问题 单项选择题

RMON警报组的实现是基于 (1) 的实现。当RMON警报组alarmStartupAlam=3时,在图4-2所示的信号变化图上,将产生 (2) 次的报警。

2()

A.3 

B.5 

C.6 

D.9

答案

参考答案:C

解析:

在RMON功能组中,①警报组的实现基于事件组的实现;②捕获组的实现基于过滤组的实现:③最高N台主机组的实现基于主机组的实现。

当RMON警报组alarmStartupAlam=3时,其报警规则是:①当第一个采样值大于上升门限时,要产生1次报警;②当采样值从大于上升门限值降到小于下降门限时,要产生1次报警;③当采样值从小于下降门限值上升至大于上升门限时,要产生1次报警;④当采样值从小于下降门限值上升到正常值范围,然后又下降到下降门限时,不产生报警:⑤当采样值从大于上升门限值下降到正常值范围,然后又升回到上升门限时,不产生报警。因此,在图4-2所示的报警信号变化图上,将产生6次的报警信息。

单项选择题
单项选择题

The dot-com collapse may have been a disaster for Wall Street, but here in Silicon Valley, it was a blessing. It was the welcome end to an abnormal condition that very nearly destroyed the area in an overabundance of success. You see, the secret to the Valley’s astounding multiple-decade boom is failure. Failure is what fuels and renews this place. Failure is the foundation for innovation.
The valley’s business ecology depends on failure the same way the tree-covered hills around us depend on fire--it wipes out the old growth and creates space for new life. The valley has always been in danger of drowning in the unwelcome waste products of success--too many people, too expensive houses, too much traffic, too little office space and too much money chasing too few startups. Failure is the safety valve, the destructive renewing force that frees up people, ideas and capital and recombines them, creating new revolutions.
Consider how the Internet revolution came to be. After half a decade of start-up struggles, for example, hundreds of millions of Hollywood dollars were going up in smoke. It all seemed like a terrible waste, but no one noticed that the collapse left one very important byproduct, a community of laid-off C++ programmers who were now expert in multimedia design, and out on the street looking for the next big thing.
These media geeks were the pioneer of the dot-com revolution. They were the Web’s business pioneers, applying their newfound media sensibilities to create one little company after another. Most of these start-ups failed, but even in failure they advanced the new medium of cyberspace. A few geeks, like Silicon Graphics founder Jim Clark, succeeded and utterly changed our lives. In 1994 Clark was unemployed after leaving the company be founded, doggedly trying to develop a new interactive-TV concept. He approached Marc Andreessen, the co-developer of Mosaic, the first widely used Internet browser, in hope of persuading Andreessen to help him de-sign his new system. Instead, Andreessen opened Clark’s eyes to the Web’s potential. Clark promptly tossed his TV plans in the trash, and the two co-founded Netscape, the cornerstone of the consumer-Web revolution.
Like the interactive-TV refugees and generations of innovators before them, the dot comers are already hatching new companies. Many are revisiting good ideas executed badly in the’ 90s, while others are striking out into entirely new spaces. This happy chaos is certain to mature into a new order likely to upset an establishment, as it delivers life-changing wonders to the rest of us. But this is just the start, for revolutions give birth to revolutions. So let’s hope for more of Silicon Valley’s successful failures.

The author writes of the experiences of Jim Clark to demonstrate

A.the hardships a web pioneer must go through.

B.the trouble in which Clark was caught.

C.the role failures positively play in revolutions.

D.the cooperation among dot-comers.