This is the 27th day of my participation in the November Gwen Challenge. Check out the event details: The last Gwen Challenge 2021

Welcome to pay attention to my computer postgraduate entrance examination column! Daily updates! Write yourself will inevitably have mistakes, welcome correction!

🐯 Data structure

In the following statement about “strings”, the incorrect description is ___. (Sun Yat-sen University, 2013)

A. A string is a special kind of linear table B. Strings can be stored consecutively or chained to C. The length of the string must be greater than zero D. "Empty string" does not have the same meaning as "blank string"Copy the code

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Answer: C

👁️🗨️ Common sense C.

  • A string is a special kind of linear table in which each node consists of only one character.
  • Sequential storage and chain storage are the two most basic storage structures. Strings are usually stored sequentially, but when strings are long and there is not so much contiguous space, a string can be divided into multiple small strings and chained storage is used between strings.
  • An empty string is a string of 0 characters, which has a length of 0. A blank string is a string composed of one or more Spaces, and its length is the number of Spaces in the string.

🦁 Computer network

The most accurate description of OSPF is ___. (University of Science and Technology of China, 2015)

SPF calculates the best route based on the link state method. SPF is an external gateway protocol between autonomous systems. SPF cannot dynamically change routes based on network communicationCopy the code

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Answer: A,

👁 ️ 🗨 ️ OSPF belongs to the internal gateway protocol, it USES the link-state algorithm, through the link state to calculate the best route, when the link state changes, send this information to all routers with flooding method, all of the routers will eventually create a link-state database, can dynamically change the routing according to the network communication situation. OSPF supports A maximum of hundreds of routers and supports networks of various scales.

🐶 Operating system

Mailbox communication is a ___ method of communication. (Nanjing University of Science and Technology, 2010)

A. direct COMMUNICATION B. indirect communication C. low-level communication D. semaphoreCopy the code

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Answer: B

👁️🗨️ By name, communication goes through a mailbox, it must be indirect.

The biggest advantage of mailbox communication is that the sender and receiver do not have to establish direct contact, there is no limit on processing time. The sender can send a message at any time, and the receiver can receive it at any time. So mailbox communication is a kind of indirect communication.

🦊 Computer composition principle

The memory that uses capacitors to store information and needs to be refreshed periodically is ___. (Guangdong University of Technology, 2014)

A.DRAM 
B.EPROM 
C.SRAM 
D.EEPROM
Copy the code

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Answer: A,

👁️🗨️ DRAM is a DynamicRAM. Dynamic DRAM is a feature that needs to be refreshed periodically.

The main principle is to record each bit with a transistor and a capacitor. However, the capacitor inevitably has leakage phenomenon, resulting in insufficient potential difference and memory loss, so unless the capacitor is regularly charged periodically, otherwise it can not ensure the memory is long.

The exercises come from @Wangdao Weibo

The analysis is written by myself, if there are any questions or mistakes, please comment.

I am Mancuoj, welcome to pay attention to me and my computer entrance examination column (≧∇ Blue)