CS 370 All worksheets

What is a system call? -A function call that specifically alters operating system data structures. -A specialized function call of interface with hardware. -A generic function call. -An interface to the services of the operating system to processes.

-An interface to the services of the operating system to processes.

What is the purpose of a Translation Lookaside Buffer (TLB)? -Reduce compulsory misses in main memory. -Implement security protocols for main memory to ensure appropriate memory segmentation. -Improve performance by reducing having to go to RAM to retrieve a page table entry. -To provide for efficient use of main memory for process execution.

-Improve performance by reducing having to go to RAM to retrieve a page table entry.

Given a 32-bit virtual address of 0x0040000C and the following partial TLB. The page size is 4096. v d tag page reference 1 0 0x10010 0x11B17 0 0 0x7FFFF 0x30F21 1 0 0x00400 0x01AC2 1 0 0x1001F 0x04CBA 1 0 0x10020 disk What would be the final 32-bit physical memory address? Respond in hex (with leading 0x).

0x01AC200C

Given a 32-bit virtual address of 0x0040002A and the following partial TLB. The page size is 8192. v d tag page reference 1 0 0x10010 0x11B17 0 0 0x7FFFF 0x30F21 1 0 0x00400 0x01AC2 1 0 0x1001F 0x04CBA 1 0 0x00200 0x01007 What would be the final 32-bit physical memory address? Respond in hex (with leading 0x).

0x0200E02A

Using a RR preemptive scheduling algorithm and the following processes; Process: p1 p2 p3 p4 ET: 20 25 10 15 Arrival Time: 0 15 30 45 What is the average waiting time (awt). The time slice is 5 and all process use their time slice. New process placed in queue before in-system process. Note, awt = completion time - execution time - arrival time.

10

What is the size of the TLB in bytes based on the following assumptions: 32-bit virtual address 32-bit physical address valid and dirty bits -> 1 bit each reference bits -> 8 bits total access bits -> 2 bits 512 TLB entries 8kb page size Respond in bytes (no comma's, no decimal point).

3200

Using a SRT preemptive scheduling algorithm and the following processes; Process: p1 p2 p3 p4 ET: 20 25 10 15 Arrival Time: 0 15 30 45 What is the average waiting time (awt). The time slice is 5 and all process use their time slice. New process placed in queue before in-system process. Note, awt = completion time - execution time - arrival time.

6.25

A process that performs a large number amount of I/O is referred to as

I/O bound

The scheduling criteria waiting time is defined as what?

Minimize time spent waiting in the ready queue for ready processes.

Given the below address stream, what is the applicable page number for the given page size. Ref Tag4KB Tag8KB Tag16KB 0x00a9bb00 0x011a7a28 0x011a777a 0x01113a98

Tag4KB Tag8KB Tag16KB 0x00a9b 0x0054d 0x002a6 0x011a7 0x008d3 0x00469 0x011a7 0x008d3 0x00469 0x01113 0x00889 0x00444 to answer take off bits according to KB 4KB= take off last 12 bits 8kB = take off last 13 bits 16KB = take off last 14 bits

Can an OS work without a Graphical User Interface (GUI)? -Yes. -No. -Only using a customized server configuration using a remote console.

Yes

Can an operating system function with only one (1) processor? -Yes. -No. -Yes, but can not support multiple processes.

Yes

Given the following table, note which set of circumstances is possible. TLB PageTable Datacache hit hit hit hit hit miss miss miss miss miss miss hit which are possible?

yes yes yes no

Why might a scheduling algorithm on a server system differ from a scheduling algorithm on a desktop system? -A server must be able to handle more jobs and more cores which requires a fundamentally different approach for a scheduling algorithm. -A desktop could more easily suspend background jobs. -A server might focus on response time and a desktop might focus on throughput. - A desktop might focus on response time and a server might focus on throughput.

- A desktop might focus on response time and a server might focus on throughput.

