the rest of the RAM
goes unused because there is no address space to map it to.
[]
Since the hardware presumably doesn't need much, presumably the RAM
_beyond_ the hardware address _could_ be used, if someone were to write
a suitable "memory manager" (as used to be done in the early days of DOS
to get round the "640k" limit (and even a little around 1M, IIRR).
Unless the hardware uses incomplete address decoding, that is.

If such a manager were to be written, of course, only software that knew
about it could use it (like DOS software that either knew about being
"loaded high" or didn't), so there probably would be insufficient
usefulness for it to be worth anybody's while, since software houses
would be unlikely to cater for it.

That won't happen on NT operating systems, the kernel will simply not
allow it.

John

J. P. Gilliver (John) wrote:
In message , "Ken Blake,
MVP" writes:
[]
All 32-bit client versions of Windows (not just Vista/XP/7) have a 4GB
address space (64-bit versions can use much more). That's the
theoretical upper limit beyond which you can not go.

But you can't use the entire 4GB of address space. Even though you
have a 4GB address space, you can only use *around* 3.1GB of RAM.
That's because some of that space is used by hardware and is not
available to the operating system and applications. The amount you can
use varies, depending on what hardware you have installed, but can
range from as little as 2GB to as much as 3.5GB. It's usually around
3.1GB.

Note that the hardware is using the address *space*, not the actual
RAM itself. If you have a greater amount of RAM, the rest of the RAM
goes unused because there is no address space to map it to.
[]
Since the hardware presumably doesn't need much, presumably the RAM
_beyond_ the hardware address _could_ be used, if someone were to write
a suitable "memory manager" (as used to be done in the early days of DOS
to get round the "640k" limit (and even a little around 1M, IIRR).
Unless the hardware uses incomplete address decoding, that is.

If such a manager were to be written, of course, only software that knew
about it could use it (like DOS software that either knew about being
"loaded high" or didn't), so there probably would be insufficient
usefulness for it to be worth anybody's while, since software houses
would be unlikely to cater for it.

That won't happen on NT operating systems, the kernel will simply not
allow it.

John

John John - MVP wrote:

That won't happen on NT operating systems, the kernel will simply not
allow it.

There is built-in support in the kernel for an application to map
unmanaged memory.

John John - MVP wrote:

That won't happen on NT operating systems, the kernel will simply not
allow it.

There is built-in support in the kernel for an application to map
unmanaged memory.

dennis wrote:
John John - MVP wrote:

That won't happen on NT operating systems, the kernel will simply not
allow it.

There is built-in support in the kernel for an application to map
unmanaged memory.

AWE, only for the applications own use, you can't develop a memory
manager around this, the kernel will not allow this to manage other
processes' memory. On 32-bit systems AWE will only be able to access
RAM above the 4GB barrier if the operating system is PAE capable, 32-bit
XP can't do it. Few applications are AWE capable, this is mostly
reserved for large database programs and other such applications.

John

dennis wrote:
John John - MVP wrote:

That won't happen on NT operating systems, the kernel will simply not
allow it.

There is built-in support in the kernel for an application to map
unmanaged memory.

AWE, only for the applications own use, you can't develop a memory
manager around this, the kernel will not allow this to manage other
processes' memory. On 32-bit systems AWE will only be able to access
RAM above the 4GB barrier if the operating system is PAE capable, 32-bit
XP can't do it. Few applications are AWE capable, this is mostly
reserved for large database programs and other such applications.

John

John John - MVP wrote:

AWE, only for the applications own use, you can't develop a memory
manager around this, the kernel will not allow this to manage other
processes' memory. On 32-bit systems AWE will only be able to access
RAM above the 4GB barrier if the operating system is PAE capable, 32-bit
XP can't do it. Few applications are AWE capable, this is mostly
reserved for large database programs and other such applications.


I'm not talking about AWE, but about mapping "device" space (physical
memory). That way you can use memory above 4G also in 32bit XP.

XP supports PAE. Its own memory manager just doesn't allow access to
memory above 4G.

John John - MVP wrote:

AWE, only for the applications own use, you can't develop a memory
manager around this, the kernel will not allow this to manage other
processes' memory. On 32-bit systems AWE will only be able to access
RAM above the 4GB barrier if the operating system is PAE capable, 32-bit
XP can't do it. Few applications are AWE capable, this is mostly
reserved for large database programs and other such applications.


I'm not talking about AWE, but about mapping "device" space (physical
memory). That way you can use memory above 4G also in 32bit XP.

XP supports PAE. Its own memory manager just doesn't allow access to
memory above 4G.

dennis wrote:
John John - MVP wrote:

AWE, only for the applications own use, you can't develop a memory
manager around this, the kernel will not allow this to manage other
processes' memory. On 32-bit systems AWE will only be able to access
RAM above the 4GB barrier if the operating system is PAE capable,
32-bit XP can't do it. Few applications are AWE capable, this is
mostly reserved for large database programs and other such applications.


I'm not talking about AWE, but about mapping "device" space (physical
memory). That way you can use memory above 4G also in 32bit XP.

XP supports PAE. Its own memory manager just doesn't allow access to
memory above 4G.

