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Operating System MCQs

1K+ questions with answers

301

To obtain better memory utilization, dynamic loading is used. With dynamic loading, a routine is not loaded until it is called. For implementing dynamic loading ____________

a special support from hardware is required
b special support from operating system is essential
c special support from both hardware and operating system is essential
d user programs can implement dynamic loading without any special support from hardware or operating system
Medium
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302

In paged memory systems, if the page size is increased, then the internal fragmentation generally ____________

a becomes less
b becomes more
c remains constant
d none of the mentioned
Medium
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303

In segmentation, each address is specified by ____________

a a segment number & offset
b an offset & value
c a value & segment number
d a key & value
Medium
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304

In paging the user provides only ________ which is partitioned by the hardware into ________ and ______

a one address, page number, offset
b one offset, page number, address
c page number, offset, address
d none of the mentioned
Medium
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305

Each entry in a segment table has a ____________

a segment base
b segment peak
c segment value
d none of the mentioned
Medium
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306

The segment base contains the ____________

a starting logical address of the process
b starting physical address of the segment in memory
c segment length
d none of the mentioned
Medium
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307

The segment limit contains the ____________

a starting logical address of the process
b starting physical address of the segment in memory
c segment length
d none of the mentioned
Medium
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308

The offset ā€˜d’ of the logical address must be ____________

a greater than segment limit
b between 0 and segment limit
c between 0 and the segment number
d greater than the segment number
Medium
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309

When the entries in the segment tables of two different processes point to the same physical location ____________

a the segments are invalid
b the processes get blocked
c segments are shared
d all of the mentioned
Medium
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310

The protection bit is 0/1 based on ____________

a write only
b read only
c read – write
d none of the mentioned
Medium
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311

If there are 32 segments, each of size 1Kb, then the logical address should have ____________

a 13 bits
b 14 bits
c 15 bits
d 16 bits
Medium
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312

Consider a computer with 8 Mbytes of main memory and a 128K cache. The cache block size is 4 K. It uses a direct mapping scheme for cache management. How many different main memory blocks can map onto a given physical cache block?

a 2048
b 256
c 64
d 8
Medium
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313

A multilevel page table is preferred in comparison to a single level page table for translating virtual address to physical address because ____________

a it reduces the memory access time to read or write a memory location
b it helps to reduce the size of page table needed to implement the virtual address space of a process
c it is required by the translation lookaside buffer
d it helps to reduce the number of page faults in page replacement algorithms
Medium
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314

If one or more devices use a common set of wires to communicate with the computer system, the connection is called ______

a CPU
b Monitor
c Wirefull
d Bus
Medium
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315

A ____ a set of wires and a rigidly defined protocol that specifies a set of messages that can be sent on the wires.

a port
b node
c bus
d none of the mentioned
Medium
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316

When device A has a cable that plugs into device B, and device B has a cable that plugs into device C and device C plugs into a port on the computer, this arrangement is called a _________

a port
b daisy chain
c bus
d cable
Medium
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317

The _________ present a uniform device-access interface to the I/O subsystem, much as system calls provide a standard interface between the application and the operating system.

a Devices
b Buses
c Device drivers
d I/O systems
Medium
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318

A ________ is a collection of electronics that can operate a port, a bus, or a device.

a controller
b driver
c host
d bus
Medium
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319

An I/O port typically consists of four registers status, control, ________ and ________ registers.

a system in, system out
b data in, data out
c flow in, flow out
d input, output
Medium
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320

The ______ register is written by the host to send output.

a status
b control
c data in
d data out
Medium
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321

The hardware mechanism that allows a device to notify the CPU is called _______

a polling
b interrupt
c driver
d controlling
Medium
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322

The CPU hardware has a wire called __________ that the CPU senses after executing every instruction.

a interrupt request line
b interrupt bus
c interrupt receive line
d interrupt sense line
Medium
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323

The _________ determines the cause of the interrupt, performs the necessary processing and executes a return from the interrupt instruction to return the CPU to the execution state prior to the interrupt.

a interrupt request line
b device driver
c interrupt handler
d all of the mentioned
Medium
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324

