A character stream device transfers _____
1. bytes one by one
2.block of bytes as a unit
3. with unpredictable response times
4. none of the mentioned
I/O is a _________ in system performance.
1.major factor
2.minor factor
3.does not matter
4.None of the mentioned
In a real time system the computer results _______
1.must be produced within a specific deadline period
2.may be produced at any time
3. may be correct
4.All of the Mentioned
In a safety critical system, incorrect operation _____
1.does not affect much
2.causes minor problems
3.causes major and serious problems
4.none of the mentioned
The __________ is used by device controllers to request service.
1.nonmaskable interrupt
2.blocked interrupt
3.maskable interrupt
4.none of the mentioned
What is Event latency?
1.the amount of time an event takes to occur from when the system started
2. the amount of time from the event occurrence till the system stops
3.the amount of time from event occurrence till the event crashes
4. the amount of time that elapses from when an event occurs to when it is serviced.
What is the disadvantage of real addressing mode?
1. there is a lot of cost involved
2.time consumption overhead
3.absence of memory protection between processes
4.restricted access to memory locations by processes
A block device transfers ________
1. bytes one by one
2.block of bytes as a unit
3.with unpredictable response times
4.None of the mentioned
A keyboard is an example of a device that is accessed through a __________ interface.
1.block stream
2.set of blocks
3. character stream
4.None of the mentioned
A non blocking system call _________
1.halts the execution of the application for an extended time
2.does not halt the execution of the application
3.does not block the interrupts
4.None of the mentioned
A ____ a set of wires and a rigidly defined protocol that specifies a set of messages that can be sent on the wires.
1. port
2. node
3. bus
4.None of the mentioned
A ________ is a collection of electronics that can operate a port, a bus, or a device.
1.controller
2.driver
3.host
4.Business Architecture Development
A ________ is a full duplex connection between a device driver and a user level process.
1.Bus
2.I/O operation
3.Stream
4.Flow
An asynchronous call ______
1.returns immediately, without waiting for the I/O to complete
2.does not return immediately and waits for the I/O to complete
3.consumes a lot of time
4.is too slow
An I/O port typically consists of four registers status, control, ________ and ________ registers.
1.system in, system out
2.data in, data out
3. flow in, flow out
4.Input, Output, InputOutput
Antilock brake systems, flight management systems, pacemakers are examples of _______
1.safety critical system
2.hard real time system
3.soft real time system
4.safety critical system and hard real time system
Buffering is done to _______
1.cope with device speed mismatch
2.cope with device transfer size mismatch
3.maintain copy semantics
4.All of the Mentioned
Caching is ________ spooling.
1.same as
2.not the same as
3.all of the mentioned
4.None of the mentioned
Caching _____
1.holds a copy of the data
2.is fast memory
3.holds the only copy of the data
4.holds output for a device
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 ________
1. errors
2.exceptions
3. interrupt handlers
4.All of the Mentioned
For large data transfers, _________ is used.
1.dma
2.programmed I/O
3.controller register
4.None of the mentioned
If one or more devices use a common set of wires to communicate with the computer system, the connection is called ______
1.CPU
2.Monitor
3.Wirefull
4.Bus
If the number of cycles spent busy – waiting is not excessive, then ____
1. interrupt driven I/O is more efficient than programmed I/O
2. programmed I/O is more efficient than interrupt driven I/O
3.both programmed and interrupt driven I/O are equally efficient
4.None of the mentioned
In a ______ real time system, it is guaranteed that critical real time tasks will be completed within their deadlines.
1.soft
2.hard
3.critical
4.None of the mentioned
In general the two interrupt request lines are _____
1.maskable & non maskable interrupts
2. blocked & non maskable interrupts
3.maskable & blocked interrupts
4.None of the mentioned
In polling _________
1. busy – wait cycles wait for I/O from device
2.interrupt handler receives interrupts
3. interrupt-request line is triggered by I/O device
4.All of the Mentioned
Interrupt latency refers to the period of time ____
1. from the occurrence of an event to the arrival of an interrupt
2. from the occurrence of an event to the servicing of an interrupt
3. from arrival of an interrupt to the start of the interrupt service routine
4.None of the mentioned
Preemptive, priority based scheduling guarantees _______
1.hard real time functionality
2.soft real time functionality
3. protection of memory
4.None of the mentioned
Priority inversion is solved by use of _________
1.priority inheritance protocol
2.two phase lock protocol
3. time protocol
4.All of the Mentioned
Real time systems must have _______
1.preemptive kernels
2.non preemptive kernels
3.preemptive kernels or non preemptive kernels
4.neither preemptive nor non preemptive kernels
Real time systems need to __________ the interrupt latency.
1.minimize
2.maximize
3.not bother about
4.None of the mentioned
Some of the properties of real time systems include _____
1.single purpose
2.inexpensively mass produced
3.small size
4.All of the Mentioned
Spooling _______
1.holds a copy of the data
2.is fast memory
3.holds the only copy of the data
4.holds output for a device
The amount of memory in a real time system is generally ________
1. less compared to PCs
2.high compared to PCs
3. same as in PCs
4.they do not have any memory
The amount of time required for the scheduling dispatcher to stop one process and start another is known as _______
1.event latency
2.interrupt latency
3.dispatch latency
4.context switch time
The CPU hardware has a wire called __________ that the CPU senses after executing every instruction.
1.interrupt request line
2. interrupt bus
3.interrupt receive line
4.interrupt sense line
The hardware mechanism that allows a device to notify the CPU is called ______
1. polling
2.interrupt
3.driver
4.controlling
The interrupt vector contains _____
1.the interrupts
2. the memory addresses of specialized interrupt handlers
3.the identifiers of interrupts
4.the device addresses
The kernel data structures include __________
1.process table
2.open file table
3.close file table
4.All of the Mentioned
The most effective technique to keep dispatch latency low is to _______
1. provide non preemptive kernels
2.provide preemptive kernels
3.make it user programmed
4.run less number of processes at a time
The ______ register is read by the host to get input.
1. flow in
2.flow out
3.data in
4. data out
The ______ register is written by the host to send output.
1.status
2.control
3.data in
4.data out
The ________ can be turned off by the CPU before the execution of critical instruction sequences that must not be interrupted.
1.nonmaskable interrupt
2.blocked interrupt
3.maskable interrupt
4.None of the mentioned
The ________ keeps state information about the use of I/O components.
1.CPU
2.OS
3.kernel
4.Shell
The _________ are reserved for events such as unrecoverable memory errors.
1.non maskable interrupts
2.blocked interrupts
3.maskable interrupts
4.None of the mentioned
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.
1. interrupt request line
2.device driver
3. interrupt handler
4.All of the Mentioned
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.
1.Devices
2.Buses
3.Device drivers
4.I/O systems
What is a dedicated device?
1.opposite to a sharable device
2.same as a sharable device
3.can be used concurrently by several processes
4. none of the mentioned
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 ____
1.port
2. daisy chain
3.bus
4.cable
Windows NT uses a __________ implementation for I/O.
1.message – passing
2.draft – passing
3.secondary memory
4.Cache