3055q11ds - All memory addresses used by a program are...

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Score:_______ Name:______________________________ ECE 3055 Quiz 11 - November 9, 2004 1. The __short term scheduler______________ in an Operating System gets the next process from the ready queue whenever a process stops running. 2. A process spends most of it’s time in the wait state. What could you conclude about the process (Explain)? It is likely an I/O bound job. Processes in the wait state are waiting for I/O operations or external events to complete. 3. How can threads improve an applications performance even in a system with only one CPU? If one or more threads is blocked waiting on I/O or other events, other threads can still run. So more overlap between I/O and CPU operations is possible even in a single application. Some new processors (ex. P4) also support hyperthreading even on only 1 CPU. 4. In a modern multiprogramming OS, what would stop a program that attempts to access memory outside of its assigned memory area? Exactly how does it work?
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Unformatted text preview: All memory addresses used by a program are checked by hardware base and limit registers whenever an application attempts to access memory. Typically this feature is built into the VM system (if it has VM). Any attempt to access memory outside of the applications memory range will generate an interrupt stopping the application and generate an error message. 5. For API calls to the OS, describe the two major approaches that can be used to support communication between processes. (in terms of memory mapping and message buffers) Page 73-74 Shared Memory messages are exchanged between processes in a shared memory data area using global variables. The OS must setup the shared memory area since it handles memory allocation. Message Passing messages are exchanged between processes using OS API interprocess communication calls. The message is buffered inside the OS. Slower but more secure....
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3055q11ds - All memory addresses used by a program are...

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