16630637
| Question | Answer |
| Compaction ist eine Lösung für das Problem external fragmentation | TRUE |
| Eine Seitentabelle hilft beim Übersetzten von physischen Adressen in virtuelle Adressen | FALSE |
| Der Hauptvorteil einer zweistufigen Seitentabelle gegenüber einer einstufigen ist, dass die zweistufige nicht vollständig im Hauptspeicher gehalten werden muss | (TRUE ?) The primary advantage of multilevel page tables: the amount of memory needed for the page table is not dictated by the size of the address space, but by the amount of memory that the process is using. |
| Eine Inode ist ein Eintrag in einem Unix Dateisystem, der einer Datei eindeutig zugeordnet ist | TRUE |
| Jeder Thread hat seinen eigenen (virtuellen) Registersatz | TRUE |
| Einen Deadlock kann man auch durch inkorrekte Verwendung von Semaphoren erzeugen | TRUE |
| Der Kernel-Mode ist ein Modus des Betriebssystems | FALSE (der CPU) |
| In der Intel-Architektur enthält das CR3-Register die Startadresse der Segmenttabelle | / |
| Relocation can be implemented using base/limit registers | TRUE |
| Virtual Memory can be implemented using software only | FALSE |
| The used bit and the dirty bit cannot both be set to 1 | FALSE |
| The ELF format is a format for storing Exended Long Files | FALSE |
| Adding more memory to a computer will make it seem to "run faster" | TRUE |
| There is no such thing as "address space layout randomization" | FALSE |
| Thrashing in a virtual memory system is caused by too many processes not having their working set resident in memory | TRUE |
| The return value of a successful exec()-system call is always > 0 | FALSE A successful exec()-system call never returns |
| Global variables are not shared accross multiple threads belonging to the same process | FALSE |
| Starvation is the case when a thread can never aquire a lock on a critical section | TRUE |
| A smaller page size leads to more TLB misses | FALSE |
| Whenever a thread reference a part of the virtual address space that is not currently loaded in the primary memory, the OS suspends execution and loads the missing information from another portion of primary memory | (FALSE ?) |
| A thread should always be able to distinguish between being temporarily blocked and deadlocked | FALSE |
| Early in his career, Elvis Presley was told: "Stick with driving a truck, because you'll never make it as a singer" | TRUE |
| It is possible for multithreading to improve the performance of an application in a single CPU system | TRUE |
| In general, there are more inodes than directories on a linux-file-system | TRUE |
| The use of a TLB eliminates the need for keeping a page table in memory | FALSE |
| Disabling Interrupts is no solution for ensuring mutual exclusion in user space | TRUE |
| The term "monitor" has nothing to do with operating systems beyond the fact that it is used to display stuff on it | FALSE |
| To wait on something inside monitor, condition variables are available | TRUE |
| The state of a thread changes from READY to RUNNING when the thread has been ready long enough |
FALSE
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1 (binary/octet-stream)
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| The state of a thread never changes from READY to BLOCKED |
TRUE
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| A MIPS processor does not use page tables | TRUE Software-filled TLB instead of page tables |
| When using the page-tables method: if linear address A is higher than linear address B, the physical address of A is not necessarily higher than the physical address of B | TRUE |
| When threads are implemented in kernel space, we do not need to switch the memory configuration when switching between two threads of the same process | TRUE |
| Ensuring mutal exclusion in critical sections is a way to get rid of the race condition problem | TRUE |
| With the Test-and-Set-Lock-instruction one can implement an atomic operation | / |
| Copy On Write is a principle that speeds up the process creation | TRUE |
| The OS resets the used bit (to 0) | TRUE |
| An operation that cannot be interrupted is called atomic | TRUE |
| It takes more effort to create a new thread than to create a new process | FALSE |
| A memory management unit is responsible for managing the user space memory | FALSE |
| CPU utilization tends to be higher when there are more processes in memory | TRUE |
| "Safe state" means that it is unlikely a deadlock will occur | FALSE |
| A virtual address consists of a page frame number, a page table number and a page size | FALSE |
| In contrast to a single-level page table, multilevel page tables result in slower page table lookups | TRUE |
| Multilevel page tables allow processes to share regions of memory while single-level page tables do not | FALSE |
| Page-based virtual memory is subject to external fragmentation | FALSE External fragmentation is the various free spaced holes that are generated in either your memory or disk space. |
| In a conventional paging system, a page table entry (PTE) will not contain an illegal-page bit | TRUE |
