COP 4600 Final Exam Actual Questions

COP 4600 Final Exam Actual Questions and Answers - Verified 100% by experts What must I/O devices be connected to in order to do anything? Ans - A computer What is a port? Ans - A set of wires that connects an I/O device and the computer.A device that allows other devices to hook up to it in turn is said to support what? Ans - Daisy-chained devices What is a bus? Ans - A common set fo wires used by more than one I/O device If devices connect to ports, what do ports connect to? Ans - Buses What is a controller? Ans - The electronics that manage a port, bus or I/O device What does the operating system actually talk to? Ans - The device's controller What is a data in register? Ans - Allows the computer to get input from the device What is a data out register? Ans - Allows the computer to send output to the device What is a status register? Ans - Indicates the current state of the device, including whether the current command has completed, whether the data registers are ready, and whether there is an error.What is a control register? Ans - A register that is used to send commands to the device What does the interrupt/trap mechanism handle? Ans - User-process calls for I/O, and notifications for those calls. Notifications from hardware about I/O completion, memory exceptions, arithmetic exceptions (divide by zero), and privilege exceptions.What is required in order for direct memory access to work? Ans - Device controllers must be given their own channel to system memory, with its own control registers.What is a device driver? Ans - A piece of software intended to handle interfacing with a particular device's controller. 1 / 2

What are some I/O device characteristics? Ans - Stream versus block, sequential versus random, synchronous versus asynchronous, sharable versus dedicated, read/write versus read-only write-only, speed of operation.What are the fundamental functions of block devices? Ans - Read, write, and seek.What are fundamental functions of character-stream devices? Ans - Get and put (often still mapped to read and write with bufferring to allow multiple bytes to be read and written) What is a socket interface? Ans - Provides a file-like metaphor for reading and writing to a network connection What are the three main functions of hardware clocks? Ans - Report the current ime, report the elapsed time, and set an interval timer to report in the future.What are clocks used by the OS for, at a minimum? Ans - To preempt processes, flush cache buffers, and to report the failure of timed-out network connections.What is the device status table? Ans - A table that is used to keep track of each device and related pending request queues.What is a spool? Ans - A special-purpose buffer that serves entire coherent jobs.What is the print spool? Ans - The OS accepts jobs quickly on the printer's behalf, and presents them to the printer in order.What are disks? Ans - Secondary storage devices that represent both the effective bottom of the memory hierarchy and the most obvious I/O devices.What are the three types of disks? Ans - Magnetic disks, optical disks, and solid state disks.What are magnetic disks? Ans - Fixed disks that are made up of a series of plateers.The platters are divided into circular tracks, and the track are then divided into sectors, and the collection of tracks at the same distance from the center is referred to as a cylinder.What allows the disk to run? Ans - A drive motor spins it What are the two important speed metrics for magnetic disks? Ans - Transfer rate and the random accss time.What is the transfer rate? Ans - The effective rate of data flow between the disk and the computer.

• / 2