Which of the following describes the scheduling in a batch system? Check all that apply. -Preemptive. - Nonpreemptive. -Allows multiple simultaneous use of resource (i.e., CPU core). -First-come, first-served (FCFS) or first-in-first-out (FIFO) .

- Nonpreemptive. -First-come, first-served (FCFS) or first-in-first-out (FIFO) .

Which of the following are criteria for which scheduling decisions could be based on? Check all that apply. -Security enforcement. - Throughput . - Response time. -Waiting time. -Turn-around time. -Policy enforcement. - CPU Utilization.

- Throughput . - Response time. - CPU Utilization. -Waiting time. -Turn-around time.

What is the purpose of a Translation Lookaside Buffer (TLB)? -Decreases paging associated with compulsory misses. -Increases associativity for paging operations. -Supports page table looking operations. -A dedicated cache that contains those page table entries that have been most recently used.

-A dedicated cache that contains those page table entries that have been most recently used.

What is paging? -Only implemented on high-end server systems (i.e., super computer centers). -Is the software implementation of the hardware device that at run time maps virtual address to physical address -A memory compaction process that eliminates the problems associated with contiguous memory allocation. -A memory management scheme that allows processes physical memory to be discontinuous. -None of these answers are fully correct

-A memory management scheme that allows processes physical memory to be discontinuous.

When a currently executing process uses its maximum allowed CPU time, what happens? -If other cores are currently free, the process time limit is re-set. -The process is terminated. -The OS scheduler is invoked and the scheduler may allow the process to retain the CPU core. -A process context switch is invoked.

-A process context switch is invoked.

When a page fault occurs, the process requesting the page must block while waiting for the page to be brought from secondary storage into physical memory. Assume that there exists a process with five threads. If one thread incurs a page fault while accessing its data, will the other user threads belonging to the same process also be affected by the page fault — that is, will they also have to wait for the faulting page to be brought into memory? -Yes. -No. -A thread would only be blocked if that thread attempted to access that memory. -They will be blocked, but it is unrelated to the page fault. -None of these answers are fully correct.

-A thread would only be blocked if that thread attempted to access that memory.

Which of the following are contiguous memory allocation strategies. -First fit. -Best fit. -Worst fit. -All of these answers are correct.

-All of these answers are correct.

Which of the following is true regarding a priority scheduling algorithm. Check all that apply. -All processes are not treated equally (for scheduling). -Each process gets a small amount CPU time (time slice). -Shares some characteristics with a first-come, first-served (FCFS) algorithm. -Possible starvation for low priority processes. All processes are treated equally (for scheduling).

-All processes are not treated equally (for scheduling). -Each process gets a small amount CPU time (time slice). -Possible starvation for low priority processes.

In what ways can a process reduce its vruntime -By increasing its NICE value -By decreasing its NICE value -By spawning child processes -By killing off child processes -None of these are correct

-By killing off child processes

How does the CFS schedule handle priorities? -Priorities are strictly enforced based on preassigned priority numbers. -Priorities are loosely enforced based on user adjustable (via 'nice') priority levels. -Based on two major priority groups; background and foreground. -CFS doesn't use priorities directly, instead processes are tracked/selected based on vruntime. -None of these responses are fully correct.

-CFS doesn't use priorities directly, instead processes are tracked/selected based on vruntime.

The term late binding is typically associated with which of the following? -Both soft and hard page faults. -Hard page faults. -Soft page faults. -DDL/SO functions. -None of these answers are correct

-DDL/SO functions.

Which of the following is true regarding a round-robin scheduling algorithm. Check all that apply. -All processes are not treated equally (for scheduling). -Each process gets a small amount CPU time (time slice). -Possible starvation for low priority processes. -Shares some characteristics with a first-come, first-served (FCFS) algorithm. -All processes are treated equally (for scheduling). -None of these answers are fully correct

-Each process gets a small amount CPU time (time slice). -Shares some characteristics with a first-come, first-served (FCFS) algorithm. -All processes are treated equally (for scheduling).