| The page number in the 24-bit address 0xABCDEF with an 512-byte page size is 0xABC | FALSE |
| Semaphore operations need to be atomic to guarantee mutal exclusion | TRUE |
| A TLB miss will cause a page fault to occur | FALSE |
| A process executes faster when running in kernel mode than when running in user mode | FALSE |
| Because of page-base virtual memory, operating systems never need to worry about allocating contiguous pages | TRUE |
| Switching among threads in the same process is more efficient than switching among processes | (TRUE ?) |
| A clock page replacement algorithm tries to approximate a Least Recently Used (LRU) algorithm | TRUE |
| Adding more memory to a computer will make it seem to "run faster" | TRUE |
| With paging the operating system can place any page of any process to any page frame in physical memory | TRUE |
| The page table is set up by the MMU | FALSE |
| The dirty bit is set by the operating system | FALSE by the hardware |
| Using mutual exclusion ensures that the system avoids deadlock | (FALSE ?) |
| The MMU resets the used bit (to 0) | (FALSE ?) |
| The POSIX execv() system call creates a new process | (FALSE ?) The exec() family of functions replaces the current process image with a new process image. |
| The operating system can (more or less) freely decide where in the virtual address space the stacl(s) are located | TRUE |
| There is no such thing as "address space layout randomization" | FALSE |
| There is no such thing as "address space layout duplication" | TRUE |
| With 64 bit addresses, only 48 bits are supported in current hardware | TRUE |
| Each page table needs to have within it a reference to each page frame in the system | FALSE |
| The base/limit register method provides relocation and protection | (TRUE ?) |
| The present bit is set by the MMU | FALSE |
| The accessed bit and the dirty bit cannot both be set to 1 | FALSE |
| Single-level page tables allow processes to share regions of memory while multilevel page tables do not | FALSE |
| Multilevel page tables are used because they allow to translate multiple levels of addresses in parallel | FALSE |
| In a conventional paging system, a page table entry (PTE) will not contain the age of the page | TRUE |
| Page-based virtual memory is subject to internal fragmentation | TRUE |
| When a thread can never acquire a lock on a critical section we call that "starviation" | TRUE |
| For a machine with 32-bit addresses, the use of a two level page table allows for a larger virtual address space than a single level page table | FALSE |
| Two-phase locking is a mechanism that prevents deadlock in database systems | TRUE |
| Ignoring the deadlock-problem is a reasonable approach for a general purpose operating system | TRUE |
| Potential deadlock involving preemtable resources can be solved by reallocation | TRUE |
| When a process supports EPT (Extended Page Table), it is able to handle the guest- and the host page table simultaneously | TRUE |
| When a VMM does binary translation, it continuously reads program code before it is executed, looks for relevant commands and changes them on the fly | (TRUE ?) |
| The Virtual-Machine-Concept was invented around 2003 | FALSE |
| On a classical UNIX-System, an inode contains all the information on a file | FALSE |
| The inode link-count indicates how often a file is referenced within the file-system | TRUE A link count telling how many hard links point to the inode |
| A logical journal writes only metadata into the journal | TRUE |
| The cow-concept is also used in file-systems | TRUE |
| A critical section is a piece of code which, when concurrently executed by multiple threads, may produce results that depend on the order these threads are executed | TRUE |
| When a user program is running, the CPU will be in supervisor mode since it is supervising the program | FALSE |
| A successful exec()-system call never returns | TRUE |
| All threads of a process share single address space | TRUE |
| A critical section is any piece of code that is protected by a mutex | FALSE |
| The TWELVE format is a format for storing binary programms | FALSE |
| User Mode and Kernel (or Supervisor) Mode are two modes of operation of a processor | TRUE |
| Since there is only one operating system running, there are no concurrency issues in operating system code | FALSE |
| One cannot implement monitors using semaphores | FALSE (One can not implement semaphores using monitors = TRUE) |
| A smaller page size leads to smaller page tables | FALSE |
| Get the cosine of a number is best implemented as a system call | FALSE |
| Semaphore are a good method to prevent deadlocks | FALSE |
| The dirty bit is set by the MMU | FALSE |
| A memory management unit translates virtual to physical addresses | TRUE |
| The MMU resets the accessed bit when the page has not been accessed for a while | FALSE |
| Address space layout randomization is meant to improve security | TRUE Address space layout randomization (ASLR) is a memory-protection process for operating systems (OSes) that guards against buffer-overflow attacks by randomizing the location where system executables are loaded into memory. |
