Processes in Linux/Unix
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Bid Check Report * * * Time: 14:04
DOT_RGGB01 WASHINGTON STATE DEPARTMENT OF TRANSPORTATION DATE: 05/28/2013 * * * BID CHECK REPORT * * * TIME: 14:04 PS &E JOB NO : 11W101 REVISION NO : BIDS OPENED ON : Jun 26 2013 CONTRACT NO : 008498 REGION NO : 9 AWARDED ON : Jul 1 2013 VERSION NO : 2 WORK ORDER# : XL4078 ------- LOW BIDDER ------- ------- 2ND BIDDER ------- ------- 3RD BIDDER ------- HWY : SR 104 TITLE : SR104 ORION MARINE CONTRACTORS, INC. BLACKWATER MARINE, LLC QUIGG BROS., INC. KINGSTON TML SLIPS 1112 E ALEXANDER AVE 12019 76TH PLACE NE 819 W STATE ST DOLPHIN PRESERVATION - PHASE 4 98520-5934 11W101 PROJECT : NH-2013(079) TACOMA WA 984214102 KIRKLAND WA 980342437 ABERDEEN WA 985200281 COUNTY(S) : KITSAP CONTRACTOR NUMBER : 100767 CONTRACTOR NUMBER : 100874 CONTRACTOR NUMBER : 680000 ENGR'S. EST. ITEM ITEM DESCRIPTION UNIT PRICE PER UNIT/ PRICE PER UNIT/ % DIFF./ PRICE PER UNIT/ % DIFF./ PRICE PER UNIT/ % DIFF./ NO. EST. QUANTITY MEAS TOTAL AMOUNT TOTAL AMOUNT AMT.DIFF. TOTAL AMOUNT AMT.DIFF. TOTAL AMOUNT AMT.DIFF. PREPARATION 1 MOBILIZATION L.S. -25.20 % -25.48 % 40.00 % 25,000.00 18,700.00 -6,300.00 18,630.00 -6,370.00 35,000.00 10,000.00 2 REMOVAL OF STRUCTURE AND OBSTRUCTION L.S. -56.10 % -65.08 % -56.71 % 115,500.00 50,700.00 -64,800.00 40,338.00 -75,162.00 50,000.00 -65,500.00 3 DISPOSAL OF CREOSOTED MATERIAL L.S. -21.05 % -8.99 % -15.79 % 47,500.00 37,500.00 -10,000.00 43,228.35 -4,271.65 40,000.00 -7,500.00 STRUCTURE 4 STRUCTURAL LOW ALLOY STEEL - DOLPHINS L.S. -
The Different Unix Contexts
The different Unix contexts • User-level • Kernel “top half” - System call, page fault handler, kernel-only process, etc. • Software interrupt • Device interrupt • Timer interrupt (hardclock) • Context switch code Transitions between contexts • User ! top half: syscall, page fault • User/top half ! device/timer interrupt: hardware • Top half ! user/context switch: return • Top half ! context switch: sleep • Context switch ! user/top half Top/bottom half synchronization • Top half kernel procedures can mask interrupts int x = splhigh (); /* ... */ splx (x); • splhigh disables all interrupts, but also splnet, splbio, splsoftnet, . • Masking interrupts in hardware can be expensive - Optimistic implementation – set mask flag on splhigh, check interrupted flag on splx Kernel Synchronization • Need to relinquish CPU when waiting for events - Disk read, network packet arrival, pipe write, signal, etc. • int tsleep(void *ident, int priority, ...); - Switches to another process - ident is arbitrary pointer—e.g., buffer address - priority is priority at which to run when woken up - PCATCH, if ORed into priority, means wake up on signal - Returns 0 if awakened, or ERESTART/EINTR on signal • int wakeup(void *ident); - Awakens all processes sleeping on ident - Restores SPL a time they went to sleep (so fine to sleep at splhigh) Process scheduling • Goal: High throughput - Minimize context switches to avoid wasting CPU, TLB misses, cache misses, even page faults. • Goal: Low latency - People typing at editors want fast response - Network services can be latency-bound, not CPU-bound • BSD time quantum: 1=10 sec (since ∼1980) - Empirically longest tolerable latency - Computers now faster, but job queues also shorter Scheduling algorithms • Round-robin • Priority scheduling • Shortest process next (if you can estimate it) • Fair-Share Schedule (try to be fair at level of users, not processes) Multilevel feeedback queues (BSD) • Every runnable proc. -
Many Slides Borrowed from Ben Zhao, Christo Wilson, & Others
12. Network Attacks Blase Ur and David Cash (many slides borrowed from Ben Zhao, Christo Wilson, & others) February 7th, 2020 CMSC 23200 / 33250 Network threat model • Network scanning • Attacks on confidentiality (e.g., eavesdropping) • Attacks on integrity (e.g., spoofing, packet injection) • Attacks on availability (e.g., denial of service (DoS)) Scanning and observing networks Network Scanning: Ping • Essential, low-level network utility • Sends a “ping” ICMP message to a host on the internet $ ping 66.66.0.255 PING 66.66.0.255 (66.66.0.255) 56(84) bytes of data. 64 bytes from 66.66.0.255: icmp_seq=1 ttl=58 time=41.2 ms • Destination host is supposed to respond with a “pong” – Indicating that it can receive packets • By default, ping messages are 56 bytes long (+ some header bytes) – Maximum size 65535 bytes • What if you send a ping that is >65535 bytes long? Ping of Death • $ ping –s 65535 66.66.0.255 – Attack identified in 1997 – IPv6 version identified/fixed in 2013 Network Scanning: Traceroute • traceroute — hops between me and host – Sends repeated ICMP reqs w/ increasing TTL Port Scanning • What services are running on a server? Nmap • 5 seconds to scan a single machine!! SYN scan Only send SYN Responses: • SYN-ACK — port open • RST — port closed • Nothing — filtered (e.g., firewall) Port Scanning on Steroids • How do you speed up scans for all IPv4? – Don’t wait for responses; pipeline – Parallelize: divide & conquer IPv4 ranges – Randomize permutations w/o collisions • Result: the zmap tool – Scan all of IPv4 in 45mins (w/ GigE cxn) – IPv4 in 5 mins w/ 10GigE Eavesdropping Tools: Wireshark, tcpdump, Bro, … Steps: 1. -
