试卷详情

2016年嵌入式系统设计师上午真题卷

开始做题

试卷预览

单选题

某幅图像具有1024×768个像素点,若每个像素具有8位的颜色深度,则可以表示(请作答此空)种不同的颜色,经4:1压缩后,其图像数据需占用( )KBWe的存储空间。

查看答案开始考试

正确答案:B

本题解析:

像素是构成数码影像的基本单元,一个像素所能表达的不同颜色数取决于每个像素的比特数(bpp)。颜色最大数可以通过取2的色彩深度次幂来得到。例如,常见的取值有:8bpp[28=256;(256色)];16bpp[216=65536;(65,536色,称为高彩色)];24bpp[224=16777216;(16,777,216色,称为真彩色)];48bpp[248=281474976710656;(281,474,976,710,656色,用于很多专业的扫描仪)。像素可以用一对数字标书,例如“1024×768”,它表示横向1024像素和纵向768像素,因此其总数为1024×768像素,若采用8bpp储存,即每个像素占用1Byte,1024×768像素占用1024×768Byte的储存空间。

图像压缩是为了减少表示数字图像时需要的数据量。图像数据之所以能被压缩,就是因为数据中存在着冗余。图像数据的冗余主要表现为:图像中相邻像素间的相关性引起的空间冗余;图像序列中不同帧之间存在相关性引起时间冗余;不同彩色平面或频谱带的相关性引起的频谱冗余。数据压缩的目的就是通过去除这些数据冗余来减少表示数据所需要的比特数。由于图像数据量的庞大,在储存、传输、处理时非常困难,因此图像数据的压缩就显得非常重要。一幅1024×768像素的图像,经过4:1压缩后,占用的存储空间为1024×768÷4=196608Byte,即192KB。

单选题

某幅图像具有1024×768个像素点,若每个像素具有8位的颜色深度,则可以表示( )种不同的颜色,经4:1压缩后,其图像数据需占用(请作答此空)KBWe的存储空间。

查看答案开始考试

正确答案:C

本题解析:

像素是构成数码影像的基本单元,一个像素所能表达的不同颜色数取决于每个像素的比特数(bpp)。颜色最大数可以通过取2的色彩深度次幂来得到。例如,常见的取值有:8bpp[28=256;(256色)];16bpp[216=65536;(65,536色,称为高彩色)];24bpp[224=16777216;(16,777,216色,称为真彩色)];48bpp[248=281474976710656;(281,474,976,710,656色,用于很多专业的扫描仪)。像素可以用一对数字标书,例如“1024×768”,它表示横向1024像素和纵向768像素,因此其总数为1024×768像素,若采用8bpp储存,即每个像素占用1Byte,1024×768像素占用1024×768Byte的储存空间。

图像压缩是为了减少表示数字图像时需要的数据量。图像数据之所以能被压缩,就是因为数据中存在着冗余。图像数据的冗余主要表现为:图像中相邻像素间的相关性引起的空间冗余;图像序列中不同帧之间存在相关性引起时间冗余;不同彩色平面或频谱带的相关性引起的频谱冗余。数据压缩的目的就是通过去除这些数据冗余来减少表示数据所需要的比特数。由于图像数据量的庞大,在储存、传输、处理时非常困难,因此图像数据的压缩就显得非常重要。一幅1024×768像素的图像,经过4:1压缩后,占用的存储空间为1024×768÷4=196608Byte,即192KB。

单选题

A real-time operating system. (RTOS) is an operating system intended to serve ( ) application process data as it comes in, typically without buffering delays. A key ( ) of a RTOS is the level of its consistency concerning the amount of time it takes to accept and complete an application’s task; the variability is jitter. A hard real-time operating system has ( ) jitter than a soft real-time operating system. The chief design goal is not high throughput, but rather a guarantee of a soft or hard performance category. A RTOS has an advanced algorithm for scheduling. (请作答此空) flexibility enables a wider, computer-system orchestration of process priorities, but a real-time OS is more frequently dedicated to a narrow set of applications. Key factors in a real-time OS are minimal ( ) latency and minimal thread switching latency.

查看答案开始考试

正确答案:A

本题解析:暂无解析

单选题

A real-time operating system. (RTOS) is an operating system intended to serve ( ) application process data as it comes in, typically without buffering delays. A key ( ) of a RTOS is the level of its consistency concerning the amount of time it takes to accept and complete an application’s task; the variability is jitter. A hard real-time operating system has (请作答此空) jitter than a soft real-time operating system. The chief design goal is not high throughput, but rather a guarantee of a soft or hard performance category. A RTOS has an advanced algorithm for scheduling. ( ) flexibility enables a wider, computer-system orchestration of process priorities, but a real-time OS is more frequently dedicated to a narrow set of applications. Key factors in a real-time OS are minimal ( ) latency and minimal thread switching latency.

