Operating Systems 2015F: Assignment 3 - Revision history

Soma at 14:14, 7 October 2015

2015-10-07T14:14:44Z

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 # There is a directory called /mydisk, and in this directory there are three files, A, B, and C.  You run the command "mount /dev/sdb1 /mydisk"; afterwards you see that /mydisk contains the file B along with a directory lost+found. We see the file B but not the files A and C because...
 #* A, B, and C still exist but are now hidden; the file B that we see is a different file that just happens to have the same filename B.
 #* A and C got randomly erased by the mount command but B was left alone.
 #* lost+found contains the old A, B, and C
 #* None of the above.

Soma at 18:36, 3 October 2015

2015-10-03T18:36:09Z

← Older revision		Revision as of 18:36, 3 October 2015
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	#* function calls are too slow		#* function calls are too slow
	#* processes cannot see kernel memory		#* processes cannot see kernel memory
			#* All of the above
	# You can create a new process running an executable by...		# You can create a new process running an executable by...
	#* making an execve system call		#* making an execve system call

Soma at 18:18, 3 October 2015

2015-10-03T18:18:10Z

← Older revision		Revision as of 18:18, 3 October 2015
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	#* DVD drive		#* DVD drive
	#* All of the above		#* All of the above
	# If a process makes many system calls (as seen by strace) but produces no library calls (as seen by ltrace), what is a reasonable assumption regarding the program?		# If a process makes many system calls (as seen by strace) but produces no library calls (as seen by ltrace), what is a reasonable assumption regarding the process and the program it is running?
	#* The ~~process~~ is multithreaded		#* The program is multithreaded
	#* The dynamic linker is broken		#* The dynamic linker is broken
	#* The process is running as root		#* The process is running as root
	#* The ~~process~~ was statically linked		#* The program was statically linked
	# If a process creates many child processes then changes an environment variable X...		# If a process creates many child processes then changes an environment variable X...
	#* X is also changed in its parent process		#* X is also changed in its parent process

Soma at 18:16, 3 October 2015

2015-10-03T18:16:47Z

← Older revision		Revision as of 18:16, 3 October 2015
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	# Standard C library routines such as printf are available in the kernel. True or False		# Standard C library routines such as printf are available in the kernel. True or False
			# Without errors, what does the fork system call return?
			#* the child’s process ID
			#* 0
			#* Both (a) and (b)
			#* None of the above.
	# What is something that userspace programs can do easily that is difficult to do from kernel code?		# What is something that userspace programs can do easily that is difficult to do from kernel code?
	#* Open a file		#* Open a file
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	#* A and C got randomly erased by the mount command but B was left alone.		#* A and C got randomly erased by the mount command but B was left alone.
	#* lost+found contains the old A, B, and C		#* lost+found contains the old A, B, and C
	~~#* None of the above.~~
	~~# Without errors, what does the fork system call return?~~
	~~#* the child’s process ID~~
	~~#* 0~~
	~~#* Both (a) and (b)~~
	#* None of the above.		#* None of the above.

Soma at 18:15, 3 October 2015

2015-10-03T18:15:48Z

← Older revision		Revision as of 18:15, 3 October 2015
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	#* Wait, a process cannot change its environment variables		#* Wait, a process cannot change its environment variables
	#* None of the above		#* None of the above
	# In playing around with the dd command in /dev you accidentally overwrote a small part of a USB drive formatted with an ext4 filesystem. You run fsck and repair the filesystem. No files have been corrupted; however, you find a directory that had a few files is now empty, and its files have now appeared /lost+found but with seemingly random numeric filenames (like #5123). What part of the filesystem ~~did~~ you ~~overwrite~~?		# In playing around with the dd command in /dev you accidentally overwrote a small part of a USB drive formatted with an ext4 filesystem. You run fsck and repair the filesystem. No files have been corrupted; however, you find a directory that had a few files is now empty, and its files have now appeared /lost+found but with seemingly random numeric filenames (like #5123). What part of the filesystem do you know you overwrote?
	#* data blocks		#* data blocks
	#* inode blocks		#* inode blocks

