A: The proposed devices and power failure interrupt requests are maskable interrupts
B: made by I / O device and the interrupt request is non-maskable interrupt power failure
C: made by I / O device is a maskable interrupt request interrupt, non-maskable interrupt is a power failure
D: made by I / O device interrupt request is non-maskable interrupt, maskable interrupt power failure
[a]:
According to whether may be shielded, the interrupt can be divided into two categories: non-maskable interrupt (also known as non-maskable interrupt) and a maskable interrupt.
Once the non-maskable interrupt request source, the CPU must unconditionally in response, while the maskable interrupt request source, the CPU can respond or not respond.
Typical examples of non-maskable interrupt source is power failure , once there, you must respond immediately and unconditionally, or perform any other work is meaningless.
Examples of typical maskable interrupt source is interrupted printer , the printer in response to the CPU interrupt request may be faster, may be slower, so as to wait for the printer is entirely possible. For the soft interrupt, which allows uninterrupted affect flag (IF-bit), so are non-maskable category.
A: opcode should be stored in the instruction register (IR), the address codes to be stored in the program counter (the PC)
B: the operation code shall be placed in the program counter (PC), the address codes stored in the instruction register should be (the IR)
C: Opcode and address codes should be stored in the instruction register (the IR)
D: the operation code and address code should be stored in the program counter (PC)
Starts running program is loaded into memory, the CPU executes an instruction when it is first taken from the memory to the buffer register DR, and then temporarily stored into the IR, the micro instruction decoder generates various operation instructions in accordance with the contents of the IR, work to control other components, to complete the desired function.
Program Counter (PC) has two function registers and count information, also called instruction counter . Execution of the program are two cases, one order of execution, the second is the implementation of the transfer. Before the program begins execution, the starting address of the program into the PC, the address of the program loaded into memory determined, i.e., so the content of PC is the address of the first instruction. When executing instructions, CPU will automatically modify the PC's content, so that it is always the address of the next instruction to be executed maintained. Since most instructions are executed in sequence, so the modification process often simply on the PC plus 1. When faced with a branch instruction address of the next instruction of a shift forward or backward from the address of the current instruction plus the obtained amount of displacement, transfer or direct branch instruction address given according to the obtained.
3, in ISO to develop and publish the MPEG family of standards, (MPEG-1) audio and video compression coding technology has been applied to the VCD, (MPEG-2) standard in audio and video compression coding technology has been applied to DVD , (MPEG-7) are not included in the standard audio and video compression technology.
A：MPEG-1
B：MPEG-2
C：MPEG-4
D：MPEG-7
[A]:
MPEG is short for Moving Picture Expert Group, initially it refers to a group of experts studied the video and audio coding standard by the International Organization for Standardization (ISO) and International Electrotechnical Commission (IEC) coalition. While MPEG is also used to name the group responsible for the development of a series of audio and video coding standards and standards for multimedia applications. The Expert Group developed so far have been developed and are standard including MPEG-1, MPEG-2, MPEG-4, MPEG-7 and MPEG-21 standard.
Wherein the MPEG-1, MPEG 2 and MPEG-4 for the primary audio, video coding technology , the MPEG-7 is a multimedia content description interface standard , the MPEG-frame 21 is a standard for multimedia applications .
VCD using MPEG-1 as standard audio and video compression coding scheme, the MPEG-2 standard, audio, video compression encoding technique is applied to a DVD.
( Reference: https://www.cnblogs.com/sunjiaojiao/p/11603519.html 5 small problem resolved )
4, assuming that each track of a magnetic disk is divided into nine physical blocks, each storing a logical record. Logical record R0, R1, ..., R8 is stored in order of arrangement in the following table on the same track, recording is as follows:
if the rotational speed of the disk is 27ms / week, at the beginning of the current head of R0. If the system sequentially processes the records using a single buffer, each time the recording process is 3ms, the process records nine maximum period (222ms): If the stored information to optimize distribution, the processing of recording a minimum of 9 time (54ms).
A：54ms
B：108ms
C：222ms
D：243ms
A：27ms
B：54ms
C：108ms
D：216ms
[A]:
System reads the recorded time is 27/9 = 3ms for the first case: the system after reading out and recording process R1, R3 will go at the beginning of the recording, so in order to read record R2, the disk must sub circle, need 27ms (turn - lap) time. Thus, the total processing time should be recorded nine 222ms because eight recording pretreatment (i.e. R1, R2, ..., R8) plus the total time to read R9 time:. 8X27ms + 6ms = 222ms.
For the second case, if the result of optimizing the distribution of the information as follows:
As can be seen from the table, when the read record processing ends and R1, R2 head immediately go to the beginning of the recording, can be immediately read out and processed, the processing records 9 Total time:
9X (3ms (read record) + 3ms (processing records)) = 9X6ms = 54ms
5, for a large-scale software, uncontrolled change will soon lead to confusion. Change control is effectively achieved, and the database required by the arrangement of the baseline concept. (Repository) does not belong to the configuration database.
A: Development Library
B: Controlled Library
C: Information Base
D: portfolio
[A]:
配置数据库一般包括开发库、受控库和产品库。
6、确定系统边界和关系规范化分别在数据库设计的(51)阶段进行。
A：需求分析和逻辑设计
B：需求分析和概念设计
C：需求分析和物理设计
D：逻辑设计和概念设计
【解析】：
需求分析阶段的任务是:对现实世界要处理的对象(组织、部门、企业等)进行详细调查，在了解现行系统的概况，确定新系统功能的过程中，确定系统边界、收集支持系统目标的基础数据及其处理方法。
逻辑设计阶段的任务之一是对关系模式进一步的规范化处理。因为生成的初始关系模式并不能完全符合要求，会有数据冗余、更新异常存在，这就需要根据规范化理论对关系模式进行分解，以消除冗余和更新异常。不过有时根据处理要求，可能还需要增加部分冗余以满足处理要求。逻辑设计阶段的任务就需要作部分关系模式的处理，分解、合并或增加冗余属性，提高存储效率和处理效率。
222.125.80.128/26包含了(62)个可用主机地址,其中最小地址是(222.125.80.129), 最大地址是(222.125.80.190)。
A：14
B：30
C：62
D：126
A：222.125.80.128
B：222.125.80.129
C：222.125.80.159
D：222.125.80.160
A：222.125.80.128
B：222.125.80.190
C：222.125.80.192
D：222.125.80. 254
【解析】：
222.125.80.129 ~ 222.125.80.190。