最新嵌入式系统|常用词汇表2

M
memory map（内存映射）
A table or diagram containing the name and address range of each peripheral addressable by the processor within the memory space. Memory maps are a helpful aid in getting to know the target.
一个在内存空间中的，包含每个外设的名字和可由处理器设置的地址范围的表格或图表。内存映射有助于了解目标机情况。

memory-mapped I/O（内存映射I/O）
An increasingly common hardware design methodology in which I/O devices are placed into the memory space rather than the I/O space. From the processors point of view, memory-mapped I/O devices look very much like memory devices.
一种日益流行的硬件设计方法，在这种方法中，I/O设备被放置在内存空间而不是I/O空间。从处理器的观点看，内存映射I/O设备看上去很象内存一样。

memory space（内存空间）
A processors standard address space. Contrast with I/O space.
一个处理器的标准地址空间。相对I/O空间。

Microcontroller（微控制器）
A microcontroller is very similar to a microprocessor. The main difference is that a microcontroller is designed specifically for use in embedded systems Microcontrollers typically include a CPU, memory (a small amount of RAM and/or ROM), and other peripherals on the same chip. Common examples are the 8051, Intels 80196, and Motorolas 68HCxx series.
微控制器很像微处理器。主要的差别在于微控制器被特殊设计用在嵌入式系统中。微控制器典型地包括CPU、内存（很小的RAM或ROM），还有其他的外设，它们在同一块芯片上。常见的例子是：8051、Intel80196、Motorola68HCxx系列。

Microprocessor（微处理器）
A piece of silicon containing a general-purpose CPU. The most common examples are Intels 80x86 and Motorolas 680x0 families.
一片包含通用CPU的硅片。常见的例子是：Intel80x86、Motorola 680x0系列。

Monitor（监视器）
In the context of this book, a debug monitor. However, there is a second meaning for this word that is associated with intertask communication. In that context, a monitor is a language-level synchronization feature.
在这本书的上下文中，是指调试监视器。然而，第二个意思与任务间通讯相关联。在那个上下文中，监视器是高级同步机制的特性。

Multiprocessing（多处理）
The use of more than one processor in a single computer system. So-called multiprocessor systems usually have a common memory space through which the processors can communicate and share data. In addition, some multiprocessor systems support parallel processing.
在单个的计算机系统中有多个处理器。被叫作“多处理器系统”的一般有公用的内存空间，处理器通过它们进行通讯和共享数据。另外，一些多处理器系统支持并行处理。

Multitasking （多任务）
The execution of multiple software routines in pseudo-parallel. Each routine represents a separate thread of execution and is referred to as a task. The operating system is responsible for simulating parallelism by parceling out the processors time.
伪并行运行的多个软件程序。每一个程序表现得像分开的“执行的线程”并且被看作是一个任务。操作系统通过分配处理器时间来模拟并行方式。

Mutex（互斥）
A data structure for mutual exclusion, also known as a binary semaphore. A mutex is basically just a multitasking-aware binary flag that can be used to synchronize the activities of multiple tasks. As such, it can be used to protect critical sections of the code from interruption and shared resources from simultaneous use.
表现互斥现象的数据结构，也被当作二元信号灯。一个互斥基本上是一个多任务敏感的二元信号，它能用作同步多任务的行为，它常用作保护从中断来的临界段代码并且在共享同步使用的资源。

mutual exclusion（互斥现象）
A guarantee of exclusive access to a shared resource. In embedded systems, the shared resource is typically a block of memory, a global variable, or a set of registers. Mutual exclusion can be achieved with the use of a semaphore or mutex.
唯一访问共享资源的保证。在嵌入式系统中，共享的资源典型的有内存块或寄存器组。互斥现象能由使用信号灯或互斥完成。

N
NVRAM
Non-Volatile Random-Access Memory. A type of RAM that retains its data even when the system is powered down. NVRAM frequently consists of an SRAM and a long-life battery.
非易失的随机访问存储器。一种能在系统关机的情况下保持它的数据的RAM。NVRAM常常由SRAM和长寿命电池组成。

O
OTP
See one-time programmable.