Job Scheduling for SAP® Contents at a Glance
Kees Verruijt, Arnoud Roebers, Anjo de Heus Job Scheduling for SAP® Contents at a Glance Foreword ............................................................................ 13 Preface ............................................................................... 15 1 General Job Scheduling ...................................................... 19 2 Decentralized SAP Job Scheduling .................................... 61 3 SAP Job Scheduling Interfaces .......................................... 111 4 Centralized SAP Job Scheduling ........................................ 125 5 Introduction to SAP Central Job Scheduling by Redwood ... 163 6Installation......................................................................... 183 7 Principles and Processes .................................................... 199 8Operation........................................................................... 237 9Customer Cases................................................................. 281 The Authors ........................................................................ 295 Index .................................................................................. 297 Contents Foreword ............................................................................................... 13 Preface ................................................................................................... 15 1 General Job Scheduling ...................................................... 19 1.1 Organizational Uses of Job Scheduling .................................. -
Humidity Definitions
ROTRONIC TECHNICAL NOTE Humidity Definitions 1 Relative humidity Table of Contents Relative humidity is the ratio of two pressures: %RH = 100 x p/ps where p is 1 Relative humidity the actual partial pressure of the water vapor present in the ambient and ps 2 Dew point / Frost the saturation pressure of water at the temperature of the ambient. point temperature Relative humidity sensors are usually calibrated at normal room temper - 3 Wet bulb ature (above freezing). Consequently, it generally accepted that this type of sensor indicates relative humidity with respect to water at all temperatures temperature (including below freezing). 4 Vapor concentration Ice produces a lower vapor pressure than liquid water. Therefore, when 5 Specific humidity ice is present, saturation occurs at a relative humidity of less than 100 %. 6 Enthalpy For instance, a humidity reading of 75 %RH at a temperature of -30°C corre - 7 Mixing ratio sponds to saturation above ice. by weight 2 Dew point / Frost point temperature The dew point temperature of moist air at the temperature T, pressure P b and mixing ratio r is the temperature to which air must be cooled in order to be saturated with respect to water (liquid). The frost point temperature of moist air at temperature T, pressure P b and mixing ratio r is the temperature to which air must be cooled in order to be saturated with respect to ice. Magnus Formula for dew point (over water): Td = (243.12 x ln (pw/611.2)) / (17.62 - ln (pw/611.2)) Frost point (over ice): Tf = (272.62 x ln (pi/611.2)) / (22.46 - -
Unix/Linux Command Reference
Unix/Linux Command Reference .com File Commands System Info ls – directory listing date – show the current date and time ls -al – formatted listing with hidden files cal – show this month's calendar cd dir - change directory to dir uptime – show current uptime cd – change to home w – display who is online pwd – show current directory whoami – who you are logged in as mkdir dir – create a directory dir finger user – display information about user rm file – delete file uname -a – show kernel information rm -r dir – delete directory dir cat /proc/cpuinfo – cpu information rm -f file – force remove file cat /proc/meminfo – memory information rm -rf dir – force remove directory dir * man command – show the manual for command cp file1 file2 – copy file1 to file2 df – show disk usage cp -r dir1 dir2 – copy dir1 to dir2; create dir2 if it du – show directory space usage doesn't exist free – show memory and swap usage mv file1 file2 – rename or move file1 to file2 whereis app – show possible locations of app if file2 is an existing directory, moves file1 into which app – show which app will be run by default directory file2 ln -s file link – create symbolic link link to file Compression touch file – create or update file tar cf file.tar files – create a tar named cat > file – places standard input into file file.tar containing files more file – output the contents of file tar xf file.tar – extract the files from file.tar head file – output the first 10 lines of file tar czf file.tar.gz files – create a tar with tail file – output the last 10 lines -
Tutorials Point, Simply Easy Learning