Soma at 18:15, 3 October 2015

2015-10-03T18:15:10Z

← Older revision		Revision as of 18:15, 3 October 2015
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	#* None of the above		#* None of the above
	# In playing around with the dd command in /dev you accidentally overwrote a small part of a USB drive formatted with an ext4 filesystem. You run fsck and repair the filesystem. No files have been corrupted; however, you find a directory that had a few files is now empty, and its files have now appeared /lost+found but with seemingly random numeric filenames (like #5123). What part of the filesystem did you overwrite?		# In playing around with the dd command in /dev you accidentally overwrote a small part of a USB drive formatted with an ext4 filesystem. You run fsck and repair the filesystem. No files have been corrupted; however, you find a directory that had a few files is now empty, and its files have now appeared /lost+found but with seemingly random numeric filenames (like #5123). What part of the filesystem did you overwrite?
	#* ~~Data~~ blocks		#* data blocks
	#* ~~inodes~~		#* inode blocks
	#* directory blocks		#* directory blocks
	#* All of the above		#* All of the above

Soma at 18:14, 3 October 2015

2015-10-03T18:14:05Z

← Older revision		Revision as of 18:14, 3 October 2015
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	#* Both A and B		#* Both A and B
	#* None of the above		#* None of the above
	#Which of the following is a character/stream device?		# Which of the following is normally assigned character/stream device on UNIX-like systems?
	#* Hard Disk drive		#* Hard Disk drive
	#* Sound card (audio device)		#* Sound card (audio device)

Soma at 18:13, 3 October 2015

2015-10-03T18:13:16Z

← Older revision		Revision as of 18:13, 3 October 2015
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	Please answer the following questions on cuLearn by 8 PM on Tuesday, October 6th.		Please answer the following questions on cuLearn by 8 PM on Tuesday, October 6th.

			# Standard C library routines such as printf are available in the kernel. True or False
	# What is something that userspace programs can do easily that is difficult to do from kernel code?		# What is something that userspace programs can do easily that is difficult to do from kernel code?
	#* Open a file		#* Open a file
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	#* DVD drive		#* DVD drive
	#* All of the above		#* All of the above
	~~# Standard C library routines such as printf are available in the kernel. True or False~~
	# If a process makes many system calls (as seen by strace) but produces no library calls (as seen by ltrace), what is a reasonable assumption regarding the program?		# If a process makes many system calls (as seen by strace) but produces no library calls (as seen by ltrace), what is a reasonable assumption regarding the program?
	#* The process is multithreaded		#* The process is multithreaded

Soma at 18:12, 3 October 2015

2015-10-03T18:12:55Z

@@ Line 20: / Line 20: @@
 #* DVD drive
 #* All of the above
 # In playing around with the dd command in /dev you accidentally overwrote a small part of a USB drive formatted with an ext4 filesystem.  You run fsck and repair the filesystem.  No files have been corrupted; however, you find a directory that had a few files is now empty, and its files have now appeared  /lost+found but with seemingly random numeric filenames (like #5123).  What part of the filesystem did you overwrite?
 #* Data blocks
@@ Line 35: / Line 46: @@
 #* Both (a) and (b)
 #* None of the above.

Soma at 18:12, 3 October 2015

2015-10-03T18:12:14Z

← Older revision		Revision as of 18:12, 3 October 2015
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	#* None of the above.		#* None of the above.
	# Without errors, what does the fork system call return?		# Without errors, what does the fork system call return?
	## the child’s process ID		#* the child’s process ID
	## 0		#* 0
	## Both (a) and (b)		#* Both (a) and (b)
	## None of the above.		#* None of the above.
			# If a process creates many child processes then changes an environment variable X...
			#* X is also changed in its parent process
	If a process creates many child processes then changes an environment variable X...		#* X is changed in all child processes
	* X is also changed in its parent process		#* Wait, a process cannot change its environment variables
	* X is changed in all child processes		#* None of the above
	* Wait, a process cannot change its environment variables		# Standard C library routines such as printf are available in the kernel. True or False
	* None of the above		# If a process makes many system calls (as seen by strace) but produces no library calls (as seen by ltrace), what is a reasonable assumption regarding the program?
			#* The process is multithreaded
			#* The dynamic linker is broken
	Standard C library routines such as printf are available in the kernel. ~~true~~ or ~~false~~		#* The process is running as root
			#* The process was statically linked

	If a process makes many system calls (as seen by strace) but produces no library calls (as seen by ltrace), what is a reasonable assumption regarding the program?

	* The process is multithreaded
	* The dynamic linker is broken
	* The process is running as root
	* The process was statically linked