XP supports PAE for DEP only, drivers and applications can't access the
memory above the 4GB barrier. From what I understand memory above the
4GB barrier was available with PAE when XP was released but too many
drivers were misbehaving and causing BSODs so Microsoft decided to put
an end to this in SP1.

I know that a certain RAM disk can apparently make use of the memory
above the 4GB barrier, I guess this is what you mean by "device space".
Although the RAM drive can map the space for use as temporary storage
for other applications the other applications still cannot use this for
their process space, the memory manager does not permit any applications
to directly manage other processes' space. Other than snake oil memory
memory optimizers there are no third party memory managers for NT
operating systems.

John

dennis wrote:
John John - MVP wrote:

AWE, only for the applications own use, you can't develop a memory
manager around this, the kernel will not allow this to manage other
processes' memory. On 32-bit systems AWE will only be able to access
RAM above the 4GB barrier if the operating system is PAE capable,
32-bit XP can't do it. Few applications are AWE capable, this is
mostly reserved for large database programs and other such applications.


I'm not talking about AWE, but about mapping "device" space (physical
memory). That way you can use memory above 4G also in 32bit XP.

XP supports PAE. Its own memory manager just doesn't allow access to
memory above 4G.

XP supports PAE for DEP only, drivers and applications can't access the
memory above the 4GB barrier. From what I understand memory above the
4GB barrier was available with PAE when XP was released but too many
drivers were misbehaving and causing BSODs so Microsoft decided to put
an end to this in SP1.

I know that a certain RAM disk can apparently make use of the memory
above the 4GB barrier, I guess this is what you mean by "device space".
Although the RAM drive can map the space for use as temporary storage
for other applications the other applications still cannot use this for
their process space, the memory manager does not permit any applications
to directly manage other processes' space. Other than snake oil memory
memory optimizers there are no third party memory managers for NT
operating systems.

John

John John - MVP wrote:


I know that a certain RAM disk can apparently make use of the memory
above the 4GB barrier, I guess this is what you mean by "device space".

With device space I mean this:
http://msdn.microsoft.com/en-us/library/ms801998.aspx

And yes, some ram-disks uses that to use memory above 4G.

Although the RAM drive can map the space for use as temporary storage
for other applications the other applications still cannot use this for
their process space

True, you need a bit more to use that kind of memory for other than data
storage.

John John - MVP wrote:


I know that a certain RAM disk can apparently make use of the memory
above the 4GB barrier, I guess this is what you mean by "device space".

With device space I mean this:
http://msdn.microsoft.com/en-us/library/ms801998.aspx

And yes, some ram-disks uses that to use memory above 4G.

Although the RAM drive can map the space for use as temporary storage
for other applications the other applications still cannot use this for
their process space

True, you need a bit more to use that kind of memory for other than data
storage.

In message , dennis
writes:
John John - MVP wrote:

AWE, only for the applications own use, you can't develop a memory
manager around this, the kernel will not allow this to manage other
processes' memory. On 32-bit systems AWE will only be able to access
RAM above the 4GB barrier if the operating system is PAE capable,
32-bit XP can't do it. Few applications are AWE capable, this is
mostly reserved for large database programs and other such applications.


I'm not talking about AWE, but about mapping "device" space (physical
memory). That way you can use memory above 4G also in 32bit XP.

XP supports PAE. Its own memory manager just doesn't allow access to
memory above 4G.

When I suggested a memory manager, I wasn't talking about going beyond
the 4G limit, I was talking about accessing the RAM within the 4G but
beyond where hardware sits on some machines, i. e. using non-contiguous
memory.
--
J. P. Gilliver. UMRA: 1960/1985 MB++G.5AL-IS-P--Ch++(p)Ar@T0H+Sh0!:`)DNAf
** http://www.soft255.demon.co.uk/G6JPG-PC/JPGminPC.htm for ludicrously
outdated thoughts on PCs. **

Reality and talent shows lack honesty. They manipulate the viewer with mawkish
stories. Contestants turn tragedies into qualifications. - Sean Lock, in Radio
Times, 20-26 June 2009

In message , dennis
writes:
John John - MVP wrote:

AWE, only for the applications own use, you can't develop a memory
manager around this, the kernel will not allow this to manage other
processes' memory. On 32-bit systems AWE will only be able to access
RAM above the 4GB barrier if the operating system is PAE capable,
32-bit XP can't do it. Few applications are AWE capable, this is
mostly reserved for large database programs and other such applications.


I'm not talking about AWE, but about mapping "device" space (physical
memory). That way you can use memory above 4G also in 32bit XP.

XP supports PAE. Its own memory manager just doesn't allow access to
memory above 4G.

When I suggested a memory manager, I wasn't talking about going beyond
the 4G limit, I was talking about accessing the RAM within the 4G but
beyond where hardware sits on some machines, i. e. using non-contiguous
memory.
--
J. P. Gilliver. UMRA: 1960/1985 MB++G.5AL-IS-P--Ch++(p)Ar@T0H+Sh0!:`)DNAf
** http://www.soft255.demon.co.uk/G6JPG-PC/JPGminPC.htm for ludicrously
outdated thoughts on PCs. **

Reality and talent shows lack honesty. They manipulate the viewer with mawkish
stories. Contestants turn tragedies into qualifications. - Sean Lock, in Radio
Times, 20-26 June 2009