...Solutions to Chapter 5 1. Explain the difference between connectionless unacknowledged service and connectionless acknowledged service. How do the protocols that provide these services differ? Solution: In an acknowledged connectionless network, reliable delivery can be achieved through the use of ACK and NAK transmissions. Such protocols are suited for communication over networks in which higher layers are sensitive to loss and the underlying network is inherently unreliable with a significant probability of loss or error. Unacknowledged networks provide simpler and faster communication for networks that are inherently reliable or provide service to higher layers that can tolerate information loss. 2. Explain the difference between connection-oriented acknowledged service and connectionless acknowledged service. How do the protocols that provide these services differ? Solution: The use of acknowledgments can provide reliable transfer over networks that are prone to error and loss. In connection oriented networks, every packet in a data flow travels on the same path through the network and the proper ordering of packets is guaranteed. In such networks, if a packet arrives out of order, the receiver immediately knows that a packet has been lost. In a connectionless network, the service needs a mechanism for dealing with unordered delivery of information. This is especially important for real-time or delay-sensitive traffic, which may require immediate retransmission and may not...
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...a) Fig 1 implies that Go-Back-N is used In fig we can notice that after the 2nd packet is lost, we are sending the 3rd packet and we get an acknowledgement for 1st packet. Indicating that 2nd packet is lost and is waiting for 2nd packet. So, the 3rd packet is discarded. It counts the timer and after timeout, it starts retransmission from 2nd packet. Here the transmission is done orderly. This is the concept of Go-Back-N. b) Fig 2 implies that Selective Repeat is used In fig we can notice that after the 2nd packet is lost, we are sending the 3rd packet and we get an acknowledgement for 3rd packet. This doesn’t indicate anything like it has lost 2nd packet, and the process is carried forward. We don’t know the 2nd packet is lost till the timeout occurs. After a timeout occurred, the 2nd packet is retransmitted. Any packet here will not wait for other packet to be delivered. This is the concept of Selective Repeat. c) The positions of the sender and receiver are shown in the next page. Also, I have given a diagram with sender and receiver including time flow and windowed packets. d) All the possible future events at the sender after time t are: I. Data received from above: Data is received from above, sender checks the next available sequence number for the packet. If that sequence number is in the window data is packetized and sent. Otherwise it is buffered or else returned to the upper layer. This return is similar to that of in Go-Back-N. II. Timeout: Here the...
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...Commands with some options: * tar - options to create and extract, preserve options, gzip compress (you should have used either of these when you created your kernel source code backup.) * chmod - options to recursively change user, group and other permissions on files/directories * chown - options to recursively change file and directory user ownership * chgrp - options to recursively change file and directory group ownership * kill - superkill vs sending other signals to a process * ps - options to list all running processes on a Linux/Gnu system * top – Interactive Linux Tasks Status Display * grep - know how to use to find specific lines of info in output/files (you should have learned about this command in Intro to Unix/Linux Systems.) Shell expansion characters - be able to respond to questions regarding usage of '*' - asterisk, all files or all matching strings '?' - question mark, single character What are the components of a Linux distribution? * Kernel * Desktop Environment * System Libraries * System Tools * Developmental Tools * File Structure Popular Distributions: * Redhat, * CentOS * Fedora * Suse * Debian * Ubuntus What sort of hardware architecture can Linux be installed on? * Intel-x86 systems * Embedded systems From what sources can Linux be installed? * CD- ROM * Hard Disk * Floopy Disk * USB * Network Installation...
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...There are hundreds of restaurants featuring all kinds of fare from brand new eateries and legendary establishments. Downtown and Midtown give you the most options when it comes to finding grub for breakfast, lunch, or dinner. Peg's Glorified Ham N Eggs is a local icon. Find hearty portions of your classic favorites or enjoy one of their signature dishes, like the Smoked Salmon Eggs Benedict. If you're closer to midtown, grab a fresh-brewed coffee from Hub Coffee Roasters before starting your day. Forget typical fast food when you're in Reno. While you're sure to find your fair share of In-N-Out, McDonald's, and Burger King, go for something different at Süp with their unique array of soups, sandwiches, and salads, or grab a slice at Blue Moon Gourmet. Downtown restaurants feature everything from international cuisine to classic American comforts and everything in between. In addition, the craft beer business is booming in Reno, so be sure to stop in to one of the dozens of breweries located downtown to taste some of the local...
