Real time midterm review

Events occuring at unpredictable times in the flow-of-control are termed:

Synchronous

Periodic

In-flow

Asynchronous

In microcontrollers GPIO stands for:

Global Public Input/Output.

General Public Input/Output.

General Purpose Input/Output.

Global Purpose Input/Output.

A system where for each possible state and each set of inputs, a unique set of outputs and the next state can be determined is called a __________system.

Firm real-time

Hard real-time

Deterministic

Unique

Firmware for an embedded system means the:

Software

None of the above.

A combination of the hardware and software

Hardware.

The type of memory used for variable data storage in the Cytron Maker Pi is:

DRAM

SRAM

SDRAM

FLASH

Anti-lock brakes, flight management systems , and pacemakers are examples of:

Soft real-time systems.

Safety critical and hard real-time systems.

Safety critical systems.

Hard real-time systems.

What does API stand for?

Application Programming Interaction.

Application Procedural Interface.

Application Programming Interface.

Address Programming Interface

How many Grove ports are on the Cytron Maker Pi RP2040 board?

How many DC motors are supported on the Cytron Maker Pi RP2040 board?

A system in which performance is degraded but not destroyed by failure to meet response time constraints is called a _________ real time system:

Firm

Soft

Hard

Batch

Event latency is the time from when:

The event occurs and the system stops.

The event occurs and when it is serviced.

The event starts and it stops.

The system starts and the event occurs.

A characteristic of an interrupt is that:

It is not efficient when the device does not often interrupt the processor.

A device notifies the processor that it needs attention.

Does not save cpu cycles.

Software constantly checks a device to see if it needs attention.

Cyclic executives:

Have short processes that appear to run concurrently.

Run with pre-emptive scheduling.

Are not easy to analyze for response times.

Are a complex form of multitasking.

Coroutines:

Are a complex form of "fairness scheduling".

Are also term "simple rtos multitasking.

Use local variables for inter-process communications.

Processes voluntarily exit at strategic points of execution.

A system where for each possible state and each set of inputs, a unique set of outputs and the next state can be determined is called a __________system.

Unique

Deterministic

Firm real-time

Hard real-time

A full-featured RTOS with processor core security, and file management and other complex features is termed.:

RTOS-Kernel.

Bare-metal.

RTOS-Executive.

RTOS-Software.

Events occuring at predictable times in the flow-of-control are termed:

Synchronous

Aperiodic

Sporadic

Asynchronous

Polled loop systems:

Are not fast.

Are not easy to analyze.

Are best used with systems with many events.

Do not require interrupts.

Polled loop systems:

Are not fast.

Are best used with systems with a limited number of events.

Require interrupts.

Are not easy to analyze.

Cyclic executives:

Are not easy to analyze for response times.

Are the simplest form of multitasking.

Run with pre-emptive scheduling.

Have long processes that appear to run concurrently.

With polling a device indicates it needs servicing by:

Setting an interrupt request line.

Indexing a vector table.

Enabling the process.

Setting a ready bit in a register.

For ARM Cortex M0 microcontrollers SVC (Supervisor Call) interrupts:

Are randomly generated.

Are hardware generated

Not commonly used with operating systems.

Are triggered with an SVC instruction.

A characteristic of device polling is that:

It is efficient when the device does not often interrupt the processor.

Software infrequently checks a device to see if it needs attention.

Wastes cpu cycles.

A device notifies the processor that it needs attention.

For ARM Cortex M0 microcontrollers PWM is:

Has only 1 output channel.

Available for only two servomotors.

Not available.

Available on all 30 GPIO pins.

With interrupts saving the progam context:

Is not necessary.

Requires a reti instruction.

Requires less stack resources.

Prevents resource conflicts.

ARM Cortex M0 microcontrollers have up to ________ possible entry points in the Interrup Vector Table.

255

A programmable timer used to ensure that the processor is running a program is a:

Watchdog Timer.

Real-Time Clock.

Phase Lock Loop.

Simulation Time Clock.

For ARM Cortex M0 microcontrollers BL subroutine calls:

Do not restore the PC - Program Counter.

Do not save the PC - Program Counter.

Cannot jump to any location.

Cannot be masked.

A characteristic of an interrupt is that:

A device does not notify the processor that it needs attention.

Software constantly checks a device to see if it needs attention.

It is efficient when the device does not often interrupt the processor.

Does not save cpu cycles.

An interrupt vector table contains the:

Interrupt mask.

Interrupt service routine address.

Interrupt name.

Interrupt priority.

With freeRTOS, when can taks be created?

Before and after the task scheduler is started.

Only after hardware initialization.

Only before the task scheduler is started.

Only after the task scheduler is started.

Cyclic executives:

Are very flexible.

Require interrupts.

Run each task at its own rate.

Are not very flexible.

Task priority is:

Not administered by the scheduler.

Set by the programmer.

The same as interrupt priority.

Directly related to the hardware.

Context switching is a:

Is dependent on the schedule response time.

Major contributor to response time.

Does not contribute to response time.

A minor contributor to response time.

In freeRTOS task information is store in:

Peripheral memory.

A task dataset.

A task control block.

Flash.

With freeRTOS more than one instance of a task is:

Not possible because you cannot create two instances of a task.

Not possible because all tasks share the same resources.

Possible because each task is given its own resources when it is created.

Possible because all tasks share the same resources.

Tasks that are not running and are not Blocked or Suspended are in the ______________ state.

Idle

Free

Ready

Open

In a real-time operating system ____________

A task must be serviced by its deadline period.

Task scheduling can only be done once.

A kernel is not required.

All tasks have the same priority.

Polled loop systems:

Are not easy to analyze their performance.

Require interrupts.

Cannot guarantee response times.

May be used for fast reaction to single events.

Programs that involve a variety of activities with different time constraints are easier to design and implement using:

Common data blocks.

Rtos tasks.

Scalability

Multiple functions

With freeRTOS a mailbox sender:

Appends an item to the queue.

Takes an item from the queue.

Writes with a LIFO process.

Overwrites and item in the queue.

The maximum number of items a queue can hold is called its:

Capacity.

Allocation.

Length.

Size.

With freeRTOS, queues can have multiple reader tasks. When the data becomes available:

Only a single task can be unblocked.

Multiple tasks can be unblocked.

Priority does not apply.

Blocking doesn't apply.

Data is normally removed from the __________ of the queue.

End

Head

Label

Tail

With freeRTOS the length of a queue can be set:

At any time.

Only when the queue is created.

At a different time than when the data items size is set.

Immediately after it is created.

With freeRTOS a mailbox is a queue can be used to hold data that can be:

Read by only a single task.

Read by only a single interrupt routine.

Can only be written to.

Can be read by any task or interrupt routine.

Queues are normally implemented as:

LIFO buffers.

Stacks.

Heaps.

FIFO buffers.

With freeRTOS a mailbox is a queue:

Of any length as it is the size that count.

Of length one.

Removes data items on reads.

Of any length as long as you only read the data.

With FreeRTOS queues, the sending and receiving tasks:

Must decide who owns the queue data.

Are completely de-coupled from data ownership.

Can have only single reading tasks.

Control the allocation of queue memory.

With freeRTOS, for queues with multiple writer tasks., the task waiting for space that unblocks is the one:

With the highest. priority

Any task as priority does not apply.

Any task as blocking doesn't apply.

With the lowest priority.

Real time midterm review

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