object code（目标代码）
A set of processor-readable opcodes and data. The output of compilers,assemblers, linkers, and locators are files containing object code.
处理器能读的操作码和数据。编译器、汇编器、连接器和定位器的输出文件都含有目标代码。

object file（目标文件）
A file containing object code. The output of a compiler or assembler.
包含目标代码的文件。编译器或汇编器的输出。

one-time programmable（一次可编程的）
Any programmable device, like a PROM, that can be programmed just once by the end user. However, this term is used almost exclusively to refer to microcontrollers with on-chip PROM.
任一可编程的设备，像PROM，仅仅能被最终用户编程一次。然而，这个术语一般被专有地使用在拥有片上PROM的微控制器上。

opcode
A sequence of bits that is recognized by the processor as one of the instructions in its instruction set.
一串被处理器验证过的二进制位的序列，它作为其指令集的一个子集。

operating system（操作系统）
A piece of software that makes multitasking possible. An operating system typically consists of a set of function calls, or software interrupts, and a periodic clock tick. The operating system is responsible for deciding which task should be using the processor at a given time and for controlling access to shared resources.
使多任务能够实现的一个软件。一个操作系统典型地由一个函数调用集、软件中断和定期时钟周期组成。一个操作系统负责决定哪一个任务在给定的时间将使用处理器，并且控制对共享资源的访问。

Oscilloscope（示波器）
A hardware debugging tool that allows you to view the voltage on one or more electrical lines. For example, you might use an oscilloscope to determine if a particular interrupt is currently asserted.
一种硬件调试工具，它让你能观察到一个或更多电路上的电压。例如：如果一个特殊的中断发生，你可以用一个示波器去检测它。

P
PROM（可编程只读存储器）
Programmable Read-Only Memory. A type of ROM that can be written (programmed) with a device programmer. These memory devices can be programmed only once, so they are sometimes referred to as write-once or one-time programmable devices.
可编程只读存储器。能被设备编程器写的一种ROM。这种内存设备可以被编程一次，所以它们有时被作为写一次或一次性编程设备来看待。

parallel processing（并行进程）
The ability to apply two or more processors to a single computation.
一种在单个计算机上运行两个或多个程序的能力。

Peripheral （外设）
A piece of hardware other than the processor, usually memory or an I/O device. The peripheral may reside within the same chip as the processor, in which case it is called an internal peripheral.
一种不同于处理器的硬件设备，常指内存或I/O设备。外设经常和处理器在一片芯片上，在这种情况下，它被称为集成外设。

physical address（物理地址）
The actual address that is placed on the address bus when accessing a memory location or register.
当访问内存位置或寄存器时，在地址总线上的真实的地址。

Preemptive（抢先）
A scheduler is said to be preemptive if it allows the running task to be suspended when a higher-priority task becomes ready. Non-preemptive schedulers are easier to implement but less appropriate for embedded systems.
当一个高优先级的任务准备好时，充许正在运行的任务被挂起的调度策略被称为优先。无优先的调度策略更容易实现一些但适合在嵌入式系统中使用。

Polling(轮询)
A method of interfacing with hardware that involves repeatedly reading a status register until the device has reached the awaited state. Device drivers are either polling or interrupt-driven, with the latter being more generally preferred
一种硬件交互方法，不断读状态寄存器，直到设备进入等待状态。设备驱动程序不是轮询的就是中断驱动的，后一种越来越成为首选的。

Priority（优先）
The relative importance of one task compared to another.
一个任务与其他任务相比的重要关系。

priority inversion（优先转置）
An unwanted software situation in which a high-priority task is delayed while waiting for access to a shared resource that is not even being used at the time. For all practical purposes, the priority of this task has been lowered during the delay period.
一种不希望发生的软件状态，在此状态一个高优先级任务因为等待访问一个那时不再使用的共享资源而被延迟。在所有的实践目标中，这个任务的优先级在延迟周期内都被降低。

Process（进程）
A word that is often confused with task or thread. The crucial distinction is that all of the tasks in a system share a common memory space. Processes, on the other hand, always have their own private memory space. Processes are common in multi-user systems but are rarely, if ever, found in embedded systems.
这个名词经常与任务或线程混淆。至关重要的差别在于系统中的所有任务共享公共的内存空间。进程，另一方面，常常有它们自己的私有内存空间。进程在多用户系统中，但少有地，如有可能，也可在嵌入式系统中。

