- 1、本文档共5页,可阅读全部内容。
- 2、有哪些信誉好的足球投注网站(book118)网站文档一经付费(服务费),不意味着购买了该文档的版权,仅供个人/单位学习、研究之用,不得用于商业用途,未经授权,严禁复制、发行、汇编、翻译或者网络传播等,侵权必究。
- 3、本站所有内容均由合作方或网友上传,本站不对文档的完整性、权威性及其观点立场正确性做任何保证或承诺!文档内容仅供研究参考,付费前请自行鉴别。如您付费,意味着您自己接受本站规则且自行承担风险,本站不退款、不进行额外附加服务;查看《如何避免下载的几个坑》。如果您已付费下载过本站文档,您可以点击 这里二次下载。
- 4、如文档侵犯商业秘密、侵犯著作权、侵犯人身权等,请点击“版权申诉”(推荐),也可以打举报电话:400-050-0827(电话支持时间:9:00-18:30)。
- 5、该文档为VIP文档,如果想要下载,成为VIP会员后,下载免费。
- 6、成为VIP后,下载本文档将扣除1次下载权益。下载后,不支持退款、换文档。如有疑问请联系我们。
- 7、成为VIP后,您将拥有八大权益,权益包括:VIP文档下载权益、阅读免打扰、文档格式转换、高级专利检索、专属身份标志、高级客服、多端互通、版权登记。
- 8、VIP文档为合作方或网友上传,每下载1次, 网站将根据用户上传文档的质量评分、类型等,对文档贡献者给予高额补贴、流量扶持。如果你也想贡献VIP文档。上传文档
查看更多
第二章作业
14. What’s the biggest advantage of implementing thread in user space? What’s the biggest disadvantage?
olution: The first advantage is that a user-level package can be implemented on an operating system that does not support threads. The second advantage is that they allow each process to have its own customized scheduling algorithm.
he disadvantage is the problem of how blocking system calls are implemented. Another problem is that if a thread starts running, no other thread in that process will ever run unless the first thread voluntarily gives up the CPU.
35. Measurements of certain system have shown that the average process runs for a time T before blocking on I/O. A process switch requires a time S, which is effectively wasted (overhead). For round-robin scheduling with quantum Q, give a formula for the CPU efficiency for each of the following:
(a) Q=∞
CPU efficiency=T/ (T+S)
QT CPU efficiency= T/ (T+S)
SQT CPU efficiency=T/ (T+ST/Q)
Q=S CPU efficiency=50%
Q nearly 0 CPU efficiency is nearly 0
36. Five jobs are waiting to be run. Their expected run times are 9, 6, 3, 5, and X. In what order should they be run to minimize average response time?(Your answer will depend on X.) Solution:
IF (X=3): X, 3, 5, 6, 9
IF (X=3 AND X=5): 3, X, 5, 6, 9
IF (X=5 AND X=6): 3, 5, X, 6, 9
IF (X=6 AND X=9): 3, 5, 6, X, 9
IF (X=9): 3, 5, 6, 9, X
37. Five batch jobs A through E, arrive at a computer center at almost the same time. They have estimated running times of 10, 6, 2, 4, and 8 minutes. Their (externally determined) priorities are 3, 5, 2, 1, and 4, respectively, with 5 being the highest priority. For each of the following scheduling algorithms, determine the mean process turnaround time. Ignore process switching overhead.
Round robin
Priority scheduling
First-come, first-served (run in order 10, 6, 2, 4, 8)
Shortest job first
For (a), assume that the system is multiprogrammed, and that each job gets its fair share of the CPU. For (b) through (d) assume that only on
您可能关注的文档
- 大班节日主题活动.docx
- 大班艺术计划.docx
- 大班英语童谣教案.docx
- 大班语言总结.docx
- 大班语言我的名字.docx
- 大班语言教学总结.docx
- 大班语言活动《小螃蟹找工作》及反思.docx
- 大班音乐优质课教案详案《面条舞》.docx
- 大班音乐律动教案《快乐洗衣》.docx
- 大班音乐活动《绿色的家》课后反思.docx
- 2024至2030年中国人造棉面料行业投资前景及策略咨询报告.docx
- 重庆市渝中区遴选公务员2024年国家公务员考试考试大纲历年真题10340笔试历年典型考题及解题思路附.docx
- 2024至2030年中国甲基苯乙酮行业深度调研及发展预测报告.docx
- 2024至2030年中国羚羊角类饮片行业深度调查与前景预测分析报告.docx
- 重庆市面向中国农业大学定向选调2024届大学毕业生2024年国家公务员考试考试大纲历年真题14笔试历.docx
- 重庆市面向西北工业大学定向选调2024届大学毕业生00笔试历年典型考题及解题思路附答案详解.docx
- 中国不动杆菌感染治疗药行业市场现状分析及竞争格局与投资发展研究报告2024-2029版.docx
- 2024至2030年全球与中国ETL软件市场现状及未来发展趋势.docx
- 初中八年级(初二)生物下册期末考试1含答案解析.docx
- 干簧式继电器项目申请报告.docx
最近下载
- (100题)2024时事政治考试题库.doc VIP
- 《“跨学科教学”在初中英语课堂中的实践探究》课题研究方案.doc
- 获奖教案《爷爷变成了幽灵》(语言领域).pdf
- 难治性肺癌中国专家共识解读.pptx VIP
- 第1课《消息二则》课件(共42张PPT) 统编版语文八年级上册.pptx VIP
- 2024年畜禽屠宰企业兽医卫生检验人员考试试题.docx
- 浅析中日两国女性对化妆的态度-以两国女大学生为研究对象-日语毕业论文.doc VIP
- 设备改进与创新技术的应用.pptx
- 【必威体育精装版原创】深度学习:《1.3.2_第1课时_有理数的减法》学历案 (5).docx VIP
- 沃森(VicRuns)VD120A-GS系列变频器说明书用户手册.doc
文档评论(0)