Routine of the operating system is run on that processor to select the next thread.

• The global queue can be organized and accessed using any of the schemes discussed

In Chapter 9, including priority-based schemes and schemes that consider execution history or anticipated processing demands.

36. At this layer of file system (model of I/O organization) symbolic names are converted to identifiers that reference the file through file descriptor.

Directory management

37. Performing input transfers in advance of requests being made and performing output transfers some time after the request is made is a technique known as

Buffering

38. The time it takes to position the head of the disk at the track is known as

Seek time.

39. The SSTF (Shortest Service Time First) disk scheduling policy selects

I/O request that requires the least movement of the disk arm from its current position

40. What is RAID?(redundant array of independent disks)

RAID is a set of physical disk drives viewed by the operating system as a single logical drive.

41. Processor issues read or write command to the DMA module by sending the following information

False

42. What is DMA?

Direct Memory Access (DMA)

a DMA module controls the exchange of data between main memory and an I/O module

43. What two objectives are paramount in designing the I/O facility?

Efficiency, generality

44. In the interests of simplicity and freedom from error, it is desirable to handle all I/O devices in a uniform manner. How is this objective called?

Generality

45. What layers does a local peripheral device (model of I/O organization) organization involve?

Logical I/O, Device I/O, Scheduling and control

46. This level of local peripheral device (model of I/O organization) organization deals with the device as a logical resource and is not concerned with the details of actually controlling the device. Logical I/O

47. This level of local peripheral device (model of I/O organization) organization converts the requested data into appropriate sequences of I/O instructions, channel commands, and controller orders. Device I/O

48. The actual queuing and scheduling of I/O operations occurs at this layer of local peripheral device (model of I/O organization). Scheduling and control

49. What is a record?

A record is a collection of related fields that can be treated as a unit by some application program. For example, an employee record would contain such fields as name, social security number, job classification, date of hire, and so on

50. A table that indicates the physical location on secondary storage of the space allocated to a file.

51. Which level of file system software architecture deals with blocks of data that are exchanged with disk or tape systems? basic file system or physical I/O

52. Which level of file system software architecture is responsible for all file I/O initiation and termination? basic I/O supervisor

53. Which level of file system software architecture enables users and applications to access records? Logical I/O

54. The least complicated form of file organization. Data are collected in the order in which they arrive. The purpose of this file organization is to accumulate the mass of data and save it. Which file organization is described? The Pile

55. The most common form of file structure. In this type of file, a fixed format is used for records. All records are of the same length, consisting of the same number of fixed-length fields in a particular order. Field

56. This form of file organization maintains the key characteristic of the sequential file\: records are organized in sequence based on a key field. Two features are added\: an index to the file to support random access, and an overflow file.

57. What is rootkit?

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