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...Establish and Manage Your Home Lawn The home lawn and turf areas surrounding churches, parks, and office buildings do more than just serve as pleasant green backdrops. The grass plants that make up the lawns serve as miniature air-conditioners and pollution-abatement centers. On a block of eight houses, the front lawns have the cooling effect of 70 tons of air-conditioning. The plants, in transpiring water to cool themselves, also cool the surrounding area. Roughly 50 percent of the heat striking a turf area is eliminated by transpiration. When the temperature of the sidewalk is 100 °F, the temperature of the adjacent turf remains near 75 °F. This cooling may last into the night, with studies showing a 13-degree cooling at 9 p.m. This air-conditioning is not free, however. An average 5,000-square-foot lawn transpires about 3,000 gallons of water on a hot summer day. If this water is not supplied by rain, it must be applied by some other means. Turfgrass also functions as a noise barrier. Studies at the Riverbank Acoustical Laboratory in Geneva, Illinois, found Kentucky bluegrass turf more sound-absorbent than a heavy carpet on a felt pad. One of the most significant byproducts of a living, green backdrop is its effect upon the atmosphere. A 250-square-foot lawn produces enough oxygen for a family of four. The average lawn traps significant amounts of carbon dioxide, peroxyacetyl nitrates, and ozone, as well as particulate matter. A most important effect is the prevention of soil...
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...欢迎来到 Ubuntu 部落 作者: Kardinal @ Ubuntu.org.cn 论坛 邮箱: 2999am[at]gmail.com 版权: 1.欢迎自由传播 2.请保留版权信息 3.未经允许，不得用于商业用途 （ 本 档 下 载 点击此处） 索引 欢迎来到 Ubuntu 部落 Ubuntu 的发音 Ubuntu 的涵义 Ubuntu 当前版本 Ubuntu 的特点 Ubuntu 相对其它 Linux 发行版的主要特点 基本操作 进入系统 命令行提示符 退出系统 安装 分区概念 安装中的注意事项 开始安装 Linux 基础 Shell 命令 Linux 程序、进程 Linux 系统简介 路径 软件 配置方式 隐藏文件 文件类型 权限 命令行 Shell、Console、Terminal rxvt-unicode 在线帮助系统 bash 中止正在运行的程序 Ctrl+s 键绑定 自定义键绑定 通配符 任务管理 管道、重定向 脱字符 Fish 设定您的默认 Shell 设定命令的搜索路径 Ubuntu 系统简介 Ubuntu 系统目录结构 启动流程 更改运行级别 服务管理 更改启动服务 手动控制服务 常用系统服务 重要配置文件 全局配置文件 用户配置文件 软件安装 DPKG APT APT 系统修复 源码包 Xwindow 简介 历史 架构及原理 Xserver Xclient Xprotocol 窗口管理器 启动流程 配置文件 X 服务器 X 客户端 字体 freetype 渲染引擎 X 核心字体 XFT 字体 系统管理 一些细节 格式约定 系统信息 uptime w who whoami last uname date cal 文件管理 一些细节 ls [路径] cd [目录路径] | [特殊路径] pwd file du [路径] less touch mkdir cp rm rmdir mv ln 文件操作 nano split [目标文件名前缀] cat sort [-o ] [-t ] [+ - ] [文件] more diff cksum [文件名] 权限管理 一些细节 chmod chown [:归属群组] chgrp SUID、SGID、Sticky bit lsattr [路径] chattr +|-|= 压缩解压 tar -c|x|u|r|t[z|j][v] -f [未打包文件] zip [参数] unzip [参数] [压缩包中将被释放的文件] 7z|7za [参数] [文件] rar [参数] [文件|文件列表|路径] 搜索 whereis locate find [路径] grep |"" [文件名] 其它 echo clear alias export shutdown halt reboot chroot 用户管理 一些细节 su [用户名] sudo [命令] passwd [用户名] chsh [-s ] [用户名] usermod useradd userdel id [用户名] finger [用户名] ...
