Windows Server 2003 's 32-bit Enterprise Edition supports more than 4G of memory

Many friends are in order to use more than 4G of memory to install the WINDOWS2003 Enterprise version, but installed after the system was found to use only 3G of memory, is not WINDOWS2003 Enterprise version 32, do not support more than 4G in the inner. Not really. "Newswan" sent a good post, for the poor English friends, fully understand or a bit difficult. Below, simple to provide you with a little reference, 2003 is to support more than 4G of memory, but in the default situation by 32-bit limit, can not use 4G or more memory, to fully use 4G above the memory will rely on PAE and awe to solve the 32-bit operating system inherent in the 4G range of memory usage restrictions.
PAE is the physical Address extension, and the Windows 2003 memory Manager uses PAE to provide more physical memory to the program. The program itself does not know the actual memory size. All memory management and PAE memory allocations are handled by the memory manager, regardless of which program is running.
AWE, an Address windowing extension, is a set of application programming interfaces (APIs) for the Memory Manager feature that enables programs to address more memory than the 4 GB of memory space for standard 32-bit addressing.
For PAE and AWE, it is important to note that the PAE, the physical Address extension, is a feature of the Windows 2003 Memory Manager, which means that it is system based and that the awe-address windowing extension is a set of application programming interfaces (APIs).
In Windows Server 2003, PAE is automatically enabled when the server uses a hot-swappable memory device. It is not possible for us ordinary people to use expensive server machines, you must use the/PAE switch in the Boot.ini file to enable PAE. Use more than 4GB of memory.
The following is an example of a Boot.ini file where the PAE switch has been added:
[boot loader]
Timeout=30
Default=multi (0) disk (0) rdisk (0) partition (2) \ Windows
[Operating Systems]
multi (0) disk (0) rdisk (0) partition (2) \windows= "WINDOWS Server 2003, Enterprise"/fastdetect/pae

A new server, memory configuration has 4GB, boot also correctly display 4G, but installed WIN2003SP1, the system shows only 3.37G, the original thought that there are hardware failures, after the inspection, according to the following do.
1. Open large memory support in the system (Windows)
To enable Windows Advanced Server or Windows Datacenter Server support
is greater than 4GB of physical memory, the parameter/pae must be added to the Boot.ini file.
[boot loader]
Timeout=0
Default=multi (0) disk (0) rdisk (0) partition (1) \WINNT
[Operating Systems]
multi (0) disk (0) rdisk (0) partition (1) \winnt= "Microsoft Windows Watts Advanced Server"
/fastdetect
To
[boot loader]
Timeout=0
Default=multi (0) disk (0) rdisk (0) partition (1) \WINNT
[Operating Systems]
multi (0) disk (0) rdisk (0) partition (1) \winnt= "Microsoft Windows Watts Advanced Server"
/fastdetect/pae
When this is done, we need to reboot the system.
2. Enable locked memory page option (Windows)
Enable locked memory page option
On the Start menu, click the Run submenu, and then type gpedit.msc in the Open box.
On the Group Policy console, expand Computer Configuration, and then expand Windows settings.
Expand Security Settings, and then expand Local Policies.
Select the User Rights Assignment check box.
The policy is displayed in the details pane.
In the details pane, double-click Lock Memory page.
In the Local Security Policy Settings dialog box, click the Add button.
In the Select User or Group dialog box, add an account that has permission to run Sqlservr.exe.

3. Enable AWE for SQL
To enable AWE, set the awe enabled to 1. Unless you specify a value for max server memory, no
Then SQL Server retains almost all available memory, leaving only 128 MB or less.

If this option has been successfully enabled, when the SQL Server 2000 instance is started, the SQL Server error log will
The message "Enabled Address Window extensions" appears.

AWE enabled is an advanced option. If you are using the sp_configure system stored procedure to change this setting, only
You can change awe enabled when show advanced options is set to 1 o'clock.
Code below, set SQL to use 6G of memory
sp_configure ' show advanced options ', 1
Reconfigure
Go
sp_configure ' awe enabled ', 1
Reconfigure
Go
sp_configure ' max server memory ', 6144
Reconfigure
Go
You must restart the SQL Server 2000 instance for the changes to take effect.
net stop MSSQLServer
NET start MSSQLServer
This way, when the SQL service is started, the 6G memory is locked up for SQL use
Windows Datacenter Server only, Windows Advanced Server, Windows Server 2003, Enterprise Edition, and Windows Server 200 3 Datacenter Edition supports PAE. In 32-bit Windows, PAE is disabled by default and must be in BOOT. INI file to enable PAE by setting the/PAE boot parameter
Why do this, because 32-bit system can only address to 4G of memory space, by modifying the boot file can make the rest of the memory as extensible physical memory but if your own memory is just 4G, it is not recommended to modify the effect is not ideal
The maximum memory capacity of the hardware support can be calculated as follows: support the maximum memory capacity =2 N-Times azimuth.
32-bit hardware support of the maximum memory capacity conversion is 2 of the 32 times, the conversion is 4g,64 bit hardware support the maximum memory capacity is 2 64, conversion is 16eb=16*1024pb=16*1024*1024tb=16*1024*1024* 1024GB.

