Obrigado Sike:
"The
CPUID flag PAE is assigned for the purpose of identifying CPUs with this capability."
Se leres os artigos acima referidos verás que o famoso PAE que falas está nos CPU's.
A Microsoft nao tras isso activado de origem... Porque será? Isto inclui o novissimo e na moda Vista x86. Os cpus trazem há muito isso de origem
Podemos fazer entao varias perguntas:
-A Microsoft nao aplicou isso nos seus O.S. de 32 bits por alguma razao. Qual será?
Aparentemente nao penso que a Microsoft goste de estar no lugar de uma empresa lider que nao suporta features avançadas para se gabar que é a melhor? É claro que se fosse 100% compativel eles activariam isso.
-Teres acesso a uma funcao suportada, caso sejas um utilizador avançado e que procures guias para o fazer???! Quão ilogico isto soa?
Nao entendo a vossa indecisao a tomar consciencia que há pouca ou nenhuma necessidade ate agora para common users usem mais de 2 gigas. E a Microsoft sabe disso, sobretudo quando tens um mercado em que nas empresas ou utilizadores que necessitem de mais de 4 gb, 8gb, 16gb... existem há muito. Esses users tem O.S. de 64 bits, coisa que a microsoft tem tambem a propor ás pessoas.
Expliquem-me entao racionalmente, se faz favor porque estão pasmados com estes factos!?
Eu leio há muito e noticia dos 2 Gb de limite na prática nao sao "news"... Isto deveria de ser conhecimento comum com tanta informacao disponivel.
Ofacto que me chateou foi de terem todos os links fornecidos, os dados, comentarios de especialistas, varias fontes e mesmo assim continuam no FUD.
http://blogs.technet.com/sysinternals/archive/1999/08/05/452897.aspx
5/8/1999
"*NEW BOOT.INI OPTIONS
Win2K Beta 3 introduces three new BOOT.INI switches. All three are related to Intel Physical Address Extensions (PAE), a technology Intel introduced with the Pentium Pro to allow x86 systems to address up to 64GB of physical memory. Traditionally, x86 systems can only address 4GB of physical memory, but with PAE and the 450NX chipset, this barrier is broken. Win2K is the first Microsoft operating system that will take advantage of PAE (Sun Solaris 7 and SCO UnixWare 7 already support PAE). There is actually a special build of the Win2K kernel, named ntkrnlpa.exe, which has the support built-in. NTLDR, the Win2K boot loader, is responsible for loading either the standard kernel, ntoskrnl.exe, or the PAE-enabled one, based on whether the system is capable of addressing more than 4GB of memory and has that amount present.
All three new BOOT.INI switches are aimed at debugging device drivers that are designed to work with large memory systems (systems with more than 4GB). The first, /PAE, has NTLDR load the PAE-version of the kernel even if the computer doesn’t have more than 4GB of memory present. The second, /NOPAE, forces NTLDR to load the standard kernel. Finally, the /NOLOWMEM switch has the Win2K kernel only use physical memory above 4GB. This forces all physical addresses used by Win2K to require more than 32-bits to represent them, and thus exercises device driver handling of large physical addresses."
Reparem nas datas.Reparem que se trata do windows 2000 beta 3. Expliquem-me.
"*THE WIN2K AWE API
I already mentioned the AWE API in the introduction to this newsletter, and referenced a Web page at Microsoft where you can learn more: http://www.microsoft.com/hwdev/NTDRIVERS/AWE.htm. On systems with more than 4GB of physical memory, Win2K’s PAE-capable kernel - ntkrnlpa.exe - is able to take advantage of all the computer’s physical memory with no modification to applications. Win2K Advanced Server will use up to 8GB of physical memory and Win2K Datacenter Server will use up to 64GB of physical memory.
While each application on a large memory system has at most 2GB of virtual memory at its disposal (3GB if the /3GB BOOT.INI switch is specified), the sum of physical memory assigned to all executing applications can equal the amount of physical memory. In addition, on Win2K the file system cache is assigned a maximum of 960MB of virtual memory, but the amount of cached file data can be much larger physical memory assigned to the cache can exceed 960MB.
The AWE API gives individual applications the ability to directly control physical memory, and more than the 2GB or 3GB limit implied by their virtual address space size. The basic idea behind the AWE API is that an application designates a portion of its virtual address space as a “window” into physical memory. Then it allocates a chunk of physical memory. The upper limit on the amount of physical memory an application can allocate is essentially the amount of physical memory on the system minus any non-paged memory already allocated by the kernel, device drivers, and other applications using the AWE API. When the application wants to access part of the physical memory it has allocated, it maps the memory into its virtual address window. Thus, the amount of physical memory the application can access with a given mapping is limited by the size of the window that it reserved. Finally, when an application is done with the physical memory it simply frees the memory and closes (deallocates) the virtual address window it created.
The APIs that correspond to these actions are exported by kernel32.dll and are as follows:
- An application calls VirtualAlloc with the MEM_PHYSICAL and MEM_RESERVE flags to create the virtual address window
- AllocateUserPhysicalPages allocates physical memory for an application
- An application uses MapUserPhysicalPages to map portions of the physical memory into its window
- FreeUserPhysicalPages frees the physical memory the application allocated
The ability for applications to directly manipulate multiple GB’s of memory is a boon to memory-intensive programs such as database servers, e-mail servers, Web servers, financial analysis and scientific applications.
While the ability to use more than 4GB of physical memory is only permitted on certain versions of Win2K, the AWE API is present on all versions. This means that on a Win2K Professional system with 4GB of memory, for example, the AWE API still gives memory-intensive applications the ability manage more than 2 or 3GB of data in physical memory."
Já mastiguei a papinha toda.
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