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SMTP SMTP: SMTP is the most common protocol for sending emails. SMTP has a client side that executes on the sender’s mail server, and a server side th 阅读全文
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Refer to: www .isc.org/community/rfcs/dns/ domain name system (DNS): 1) a distributed database implemented in a hierarchy of DNS servers and 2) an app 阅读全文
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DHCP (Dynamic Host Configuration Protocol): An application-layer client-server protocol for allowing a device to automatically obtain an IP address. D 阅读全文
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An IPv6 address is 128 bits long, written in 8 group of 2 bytes in hexadecimal notation (each digit indicates 8 bits). Collapsing 0s Can collapse a gr 阅读全文
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Node: any device that runs a link-layer protocol. E.g. hosts, routers, switches, WiFi access points. Link: communication channel that connects adjacen 阅读全文
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Scenario: user (68.85.2.101) connects to School network’s Ethernet switch and downloads a webpage from Google; Ethernet switch is connected to School’ 阅读全文
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Thread and Networking Threads, AsyncTasks & Handler Java thread Java Thread: a java thread is represented by an object of type java.lang.thread. Java 阅读全文
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* 以下内容基于64位机 jdk 8。 Oop模型 -- Java中的对象在jvm中的表现形式。 oopDesc: 顶层类。_compressed_klass即为压缩指针。 /openjdk/hotspot/src/share/vm/oops/oop.hpp class oopDesc { frie 阅读全文
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执行引擎：JVM运行Java程序的一套子系统。 如何理解Java是半编译半解释型语言？ 1. javac编译，java执行； 2. 字节码解释器解释执行，模板解释器编译执行。 两种解释器 -- a) 字节码解释器; b) 模板解释器 字节码解释器：将Java字节码解释称C++代码（java代码->j 阅读全文
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今天做练习的时候任务需要从manpage里找一个关键词，问题出在apropos对几乎给出的所有输入都报 “nothing appropriate”，所以不是输入表达式的问题，因为即使apropos whatis都会return nothing appropriate。 网上找的第一条解决方案是sud 阅读全文