Operating Systems 2015F: Assignment 5: Difference between revisions

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Within a UNIX filesystem, one inode can be referred to by many different pathnames (filenames). What is another term for these names?
- hard links
- symbolic links
- URLs
- all of the above
A modern monolithic operating system kernel typically implements
- scheduling \& address space management
- some device drivers
- a TCP/IP stack
- All of the above
An OS that is based upon a microkernel architecture will typically:
- have most device drivers and filesystem code run within separate userspace processes
- have most OS code run in CPU supervisor mode
- support loadable kernel modules
- All of the above
A typical executing application is best described as a:
- kernel
- process
- thread
- system call
When a running program X requests data from a file F whose contents are on disk, the OS will:
- save X's current state
- schedule a disk request for F's data blocks
- load the state of another ready-to-run program Y (which may be X)
- All of the above
When a regular process is running on a single-CPU system, all of the following are true except:
- The kernel is running.
- Disks can be writing data to memory.
- The CPU will generate an exception (software interrupt) if certain addresses are accessed.
- The CPU is in user mode.
Modern virtual memory systems:
- Logically divide RAM into fixed-sized chunks
- Store portions of processes on disk
- Allocate a logical address space to each process that is distinct from the physical memory map
- All of the above
The ``dirty bit in a page table entry indicates that:
- A security violation has occurred
- The corresponding page has been accessed.
- The corresponding page has been modified.
- The corresponding page is shared between multiple processes.
An inode contains all of the following except:
- user ID
- filename
- time of last data modification
- link count
When checking the consistency of a filesystem (e.g. after a loss of power), all of the following must be checked except:
- inode reference counts
- pointers to data blocks (in inodes or indirect blocks)
- contents of data blocks of regular files
- block free list
If a system automatically boots into a defective kernel (e.g., one that crashes on startup), you can recover the system by:
- Select a different kernel in the bootloader
- Perform a soft reboot of the system
- Perform a hard reboot of the system
- Press Alt-SysRq-R
Virtual memory is prohibitively expensive on a system that lacks a TLB because
- Every memory access then requires a system call.
- The page table has to be checked on every memory access
- The process table has to be updated on every tick interval.
- None of the above

Solutions

Within a UNIX filesystem, one inode can be referred to by many different pathnames (filenames). What is another term for these names?
- hard links
- symbolic links
- URLs
- all of the above
A modern monolithic operating system kernel typically implements
- scheduling \& address space management
- some device drivers
- a TCP/IP stack
- All of the above
An OS that is based upon a microkernel architecture will typically:
- have most device drivers and filesystem code run within separate userspace processes
- have most OS code run in CPU supervisor mode
- support loadable kernel modules
- All of the above
A typical executing application is best described as a:
- kernel
- process
- thread
- system call
When a running program X requests data from a file F whose contents are on disk, the OS will:
- save X's current state
- schedule a disk request for F's data blocks
- load the state of another ready-to-run program Y (which may be X)
- All of the above
When a regular process is running on a single-CPU system, all of the following are true except:
- The kernel is running.
- Disks can be writing data to memory.
- The CPU will generate an exception (software interrupt) if certain addresses are accessed.
- The CPU is in user mode.
Modern virtual memory systems:
- Logically divide RAM into fixed-sized chunks
- Store portions of processes on disk
- Allocate a logical address space to each process that is distinct from the physical memory map
- All of the above
The ``dirty bit in a page table entry indicates that:
- A security violation has occurred
- The corresponding page has been accessed.
- The corresponding page has been modified.
- The corresponding page is shared between multiple processes.
An inode contains all of the following except:
- user ID
- filename
- time of last data modification
- link count
When checking the consistency of a filesystem (e.g. after a loss of power), all of the following must be checked except:
- inode reference counts
- pointers to data blocks (in inodes or indirect blocks)
- contents of data blocks of regular files
- block free list
If a system automatically boots into a defective kernel (e.g., one that crashes on startup), you can recover the system by:
- Select a different kernel in the bootloader
- Perform a soft reboot of the system
- Perform a hard reboot of the system
- Press Alt-SysRq-R
Virtual memory is prohibitively expensive on a system that lacks a TLB because
- Every memory access then requires a system call.
- The page table has to be checked on every memory access
- The process table has to be updated on every tick interval.
- None of the above

@@ Line 57: / Line 57: @@
 #* Every memory access then requires a system call.
 #* The page table has to be checked on every memory access
+#* The process table has to be updated on every tick interval.
+#* None of the above
+==Solutions==
+#  Within a UNIX filesystem, one inode can be referred to by many different pathnames (filenames).  What is another term for these names?
+#* '''hard links'''
+#* symbolic links
+#* URLs
+#* all of the above
+#  A modern monolithic operating system kernel typically implements
+#* scheduling \& address space management
+#* some device drivers
+#* a TCP/IP stack
+#* '''All of the above'''
+#  An OS that is based upon a microkernel architecture will typically:
+#* '''have most device drivers and filesystem code run within separate userspace processes'''
+#* have most OS code run in CPU supervisor mode
+#* support loadable kernel modules
+#* All of the above
+#  A typical executing application is best described as a:
+#* kernel
+#* '''process'''
+#* thread
+#* system call
+#  When a running program X requests data from a file F whose contents are on disk, the OS will:
+#* save X's current state
+#* schedule a disk request for F's data blocks
+#* load the state of another ready-to-run program Y (which may be X)
+#* '''All of the above'''
+#  When a regular process is running on a single-CPU system, all of the following are true '''except''':
+#* '''The kernel is running.'''
+#* Disks can be writing data to memory.
+#* The CPU will generate an exception (software interrupt) if certain addresses are accessed.
+#* The CPU is in user mode.
+#  Modern virtual memory systems:
+#* Logically divide RAM into fixed-sized chunks
+#* Store portions of processes on disk
+#* Allocate a logical address space to each process that is distinct from the physical memory map
+#* '''All of the above'''
+#  The ``dirty'' bit in a page table entry indicates that:
+#* A security violation has occurred
+#* The corresponding page has been accessed.
+#* '''The corresponding page has been modified.'''
+#* The corresponding page is shared between multiple processes.
+# An inode contains all of the following '''except''':
+#* user ID
+#* '''filename'''
+#* time of last data modification
+#* link count
+# When checking the consistency of a filesystem (e.g. after a loss of power), all of the following must be checked '''except''':
+#* inode reference counts
+#* pointers to data blocks (in inodes or indirect blocks)
+#* '''contents of data blocks of regular files'''
+#* block free list
+# If a system automatically boots into a defective kernel (e.g., one that crashes on startup), you can recover the system by:
+#* '''Select a different kernel in the bootloader'''
+#* Perform a soft reboot of the system
+#* Perform a hard reboot of the system
+#* Press Alt-SysRq-R
+# Virtual memory is prohibitively expensive on a system that lacks a TLB because
+#* Every memory access then requires a system call.
+#* '''The page table has to be checked on every memory access'''
 #* The process table has to be updated on every tick interval.
 #* None of the above