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...Installation Guidelines GRUB/LILO GRUB is the boot loader of choice for RedHat installations; however LILO may always be used in the case of most flavors of LINUX. GRUB/LILO can receive many different kernel level commands and it poses a major security risk if an attacker is able to compromise the kernel. In response you can make sure that only authorized users are able to perform those commands by password protecting during the installation process. If using GRUB, the password is by default stored as clear text, and so you will want modify the /etc/grub.conf file to store the password in an MD5 checksum. $ /sbin/grub–md5–crypt Password: (at the prompt enter the GRUB password you created at installation and press enter) $ #%t%661GFGftffgctTFTDd (This is the MD5 hash) edit the grub.conf file and replace the clear text password with the MD5 Hash. You must use the –MD5 option or the password will be stored as the MD5 Hash and not the encrypted password. Password – md5 $1$m0tLR/ $#%t%661GFGftffgctTFTDd Partitioning Partitioning correctly will help to mitigate against one specific type of denial of service. For example and attack designed to fill up a /tmp or spool directory. If your files are on the same partition as the directory under attack, your system could be rendered unusable. One should use a partition strategy where those directories that are most likely to be filled by an attacker. Typically this is /var and /home . If you are using a server for ftp or e–mail, you...
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...E Poole Beecham English 101 10059 19 April 2010 Genetic Testing Imagine choosing your daughter to have high intelligence. No one would fault the parents for giving their daughter this advantage for life. Parents can make the decision to use any safe drug or therapy to enhance their future children to make them smarter, better, stronger, to increase their intelligence, height, or other traits (Zane). Testing for medical tendencies to screen and reduce the possibility of future illness or diseases is now feasible. Genetic testing can enhance and improve lives with immeasurable benefits. The rewards of this testing outweigh any reservations. Genetic testing are examinations of blood and other tissues of the body that doctors in the medical field prepare to test for possible defects of the body. These DNA based tests generally involves direct examination of the DNA molecule itself and are very sophisticated techniques of testing genetic disorders in the bodies of human beings. Prenatal genetic testing with the procedure of pre-implantation genetic diagnosis, or PGD is a technique whereby testing is performed of an approximate three-day-old embryo to confirm that it does not carry a particular disease or diseases (Naik). The test predicts, with variable confidence, what the possible medical problems will be in the future. Then the doctor implants this embryo, which is free of that syndrome, in the mother's womb. It appears to be relatively easy to check the DNA and eliminate...
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...they are such cheap baits to make. A package of jig heads can cost anywhere from three dollars to over ten dollars. Jig heads can last a long time if they do not get snagged on debris or rocks (Under 2017). Another common bait used for many different species of fish are soft plastics. They are commonly used for bass, but work for many other species of fish as well. These baits can be rigged in many different ways, and can be fished in many different ways. These baits are a good choice for beginning anglers, because it can help teach them how to use a moving bait (Bartkowski 2017). There are many different varieties and styles of soft plastics that are used. The different types include worms, creature baits, craws, squids, twisty tails, grubs, and a few others. They all have different rigging styles that can be used to hook them onto an angler’s line. Anglers can attach soft plastics to jig heads, or even just a plain hook. An angler can use a soft plastic as a trailer on a jig. A trailer is a bait that goes underneath the skirting on the bait and slides all the way onto the hook. This is so that the hook is completely covered and the fish will not see it. An angler can fish soft plastics weightless, which allows the bait to be more buoyant and sit higher in the water column and it sinks slower. Weightless soft plastics work extremely well with bass while they are spawning, because the bait does not make a loud splash when it hits the water (Bartkowski 2017). Soft plastic baits...