Which of the following is/are true regarding paging? Check all that apply. -Is the modern version of the first fit memory allocation strategy. -Requires a page size of 4096. -Eliminates most of the problems of contiguous memory allocation. -Works due to the principal of locality.

-Eliminates most of the problems of contiguous memory allocation. -Works due to the principal of locality.

Which of the following are considered goals of an OS scheduler? Check all that apply. -Ensure fairness. -Starvation freedom. -Good response time. -Implement preemption. -Policy enforcement.

-Ensure fairness. -Starvation freedom. -Good response time. -Policy enforcement.

Which of the following is a key problem with contiguous memory allocation strategies. -No specific issue, but provides overall less performance than other approaches. -Separation of data and code. -Fragmentation. -Limits implementation of segmentation.

-Fragmentation.

Which of the following is contained in the page/swap file? -A subset of the swapped out pages for the executing process. -Dirty data pages from the executing process (since instruction pages do not change). -Full copy of the executing process. -Swapped out pages of the executing process.

-Full copy of the executing process.

Given the following table; TLB PageTable Datacache hit hit hit hit hit miss miss miss miss miss miss hit Performance?

-Fully completed within CPU. -Only address translation completed -Page fault. -Illegal.

What is meant by a hard real time system? -Scheduling algorithms that execute in a timed, scheduled manner. -Guaranteed to meet any scheduling requirements (within certain limits). -Refers to the notion that the kernel tries to schedule applications within timing deadlines, but the kernel does not promise to always achieve these goals. -None of these responses are fully correct.

-Guaranteed to meet any scheduling requirements (within certain limits).

Which of the following is true regarding the memory management unit (MMU)? -Improves overall performance since since most programs exhibit both temporal and spatial locality. -Performs the hardware implementation for DLL's or SO's. -Addresses generated by the process. -Hardware that, at run time, helps maps virtual address to physical address.

-Hardware that, at run time, helps maps virtual address to physical address.

What is temporal locality? -A reference to cache management protocols. -If an item is referenced, items whose addresses are close by will tend to be referenced soon. -If an item is referenced, it will tend to be referenced again soon. -Programs access a relatively small portion of their address space at any instant of time. -None of these answers are fully correct.

-If an item is referenced, it will tend to be referenced again soon.

What is spatial locality? -A reference to cache management protocols. -If an item is referenced, items whose addresses are close by will tend to be referenced soon. -If an item is referenced, it will tend to be referenced again soon. -Programs access a relatively small portion of their address space at any instant of time. -None of these answers are fully correct.

-If an item is referenced, items whose addresses are close by will tend to be referenced soon

Under what circumstance might a call to a library function (from a DLL/SO library) cause a soft fault? -Such a call will not cause a page fault. -It will always cause a page fault (which might be soft or hard). -If the DLL/SO function being called is currently in memory. -If the DLL/SO function being called is not currently in memory.

-If the DLL/SO function being called is currently in memory.

Under what circumstance might a call to a library function (from a DLL/SO library) cause a hard fault? -Such a call will not cause a page fault. -It will always cause a page fault (which might be soft or hard). -If the DLL/SO function being called is currently in memory. -If the DLL/SO function being called is not currently in memory.

-If the DLL/SO function being called is not currently in memory.

Which of the following is true regarding swapping? -The need for swapping has been elminated by the availability of cheap RAM storage. -All modern OS's use swapping due to its very high performance. -Is part of the hardware that, at run time, maps virtual address to physical address. -If there is not enough memory available to keep all running processes in memory at the same time, then some processes who are not currently using the CPU may have their memory swapped out to a secondary storage called the backing store.

-If there is not enough memory available to keep all running processes in memory at the same time, then some processes who are not currently using the CPU may have their memory swapped out to a secondary storage called the backing store.

In the context of paging, which is true regarding a hard (or major) fault? Check all that apply. -Indicates that the page was placed into the free list and subsequently swapped out. -Indicates that the page was placed into the free list but not yet swapped out. -The page is not in memory and needs to be read from secondary storage. -The page is already in memory and does not need to be read from secondary storage. -None of these answers are fully correct.

