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Flashcards

OS Internals (D2)

jeriel.juarbe Unix College English 65 cards

Cards in this deck (65)

  1. 1What routines can be invoked by a program to access system resources?System Calls
  2. 2What are the built-in commands to examine system calls?Linux= strace
    Solaris= truss
  3. 3What syntax is used to output the system calls needed in the execution of the date command/system call in Linux to a file called date.out in the /temp directory?strace -o /temp/date.out date
  4. 4What command is used to display a summary table of all system calls and a number of errors?strace -c date
    (linux)
  5. 5Who is the parent process for all processes?init
    (PID 1)
  6. 6What are the 3 categories of system calls?1) Low-level FIle
    2) Process Control
    3) Common system calls
  7. 7What are the 5 system calls used to create and control a process in *nix1) Fork
    2) exec
    3) exit
    4) wait
    5) kill
  8. 8System call fork() does what?used to create a child process in the image of the parent process
  9. 9system call wait() does what?function that blocks the calling process until one of its child processes exits or a signal is received
  10. 10what does the system call exit() do?terminates the current process and typically performs cleanup afterwards
  11. 11Which common system call returns info pertaining to the platform?uname()
  12. 12What are the processes running in the background called?Daemons
    Examples: cron, sendmail, and cups
  13. 13child processes that have not been wait()ed for are called ________?zombie processes
  14. 14What function can be build upon and around system calls to allow for the perception of varied access to devices?library functions
  15. 15______ contains helper code and data that provides the services to independent programs.Libraries
  16. 16this Allows a device driver, or any other kernel service to be linked into and removed from the kernel while it is runningLoadable Kernel Modules (LKMs)
  17. 17In linux, what command shows the status of currently loaded LKM's by listing /proc/moduleslsmod
  18. 18In Linux which command is used to dynamically change some parameters of the linux kernelsysctl
  19. 19this command provides an interface that allows you to examine and change several hundred kernel parameters?sysctl
  20. 20Which command syntax will list all tunable kernel modules and their values in Linux?sysctl -a
  21. 21What command syntax is used to MODIFY tunable kernel modules?sysctl -w
    Example:
    sysctl -w vm.swapiness=10
  22. 22sysctl values are loaded at boot from what file?/etc/sysctl.conf
  23. 23sysctl -a =?shows all current tunable settings
  24. 24sysctl -w =?modify on the fly
  25. 25What Linux syntax is used to change the vm.swapinness kernel module value from 11 to 12?sysctl -w vm.swappiness=12
  26. 26After modifying kernel modules in Linux, what command will force sysctl.conf changes at anytime after rebooting?sysctl -p
  27. 27What configuration file is used to modify Solaris Kernel?/etc/system
  28. 28What command will display currently installed kernel modules in SOLARIS?modinfo
  29. 29What command will display device config info to include sys h/w, pseudo devices, loadable modules, and selected kernel parameters and their values, but will not display RAM in Solaris?sysdef
  30. 30Which command is used to view linux and solaris running processes?ps -elf
  31. 31What process has the PID of 0?the scheduler process
  32. 32What signal is sent external to the current running process to gain the attention of or interrupt that process?Interrupt
  33. 33True or False: Most processes are usually in a sleep state, waiting on an eventTrue
  34. 34What does O mean in regards to the state of a process in Solaris?process running on the CPU
  35. 35What does S mean in regards to process states in Linux?Sleeping-process waiting for some resource
  36. 36What term is this: -A signal generated by the hardware when it wants the processors attentionInterrupt
  37. 37What term is this: -software written to catch an exception generated by the CPUTRAP
  38. 38What is this term: -are process-level interrupt requests that can sent in a number of ways?Signals
  39. 39What are the 3 ways that signals are sent?1) Terminal=ctrl+alt+del
    2) Administrator=kill or pskill
    3) Kernel= divide by zero
  40. 40Which command displays all signals available?kill -l
  41. 41What are the 5 signals we are concerned about?1) sigup
    2) sigint
    3) sigquit
    4) sigkill
    5) sigterm
  42. 42SIGTERM =?KILL
  43. 43SIGKILL =?kill -9
  44. 44SIGINT =?CTRL-C
  45. 45SIGHUP =?I made a change (hangup-restart Daemon)
  46. 46SIGQUIT =?quits the terminal
  47. 47This presents each user with a prompt, executes user commands, and supports a custom environment for each userSHELL
  48. 48True or False: the shell is both an interpreter and a scripting language.TRUE
  49. 49What is a login shell?mean a shell was received after user authentication.
  50. 50Where are the system default variables located and user defined in the Bourne (sh) shell?/etc/profile
    ~/.profile
  51. 51Where are the system default variables located and user defined in the Bourne-Again (bash) shell?/etc/bashrc or /etc/profile
    ~/.bash_profile (varies)
  52. 52What shell can be configured to restrict the activities of a user by keeping that user in their home directory?restricted shell
  53. 53True or False: the user may change their shell with the proper permissions by simply typing in the shell nameTRUE
  54. 54What command is used to automatically update a users shell in the /etc/passwd file?chsh
    (LINUX only!)
  55. 55what sytax is used to change (permanently) a users login shell to the bourne shell?chsh -s /bin/sh billy
  56. 56With a restricted shell a user may not do what 4 things?1) use cd command
    2) set or change value of PATH, ENV, or SHELL variables
    3) navigate passed the users own directory 4) use output redirection (> or >>)
  57. 57True or False: A restricted shell (rssh) can be configured and used to specifically restrict a user to use scp or sftpTRUE
  58. 58What syntax is used to add the path /usr/openwin/demo to my current path variable?PATH=$PATH:/usr/openwin/demo
  59. 59What syntax is used to to replace the current PATH value?PATH=/usr/xpg4/bin
  60. 60What describes a section of a file system that is sectioned off for a particular user?chroot jail
  61. 61What type of shell will prevent a non-root user the ability to login on a *nix system?Linux=Nologon
    Solaris=Noshell
  62. 62PATH=$PATH: =?adds to /appends the path
  63. 63PATH=/whateverreplaces the Path
  64. 64These are in the users' total environment and are usually in UPPERCASE.Environmental variables
  65. 65TRUE or False: Changing values to variables are not permanent unless you make the changes in the ~/.bash_profile (LINUX) or ~/.profile (SOLARIS) of the user's home directoryTRUE

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Description
College Unix Flashcards on OS Internals (D2), created by jeriel.juarbe on 19/08/2014.
Created by
jeriel.juarbe · Aug 2014
Updated
Feb 3, 2018
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