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...Full Circle THE INDEPENDENT MAGAZINE FOR THE UBUNTU LINUX COMMUNITY ISSUE #90 - October 201 4 Photo: miss_millions (Flickr.com) P R I S O N AR C H I T E C T BUILD YOUR OWN OPEN SOURCE PRISON Fu ll Ci rcle M a g a zi n e i s n e i th e r a ffi li a te d wi th , n o r e n d o rse d b y, Ca n o n i ca l Ltd . full circle magazine #90 1 contents ^ HowTo OpenConnect to Cisco p.1 4 Full Circle THE INDEPENDENT MAGAZINE FOR THE UBUNTU LINUX COMMUNITY Linux News p.04 BACK NEXT MONTH LibreOffice p.1 5 Command & Conquer p.1 2 Arduino p.25 LinuxLabs p.XX Broadcast With WCS p.1 7 Linux Labs p.28 Review p.36 My Story p.37 BACK NEXT MONTH Blender p.XX Letters p.40 Tuxidermy p.41 Q&A p.42 BACK NEXT MONTH Inkscape BACK NEXT MONTH Ubuntu Women p.XX Ubuntu Games p.44 Graphics p.22 Security p.XX The articles contained in this magazine are released under the Creative Commons Attribution-Share Alike 3.0 Unported license. This means you can adapt, copy, distribute and transmit the articles but only under the following conditions: you must attribute the work to the original author in some way (at least a name, email or URL) and to this magazine by name ('Full Circle Magazine') and the URL www.fullcirclemagazine.org (but not attribute the article(s) in any way that suggests that they endorse you or your use of the work). If you alter, transform, or build upon this work, you must distribute the resulting work under...
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...edhat® ® Te r r y C o l l i n g s & K u r t W a l l UR ON IT OOLS IN Y T C E CD-R L TH O ED UD M Linux Solutions from the Experts at Red Hat ® ® P R E S S™ SEC Red Hat® Linux® Networking and System Administration Red Hat® Linux® Networking and System Administration Terry Collings and Kurt Wall M&T Books An imprint of Hungry Minds, Inc. Best-Selling Books G Digital Downloads G e-Books G Answer Networks e-Newsletters G Branded Web Sites G e-Learning New York, NY G Cleveland, OH G Indianapolis, IN Red Hat® Linux® Networking and System Administration Published by Hungry Minds, Inc. 909 Third Avenue New York, NY 10022 www.hungryminds.com Copyright © 2002 Hungry Minds, Inc. All rights reserved. No part of this book, including interior design, cover design, and icons, may be reproduced or transmitted in any form, by any means (electronic, photocopying, recording, or otherwise) without the prior written permission of the publisher. Library of Congress Control Number: 2001093591 ISBN: 0-7645-3632-X Printed in the United States of America 10 9 8 7 6 5 4 3 2 1 1O/RT/QT/QS/IN Distributed in the United States by Hungry Minds, Inc. Distributed by CDG Books Canada Inc. for Canada; by Transworld Publishers Limited in the United Kingdom; by IDG Norge Books for Norway; by IDG Sweden Books for Sweden; by IDG Books Australia Publishing Corporation Pty. Ltd. for Australia and New Zealand; by TransQuest Publishers Pte Ltd. for Singapore, Malaysia, Thailand...
