上v2ex的都是软电工么,随便google一下或者找本书翻下就有答案: 64bits of address space is over 17 billion GB, but current 64-bit hardware limits this to smaller values. And Windows implementation limits in the current versions of 64-bit Windows reduce this to 8192 GB (8 TB. http://books.google.de/books?id=VgjAQjsc6g8C&pg=PT48