Ch 7 and 8

A set of flashcards for reviewing chapters seven and eight of understanding operating systems

80 cards   |   Total Attempts: 182
  

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The total time required to access data in secondary storage
Access time
A storage-saving and I/O saving technique that groups individual records into a block that's stored and retrieved as a unit
Blocking
Buffers
Temporary storage areas residing in main memory, channels, and control units
Channel status word (CSW)
Contains info on the indicating the condition of the channel, with 3 bits for 3 components of the I/O system-channel, control unit, device
C-LOOK
A scheduling strategy for direct access storage devices thats an optimization of C-SCAN
C-SCAN
Scheduling strategy for direct access storage devices used to optimize seek time (circular-scan)
Cylinder
Describes virtual tube formed when two or more R/W heads are positioned at the same track, at the same position on the surface
Dedicated device
A device that can be assigned to only one job at a time
Direct memory access (DMA)
I/O technique that allows a control unit to access main memory directly and transfer data without the intervention of the CPU
Direct access storage device (DASD)
Any secondary storage device that can directly read or write to a specific place, sometimes called random access storage device
First come first serve (FCFS)
Simplest scheduling algorithm for direct access storage devices that satisfies track requests in the order in which they arrive
Flash memory
Type of nonvolatile memory used as a secondary storage device that can be erased ad reprogrammed in blocks of data
Hamming code
Error-detecting and error-correcting code that greatly imporves the reliability of data
I/O channel
Specialized programmable unit between the CPU and the control units; synchronizes the fast speed of the CPU with the slow speed of the I/O device
I/O channel program
Program that controls the channels