In user mode, the executing code has no ability to directly access hardware or reference memory. Code running in user mode must delegate to system APIs to access hardware or memory.

在用户态，代码不具备直接访问硬件或者访问内存的能力，而必须借助操作系统提供的可靠的、底层的API来访问硬件或者内存。

youdao

Last year Apple upped its game another notch, randomizing the location of code in memory so that hackers can't even locate commands to hijack them.

FORBES: Magazine Article

Currently Enterprise systems ship with Error Correcting Code (ECC) memory, but most consumer systems do not.

FORBES: Bitsquatting: Machine-Garbled Internet Connections

As part of its Digital Service Efficiency effort to reduce power consumption in its data centers, eBay slightly changed some of its software code so that the code would require less memory.

FORBES: EBay's MPG For Data Centers