-Indicates that the page was placed into the free list and subsequently swapped out. -The page is not in memory and needs to be read from secondary storage.

In the context of paging, which is true regarding a soft (or minor) fault? Check all that apply. -Indicates that the page was placed into the free list and subsequently swapped out. -Indicates that the page was placed into the free list but not yet swapped out. -The page is not in memory and needs to be read from secondary storage. -The page is already in memory and does not need to be read from secondary storage. -None of these answers are fully correct.

-Indicates that the page was placed into the free list but not yet swapped out. -The page is already in memory and does not need to be read from secondary storage.

In the context of operating systems, what does the term booting refer to? -It refers to the power switch for a computer system. -Starting the GUI (graphical user interface) for the operating system. -Putting shoes on the computer. -It is a process of turning on the computer by loading the kernel.

-It is a process of turning on the computer by loading the kernel.

Which of the following is true regarding processor cache configurations? Check all that apply. -L1 is shared between all cores. -L3 must be included in processes to ensure cache functionality. -L1 is split into L1 Data and L1 Instruction caches. -If an L3 is present, L2 may be per core. -If an L3 is present, L2 may be shared.

-L1 is split into L1 Data and L1 Instruction caches. -If an L3 is present, L2 may be per core. -If an L3 is present, L2 may be shared.

What is a feature of the Completely Fair Scheduler (CFS). Check all that apply. -Ensure equal allocation of available CPU cores to processes in the system. -Ensure equal CPU time for all processes in the system. -Maintain balance (fairness) in providing CPU time to tasks. -Ensure no process is starved. -None of these responses are fully correct.

-Maintain balance (fairness) in providing CPU time to tasks. -Ensure no process is starved.

What is the primary data structure used by the Completely Fair Scheduler (CFS)? -Maintains a limited size array (to ensure speed), that is dynamically extendable. -In a ready queue using a dynamically modified linked list. -Maintained in a time-ordered red-black tree for each CPU. -None of these responses are fully correct

-Maintained in a time-ordered red-black tree for each CPU.

What would be an appropriate application for static partitioning? -General use computing. -Large scale computing (i.e., super computers) with limited job mixes. -Many embeded systems. -Older small systems, with limited functionality that only allow a limited number of processes.

-Many embeded systems.

Why might a process involuntarily give up the CPU? Assume a non-preemptive environment. Check all that apply. -A higher priority process enters the system. -The processes requests an I/O operation. -The processes time slice expires. -The processes I/O request is completed. -The process terminates. -None of these responses are fully correct.

-None of these responses are fully correct.

Which of the following is true regarding a physical address? Check all that apply. -Visible to the process. -Not visible to the process. -Is generated by the program. -Is seen by the memory hardware.

-Not visible to the process. -Is seen by the memory hardware.

System calls use an API (Application Programming Interface). What is the advantage of using an API for system calls? -Eases development of system call documentation and associated examples. -No specific advantage, but is standard practice. -Limits the type and number of system calls. -Portability and consistency. -None of these are correct

-Portability and consistency.

Which of the following describes scheduling in an interactive system? Check all that apply. -Preemptive. -Nonpreemptive. -Allows sharing of resource (i.e., CPU core). -First-come, first-served (FCFS) or first-in-first-out (FIFO).

-Preemptive -Allows sharing of resource (i.e., CPU core).

As discussed in class, what key actions occurs during a system call? -Opening of an interprocess communications channel to transfer interfaction between the operating system and the process. -The operating system interface. -Depends on the specific system call being invoked. -Privilege escalation and privilege de-escalation.

-Privilege escalation and privilege de-escalation.

What does it mean for a scheduling system to be preemptive? Check all that apply. -Processes are allow to run for some maximum allowed time (time-slice). -Select the next process to schedule when current process blocks. -Processes are preempted in order to more effectively share the CPU core. -Processes are not preempted and they execute until completion.

