After class exercise 8 (I/O system )

one . Single choice questions ( common 10 topic ,100 branch )

1. ( Single choice questions )
I/O Addressing methods can usually be divided into unified addressing and non-uniform addressing ,(         )

* A.  Uniform addressing is to I/O An address is considered part of a memory address , Available special I/O Instruction to access the device
* B.  Non uniform addressing refers to I/O Address and memory address are separate , So yes I/O Access must have a dedicated I/O instructions
* C.  Uniform addressing refers to I/O Address and memory address are separate , So it can be realized with memory access instruction CPU Access to devices
* D.  Non uniform addressing is to I/O An address is considered part of a memory address , But yes I/O Access must have a dedicated I/O instructions
My answer : B right key : B

10 branch

2. ( Single choice questions )
about DMA  mode , The following description is correct (        )

* A. DMA  Since this method can be used for information transmission of high-speed peripheral devices , It can also replace the interrupt mode
* B. DMA  Mode cannot replace interrupt mode
* C. DMA  Mode is a pure software mode
* D. DMA  Mode is an operation mode independent of main memory
My answer : B right key : B

10 branch

3. ( Single choice questions )
In the following devices ,(       ) With input and output functions

* A.  disc drive
* B.  keyboard
* C.  Traditional display ( No touch function )
* D.  printer
My answer : A right key : A

10 branch

4. ( Single choice questions )
Among the following options , stay I/O The information transmitted on the data line of the bus includes (         )

I.   I/O Command word in interface    

II.  I/O Status word in interface    

III. Interrupt type number

* A. only I and II
* B. only I and III
* C. only II and III
* D. I,II,III
My answer : D right key : D

10 branch

5. ( Single choice questions )
At present, the letter and character coding commonly used in minicomputers and microcomputers is (          )

* A. BCD code
* B.  Hex code
* C. ASCII code
* D.  Complement
My answer : C right key : C

10 branch

6. ( Single choice questions )
use DMA When transmitting data by , Each data transfer takes up (           ) Time

* A.  One instruction cycle
* B.  One machine cycle
* C.  One storage cycle
* D.  One clock cycle
My answer : C right key : C

10 branch

7. ( Single choice questions )
Suppose a computer's display memory is used DRAM Chip implementation , If required, the display resolution is 1600×1200, Color depth is 24 position , Frame rate is 85Hz, Displays the total bandwidth 50%
Used to refresh the screen , The total bandwidth of video memory required is at least about (           )

* A. 245 Mb/S
* B. 979 Mb/S
* C. 1958 Mb/S
* D. 7834 Mb/S
My answer : D right key : D

10 branch

Answer analysis :

be careful Mb/S and MB/S Differences between

8. ( Single choice questions )

Hypothetical benchmark procedure A The running time on a computer is 100 second , among 90 Second is CPU time , The rest are I/O time . if CPU Speed increase 50%,I/O Constant speed , Then run the program A The time taken is ( 
     )

* A. 55 second
* B. 60 second
* C. 65 second
* D. 70 second
My answer : D right key : D

10 branch

Answer analysis :

CPU time 90 second ,I/O time 10 second ,

CPU Speed increase 50%, New time t*(1+50%)=90, calculation t=60 second

I/O Time is not mentioned , still 10 second

To sum up, the results are as follows:

9. ( Single choice questions )

Main frequency of a computer 50MHz, It is controlled by regular query A equipment I/O, The number of clock cycles used by the query program to run once is at least 500, In equipment A Working period , To ensure no data loss , It needs to be queried at least every second 200 second , be CPU For equipment A of I/O Total time CPU The percentage of time is at least (    
   )

* A. 0.02 %
* B. 0.05 %
* C. 0.20 %
* D. 0.50 %
My answer : C right key : C

10 branch

Answer analysis :

Dominant frequency 50MHz, Then a clock 20ns,

The query program runs once 500 Cycles , Then one query 20ns*500=10us

Queries per second at least 200 second , The time used in the query 10us*200=2ms

The above calculation unit period is seconds , Then the proportion is 2ms/1=0.002

10. ( Single choice questions )
When the host and device transmit data , use (        ), The host and equipment work in serial

* A.  Program query mode
* B.  Interrupt mode
* C. DMA mode
* D.  The above three can be used
My answer : A right key : A

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