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...PRINTED BY: Norman Puga . Printing is for personal, private use only. No part of this book may be reproduced or transmitted without publisher's prior permission. Violators will be prosecuted. Essential Linux Administration: A Comprehensive Guide for Beginners Page 1 of 4 PRINTED BY: Norman Puga . Printing is for personal, private use only. No part of this book may be reproduced or transmitted without publisher's prior permission. Violators will be prosecuted. ESSENTIAL LINUX ® ADMINISTRATION: A COMPREHENSIVE GUIDE FOR BEGINNERS i CHUCK EASTTOM WITH SERGE PALLADINO Course Technology PTR A part of Cengage Learning 9781133795308 i ii Essential Linux Administration: A Comprehensive Guide for Beginners Chuck Easttom with Serge Palladino Publisher and General Manager, Course Technology PTR: Stacy L. Hiquet Associate Director of Marketing: Sarah Panella Manager of Editorial Services: Heather Talbot Marketing Manager: Mark Hughes Acquisitions Editor: Heather Hurley Project and Copy Editor: Marta Justak Technical Reviewer: Danielle Shaw Interior Layout Tech: MPS Limited, a Macmillan Company Cover Designer: Mike Tanamachi Indexer: Sharon Shock Proofreader: Kelly Talbot © 2012 Course Technology, a part of Cengage Learning. ALL RIGHTS RESERVED. No part of this work covered by the copyright herein may be reproduced, transmitted, stored, or used in any form or by any means graphic, electronic, or mechanical, including but not limited to photocopying, recording...
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...WHEAT (Triticumaestivum) BACKGROUND TO THE CROP It is the one of most important food grain crops in India and occupies approximately 230 million ha all over the world. India is the second largest producer of wheat, with 25million ha area under cultivation resulting in wheat production of 70 million tonnes. About one tenth of the globe’s production is from India. Wheat is grown during winter in the states of Punjab, Haryana, Uttar Pradesh, Bihar, Rajasthan, Madhya Pradesh and Maharashtra. While in the northern states it is grown as an irrigated crop, it is grown largely under rain-fed conditions and with little or no irrigation support in many parts of Madhya Pradesh and Maharashtra. In Maharashtra, wheat is grown in 7 lakh ha with average productivity of 13.2 q/ha against the national average of about 26.5 q/ha. Out of the four species, Triticum aestivum occupies almost 90% of the total wheat area. Soil Requirement Well-drained loams and clay loams are ideal for wheat cultivation. However, a good crop can be raised in sandy loams and black soils also. Soil pH below 6.5 and above 7.8 is not suitable. Season and Duration Being a low temperature crop, wheat is grown in winter, from the end of October to February under rain-fed conditions, and from the middle of November to March/April under irrigated conditions. Total duration of the crop ranges from 110 to 120 days under irrigated conditions, and 100–110 days under rain-fed conditions. Cropping Pattern Wheat...
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...John Holbrook Step by Step Installation of a Secure Linux Web, DNS and Mail Server Feb 10, 2004 GIAC GSEC Practical – Version 1.4b, Option 1 Key fingerprint = AF19 FA27 2F94 998D FDB5 DE3D F8B5 06E4 A169 4E46. 1 Table of Contents Abstract................................. Introduction.........................................................................................................................4 Current Setup..................................................................................................................4 Reasons for new install ..................................................................................................4 Sudo...............................................................................................................................5 Security Comparison of Redhat 9.0 and Openna 1.0..........................................................7 Default Installed Services...............................................................................................7 Configuration Notes............................................................................................................8 The New Setup...............................................................................................................8 Layers of Protection........................................................................................................9 Verifying Integrity of Downloaded Files.................................
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...onaryDictionary of Ònìchà Igbo 2nd edition of the Igbo dictionary, Kay Williamson, Ethiope Press, 1972. Kay Williamson (†) This version prepared and edited by Roger Blench Roger Blench Mallam Dendo 8, Guest Road Cambridge CB1 2AL United Kingdom Voice/ Fax. 0044-(0)1223-560687 Mobile worldwide (00-44)-(0)7967-696804 E-mail R.Blench@odi.org.uk http://www.rogerblench.info/RBOP.htm To whom all correspondence should be addressed. This printout: November 16, 2006 TABLE OF CONTENTS Abbreviations: ................................................................................................................................................. 2 Editor’s Preface............................................................................................................................................... 1 Editor’s note: The Echeruo (1997) and Igwe (1999) Igbo dictionaries ...................................................... 2 INTRODUCTION........................................................................................................................................... 4 1. Earlier lexicographical work on Igbo........................................................................................................ 4 2. The development of the present work ....................................................................................................... 6 3. Onitsha Igbo ...................................................................................................
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