Term
| What are the goals of an OS Design? |
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Definition
| The goals of OS design are to make the computer more convenient to use, to allow the system resources, and permit effective development. |
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Term
| What is the Kernel of an OS? |
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Definition
The kernel controls the execution of the processors.
It manages thread scheduling
process switching
exception and interrupt handling
and multilevel process synchronization. |
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Term
| What are the responsibilities of an OS with regard to resource management? |
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Definition
Tracks the status of resources.
Determines who gets what resources.
Allocates resources.
Retrieves resources. |
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Term
| Explain the difference between monolithic kernel and microkernel. |
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Definition
Monolithic: include most of the functionality it the OS. Is a single process with elements sharing the same address space.
Microkernel: Only a few essential functions are in the kernel. Other services are provided by processes that run in user mode. |
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Term
| What is the PCB (Process Control Block). |
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Definition
| The PCB is a data structure that stores information for processes. It is the main tool to allow interrupts and multiprocessing. |
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Term
| What is swapping and what is its purpose? |
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Definition
| Swapping is the process that switches the contents of an area in main stores with an area in secondary memory. When process are not ready they get swapped into secondary memory, then a new process is brought into the main. |
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Term
| Why do we need dual mode of operation? |
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Definition
| The reason we need duel mode operation is so that we can protect kernel mode processes such as the PCB's from being interfered with by user programs. |
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Term
| What is the difference between an interrupt and a trap? |
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Definition
Interrupt: An external process that is brought about by the clock, I/O, or a memory fault.
Trap: A trap is an error or exception in the currently running process. If the condition is fatal the process moves to an exit state. |
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Term
| What are the advantages of ULT's (user level threads) over KLT's (kernel level threads)? |
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Definition
Thread switching does not require kernel mode.
Scheduling can be application specific.
User level threads can run on any OS.s |
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Term
| What are the advantages of KLT's (Kernel level threads) over ULT's (User level threads)? |
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Definition
When a ULT executes a call on a blocked thread not only is it blocked but all threads in that process are blocked.
In a pure ULT strategy a multithreaded application cannot take advantage of multiprocessing. |
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Term
| What resources are typically shared by all threads of a process? |
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Definition
| Threads of the same process share memory, code section, data section, and OS resources. |
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Term
| What is the basic requirement for the execution of concurrent processes? |
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Definition
| The ability to enforce mutual exclusion. |
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Term
| What is the distinction between competing processes and cooperating processes? |
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Definition
Competing processes use the same resources. Such as a file.
Cooperating processes share resources and may not be aware of eachother. |
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Term
| What is the difference between a weak and strong semaphore? |
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Definition
Weak semaphores do not specify what method to remove processes with.
Strong semaphores use a FIFO method to remove processes. |
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Term
| What is the difference between a binary and general semaphore? |
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Definition
A general semaphore has an integer tracking the number of items in the buffer.
A binary semaphore only has two states, 0 and 1. It is a more restricted version. |
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Term
| What is the difference between blocking and non-blocking with respect to messages? |
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Definition
Blocking is where the process must wait to receive the message before it continues.
Non-blocking is where the process continues to execute while the message is in transit. |
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Term
The processor control's the operations of the computer and performs its data processing functions.
T or F |
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Definition
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Term
Cache memory is invisible to the Operating System.
T or F |
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Definition
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Term
Interrupts are provided primarily as a way to improve processor utilization.
T or F |
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Definition
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Term
An SMP can be defined as a stand alone computer system with two or more similar processors of comparable capability.
T or F |
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Definition
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Term
The operating system acts as an interface between computer hardware and the human user.
T or F |
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Definition
| False. An operating system acts as an interface between applications and the computer hardware. |
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Term
The OS frequently relinquishes control and must depend on the processor to allow it to regain control.
T or F |
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Definition
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Term
One of the driving forces in operating system evolution is advancement in the underlying hardware technology.
T or F |
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Definition
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Term
A processor itself is not a resources so the OS is not involved in determining how much of the processor time is devoted to the execution of a user program.
T or F |
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Definition
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Term
A monolithic kernel is implemented as a single process with all elements sharing the same address space.
T or F |
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Definition
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Term
The user has direct access to the processor with a batch-processing type of OS.
T or F |
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Definition
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Term
The phrase "Control is passed to a job" means that the processor is now fetching and executing instructions from the monitor program.
T or F |
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Definition
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Term
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Definition
| A situation in which multiple threads or processes read and write a share data item and the final result depends on the relative timing of their execution. |
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Term
Terminating a process does not terminate all threads in that process.
T or F |
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Definition
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