-Processes are allow to run for some maximum allowed time (time-slice). -Select the next process to schedule when current process blocks. -Processes are preempted in order to more effectively share the CPU core.

What is the principal of locality? -A reference to cache management protocols. -If an item is referenced, items whose addresses are close by will tend to be referenced soon. -If an item is referenced, it will tend to be referenced again soon. -Programs access a relatively small portion of their address space at any instant of time. -None of these answers are fully correct.

-Programs access a relatively small portion of their address space at any instant of time.

What is meant by a soft real time system? -Scheduling algorithms that execute in a timed, scheduled manner. -Guaranteed to meet any scheduling requirements (within certain limits). -Refers to the notion that the kernel tries to schedule applications within timing deadlines, but the kernel does not promise to always achieve these goals. -None of these responses are fully correct.

-Refers to the notion that the kernel tries to schedule applications within timing deadlines, but the kernel does not promise to always achieve these goals.

Which of the following are scheduling algorithms for an interactive system? Check all that apply. -Round-robin scheduling. -Priority scheduling. -Shortest remaining time. -Multiple queue scheduling. -Random scheduling.

-Round-robin scheduling. -Priority scheduling. -Shortest remaining time. -Multiple queue scheduling.

What does it mean for a scheduling system to be nonpreemptive? Check all that apply. -Processes are allow to run for some maximum allowed time (time-slice). -Select the next process to schedule when current process blocks. -Processes are preempted in order to more effectively share the CPU core. -Processes are not preempted and they execute until completion.

-Select the next process to schedule when current process blocks. -Processes are not preempted and they execute until completion.

A process that executes in the background is referred to as what? Check all that apply. -Magic. -Service. -Virus. -Daemon.

-Service. -Daemon.

Which of the following scheduling algorithms are typically associated with a batch environment? Check all that apply. -Multiple queue scheduling. -Round-robin scheduling. -Shortest job next (SJN). -First-come, first-served (FCFS) or first-in-first-out (FIFO) . -Random scheduling.

-Shortest job next (SJN). -First-come, first-served (FCFS) or first-in-first-out (FIFO) .

What is an operating system? -The operating system is the computer hardware. -The operating system is the shell. -The operating system is the GUI interface between the user and the software applications. -The operating system is responsible for managing the resources.

-The operating system is responsible for managing the resources.

The xv6 OS uses a state called RUNABLE. What does this mean? -The process is being admitted into the system. -The process is ready to be executed. -The process is being executed. -The process is waiting an I/O operaton to be completed. -The process is terminating. -None of these responses are fully correct.

-The process is ready to be executed.

If a process is blocked, what does that mean? -The process is being admitted into the system. -The process is ready to be executed. -The process is being executed. -The process is waiting an I/O operation to be completed. -The process is terminating. -None of these responses are fully correct.

-The process is waiting an I/O operation to be completed.

Why might a process involuntarily give up the CPU? Assume a preemptive environment. Check all that apply. -A higher priority process enters the system. -The process terminates. -The processes requests an I/O operation. -The processes time slice expires. -The processes I/O request is completed. -None of these responses are fully correct.

-The processes time slice expires.

The maximum allowed CPU time a process is allowed to execute (per turn using the CPU core) is referred to as what? Check all that apply. -Iota. -Time slice. -Interval. -Quantium.

-Time slice. -Quantium.

What is the purpose or goal of paging? -Reduce compulsory misses in main memory. -Implement security protocols for main memory to ensure appropriate memory segmentation. -Increase memory performance for executing processes. -To provide for efficient use of main memory for process execution. -None of these answers are fully correct

-To provide for efficient use of main memory for process execution.

How is the next process selected by the Completely Fair Scheduler (CFS)? -Uses the next process pointer into the ready array. -Selects the current head or front of the ready queue. -Uses the left-most node of the red-black tree to schedule next to maintain fairness. -None of these answers is fully correct.

-Uses the left-most node of the red-black tree to schedule next to maintain fairness.