| Each file in NTFS is represented by a variable-depth tree of extents | (TRUE ?) |
| In a COW file system, if we update a block, we write it and all the blocks on the path from it to the root to new locations | TRUE |
| FFS places data to optimize for the common case where a file's data blocks and meta data and different files from the same directory are accessed together | TRUE |
| The FAT file system lacks support for modern reliability technology | TRUE lack of modern reliability techniques |
| One cannot implement semaphores using monitors | TRUE |
| 3072 cannot be a valid page size | TRUE |
| 32 cannot be a valid page size | FALSE |
| A logical address of 0xA3213456 on a 32-bit page-based virtual memory system with 4KB pages has the offset 0x3456 | FALSE 4KB pages - 12 bit offset -> offset would be 0x456 |
| A monitor is one solution to solve the mutual exclusion problem | TRUE |
| A program containing a race condition will always result in data corruption or some other incorrect behavior | FALSE |
| A program containing a race condition will never result in data corruption or some other incorrect behavior | FALSE |
| A program containing a race condition will sometimes result in data corruption or some other incorrect behavior | TRUE |
| A race condition occurs when the outcome of processes is dependent on the exact order of execution among them. | TRUE |
| A race condition occurs when a process cannot make progress because another one is blocking it | FALSE |
| The working set model is used to compute the average number of frames a job will need in order to run smoothly without causing thrashing | FALSE |
| The FAT file system does not support hard links | TRUE No hard links |
| When the link count in an inode becomes 0, the file can be deleted | TRUE Inode link-count 0: - no more reference within file system - file can be deleted |
| In NTFS, the MFT contains at least one nonresident data attribute for each file | FALSE |
| In NTFS, a file may have multiple file name attributes | TRUE NTFS: File name and file number of parent directory may have multiple file name attributes (hard link) |
| COW file systems never overwrite existing data or metadata | TRUE |
| COW file systems perform better, because they gain from converting small random writes to large sequential ones | TRUE |
| A ZFS file-system is limited to one physical device | FALSE |
| Google, Amazon etc. estimate they lose 5%-10% of their customers if their response time increases by 100 milliseconds | TRUE |
| If tasks are equal in size, round robin schedule will have very good average response time | (FALSE ?) |
| A user-level process cannot modify its own page table entries | TRUE |
| By manipulating the assignment of tasks to priority queues, an MFQ scheduler can achieve a balance between responsiveness, low overhead and fairness | TRUE |
| The scheduler is the part of the operating system that determines the priority of each process | (FALSE ?) |
| A TLB is needed for correct execution of a program | FALSE |
| Each physical page belongs to only one process | FALSE |
| Every interrupt changes the CPU from user mode to kernel mode | TRUE |
| The VFS layer handles journalling for Very Large File Systems | FALSE virtual file system layer - interface allowing to use different file systems |
| Shortest Job First (SJF) or Shortest Completion Time First (SCTF) schedule is difficult to build on real operating systems | TRUE SJF Downsides: impossible to implement |
| The operating system has to reset the accessed bit when the page has not been accessed for a while | FALSE |
| The kernel is mapped into each user-level application process address space in order for applications to access the kernel's data conveniently | FALSE |
| In 32-bit x86 with paging turned on a machine instruction auch as "mov 0x02000000, %eax" could potentially involve three accesses to memory | (TRUE ?) |
| On x86, upon a TLB miss, the kernel traverses the 2-level page table to fill in the virtual to physical access mapping in the TLB | FALSE |
| Reading a random location in a big file is usually faster in an inode-based file-system than in a FAT file system | TRUE FAT: Poor random access -> need to traverse FAT |
| For better sequential read/write performance, a file system should try to allocate consecutive blocks to a file | (TRUE ?) |
| A guest OS kernel can't access the code and data of the VMM (such as the shadow page table) | (TRUE ?) |
| A hard link is indistinguishable from the original file itself | TRUE A hard link to a file is indistinguishable from the original name for the file; there's no particular link that is more the "real name" for the file than any other. |
| COW file systems overwrite metadata only | FALSE |
| System calls do not change the Fpriviledge-level of the processor | FALSE |
| In practice, all 64 bits are used with IA-64 addressing | FALSE |
| A physical address space is at least as large as a virtual address space | FALSE |
| A smaller page size leads to larger page tables | TRUE |
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