I. The Result of Sign-in

• Let us take a look at the screenshot of the sign-in result
  
• There are thirty nine students in our class. Thirty one students have signed in and eight students have not. Six students asked for leave and two students are late for the class.

II. Numbers

• Numbers are very important in our learning, work and life.
• When we talk about nubmers, there are two ways of using numbers. In one case, we only care about “how many” or “quantity”, and we use “cardinal numbers”. For example, I ask you how many apples you have eaten. You answer that you have eaten six apples. – one, two, three, four, five, six… In the other case, we care about the “order” of the things, and we use “ordinal numbers”. For example, I ask you which season in a year summer is. You answer that summer is the second season in a year. – first, second, third, fourth, fifth, sixth…
• I want to say that he is No. 1 in his learning in our class. There are several ways to express this fact.
• He is the first one in our class.
• He comes first in our class.
• He is second to none in our class.

III. Software Categories

• Software can fall into two categories: System Software and Application Software.
  S o f t w a r e { S y s t e m   S o f t w a r e A p p l i c a t i o n   S o f t w a r e Software
  {System SoftwareApplication Software $$\{\begin{array}{l}SystemSoftware\\ ApplicationSoftware\end{array}$$
  Software{System SoftwareApplication Software​
• System software can fall into three categories: OS (Operating System), Language Processors, DBMS (DataBase Management System).
  S y s t e m   S o f t w a r e { O S : O p e r a t i n g   S y s t e m { W i n d o w s L i n u x { U b u n t u C e n t O S M a c O S L a n g u a g e   P r o c e s s o r s { C o m p i l e r I n t e r e p t e r A s s e m b l e r D B M S { S Q L   D B M S { M y S Q L O r a c l e S Q L   S e r v e r D B 2 O c e a n B a s e N o S Q L   D B M S { H B a s e R e d i s M o n g o D B System\ Software
  \begin{cases} OS: Operating\ System \begin{cases} Windows\\ Linux\begin{cases} Ubuntu\\ CentOS\\ \end{cases} $$\text{begin{cases} OS: Operating System begin{cases} Windows Linuxbegin{cases} Ubuntu CentOS end{cases}}$$
  \\ MacOS\\ \end{cases}\\ Language\ Processors
  ⎧⎩⎨CompilerInterepterAssembler $$\{\begin{array}{l}Compiler\\ Interepter\\ Assembler\end{array}$$
  \\ DBMS
  \begin{cases} SQL\ DBMS \begin{cases} MySQL\\ Oracle\\ SQL\ Server\\ DB2\\ OceanBase\\ \end{cases} $$\text{begin{cases} SQL DBMS begin{cases} MySQL Oracle SQL Server DB2 OceanBase end{cases}}$$
  \\ NoSQL\ DBMS
  ⎧⎩⎨HBaseRedisMongoDB $$\{\begin{array}{l}HBase\\ Redis\\ MongoDB\end{array}$$
  \\ \end{cases}\\ \end{cases} System Software⎩⎪⎪⎪⎪⎪⎪⎪⎪⎪⎪⎪⎪⎪⎪⎪⎪⎪⎪⎪⎪⎪⎪⎪⎪⎪⎪⎪⎪⎪⎪⎨⎪⎪⎪⎪⎪⎪⎪⎪⎪⎪⎪⎪⎪⎪⎪⎪⎪⎪⎪⎪⎪⎪⎪⎪⎪⎪⎪⎪⎪⎪⎧​OS:Operating System⎩⎪⎪⎪⎨⎪⎪⎪⎧​WindowsLinux{UbuntuCentOS​MacOS​Language Processors⎩⎪⎨⎪⎧​CompilerInterepterAssembler​DBMS⎩⎪⎪⎪⎪⎪⎪⎪⎪⎪⎪⎪⎪⎪⎨⎪⎪⎪⎪⎪⎪⎪⎪⎪⎪⎪⎪⎪⎧​SQL DBMS⎩⎪⎪⎪⎪⎪⎪⎨⎪⎪⎪⎪⎪⎪⎧​MySQLOracleSQL ServerDB2OceanBase​NoSQL DBMS⎩⎪⎨⎪⎧​HBaseRedisMongoDB​​​
• OceanBase是阿里巴巴和蚂蚁金服 100% 自主研发的金融级分布式关系数据库，在普通硬件上实现金融级高可用，在金融行业首创“三地五中心”城市级故障自动无损容灾新标准，同时具备在线水平扩展能力，创造了 6100万次/秒处理峰值的业内纪录，在功能、稳定性、可扩展性、性能方面都经历过严格的检验。
• Next time we will talk about Operating Systems.

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原文链接：howard2005.blog.csdn.net/article/details/123786052