Which of the following is true regarding a logical or virtual address? Check all that apply. -Visible to the process. -Not visible to the process. -Is generated by the program. -Is seen by the memory hardware.

-Visible to the process. -Is seen by the memory hardware.

Which of the following are true regarding the virtual run time as used in the Completely Fair Scheduler (CFS)? -Set to ts/f where ts is the time-slice and f is the fraction of the last time-slice used. -Represents the cumulative total execution time used by the process/thread. -When a process/thread runs, it accumulates vruntime (runtime of the process/thread divided by its weight). -None of these responses are fully correct.

-When a process/thread runs, it accumulates vruntime (runtime of the process/thread divided by its weight).

When might a call to a library function cause a page fault? -It is unlikely a basic function call will cause a page fault. -Function calls only cause soft faults (not hard faults). -When that function is on a page that is not currently in memory. -Only when the call is to a function in a DLL/SO.

-When that function is on a page that is not currently in memory.

A certain computer provides its users with a virtual-memory space of 232 bytes. The virtual memory is implemented by paging, and the page size is 4096 bytes. A user process generates the virtual address 1112345610 (0x00a9bb00). Answer in hex. Note, a hex number must be proceeded with 0x. What is the page number (tag)? What is the page offset?

0x00A9B 0xB00

Given the following table; TLB PageTable Datacache hit hit hit hit hit miss miss miss miss miss miss hit Which row (by number) represents a represents the best performance?

1

Given the following table; TLB PageTable Datacache hit hit hit hit hit miss miss miss miss miss miss hit Which row (by number) represents the best case in terms of performance?

1

Consider the following page reference string: 1 2 3 4 2 1 5 6 2 1 2 3 7 6 3 2 1 2 3 6 Assuming demand paging with four frames; How many page faults would occur for the LRU replacement algorithm. ____________ Show the final state of the four (4) frames. Initially, start from top to bottom. LRU Page ? ? ? ? ? ? ? ? The LRU is a number 1 (least recently accessed), 2, 3, or 4 (most recently accessed) and the Page is one of the referenced pages (as listed above)

10 AGE PAGE 4 6 2 2 3 3 1 1

Consider the following page reference string: 4 5 3 1 2 1 5 6 2 1 2 5 7 6 3 2 5 2 3 6 Assuming demand paging with four frames; How many page faults would occur for the FIFO replacement algorithm. ___________ AGE Page ? ? ? ? ? ? ? ? The Age is a number 1 (oldest), 2, 3, or 4 (newest) and the Page is one of the referenced pages (as listed above).

11 AGE PAGE 2 3 3 2 4 6 1 7

Consider the following page reference string: 4 5 3 1 2 1 5 6 2 1 2 5 7 6 3 2 5 2 3 6 Assuming demand paging with four frames; How many page faults would occur for the LRU replacement algorithm. _______ Show the final state of the four (4) frames. Initially, start from top to bottom. LRU Page ? ? ? ? ? ? ? ? The LRU is a number 1 (least recently accessed), 2, 3, or 4 (most recently accessed) and the Page is one of the referenced pages (as listed above).

11 LRU Page 3 3 2 2 1 5 4 6

Consider the following page reference string: 7 0 1 2 0 3 0 4 2 3 0 3 2 1 2 0 1 7 0 1 Assuming demand paging with four frames; How many page faults would occur for the LRU replacement algorithm. ______________ Show the final state of the four (4) frames. Initially, start from top to bottom. LRU Page ? ? ? ? ? ? The Age is a number 1 (oldest), 2, 3, or 4 (newest) and the Page is one of the referenced pages (as listed above).

12 LRU Page 3 1 2 0 1 7

Consider a virtual memory system with the following properties: 36-bit virtual address 16 KB pages 32-bit physical address What is the total size of the page table for each process on this processor, assuming that the valid, protection, dirty, and use bits take a total of 6 bits and that all the virtual pages are in use. Assume that disk addresses are not store in the page table. Respond with megabytes (do not enter MB, one decimal point, one digit after the decimal point).

