RISC（精简指令集计算机）

 Reduced Instruction Set Computer. Describes the architecture of a processor family. RISC processors generally feature fixed-length instructions, a load-store memory architecture, and a large number of general-purpose registers and/or register windows. The MIPS processor family is an excellent example. Contrast with CISC. 精简指令集计算机。一个处理器族的描述。RISC处理器一般的特征是固定长度的指令集，一个负载储备存储结构，和大量通用寄存器，及寄存器窗口。MIPS处理器族是极好的例子。相对CISC而言。

 

 ROM（只读存储器） Read-Only Memory. A broad classification of memory devices that includes all devices in which the individual memory locations may be read, but not written. 只读存储器。一个包括所的的每个地址只能被读，不能被写的存储器的大概分类。

 

 ROM emulator（ROM模拟器） A debugging tool that takes the place of-or emulates-the ROM on your target board. A ROM emulator acts very much like a debug monitor, except that it includes its own serial or network connection to the host. 一种在你的目标板上代替或模拟ROM的调试工具。ROM模拟器动作起来象一个除错监视器，除了它包含自己连到主机上的串口或网络外。

 

ROM monitor See debug monitor.

RTOS（实时操作系统）

 Real-Time Operating System. An operating system designed specifically for use in real-time systems. 实时操作系统。一种被特殊设计来用在实时系统中的操作系统。

 

 race condition（竞争状态） A situation in which the outcome of a program may be affected by the exact order in which the instructions are executed. Race conditions are only an issue where interrupts and/or preemption are possible and where critical sections exist. 一种程序运行的结果可能被指令执行的顺序影响的情形。竞争状态仅仅有一种情况下产生，在此处中断或（和）优先抢占是充许的并且有一个临界区存在。

 

 real-time system（实时系统） Any computer system, embedded or otherwise, that has deadlines. The following question can be used to distinguish real-time systems from the rest: "Is a late answer as bad, or even worse, than a wrong answer?" In other words, what happens if the computation doesn"t finish in time? If nothing bad happens, it"s not a real-time system. If someone dies or the mission fails, it"s generally considered "hard" real-time, which is meant to imply that the system has "hard" deadlines. Everything in between is "soft" real-time. 任何计算机系统，嵌入的或其他的，有一个死线。以下的问题可经被用来区分实时系统与其他的系统：“是迟到的回答坏，还是一个错误的回答坏？”换句话说，如果计算机没有在指定时间内完成它的工作会发生什么？如果什么也没有发生，它不是一个实时系统。如果一些人死或任务失败，它被认为是“硬”实时系统，意思是系统有一个“硬”死线。介于两者之间的是“软”实时系统。

 

Recursive（递归） Said of software that calls itself. Recursion should generally be avoided in an embedded system, since it frequently requires a large stack. 自己调用自己的程序的说法。递归一般在嵌入式系统中是不充许的，因为它常常占有大量的堆栈空间。