Linked by Thom Holwerda on Wed 5th Jan 2011 22:09 UTC
Windows And this is part two of the story: Microsoft has just confirmed the next version of Windows NT (referring to it as NT for clarity's sake) will be available for ARM - or more specifically, SoCs from NVIDIA, Qualcomm, and Texas Instruments. Also announced today at CES is Microsoft Office for ARM. Both Windows NT and Microsoft Office were shown running on ARM during a press conference for the fact at CES in Las Vegas.
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RE[3]: enough bits?
by Thom_Holwerda on Thu 6th Jan 2011 13:02 UTC in reply to "RE[2]: enough bits?"
Thom_Holwerda
Member since:
2005-06-29

So 32 bit being limited to 4GB is mostly a market bending nothing more by Microsoft.


Lolwut?

Windows' 32bit client versions do PAE but limits the *operating system* to 4GB anyway due to problems it caused with instability with some drivers (Windows Server 32bit do support more than 4GB).

"However, by the time Windows XP SP2 was under development, client systems with more than 4GB were foreseeable, so the Windows team started broadly testing Windows XP on systems with more than 4GB of memory. Windows XP SP2 also enabled Physical Address Extensions (PAE) support by default on hardware that implements no-execute memory because its required for Data Execution Prevention (DEP), but that also enables support for more than 4GB of memory.

What they found was that many of the systems would crash, hang, or become unbootable because some device drivers, commonly those for video and audio devices that are found typically on clients but not servers, were not programmed to expect physical addresses larger than 4GB. As a result, the drivers truncated such addresses, resulting in memory corruptions and corruption side effects. Server systems commonly have more generic devices and with simpler and more stable drivers, and therefore hadn't generally surfaced these problems. The problematic client driver ecosystem led to the decision for client SKUs to ignore physical memory that resides above 4GB, even though they can theoretically address it."


http://blogs.technet.com/b/markrussinovich/archive/2008/07/21/30920...

However, *applications* in 32bit Windows can access more than 4GB if they want to using AWE (Address Windowing Extensions).

In other words, you're talking out of your ass.

Edited 2011-01-06 13:03 UTC

Reply Parent Score: 1

RE[4]: enough bits?
by malxau on Thu 6th Jan 2011 15:12 in reply to "RE[3]: enough bits?"
malxau Member since:
2005-12-04

"So 32 bit being limited to 4GB is mostly a market bending nothing more by Microsoft.
Lolwut? Windows' 32bit client versions do PAE but limits the *operating system* to 4GB anyway due to problems it caused with instability with some drivers (Windows Server 32bit do support more than 4GB).
...
However, *applications* in 32bit Windows can access more than 4GB if they want to using AWE (Address Windowing Extensions).
"

A Windows client SKU won't address more than 4Gb of physical memory. This means that applications can't use those physical pages either. If an app can use those physical pages, you'll have those pages going through device drivers, which is what the article claims is not supported. If an application attempts to address more than 4Gb of memory, this can only be achieved by paging (ie., giving more than 4Gb of virtual address space but without more than 4Gb of physical pages.) So if you want to put 8Gb of RAM in a machine and actually use it, you have to choose between a 64-bit client SKU or a 32-bit server SKU; a 32-bit client SKU will not use half of that memory.

In other words, you're talking out of your ass.


Please don't include this kind of discourse. It's not constructive, helpful, or informative.

Reply Parent Score: 0

RE[5]: enough bits?
by Carewolf on Thu 6th Jan 2011 15:58 in reply to "RE[4]: enough bits?"
Carewolf Member since:
2005-09-08

I think the confusion is that Windows is usually limited to only using 3Gbyte RAM, but using PAE allows it to use up to 4Gbyte (even in client versions). Also the AWE API can be used in the client versions to access that extra 1-2Gbyte of memory if needed. (

Reply Parent Score: 2

RE[5]: enough bits?
by Thom_Holwerda on Thu 6th Jan 2011 19:34 in reply to "RE[4]: enough bits?"
Thom_Holwerda Member since:
2005-06-29

A Windows client SKU won't address more than 4Gb of physical memory. This means that applications can't use those physical pages either.


This is simply wrong.

"Address Windowing Extensions (AWE) is a set of extensions that allows an application to quickly manipulate physical memory greater than 4GB. Certain data-intensive applications, such as database management systems and scientific and engineering software, need access to very large caches of data. In the case of very large data sets, restricting the cache to fit within an application's 2GB of user address space is a severe restriction. In these situations, the cache is too small to properly support the application.

AWE solves this problem by allowing applications to directly address huge amounts of memory while continuing to use 32-bit pointers. AWE allows applications to have data caches larger than 4GB (where sufficient physical memory is present). AWE uses physical nonpaged memory and window views of various portions of this physical memory within a 32-bit virtual address space."


http://msdn.microsoft.com/en-us/library/aa366527(v=vs.85).aspx

Reply Parent Score: 1