Processor（处理器）
A generic term that does not distinction between microprocessor, microcontroller, and digital signal processor.
一个对于微处理器、微控制器他数字信号处器无差别的通用术语。

processor family（处理器族）
A set of related processors, usually successive generations from the same manufacturer. For example, Intels 80x86 family began with the 8086 and now includes the 80186, 286, 386, 486, Pentium, and many others. The later models in a family are typically backwards-compatible with the ones that came before.
一个相关的处理器集，常常连续地从一个生产商产生。例如：Intels 80x86族开始从8086开始，现在有80186, 286, 386, 486, Pentium及其他。在一个族中，稍后的产品典型地向后兼容在它以前生产的产品。

processor-independent（处理器无关）
A piece of software that is independent of the processor on which it will be run. Most programs that can be written in a high-level language are processor-independent. Contrast with processor-specific.
一个与处理器无关的，并能在其上运行的软件。大多数用高级语言编写程序是处理器无关的。相对于处理器定制。

processor-specific（处理器定制）
A piece of software that is highly dependent on the processor on which it will be run. Such code must usually be written in assembly language. Contrast with processor-independent.
一个高度依赖处理器的软件，在上其才能运行。一些代码必须用汇编语言编写。相对于处理器无关。

Profiler（明细观察程序）
A software development tool that collects and reports execution statistics for your programs. These statistics include the number of calls to each subroutine and the total amount of time spent within each. This data can be used to learn which subroutines are the most critical and, therefore, demand the greatest code efficiency.
一种报告你的程序运行统计数据的软件调试工具。这些统计数据包括调用每个子程序的次数和用去的时间。这些数据常被用来了解哪些子程序是最关键的，并且，由此要求使最好的代码有效率。

program counter
See instruction pointer.

R

RAM（随机访问存储器）
Random-Access Memory. A broad classification of memory devices that includes all devices in which individual memory locations may be read or written as required.
随机访问存储器。一个包含了所有每个地址能被按需读写的存储设备的粗略分类。

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 doesnt finish in time? If nothing bad happens, its not a real-time system. If someone dies or the mission fails, its 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。

Reentrant（可再入的）
Said of software that can be executed multiple times simultaneously. A reentrant function can be safely called recursively or from multiple tasks. The key to making code reentrant is to ensure mutual exclusion whenever accessing global variables or shared registers.
可同时多次运行的程序的说法。可再入的函数可以被安全地递归调用或由多任务多次调用。使代码可再入的关键在于确保在访问全局变量或共享寄存器时互斥现象发生。

Register（寄存器）
A memory location that is part of a processor or an I/O device. In other words, its not normal memory. Generally, each bit or set of bits within the register controls some behavior of the larger device.
是处理器或I/O设备一部分的储存器的地址。换句话说，不是标准的储存器。一般地，在寄存器控制每一二进制位或二进制位的集控制大量设备的一些行为。

Relocatable（可重定位的）
A file containing object code that is almost ready for execution on the target. The final step is to use a locator to fix the remaining relocatable addresses within the code. The result of that process is an executable.
包含几乎可以准备好在目标机上运行的目标代码的文件。最后一步是使用定位程序去整理保留在代码中的可重定位地址。这个步骤的结果是一个可执行的程序。

reset address（重启地址）
The address from which the first instruction will be fetched after the processor is powered on or reset.
一个处理器上电或重启后第一个指令能被从之取出来的地址。

reset code（重启代码）
A small piece of code that is placed at the reset address. The reset code is usually written in assembly language and may simply be the equivalent of jump to the startup code.
一段被放置在重启地址的代码。重启代码一般用汇编语言编写并且可能相当简单，只是与”跳转到开始代码”这样的意思相同。

reset vector
See reset address.

S
SRAM（静态随机访问储存器）
Static Random-Access Memory. A type of RAM that retains its contents as long as the system is powered on. Data stored in an SRAM is lost when the system is powered down or reset.
静态随机访问储存器。一种在系统上电时以保持它的内容的储存器。当系统断电或重启时，保存在SRAM中的内容将丢失。

Scheduler（调度程序）
The part of an operating system that decides which task to run next. This decision is based on the readiness of each task, their relative priorities, and the specific scheduling algorithm implemented.
操作系统中决定下一次哪个任务运行的那部分。决定基于每一个任务的就绪，它们的优先级关系，和特殊调度算法的实现。

Semaphore（信号灯）
A data structure that is used for intertask synchronization. Semaphores are usually provided by the operating system.
用于进程间同步的数据结构。信号灯常常由操作系统提供。