查看答案开始考试

正确答案:C

本题解析:暂无解析

单选题

A real-time operating system. (RTOS) is an operating system intended to serve ( ) application process data as it comes in, typically without buffering delays. A key (请作答此空) of a RTOS is the level of its consistency concerning the amount of time it takes to accept and complete an application’s task; the variability is jitter. A hard real-time operating system has ( ) jitter than a soft real-time operating system. The chief design goal is not high throughput, but rather a guarantee of a soft or hard performance category. A RTOS has an advanced algorithm for scheduling. ( ) flexibility enables a wider, computer-system orchestration of process priorities, but a real-time OS is more frequently dedicated to a narrow set of applications. Key factors in a real-time OS are minimal ( ) latency and minimal thread switching latency.

查看答案开始考试

正确答案:A

本题解析:暂无解析

单选题

A real-time operating system. (RTOS) is an operating system intended to serve (请作答此空) application process data as it comes in, typically without buffering delays. A key ( ) of a RTOS is the level of its consistency concerning the amount of time it takes to accept and complete an application’s task; the variability is jitter. A hard real-time operating system has ( ) jitter than a soft real-time operating system. The chief design goal is not high throughput, but rather a guarantee of a soft or hard performance category. A RTOS has an advanced algorithm for scheduling. ( ) flexibility enables a wider, computer-system orchestration of process priorities, but a real-time OS is more frequently dedicated to a narrow set of applications. Key factors in a real-time OS are minimal ( ) latency and minimal thread switching latency.

查看答案开始考试

正确答案:B

本题解析:暂无解析

单选题

A real-time operating system. (RTOS) is an operating system intended to serve ( ) application process data as it comes in, typically without buffering delays. A key ( ) of a RTOS is the level of its consistency concerning the amount of time it takes to accept and complete an application’s task; the variability is jitter. A hard real-time operating system has ( ) jitter than a soft real-time operating system. The chief design goal is not high throughput, but rather a guarantee of a soft or hard performance category. A RTOS has an advanced algorithm for scheduling. ( ) flexibility enables a wider, computer-system orchestration of process priorities, but a real-time OS is more frequently dedicated to a narrow set of applications. Key factors in a real-time OS are minimal (请作答此空) latency and minimal thread switching latency.

查看答案开始考试

正确答案:C

本题解析:暂无解析

单选题

以下关于特权指令的叙述中,错误的是()。

查看答案开始考试

正确答案:D

本题解析:

本题考查计算机状态和特权指令概念。计算机运行时的状态可以分为系统态(或称管态)和用户态(或称目态)两种。当计算机处于系统态运行时,它可以执行特权指令,而处于用户态运行时,则不能执行特权指令,如果此时程序中出现特权指令,机器将会发出特权指令使用错误的中断。所谓特权指令集是计算机指令集的一个子集,特权指令通常与系统资源的操纵和控制有关,例如,访外指令用于通道启动通道;时钟控制指令用于取、置时钟寄存器的值;程序状态字控制指令用于取、置程序状态字;通道控制指令用于访问通道状态字;中断控制指令则用于访问中断字等。

单选题

以下关于Cache和主存叙述中,不正确的是()。

查看答案开始考试

正确答案:D

本题解析:

本题考查存储技术中的Cache基础知识。Cache是一种高速缓冲存储器,是为了解决CPU和主存之间速度不匹配而采用的一项技术。Cache是介于CPU和主存之间的小容量存储器,但是其存储速度要高于主存。从功能上来看,它是主存的缓冲存储器,由高速SRAM组成。CPU和Cache之间的数据交换是以字为单位,而Cache和主存之间的交换是以块为单位进行的。Cache的一个重要指标是Cache的命中率。主存和Cache之间的地址映射方式包括全相连方式、直接方式和组相连方式三种。其中全相连映射方式中,将主存的一个块的地址与内容一起存于Cache的行中,其中块地址存于Cache的标记部分。直接映射是一种多对一的映射关系,但一个主存块只能拷贝到Cache的一个特定行位置上。组映射方式中每组行数的取值一般较小。当CPU对Cache的修改后,如何与主存内容保持一致,可以选用写回法、全写法和写一次法当中的任何一个。

单选题

以下关于中断的叙述中,不正确的是()。

查看答案开始考试

正确答案:C

本题解析:

本题考查中断响应的基础知识。中断响应是一个软硬件结合起来处理系统例外事件的机制。硬件响应中断时,进行新老程序状态字的交换。所谓程序状态字,是指CPU的一些重要寄存器内容的有序集合。老程序状态字是指系统正在运行时的程序状态字,新程序状态字是指存放在内存制定单元的程序状态字,新程序状态字中的指令地址寄存器就是操作系统的入口地址。通过交换程序状态字,系统转入运行操作系统的程序。中断处理的工作将由操作系统完成。操作系统判别产生中断的原因,根据中断的原因调用相应的中断处理例程,完成中断处理。在中断处理结束后,再运行进程管理中的进程调度程序,将某个进程运行时的程序状态字内容填入相应的硬件寄存器中,从而使该进程投入运行。

其他考生还关注了更多 +