VARIAN 100010077-06 终端面板

VARIAN 100010077-06  终端面板

数字信号处理器(DSP)专门用于信号处理。

图形处理单元(GPU)处理器主要是为实时渲染图像。

存在其他专门单位，用于视频处理和计算机视觉。(参见:硬件加速。)

微控制器在嵌入式系统和外围设备。

片上系统通常将一个或多个微处理器和微控制器内核与无线电调制解调器等其他组件集成在一起，用于智能手机和平板电脑。

微处理器可以根据它们的字长(衡量其复杂性的一种方法)来选择用于不同的应用。较长的字长允许每个时钟周期以执行更多的计算，但是对应于具有更高待机和操作的物理上更大的集成电路管芯功率消耗。4位、8位或12位处理器广泛集成到运行嵌入式系统的微控制器中。

当系统   要处理大量数据或需要更灵活的用户界面使用16位、32位或64位处理器。一个8- or16位可以选择处理器而不是32位处理器片上系统或微控制器应用低功率电子设备或者是的一部分混合信号集成电路具有噪声敏感型片内模拟电子学例如高分辨率模数转换器或两者。有些人说，在8位芯片上运行32位算法可能会消耗更多的功率，因为芯片必须用多条指令执行软件。然而，也有人说，在运行同等软件例程时，现代8位芯片总是比32位芯片更省电。

在现代计算机中，硬式磁盘机(硬盘)或固态硬盘(固态硬盘)通常用作辅助存储。这存取时间硬盘或固态硬盘的每字节通常以毫秒(千分之一秒)，而主存储的每字节访问时间以纳秒(十亿分之一秒)。因此，辅助存储比主存储慢得多。轮流光存贮器设备，如激光唱片和数字影碟驱动器的访问时间甚至更长。辅助存储技术的其他示例包括usb闪存驱动,软盘,磁带,纸带,穿孔卡片，以及RAM磁盘。

一旦磁盘读/写磁头在HDD上，到达适当的位置，并且数据、轨道上的后续数据可以非常快速地被访问。为了减少寻道时间和旋转延迟，数据以大型连续块的形式传输到磁盘或从磁盘传输。磁盘上的顺序或块访问比随机访问快几个数量级，并且已经开发了许多复杂的范例来设计基于顺序和块访问的高效算法。减少I/O瓶颈的另一种方法是并行使用多个磁盘，以增加主内存和辅助内存之间的带宽。[5]

大多数计算机操作系统使用的概念虚拟内存，允许利用比系统中物理可用容量更多的主存储容量。随着主内存填满，系统会将最少使用的块(页)复制到辅助存储器上的交换文件或页面文件中，以便以后需要时检索它们。如果将大量页面移动到较慢的辅助存储，系统性能会降低。

VARIAN 100010077-06  终端面板

Digital signal processor (DSP) is specially used for signal processing.

Graphics processing unit (GPU) processor is mainly used to render images in real time.

Other specialized units exist for video processing and computer vision. (See: Hardware Acceleration. )

Microcontrollers are used in embedded systems and peripherals.

System-on-a-chip usually integrates one or more microprocessors and microcontroller cores with other components such as radio modems for smart phones and tablets.

Microprocessors can be selected for different applications according to their word length (a measure of their complexity). A longer word length allows more calculations to be performed per clock cycle, but corresponds to physically greater power consumption of the integrated circuit die with higher standby and operation. 4-bit, 8-bit or 12-bit processors are widely integrated into microcontrollers running embedded systems.

Use a 16-bit, 32-bit or 64-bit processor when the system needs to process a large amount of data or needs a more flexible user interface. An 8- or16-bit processor can be selected instead of a 32-bit processor. A system-on-chip or microcontroller uses low-power electronic devices, or a part of mixed-signal integrated circuits has noise-sensitive on-chip analog electronics such as a high-resolution analog-to-digital converter or both. Some people say that running a 32-bit algorithm on an 8-bit chip may consume more power because the chip must execute software with multiple instructions. However, some people say that modern 8-bit chips always save more power than 32-bit chips when running equivalent software routines.

In modern computers, hard disk drives (hard disks) or solid state disks (solid state disks) are usually used as auxiliary storage. This access time is usually in milliseconds (thousandths of a second) per byte of hard disk or solid state disk, while the access time per byte of main storage is in nanoseconds (billionths of a second). Therefore, secondary storage is much slower than primary storage. The access time of rotating optical storage devices, such as compact discs and digital disc drives, is even longer. Other examples of auxiliary storage technologies include usb flash drives, floppy disks, magnetic tapes, paper tapes, punched cards, and RAM disks.

Once the disk read/write head is on the HDD, it reaches the appropriate position, and the data and subsequent data on the track can be accessed very quickly. In order to reduce seek time and rotation delay, data is transferred to or from disk in the form of large continuous blocks. Sequential or block access on disk is several orders of magnitude faster than random access, and many complex paradigms have been developed to design efficient algorithms based on sequential and block access. Another way to reduce I/O bottleneck is to use multiple disks in parallel to increase the bandwidth between main memory and auxiliary memory. [5]

The concept of virtual memory used by most computer operating systems allows the use of more main storage capacity than the physical available capacity in the system. As the main memory fills up, the system will copy the least used blocks (pages) to the swap file or page file on the auxiliary memory, so as to retrieve them later when needed. If a large number of pages are moved to slower secondary storage, system performance will be degraded.