Tutorials Point, Simply Easy Learning UML Tutorial Tutorialspoint.com UNIX is a computer Operating System which is capable of handling activities from multiple users at the same time. Unix was originated around in 1969 at AT&T Bell Labs by Ken Thompson and Dennis Ritchie. This tutorial gives an initial push to start you with UNIX. For more detail kindly check tutorialspoint.com/unix What is Unix ? The UNIX operating system is a set of programs that act as a link between the computer and the user. The computer programs that allocate the system resources and coordinate all the details of the computer's internals is called the operating system or kernel. Users communicate with the kernel through a program known as the shell. The shell is a command line interpreter; it translates commands entered by the user and converts them into a language that is understood by the kernel. Unix was originally developed in 1969 by a group of AT&T employees at Bell Labs, including Ken Thompson, Dennis Ritchie, Douglas McIlroy, and Joe Ossanna. There are various Unix variants available in the market. Solaris Unix, AIX, UP Unix and BSD are few examples. Linux is also a flavour of Unix which is freely available. Several people can use a UNIX computer at the same time; hence UNIX is called a multiuser system. A user can also run multiple programs at the same time; hence UNIX is called multitasking. Unix Architecture: Here is a basic block diagram of a UNIX system: 1 | P a g e Tutorials Point, Simply Easy Learning The main concept that unites all versions of UNIX is the following four basics: Kernel: The kernel is the heart of the operating system. -
Chapter 3: Processes
Chapter 3: Processes Operating System Concepts – 9th Edition Silberschatz, Galvin and Gagne ©2013 Chapter 3: Processes Process Concept Process Scheduling Operations on Processes Interprocess Communication Examples of IPC Systems Communication in Client-Server Systems Operating System Concepts – 9th Edition 3.2 Silberschatz, Galvin and Gagne ©2013 Objectives To introduce the notion of a process -- a program in execution, which forms the basis of all computation To describe the various features of processes, including scheduling, creation and termination, and communication To explore interprocess communication using shared memory and message passing To describe communication in client-server systems Operating System Concepts – 9th Edition 3.3 Silberschatz, Galvin and Gagne ©2013 Process Concept An operating system executes a variety of programs: Batch system – jobs Time-shared systems – user programs or tasks Textbook uses the terms job and process almost interchangeably Process – a program in execution; process execution must progress in sequential fashion Multiple parts The program code, also called text section Current activity including program counter, processor registers Stack containing temporary data Function parameters, return addresses, local variables Data section containing global variables Heap containing memory dynamically allocated during run time Operating System Concepts – 9th Edition 3.4 Silberschatz, Galvin and Gagne ©2013 Process Concept (Cont.) Program is passive entity stored on disk (executable -
Backup and Restore Cisco Prime Collaboration Provisioning
Backup and Restore Cisco Prime Collaboration Provisioning This section explains the following: • Perform Backup and Restore, page 1 • Back Up the Single-Machine Provisioning Database, page 2 • Restore the Single-Machine Provisioning Database, page 3 • Schedule Backup Using the Provisioning User Interface, page 5 Perform Backup and Restore Cisco Prime Collaboration Provisioning allows you to backup your data and restore it. You can schedule periodic backups using the Provisioning UI (Schedule Backup Using the Provisioning User Interface, on page 5). There are two backup and restore scenarios; select the set of procedures that matches your scenario: • Backup and restore on a single machine, with the same installation or a new installation. For this scenario, see Schedule Backup Using the Provisioning User Interface, on page 5. Note When backing up files, you should place the files on a different file server. Also, you should burn the backup data onto a CD. Cisco Prime Collaboration Provisioning allows you to back up system data and restore it on a different system in the event of total system failure. To restore the backup from another system, the following prerequisites must be met: • Ensure that the server to which data is restored has the same MAC address as that of the system that was backed up (the IP address and the hostname can be different). • If you are unable to assign the MAC address of the original system (the one that was backed up) to another system, contact the Engineering Team for information on a new license file (for a new MAC address). Cisco Prime Collaboration Provisioning Install and Upgrade Guide, 12.3 1 Backup and Restore Cisco Prime Collaboration Provisioning Back Up the Single-Machine Provisioning Database • The procedure to backup and restore data on a different system is the same as the procedure to backup and restore data on the same system. -