12.58 or 12.6

If the page size is 8192, how many bits are required for the page offset? -10 -11 -12 -13

13

Given a fixed partitioning scheme with equal-size partitions of 2048 bytes and a total main memory size of 2^24 bytes. A page table is maintained that includes a pointer to a physical page for each resident process. How many bits are required for the pointer?

13 to solve take 2 ^24, 24 bits will be the first part of physical page and 2^11 = 2048 which is 11 bits. 24-11 = 13

Consider the following page reference string: 1 2 3 4 2 1 5 6 2 1 2 3 7 6 3 2 1 2 3 6 Assuming demand paging with four frames; How many page faults would occur for the FIFO replacement algorithm. ______________ Show the final state of the four (4) frames. Initially, start from top to bottom. AGE Page ? ? ? ? ? ? ? ? The Age is a number 1 (oldest), 2, 3, or 4 (newest) and the Page is one of the referenced pages (as listed above).

14 AGE PAGE 3 1 4 3 1 6 2 2

Consider the following page reference string: 7 0 1 2 0 3 0 4 2 3 0 3 2 1 2 0 1 7 0 1 Assuming demand paging with four frames; How many page faults would occur for the FIFO replacement algorithm. ______________ Show the final state of the four (4) frames. Initially, start from top to bottom. AGE Page ? ? ? ? ? ? The Age is a number 1 (oldest), 2, 3, or 4 (newest) and the Page is one of the referenced pages (as listed above).

15 AGE PAGE 1 7 2 0 3 1

Given the following table; TLB PageTable Datacache hit hit hit hit hit miss miss miss miss miss miss hit Which row (by number) represents the worst case in terms of performance?

2

Given the following table; TLB Page Table Data Cache 1 hit hit hit 2 hit hit miss 3 miss miss miss 4 miss miss hit Which row (by number) represents a page fault?

3

Consider a virtual memory system with the following properties: 33-bit virtual address 8 KB pages 31-bit physical address What is the total size of the page table for each process on this processor, assuming that the valid, protection, dirty, and use bits take a total of 10 bits and that all the virtual pages are in use. Assume that disk addresses are not store in the page table. Respond with megabytes (do not enter MB, one decimal point, exactly two digit afters the decimal point).

3.67

What is the size of the TLB in bytes based on the following assumptions: 32-bit virtual address 32-bit physical address valid and dirty bits -> 1 bit each reference bits -> 8 bits total access bits -> 2 bits 512 TLB entries 4kb page size Respond in bytes (no comma's, no decimal point).

3328

Using a SRT preemptive scheduling algorithm and the following processes; Process: p1 p2 p3 p4 ET: 15 25 10 5 Arrival Time: 0 10 20 30 The time slice is 5 and new processes are placed in queue before in-system process. Note, awt = completion time - execution time - arrival time. What is the average waiting time (awt).

5

Using a FCFS non preemptive scheduling algorithm and the following processes; Process: p1 p2 p3 p4 ET : 20 25 10 15 ArrivalTime: 0 15 30 45 What is the average waiting time (awt). Note, awt = completion time - execution time - arrival time.

7.5

Using a SJF non preemptive scheduling algorithm and the following processes; Process: p1 p2 p3 p4 ExecutionTime: 20 25 15 10 ArrivalTime: 0 15 30 40 What is the average waiting time (awt). Note, awt = completion time - execution time - arrival time

8.75

What is a process? -A suspended thread. -A thread. -A program. -A program being executed.

A program being executed if this was a check all that apply then answer is a suspended thread a thread a program being executed

With regard to address binding, match the correct columns. Compile time. ________________ Load time. ___________________ Execution time. _________________

Absolute code. Relocatable code. DLL's/SO's Other Incorrect Match Options: Not loaded until/unless needed via a call. Random binding.

A process that performs a large number of calculations is referred to as

Compute bound

Given the following table; TLB PageTable Datacache Legal? hit hit hit ? hit hit miss ? miss miss miss ? miss miss hit ?

