Program Received Signal Sigsegv Segmentation Fault Gdb
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University of California at Berkeley College of Engineering Department of Electrical Engineering and Computer Science
University of California at Berkeley College of Engineering Department of Electrical Engineering and Computer Science EECS 61C, Fall 2003 Lab 2: Strings and pointers; the GDB debugger PRELIMINARY VERSION Goals To learn to use the gdb debugger to debug string and pointer programs in C. Reading Sections 5.1-5.5, in K&R GDB Reference Card (linked to class page under “resources.”) Optional: Complete GDB documentation (http://www.gnu.org/manual/gdb-5.1.1/gdb.html) Note: GDB currently only works on the following machines: • torus.cs.berkeley.edu • rhombus.cs.berkeley.edu • pentagon.cs.berkeley.edu Please ssh into one of these machines before starting the lab. Basic tasks in GDB There are two ways to start the debugger: 1. In EMACS, type M-x gdb, then type gdb <filename> 2. Run gdb <filename> from the command line The following are fundamental operations in gdb. Please make sure you know the gdb commands for the following operations before you proceed. 1. How do you run a program in gdb? 2. How do you pass arguments to a program when using gdb? 3. How do you set a breakpoint in a program? 4. How do you set a breakpoint which which only occurs when a set of conditions is true (eg when certain variables are a certain value)? 5. How do you execute the next line of C code in the program after a break? 1 6. If the next line is a function call, you'll execute the call in one step. How do you execute the C code, line by line, inside the function call? 7. -
Mac OS 8 Update
K Service Source Mac OS 8 Update Known problems, Internet Access, and Installation Mac OS 8 Update Document Contents - 1 Document Contents • Introduction • About Mac OS 8 • About Internet Access What To Do First Additional Software Auto-Dial and Auto-Disconnect Settings TCP/IP Connection Options and Internet Access Length of Configuration Names Modem Scripts & Password Length Proxies and Other Internet Config Settings Web Browser Issues Troubleshooting • About Mac OS Runtime for Java Version 1.0.2 • About Mac OS Personal Web Sharing • Installing Mac OS 8 • Upgrading Workgroup Server 9650 & 7350 Software Mac OS 8 Update Introduction - 2 Introduction Mac OS 8 is the most significant update to the Macintosh operating system since 1984. The updated system gives users PowerPC-native multitasking, an efficient desktop with new pop-up windows and spring-loaded folders, and a fully integrated suite of Internet services. This document provides information about Mac OS 8 that supplements the information in the Mac OS installation manual. For a detailed description of Mac OS 8, useful tips for using the system, troubleshooting, late-breaking news, and links for online technical support, visit the Mac OS Info Center at http://ip.apple.com/infocenter. Or browse the Mac OS 8 topic in the Apple Technical Library at http:// tilsp1.info.apple.com. Mac OS 8 Update About Mac OS 8 - 3 About Mac OS 8 Read this section for information about known problems with the Mac OS 8 update and possible solutions. Known Problems and Compatibility Issues Apple Language Kits and Mac OS 8 Apple's Language Kits require an updater for full functionality with this version of the Mac OS. -
Linux Tutorial Last Updated: September 29 2021 for Windows Users
VLAAMS SUPERCOMPUTER Innovative Computing CENTRUM for A Smarter Flanders Linux Tutorial Last updated: September 29 2021 For Windows Users Authors: Jasper Devreker (UGent), Ewan Higgs (UGent), Kenneth Hoste (UGent) Acknowledgement: VSCentrum.be Audience: This document is a hands-on guide for using the Linux command line in the context of the UGent HPC infrastructure. The command line (sometimes called ’shell’) can seems daunting at first, but with a little understanding can be very easy to use. Everything you do startsatthe prompt. Here you have the liberty to type in any commands you want. Soon, you will be able to move past the limited point and click interface and express interesting ideas to the computer using the shell. Gaining an understanding of the fundamentals of Linux will help accelerate your research using the HPC infrastructure. You will learn about commands, managing files, and some scripting basics. Notification: In$ commands this tutorial specific commands are separated from the accompanying text: These should be entered by the reader at a command line in a terminal on the UGent-HPC. They appear in all exercises preceded by a $ and printed in bold. You’ll find those actions ina grey frame. Button are menus, buttons or drop down boxes to be pressed or selected. “Directory” is the notation for directories (called “folders” in Windows terminology) or specific files. (e.g., “/user/home/gent/vsc400/vsc40000”) “Text” Is the notation for text to be entered. Tip: A “Tip” paragraph is used for remarks or tips. They can also be downloaded from the VSC website at https://www.vscentrum.be. -
Xerox 4050/4090/4450/4650 Laser Printing Systems Message Guide
