命令按钮控件属于()

子程序返回主程序的语句是()

A.CLOSE 

B.RETURNS 

C.RETURN 

D.QUIT

ost all IT resources can be delivered as a cloud service: applications, compute power, storage capacity, networking,programming tools,even communication services and collaboration （72）。

Cloud computing began as large-scale Internet service providers such as Google,Amazon,and others built out their infrastructure. An architecture emerged: massively scaled, （73） distributed system resources,abstracted as virtual IT services and managed as continuously configured, pooled resources. In this architecture, the data is mostly resident on （74）“somewhere on the Intemet”and the application runs on both the "cloud servers”and the user’s browser.

Both clouds and grids are built to scale horizontally very efficiently. Both are built to

withstand failures of （75） elements or nodes. Both are charged on a per-use basis. But while grids typically process batch jobs, with a defined start and end point, cloud services can be continuous. What’s more, clouds expand the types ofresources available —— file storage, databases, and Web services —— and extend the applicability to Web and enterprise applications.

(71)

A. hardware

B. computers

C. services

D. software

A.RSA

B.RC-5

C.MD5

D.ECC

)。

A.原子性

B.一致性

C.隔离性

D.持久性

（74）

A. clients

B. middleware

C. servers

D. hard disks

分布式事务故障不同于集中式事务故障的是(59)。

A.介质故障

B.系统故障

C.事务故障

D.通信故障

关系数据库是(68)的集合，其结构是由关系模式定义的。

A.元组

B.列

C.字段

D.表

（73）

A. horizontally

B. vertically

C. inclined

D. decreasingly

对于事务故障的恢复，下列描述正确的是(70)。

A.事务故障的恢复不需要访问日志文件

B.事务故障恢复时需要REDO已提交的事务

C.事务故障恢复时需要正向扫描日志，对该事务进行UNDO操作

D.事务故障恢复时需要反向扫描日志，对该事务进行UNDO操作