Why can Windows 2003 Server support more than 4 gigabytes of memory? To be precise the 32bit version can support 32G of memory. This is because MS developed the PAE function for the Server system namely physical address extension physical address extension. This function can expand the addressing space of the memory 32bit to 48bit or 64bit so that the theoretical maximum supported memory is 16 * 1024 * 1024 * 1024G = such a large space and Microsoft intentionally limits it to 32GB and 64-bit systems limit it to 64GB. The inconsistency of restriction conditions is to distinguish the version difference otherwise no one will choose 64bit server system (now almost no enterprise chooses 64bit 32bit is enough ^_^).
Why are there restrictions?
1. There is no motherboard that can support so much memory now.
2. There is no application that requires such a large amount of memory. Servers that require large memory are generally used by the state and their servers will not use windows systems.< br/>3. There is no test environment and Microsoft cannot verify whether the system is stable after 64G of memory.
Windows Server 2003 Enterprise Edition (Enterprise Edition):
* Support 8 Node cluster NUMA; support 8-channel SMP
* Memory support: (i386) 32-bit version supports 32GB memory (X64) 64-bit version supports 64GB memory
windows 2003 only supports small memory by default Mode (maximum 3G) greater than 3G you need to edit Boot.ini plus the /pae parameter to enable the large memory mode to support 3G or more memory. Edit Boot.ini according to the above operation and restart. There is still a problem with your memory compatibility. Here is a 2003 Example of boot.ini:
default=multi(0)disk(0)rdisk(0)partition(1)\\WINDOWS < br/>[operating systems]
multi(0)disk(0)rdisk(0)partition(1)\\WINDOWS=\u0026quot;Windows Server 2003 Enterprise\u0026quot; /fastdetect /usepmtimer /NoExecute=OptIn /PAE
Windows Server 2003 Web Edition: Provide a Web hosting and service platform for rapid development and deployment of Web services and applications. Support 2-channel SMP (Symmetric Multiprocessing) system 2GB memory.
Windows Server 2003 Standard Edition: For small and medium enterprises and departmental applications. Support 4-channel SMP 4GB memory.
Windows Server 2003 Enterprise Edition: suitable for use by centers and large organizations there are 32-bit and 64-bit versions. Support 8-node cluster NUMA; support 8-channel SMP of which 32-bit version supports 32GB memory and 64-bit version supports 64GB memory.
Windows Server 2003 Data Center Edition: For enterprises that require strong scalability and high availability there are 32-bit and 64-bit versions. The 32-bit version supports 32-channel SMP 64GB memory; the 64-bit version supports 64-channel SMP 512GB memory; both versions support 8-node clusters NUMA
To enable Windows 2003 to support physical memory greater than 4GB you must set the parameter /pae is added to the boot.ini file.
This problem was discovered when the server was just bought back. Why does a good 4G memory motherboard only recognize it as 3G? Modifying the BIOS three times and four times can only make the motherboard recognize it as 3.3G and 3.5G. so annoying. . .
It turns out that some servers have memory holes so 3.3G-3.8G are normal. This part of the empty memory is consumed as hardware. If there is too much difference you must upgrade the motherboard BIOS and array card. Firmware is fine.
If it is XP or 2003 series add /PAE parameter in BOOS.INI to access extended memory normally. If it exceeds 1G add the /USERVA=3030 parameter to optimally configure the virtual memory.
It is produced by an important security function in win2003 SP1-\u0026ldquo;Data Execution Protection Function (abbreviation: DEP)\u0026rdquo;.
You can find it in \u0026ldquo;Control Panel\u0026rarr;System\u0026rarr;Advanced\u0026rarr;Settings\u0026rarr;Data Execution Protection\u0026rdquo;.
When you switch between these two items \u0026ldquo;/NoExecute=OptIn\u0026rdquo; will also become \u0026ldquo;/NoExecute=Optout\u0026rdquo;.
Note: This feature requires hardware support: including AMD Athlon 64 AMD Opteron Intel’s Itanium and Itanium 2. It is said that companies such as nVIDIA VIA Transmeta also plan to add this technology to their chips. It is recommended that ordinary users do not modify it otherwise it will cause unstable system operation.
/NoExecute=alwaysoff is to turn off the data execution protection function
/NoExecute=OptIn means that the first item is selected that is “only for\u0026hellip;\u0026hellip;\u0026rdquo; that item
/NoExecute=Optout means that the second item is selected
/noexecute=AlwaysOff it is equivalent to turning off the DEP and EVP functions and all programs blocked by it can run normally< br/>
/NoExecute=OptOut --DEP is turned on and all services use dep
v If your server memory is greater than 3G the system is not supported by Win2003 You can read this article when you are over 3G
This article introduces Physical Address Extension (PAE) and Address Windowing Extension (AWE) and explains how they work together. This article will also discuss memory usage limits beyond the 4 GB inherent in 32-bit operating systems.