In general the two interrupt request lines are ____________

a maskable & non maskable interrupts
b blocked & non maskable interrupts
c maskable & blocked interrupts
d none of the mentioned
Medium
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325

The _________ are reserved for events such as unrecoverable memory errors.

a non maskable interrupts
b blocked interrupts
c maskable interrupts
d none of the mentioned
Medium
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326

The ________ can be turned off by the CPU before the execution of critical instruction sequences that must not be interrupted.

a nonmaskable interrupt
b blocked interrupt
c maskable interrupt
d none of the mentioned
Medium
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327

The __________ is used by device controllers to request service.

a nonmaskable interrupt
b blocked interrupt
c maskable interrupt
d none of the mentioned
Medium
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328

The interrupt vector contains ____________

a the interrupts
b the memory addresses of specialized interrupt handlers
c the identifiers of interrupts
d the device addresses
Medium
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329

Division by zero, accessing a protected or non existent memory address, or attempting to execute a privileged instruction from user mode are all categorized as ________

a errors
b exceptions
c interrupt handlers
d all of the mentioned
Medium
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330

For large data transfers, _________ is used.

a dma
b programmed I/O
c controller register
d none of the mentioned
Medium
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331

A character stream device transfers ____________

a bytes one by one
b block of bytes as a unit
c with unpredictable response times
d none of the mentioned
Medium
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332

What is a dedicated device?

a opposite to a sharable device
b same as a sharable device
c can be used concurrently by several processes
d none of the mentioned
Medium
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333

A keyboard is an example of a device that is accessed through a __________ interface.

a block stream
b set of blocks
c character stream
d none of the mentioned
Medium
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334

In polling ____________

a busy – wait cycles wait for I/O from device
b interrupt handler receives interrupts
c interrupt-request line is triggered by I/O device
d all of the mentioned
Medium
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335

A non blocking system call _________________

a halts the execution of the application for an extended time
b does not halt the execution of the application
c does not block the interrupts
d none of the mentioned
Medium
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336

An asynchronous call ____________

a returns immediately, without waiting for the I/O to complete
b does not return immediately and waits for the I/O to complete
c consumes a lot of time
d is too slow
Medium
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337

Buffering is done to ____________

a cope with device speed mismatch
b cope with device transfer size mismatch
c maintain copy semantics
d all of the mentioned
Medium
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338

Caching is ________ spooling.

a same as
b not the same as
c all of the mentioned
d none of the mentioned
Medium
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339

Caching ____________

a holds a copy of the data
b is fast memory
c holds the only copy of the data
d holds output for a device
Medium
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340

Spooling ____________

a holds a copy of the data
b is fast memory
c holds the only copy of the data
d holds output for a device
Medium
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341

The ________ keeps state information about the use of I/O components.

a CPU
b OS
c kernel
d shell
Medium
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342

The kernel data structures include ____________

a process table
b open file table
c close file table
d all of the mentioned
Medium
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343

A ________ is a full duplex connection between a device driver and a user level process.

a Bus
b I/O operation
c Stream
d Flow
Medium
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344

I/O is a _________ in system performance.

a major factor
b minor factor
c does not matter
d none of the mentioned
Medium
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345

If the number of cycles spent busy – waiting is not excessive, then ____________

a interrupt driven I/O is more efficient than programmed I/O
b programmed I/O is more efficient than interrupt driven I/O
c both programmed and interrupt driven I/O are equally efficient
d none of the mentioned
Medium
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346

In real time operating system ____________

a all processes have the same priority
b a task must be serviced by its deadline period
c process scheduling can be done only once
d kernel is not required
Medium
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347

Hard real time operating system has ______________ jitter than a soft real time operating system.

a less
b more
c equal
d none of the mentioned
Medium
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348

For real time operating systems, interrupt latency should be ____________

a minimal
b maximum
c zero
d dependent on the scheduling
Medium
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349

In rate monotonic scheduling ____________

a shorter duration job has higher priority
b longer duration job has higher priority
c priority does not depend on the duration of the job
d none of the mentioned
Medium
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350

In which scheduling certain amount of CPU time is allocated to each process?

a earliest deadline first scheduling
b proportional share scheduling
c equal share scheduling
d none of the mentioned
Medium
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