为什么 32 位操作系统支持 4 GB RAM? [英] Why does a 32-bit OS support 4 GB of RAM?
问题描述
只是阅读 purdue 关于操作系统的讲座中的一些笔记,它说:
程序将内存视为一个数组从地址 0 到 2^32-1(0 到4GB-1)
A program sees memory as an array of bytes that goes from address 0 to 2^32-1 (0 to 4GB-1)
为什么是 4 GB?
推荐答案
因为 32 位能够表示最大为 232 - 1 = 4294967295 = 4 GiB - 1 的数字,因此地址可达232 个单独的字节,然后是 4 GiB.
Because 32 bits are able to represent numbers up to 232 − 1 = 4294967295 = 4 GiB − 1 and therefore address up to 232 individual bytes which would be 4 GiB then.
不过,有一些方法可以规避这一点.例如,使用 PAE 即使是 32 位操作系统也可以支持更多内存.不过,从历史上看,这最常用于服务器.此外,非服务器 Windows SKU 不支持它.不过,鉴于 64 位 CPU、操作系统和驱动程序支持已经司空见惯,现在这一切都没有实际意义.
There are ways to circumvent that, though. For example using PAE even a 32-bit operating system can support more memory. Historically this has most commonly been used on servers, though. Also, the non-server Windows SKUs don't support it. By now all that is moot, though, given that 64-bit CPUs, OSes and driver support are commonplace.
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