XEROX Xerox 4050/4090/4450/4650 Laser Printing Systems Message Guide April 1995 720P93980 Xerox Corporation 701 S. Aviation Boulevard El Segundo, CA 90245 © 1991, 1992, 1993, 1994, 1995 by Xerox Corporation. All rights reserved. Copyright protection claimed includes all forms and matters of copyrightable material and information now allowed by statutory or judicial law or hereinafter granted, including without limitation, material generated from the software programs which are displayed on the screen, such as icons, screen displays, looks, etc. Printed in the United States of America Publication number: 720P93980 Xerox® and all Xerox products mentioned in this publication are trademarks of Xerox Corporation. Products and trademarks of other companies are also acknowledged. Changes are periodically made to this document. Changes, technical inaccuracies, and typographic errors will be corrected in subsequent editions. This document was created on the Xerox 6085 Professional Computer System using GobalView software. The typeface is Optima. Table of contents Introduction vii Document conventions vii Related publications viii 1. Compress command messages 1-1 2. Data Capture Utility messages 2-1 System failure or reload messages 2-6 3. Disk Save and Restore command messages 3-1 4. File Conversion Utility messages 4-1 5. General Floppy Utility messages 5-1 FLF messages 5-15 6. Forms Description Language compilation messages 6-1 7. Host Interface Processor messages 7-1 8. Interpress Font Utility messages 8-1 9. Operating System Software messages 9-1 OS level 0: Confirmation messages 9-1 OS level 1: Informational messages 9-7 OS level 2: Routine maintenance messages 9-37 OS level 3: Printer problem messages 9-59 OS level 4: System or tape problem messages 9-64 OS level 6: Job integrity problem messages 9-68 OS level 7: System problem messages 9-88 OS level 8: Probable severe software errors 9-93 OS level 9: Probable severe hardware errors 9-99 10. -
UNIX X Command Tips and Tricks David B
SESUG Paper 122-2019 UNIX X Command Tips and Tricks David B. Horvath, MS, CCP ABSTRACT SAS® provides the ability to execute operating system level commands from within your SAS code – generically known as the “X Command”. This session explores the various commands, the advantages and disadvantages of each, and their alternatives. The focus is on UNIX/Linux but much of the same applies to Windows as well. Under SAS EG, any issued commands execute on the SAS engine, not necessarily on the PC. X %sysexec Call system Systask command Filename pipe &SYSRC Waitfor Alternatives will also be addressed – how to handle when NOXCMD is the default for your installation, saving results, and error checking. INTRODUCTION In this paper I will be covering some of the basics of the functionality within SAS that allows you to execute operating system commands from within your program. There are multiple ways you can do so – external to data steps, within data steps, and within macros. All of these, along with error checking, will be covered. RELEVANT OPTIONS Execution of any of the SAS System command execution commands depends on one option's setting: XCMD Enables the X command in SAS. Which can only be set at startup: options xcmd; ____ 30 WARNING 30-12: SAS option XCMD is valid only at startup of the SAS System. The SAS option is ignored. Unfortunately, ff NOXCMD is set at startup time, you're out of luck. Sorry! You might want to have a conversation with your system administrators to determine why and if you can get it changed. -
Compiling and Debugging Basics
Compiling and Debugging Basics Service CoSiNus IMFT P. Elyakime H. Neau A. Pedrono A. Stoukov Avril 2015 Outline ● Compilers available at IMFT? (Fortran, C and C++) ● Good practices ● Debugging Why? Compilation errors and warning Run time errors and wrong results Fortran specificities C/C++ specificities ● Basic introduction to gdb, valgrind and TotalView IMFT - CoSiNus 2 Compilers on linux platforms ● Gnu compilers: gcc, g++, gfortran ● Intel compilers ( 2 licenses INPT): icc, icpc, ifort ● PGI compiler fortran only (2 licenses INPT): pgf77, pgf90 ● Wrappers mpich2 for MPI codes: mpicc, mpicxx, mpif90 IMFT - CoSiNus 3 Installation ● Gnu compilers: included in linux package (Ubuntu 12.04 LTS, gcc/gfortran version 4.6.3) ● Intel and PGI compilers installed on a centralized server (/PRODCOM), to use it: source /PRODCOM/bin/config.sh # in bash source /PRODCOM/bin/config.csh # in csh/tcsh ● Wrappers mpich2 installed on PRODCOM: FORTRAN : mympi intel # (or pgi or gnu) C/C++ : mympi intel # (or gnu) IMFT - CoSiNus 4 Good practices • Avoid too long source files! • Use a makefile if you have more than one file to compile • In Fortran : ” implicit none” mandatory at the beginning of each program, module and subroutine! • Use compiler’s check options IMFT - CoSiNus 5 Why talk about debugging ? Yesterday, my program was running well: % gfortran myprog.f90 % ./a.out % vmax= 3.3e-2 And today: % gfortran myprog.f90 % ./a.out % Segmentation fault Yet I have not changed anything… Because black magic is not the reason most often, debugging could be helpful! (If you really think that the cause of your problem is evil, no need to apply to CoSiNus, we are not God!) IMFT - CoSiNus 6 Debugging Methodical process to find and fix flows in a code. -