Legal Legal Illegal Illegal

For a virtual memory environment; Is it necessary for all of the pages of a process to be in main memory while the process is executing? Must all of the pages of a process in main memory be contiguous? Must the virtual pages be in a specific order? Must the physical pages be in a specific order? Must answer with Yes or No (do not abbreviate).

No No Yes No

Which of the following scheduling criteria is more important. -Throughput. -Response time. -Minimum time spent waiting in ready queue -None of these answers are correct.

None of these answers are correct.

Given the below address stream, what is the applicable page number for the given page size. Ref Tag4KB Tag8KB Tag16KB 0x08fff ? ? ? 0x07a28 ? ? ? 0x0777a ? ? ? 0x03a98 ? ? ? 0x01c19 ? ? ? 0x01000 ? ? ? 0x022d0 ? ? ?

Tag4KB Tag8KB Tag16KB 0x08 0x04 0x02 0x07 0x03 0x01 0x07 0x03 0x01 0x03 0x01 0x00 0x01 0x00 0x00 0x01 0x00 0x00 0x02 0x00 0x00

What does it mean when an operating system supports Symmetric Multiprocessing (SMP)? -Each processor is assigned a specific task. -Refers to a smaller system, typically dedicated to a specific task. -That a specific processor is assigned as the primary. -That each processor can perform any assigned task.

That each processor can perform any assigned task.

Class discussions focused on a text-based operating system interface. What other approache(s) are there for operating system interfaces. Check all that apply. -Touch-based. -Headless. -Graphical User Interface (GUI). -Remote system calls.

Touch-based Graphical User Interface (GUI).

In an operating system, what are the basic modes of operation? Check all that apply. -Compute mode. -User mode. -I/O mode. -Kernel mode.

User mode. Kernel mode.

A simplified view of thread states is READY, RUNNING, and BLOCKED, where a thread is either ready and waiting to be scheduled, is running on the processor, or is blocked (for example, waiting for I/O). --------- > READY ---------------- | ^ | | | | BLOCKED <----- RUNNING <----- Assuming a thread is in the RUNNING state, answer the following questions. Will the thread change state if it incurs a page fault? [ Select ] ["Yes", "No"] If the thread change state if it incurs a page fault > what state would it change to? [ Select ] ["READY", "BLOCKED", "RUNNING"] Will the thread change state if it generates a TLB miss that is resolved in the page table? [ Select ] ["Yes", "No"] If the thread change state when it generates a TLB miss that is resolved in the page table -> what state would it change to? [ Select ] ["READY", "BLOCKED", "RUNNING"] Will the thread change state when a page fault is fully resolved? [ Select ] ["Yes", "No"] If the thread change state when a page fault is resolved -> what state would it change to?

Yes Blocked yes blocked yes ready

Broadly speaking, most processes ______________. -are preemptive. -are compute bound. -are I/O bound. -alternate between bursts of computing and I/O (disk or network).

alternate between bursts of computing and I/O (disk or network).

Using a FCFS nonpreemptive scheduling algorithm and the following processes; Process: p1 p2 p3 ET: 8 4 1 Arrival Time: 0 0.4 1 The time slice is 1 and new processes are placed in queue before in-system process. Note, awt = completion time - execution time - arrival time. Show the timeline. Enter p1, p2, or p3 -> left to right, top to bottom.

p1 p1 p1 p1 p1 p1 p1 p1 p2 p2 p2 p2 p3 What is the average waiting time (awt). 6.2

Using a Round Robin preemptive scheduling algorithm and the following processes; Process: p1 p2 p3 Execution Time: 8 4 1 Arrival Time: 0 0.4 1 The time slice is 1 and new processes are placed in queue before in-system process. Note, awt = completion time - execution time - arrival time. Show the timeline. Enter p1, p2, or p3 -> left to right, top to bottom.

p1 p2 p3 p1 p2 p1 p2 p1 p2 p1 p1 p1 p1 What is the average waiting time (awt). 3.53