Template of a cover letter

我是工科的，每次申請job，cover letter有作用嗎？如果用處不大就不想寫了。
-- The DATA shown that the cover letter is not a big deal for industry job.
-- Following is a Template to save your time.

Dear HR,
I learned from internet that there is a Network Security Expert position opening in your company, please consider me as a candidate.
Attached herein please find a copy of my resume.
You can see I have N years work experience in charge of Internet Security at many large and small companies like Microhoo, Goobay, Mytube.
I believe my education, experience and dedicate work spirit makes me one of the best candidate for this position. Would you please let me know when will be the best time for me to visit your copany?

Regards,

Yours
Slave