Blank Screen Xbox One
Blank Screen Xbox One Typhous and Torricellian Waiter lows, but Ernest emptily coquette her countermark. Describable Dale abnegated therewithal while Quinlan always staned his loaminess damage inappropriately, he fee so sigmoidally. Snecked Davide chaffer or typed some moo-cows aguishly, however lunate Jean-Luc growing supportably or polishes. Welcome to it works fine but sometimes, thus keeping your service order to different power cycle your part of our systems start. Obs and more updates, and we will flicker black? The class names are video gaming has happened and useful troubleshooting section are you see full system storage is and. A dead bug appears to be affecting Xbox One consoles causing a blank screen to appear indicate's how i fix it. Fix the Black Screen Starting Games On XBox One TeckLyfe. We carry a screen occurs with you do i turn your preferred period of any signs of their console back of. Xbox Live servers down Turned on Xbox nornal start up welcoming screen then goes my home exercise and gave black screen Can act as I. Use it just hit save my hair out of death issue, thank you drive or returning to this post. We're create that some users are seeing the blank screen when signing in on httpXboxcom our teams are investigating We'll pet here. We go back in order to go to color so where a blank screen design. It can do you have a blank loading menu in our own. Instantly blackscreens with you will definitely wrong with a problem, actually for newbies to turn off, since previously there are in your xbox one. -
IBM PC (5150) the BIOS (Basic Input/Output August 12Th Aug
The only proprietary part was IBM PC (5150) the BIOS (Basic Input/Output August 12th Aug. 12, 1981 System), but IBM published enough of its technical details At the NYC Waldorf-Astoria, and that other manufacturers could Dorothy Elizabeth in Boca Raton, Florida, IBM eventually create PC released the IBM PC (aka the compatibles; the so-called Denning IBM 5150). It had been “clones”. developed in under a year by the In 1982, the MPC 1600-1 [June Born: Aug. 12, 1945; “Project Chess” [Oct 20] team 00] and the Compaq Portable Michigan ??, USA led by Don Estridge [June 23]. [Nov 4] were announced, and in In the mid 1980s, Denning and It featured an Intel 8088 CPU 1984, Phoenix Technology’s Peter G. Neumann developed the [July 1], 16 KB of RAM, and a released a legal copy of the BIOS Intrusion Detection Expert mono display. It used a tape [July 10]. The clone market System (IDES) that went on to cassette drive for external helped solved the PC's price become the basis for many memory, but this was later problem, through competition. cyber-security applications. It replaced by (a rather costly) The PC's popularity did have one employed a rule-based system to 5.25-inch floppy disk drive. detect problems, along with a major drawback – any non- statistical anomaly component clones aimed at the home or based on profiles of users and small business markets quickly systems. dropped from favor, and disappeared. Denning was one of several academics asked to review the The IBM PC could run several Skipjack encryption algorithm different OSes, but Microsoft’s for the Clipper chip [April 16]. -
Lecture 15 15.1 Paging
CMPSCI 377 Operating Systems Fall 2009 Lecture 15 Lecturer: Emery Berger Scribe: Bruno Silva,Jim Partan 15.1 Paging In recent lectures, we have been discussing virtual memory. The valid addresses in a process' virtual address space correspond to actual data or code somewhere in the system, either in physical memory or on the disk. Since physical memory is fast and is a limited resource, we use the physical memory as a cache for the disk (another way of saying this is that the physical memory is \backed by" the disk, just as the L1 cache is \backed by" the L2 cache). Just as with any cache, we need to specify our policies for when to read a page into physical memory, when to evict a page from physical memory, and when to write a page from physical memory back to the disk. 15.1.1 Reading Pages into Physical Memory For reading, most operating systems use demand paging. This means that pages are only read from the disk into physical memory when they are needed. In the page table, there is a resident status bit, which says whether or not a valid page resides in physical memory. If the MMU tries to get a physical page number for a valid page which is not resident in physical memory, it issues a pagefault to the operating system. The OS then loads that page from disk, and then returns to the MMU to finish the translation.1 In addition, many operating systems make some use of pre-fetching, which is called pre-paging when used for pages. -
NASM for Linux