PAE improves the ability of the IA32 processor to handle more than 4 GB of physical memory. Microsoft Windows 2000 Advanced Server Microsoft Windows 2000 Datacenter Server Microsoft Windows Server 2003 Enterprise Edition and Microsoft Windows Server 2003 Datacenter Edition can use PAE to take advantage of physical memory in excess of 4GB. To enable PAE you need to use the /PAE parameter in the Boot.ini file.
Note: Only when the server uses hot-add memory devices Windows Server 2003 Enterprise Edition and Windows Server 2003 Datacenter Edition will automatically enable PAE. In this case there is no need to use the /PAE switch on systems that are configured to use hot-add memory devices. In other cases the /PAE switch must be used in the Boot.ini file to utilize memory greater than 4GB.
Typically a process running under Windows 2000 or Windows Server 2003 can access up to 2 GB of memory address space (assuming that the /3GB parameter is not used) some of which are physical memory and others Is virtual memory. The more programs you run (and therefore the more processes) the closer the memory address space occupied is to the maximum of 2 GB.
When this happens the paging process will increase significantly and will have a negative impact on performance. Windows 2000 and Windows Server 2003 memory managers use PAE to provide programs with more physical memory. This reduces the need to swap page file memory thereby improving performance. The program itself does not know the actual memory size. All memory management and PAE memory allocation are handled by the memory manager regardless of the running program.
When using the /3GB parameter the above information is valid for the running program. A program that requires 3 GB of memory is more likely to have more of the memory it needs in physical memory than in paged virtual memory. This will enhance the performance of programs that can use the /3GB parameter. The exception is when the /3GB parameter is used with the /PAE parameter. In this case the operating system will not use any more than 16 GB of memory. This behavior is caused by kernel virtual memory space considerations. Therefore if the system restarts using the /3GB entry in the Boot.ini file and the system's physical memory exceeds 16 GB the operating system does not use additional physical random access memory (RAM). If you do not use the /3GB switch when you restart your computer you will be able to use all the physical memory.
AWE is a set of application programming interface (API) for memory manager functions which enables programs to address more memory \u0026mdash; 4 GB of memory space beyond standard 32-bit addressing. AWE enables programs to reserve physical memory as non-paged memory and then dynamically map portions of non-paged memory to the program's memory working set. This process enables memory-intensive programs (such as large database systems) to reserve large amounts of physical memory for data without having to swap paging files for use. Instead data is exchanged in the working set and the reserved memory exceeds the 4 GB range. In addition the memory range beyond 4 GB is open to the memory manager and AWE functions through PAE. Without PAE AWE cannot reserve more than 4 GB of memory.
The following is an example of a Boot.ini file with the PAE switch added:
multi(0)disk(0)rdisk(0)partition(2)\\WINDOWS=\u0026quot;Windows Server 2003 Enterprise\u0026quot; /fastdetect /PAE
Warning: The contents of the Boot.ini file vary according to your configuration. For more information please click the following article number to view the corresponding article in the Microsoft Knowledge Base:
317526 (://support.microsoft.com/kb/317526/) How to use Windows Server 2003 Edit the Boot.ini file
In short PAE is a feature of the Windows 2000 and Windows Server 2003 memory manager which provides more physical memory for programs that request memory. The program does not know that some of the memory it is using is in the range greater than 4 GB just as the program does not know that the memory it requested is actually in the page file.
AWE is an API set that enables programs to reserve large memory blocks. The reserved memory is non-paged and can only be used by the program. For more information about AWE and PAE please click the article number below to view the corresponding article in the Microsoft Knowledge Base:
268363 (://support.microsoft.com/kb/268363/) Windows 2000 Intel Physical Address Extension (PAE) in the
If you add more memory to the system the BIOS may recognize all the physical RAM installed in the server but Windows will only recognize Part of RAM. If the server has the redundant memory function or memory mirroring function enabled all remaining memory may not be visible to Windows. Redundant memory provides a failover memory block for the system when a memory block fails. Memory mirroring splits the memory block into a mirrored set. Both functions are enabled or disabled in the BIOS and cannot be accessed through Windows. To modify the settings of these functions you may have to refer to the system user manual or the OEM website. In addition you may have to contact the hardware vendor.