The Linux Command Line
The Linux Command Line Fifth Internet Edition William Shotts A LinuxCommand.org Book Copyright ©2008-2019, William E. Shotts, Jr. This work is licensed under the Creative Commons Attribution-Noncommercial-No De- rivative Works 3.0 United States License. To view a copy of this license, visit the link above or send a letter to Creative Commons, PO Box 1866, Mountain View, CA 94042. A version of this book is also available in printed form, published by No Starch Press. Copies may be purchased wherever fine books are sold. No Starch Press also offers elec- tronic formats for popular e-readers. They can be reached at: https://www.nostarch.com. Linux® is the registered trademark of Linus Torvalds. All other trademarks belong to their respective owners. This book is part of the LinuxCommand.org project, a site for Linux education and advo- cacy devoted to helping users of legacy operating systems migrate into the future. You may contact the LinuxCommand.org project at http://linuxcommand.org. Release History Version Date Description 19.01A January 28, 2019 Fifth Internet Edition (Corrected TOC) 19.01 January 17, 2019 Fifth Internet Edition. 17.10 October 19, 2017 Fourth Internet Edition. 16.07 July 28, 2016 Third Internet Edition. 13.07 July 6, 2013 Second Internet Edition. 09.12 December 14, 2009 First Internet Edition. Table of Contents Introduction....................................................................................................xvi Why Use the Command Line?......................................................................................xvi -
Text Editing in UNIX: an Introduction to Vi and Editing
Text Editing in UNIX A short introduction to vi, pico, and gedit Copyright 20062009 Stewart Weiss About UNIX editors There are two types of text editors in UNIX: those that run in terminal windows, called text mode editors, and those that are graphical, with menus and mouse pointers. The latter require a windowing system, usually X Windows, to run. If you are remotely logged into UNIX, say through SSH, then you should use a text mode editor. It is possible to use a graphical editor, but it will be much slower to use. I will explain more about that later. 2 CSci 132 Practical UNIX with Perl Text mode editors The three text mode editors of choice in UNIX are vi, emacs, and pico (really nano, to be explained later.) vi is the original editor; it is very fast, easy to use, and available on virtually every UNIX system. The vi commands are the same as those of the sed filter as well as several other common UNIX tools. emacs is a very powerful editor, but it takes more effort to learn how to use it. pico is the easiest editor to learn, and the least powerful. pico was part of the Pine email client; nano is a clone of pico. 3 CSci 132 Practical UNIX with Perl What these slides contain These slides concentrate on vi because it is very fast and always available. Although the set of commands is very cryptic, by learning a small subset of the commands, you can edit text very quickly. What follows is an outline of the basic concepts that define vi. -
Blue Coat SGOS Command Line Interface Reference, Version 4.2.3
Blue Coat® Systems ProxySG™ Command Line Interface Reference Version SGOS 4.2.3 Blue Coat ProxySG Command Line Interface Reference Contact Information Blue Coat Systems Inc. 420 North Mary Ave Sunnyvale, CA 94085-4121 http://www.bluecoat.com/support/contact.html [email protected] http://www.bluecoat.com For concerns or feedback about the documentation: [email protected] Copyright© 1999-2006 Blue Coat Systems, Inc. All rights reserved worldwide. No part of this document may be reproduced by any means nor modified, decompiled, disassembled, published or distributed, in whole or in part, or translated to any electronic medium or other means without the written consent of Blue Coat Systems, Inc. All right, title and interest in and to the Software and documentation are and shall remain the exclusive property of Blue Coat Systems, Inc. and its licensors. ProxySG™, ProxyAV™, CacheOS™, SGOS™, Spyware Interceptor™, Scope™, RA Connector™, RA Manager™, Remote Access™ are trademarks of Blue Coat Systems, Inc. and CacheFlow®, Blue Coat®, Accelerating The Internet®, WinProxy®, AccessNow®, Ositis®, Powering Internet Management®, The Ultimate Internet Sharing Solution®, Permeo®, Permeo Technologies, Inc.®, and the Permeo logo are registered trademarks of Blue Coat Systems, Inc. All other trademarks contained in this document and in the Software are the property of their respective owners. BLUE COAT SYSTEMS, INC. DISCLAIMS ALL WARRANTIES, CONDITIONS OR OTHER TERMS, EXPRESS OR IMPLIED, STATUTORY OR OTHERWISE, ON SOFTWARE AND DOCUMENTATION FURNISHED HEREUNDER INCLUDING WITHOUT LIMITATION THE WARRANTIES OF DESIGN, MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL BLUE COAT SYSTEMS, INC., ITS SUPPLIERS OR ITS LICENSORS BE LIABLE FOR ANY DAMAGES, WHETHER ARISING IN TORT, CONTRACT OR ANY OTHER LEGAL THEORY EVEN IF BLUE COAT SYSTEMS, INC.