1 NASM for Linux Microprocessors II 2 NASM for Linux Microprocessors II NASM Package nasm package available as source or as executables Typically /usr/bin/nasm and /usr/bin/ndisasm Assembly NASM Linux requires elf format for object files ELF = Executable and Linking Format Typical header size = 330h bytes for nasm −f elf [−o <output>] <filename> Linking Linux Object files can be linked with gcc gcc [−options] <filename.o> [other_files.o] Disassembly View executable as 32-bit assembly code ndisasm −e 330h –b 32 a.out | less objdump –d a.out | less Fall 2007 Hadassah College Dr. Martin Land Fall 2007 Hadassah College Dr. Martin Land 3 NASM for Linux Microprocessors II 4 NASM for Linux Microprocessors II gcc Stages Example — 1 Stages of Gnu C compilation factorial2.c #include <math.h> main #include <stdio.h> sets j = 12 main() Source Translation Assembly Object Executable calls factorial 10,000,000 times Code Unit Code Code File { int times; prog.c prog.i prog.s prog.o a.out int i , j = 12; preprocess compile assemble link for (times = 0 ; times < 10000000 ; ++times){ i = factorial(j); gcc -E } gcc -S printf("%d\n",i); gcc -c } gcc int factorial(n) int n; factorial calculates n! by recursion { if (n == 0) return 1; else return n * factorial(n-1); } Fall 2007 Hadassah College Dr. Martin Land Fall 2007 Hadassah College Dr. Martin Land 5 NASM for Linux Microprocessors II 6 NASM for Linux Microprocessors II Example — 2 Example — 3 ~/gcc$ gcc factorial2.c Compile program as separate files produces executable a.out factorial2a.c ~/gcc$ time a.out main() { 479001600 int times; int i,j=12; for (times = 0 ; times < 10000000 ; ++times){ real 0m9.281s i = factorial(j); factorial2b.c } #include <math.h> printf("%d\n",i); user 0m8.339s #include <stdio.h> } sys 0m0.008s int factorial(n) int n; { Program a.out runs in 8.339 seconds on 300 MHz if (n == 0) Pentium II return 1; else return n * factorial(n-1); } Fall 2007 Hadassah College Dr. -
Troubleshooting and Recovering from Problems
Microsoft Windows 7 Unleashed, Paul McFedries, Sams Publishing, 0672330695, July, 201 CHAPTER 21 IN THIS CHAPTER . Troubleshooting Strategies: Troubleshooting and Determining the Source of a Problem Recovering from . General Troubleshooting Tips Problems . More Troubleshooting Tools . Troubleshooting Using Online Resources If it was so, it might be; and if it were so, it would be; but as it isn’t, it ain’t. That’s logic. Recovering from a Problem —Lewis Carroll A long time ago, somebody proved mathematically that it was impossible to make any reasonably complex software program problem-free. As the number of variables increase, as the interactions of subroutines and objects become more complex, and as the underlying logic of a program grows beyond the ability of a single person to grasp all at once, errors inevitably creep into the code. Given Windows 7’s status as possibly the most complex software ever created, the bad news is that there are certainly problems lurking in the weeds. However, the good news is that the overwhelm- ing majority of these problems are extremely obscure and appear only under the rarest circumstances. This doesn’t mean that you’re guaranteed a glitch-free computing experience—far from it. Third-party programs and devices cause the majority of computer woes, either because they have inherent problems themselves or because they don’t get along well with Windows 7. Using software, devices, and device drivers designed for Windows 7 can help tremendously, as can the maintenance program I outlined in Chapter 7, “Maintaining Your Windows 7 System.” But computer problems, like the proverbial death and taxes, are certainties in life, so you need to know how to troubleshoot and resolve the problems that will inevitably come your way. -
Memory Management
Memory management Virtual address space ● Each process in a multi-tasking OS runs in its own memory sandbox called the virtual address space. ● In 32-bit mode this is a 4GB block of memory addresses. ● These virtual addresses are mapped to physical memory by page tables, which are maintained by the operating system kernel and consulted by the processor. ● Each process has its own set of page tables. ● Once virtual addresses are enabled, they apply to all software running in the machine, including the kernel itself. ● Thus a portion of the virtual address space must be reserved to the kernel Kernel and user space ● Kernel might not use 1 GB much physical memory. ● It has that portion of address space available to map whatever physical memory it wishes. ● Kernel space is flagged in the page tables as exclusive to privileged code (ring 2 or lower), hence a page fault is triggered if user-mode programs try to touch it. ● In Linux, kernel space is constantly present and maps the same physical memory in all processes. ● Kernel code and data are always addressable, ready to handle interrupts or system calls at any time. ● By contrast, the mapping for the user-mode portion of the address space changes whenever a process switch happens Kernel virtual address space ● Kernel address space is the area above CONFIG_PAGE_OFFSET. ● For 32-bit, this is configurable at kernel build time. The kernel can be given a different amount of address space as desired. ● Two kinds of addresses in kernel virtual address space – Kernel logical address – Kernel virtual address Kernel logical address ● Allocated with kmalloc() ● Holds all the kernel data structures ● Can never be swapped out ● Virtual addresses are a fixed offset from their physical addresses.