Operating system memory support
Windows
Both the WindowsNT4.0 server and the Enterprise version belong to the 32-bit server operating system, and the maximum memory support is only 4 G.
The WINDOWS2000 Series server version of the operating system can support the highest capacity is the data center version, can support 32G; The Advanced Server Edition supports only the highest 8G memory capacity, and the 2000 normal Server Edition supports only the highest 4G of memory capacity.
Windows2003enterprise supports up to 32G of memory.
The new 64-bit Vista highest version supports maximum 128G memory.
Linux
The Linux kernel kernel is 32-bit and supports only the maximum 4G of memory.
Linux's Bigmem and SMP cores, which are 64-bit operating systems, support up to 64G of RAM.
Some operating systems limit the amount of memory in the kernel code, so it is a 64-bit operating system, which, by default, supports only a specific maximum memory capacity, and PAE extension settings are required to achieve maximum supported memory capacity. In Windows2003enterprise, for example, if you insert 4G memory directly, and do not make any changes, the system can identify the physical memory may be only 3G, you need to set in the system boot file PAE memory expansion support.
The maximum memory addressing space allowed for the x86 32 schema is 4GB. The Intel Physical Address Extension (PAE) is a 36-bit memory addressing mode that allows 32 system addressing capabilities exceeding 4GB.

The PAE requires appropriate hardware and operating system support. Processor is Intel Pentium Pro above, operating system supports Windows NT 4.0 Enterprise Edition, Windows 2000 Advanced Server Edition and Datacenter Edition, and Windows Server 2003 Enterprise Edition and Datacenter Edition.

Windows uses PAE's 4KB page to map 64GB physical memory to the 32-bit (4GB) virtual address space. The way to allow PAE in Windows 2000 and Windows Server 2003 is to add the/PAE switch in boot.ini.
Address Windows Extensions (AWE) is a set of Windows APIs that can benefit from PAE, allowing applications to access more than 4GB of physical memory directly. Some programs, such as SQL Server 2000 Enterprise Edition, are written using these APIs to achieve significant performance gains for each processor with more than 2G of memory addressing.
The method for editing the Boot.ini file activates PAE is as follows:
Open the system in Control Panel
Select Advanced
Click the Set button on the Start and resume page
Click Edit, Notepad to open Boot.ini file
Edit the ARC path and add the/PAE switch later

1, theoretically 32-bit system can only support the maximum 4G memory.
A: That seems to be true, but Microsoft has told us that this is not the case-the enterprise, Datacenter version of Windows supports the largest 32G and 64G of memory, respectively.

2, My computer has 4G of memory, but why the system tells me that memory only 3.x G.
A: Because some motherboard chipsets manage the physical address of other hardware in a 4G memory address, these computers usually recognize and use the maximum memory capacity between 3.25-3.75g. If you want the system to recognize the full 4G memory, your motherboard must support a technology called PAE (Physical Address extension).

3, my motherboard support PAE, why still can't use full 4G of memory.
A: This is due to operating system limitations, currently in 32-bit Windows, only the server version (2003/2008) supports 4G or more of memory (Windows Server 2003 Web Edition supports only 2G memory) and needs to be added at the end of the system's startup PAE option (edited in Boot.ini).

4, 32-bit systems, the maximum amount of memory a single process can access.
A: The limit of user mode memory access for a single process under the 32-bit Windows operating system is 2G, if the/3g switch is set in Boot.ini, the maximum is 3G, and more than 3G will not be accessible.

5. How to allow a single process to access memory larger than 2g/3g.
A: The 32-bit operating system can only extend memory through AWE. AWE (Address Windowing Extensions) is a set of extensions to the memory management features of Windows that enable applications to use more memory than 2-3 GB of memory that can be used through standard 32-bit addressing. AWE allows the application to acquire physical memory and then dynamically map the view of non-paged memory to the 32-bit address space. Although the 32-bit address space is limited to 4 GB, paging memory can be much larger than 4 GB. This enables applications that require large amounts of memory, such as large database systems, to use much more memory than the 32-bit address space supports.


The amount of memory supported by Windows versions (physical memory)
The amount of memory supported by Windows versions (physical memory)
Windows 2000 Data Center Edition: 32G
Windows 2000 Advanced Server Edition: 8G
Windows 2000 Professional Edition: 4G
Windows Server 2003 32-bit Web version: 2G
Windows Server 2003 32/64-bit Standard version: 4G/32G
Windows Server 2003 32/64-bit Enterprise Edition: 32G/1TB
Windows Server 2003 32/64-bit data center version: 64G/1TB
Windows Xp/vista 32-bit: <4g
Windows XP 64-bit: 32G
Windows Vista 64-bit: 128G
Server2008 R2 No 32-bit version
Old version Support:
Maximum Memory (32-bit): 4GB RAM (Standard Edition) or 64GB RAM (Enterprise and Data Center Edition)
Maximum Memory (64-bit): 32GB RAM (Standard Edition) or 2TB RAM (Enterprise, Datacenter and itanium-based)