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· Provide a means of exchanging data between the external environment and the computer. · Peripheral device - An external device connected to an I/O module. · Three categories: 1) Human readable · Suitable for communicating with the computer user Eg : Video display terminals (VDTs), printers 2) Machine readable · Suitable for communicating with equipment Eg : Magnetic disk and tape systems, sensors and actuators 3) Communication · Suitable for communicating with remote devices such as a terminal, a machine readable device, or another computer
About DPHI FRIENDS I AM DHANESH. I ADD THIS BLOG FOR AN EDUCATION PURPOSE
7.1 List three broad classifications of external, or peripheral, devices. Ans: We can broadly classify external devices into three categories:
7.3 What are the major functions of an I/O module? Ans:The major functions or requirements for an I/O module fall into the following categories: 7.4 List and briefly define three techniques for performing I/O. Ans: Three techniques for performing I/O are given bellow :
7.5 What is the difference between memory-mapped I/O and isolated I/O? Differences Between Isolated I/O and Memory Mapped I/O:
Memory-mapped I/O: With memory-mapped I/O, there is a single address space for memory locations and I/O devices. The processor treats the status and data registers of I/O modules as memory locations and uses the same machine instructions to access both memory and I/O devices. Isolated I/O: With isolated I/O, a command specifies whether the address refers to a memory location or an I/O device. The full range of addresses may be available for both
The __________ unit is capable of mimicking the processor and of taking over control of the system bus just like a processor.
__________ external devices are suitable for communicating with electronic equipment.
The requested operations and data are converted into appropriate sequences of I/O instructions, channel commands, and controller orders at the __________ layer.
__________ external devices are suitable for communicating with modems.
__________ is a technique that smoothes out peaks in I/O demand.
The advantage of _________ is that it provides extremely high data availability
The _________ technique is used on a Windows server to optimize the use of threads.
On a moveable-head system, the time it takes to position the head at the track is known as ________ .
The advantage of __________ is that it provides extremely high data availability
The __________ technique allows multiple simultaneous I/O requests against a single device or file.
signaling an event object
__________ are an efficient way of making consistent snapshots of volumes so that they can be backed up.
RAID 5 is organized in a similar fashion to _________ , but is different in the fact that RAID 5 distributes the parity strips across all disks.
The disk scheduling algorithm that implements two sub-queues in a measure to avoid the problem of "arm stickiness" is the __________ .
The simplest type of support that the operating system can provide is _________ .
External devices that engage in I/O with computer systems are grouped into three categories: human readable, machine readable, and __________ .
Disk drives, USB keys, sensors, and controllers are examples of __________ external I/O devices.
A __________ module controls the exchange of data between main memory and an I/O module.
direct memory access (DMA)
Two objectives are paramount in designing the I/O facility: generality and __________ .
The __________ module deals with the device as a logical resource and is not concerned with the details of actually controlling the device.
The _________ layer deals with the logical structure of files and with the operations that can be specified by users, such as open, close, read, and write.
At the _________ layer, symbolic file names are converted to identifiers that either reference the file directly or indirectly through a file descriptor or index table.
The __________ policy is to select the disk I/O request that requires the least movement of the disk arm from its current position.
shortest-service-time-first (SSTF)
A __________ transfers data in and out as a stream of bytes, with no block structure.
When more than two buffers are used, the collection of buffers is itself referred to as a __________, with each individual buffer being one unit.
The sum of the seek time and the rotational delay equals the __________ , which is the time it takes to get into position to read or write.
The simplest form of scheduling is ___________ scheduling, which processes items from the queue in sequential order.
first-in-first-out (FIFO)
A set of logically consecutive strips that maps exactly one strip to each array member is referred to as a __________ .
The term _________ is usually used to apply to a memory that is smaller and faster than main memory, and that is interposed between main memory and the processor.
Windows supports two sorts of RAID configurations: Software RAID and __________ .
A _________ is the basic element of data.
A __________ is responsible for starting I/O operations on a device and processing the completion of an I/O request.
A _________ is a collection of related fields that can be treated as a unit by some application program.
An objective of the __________ is to provide a standardized set of I/O interface routines to user processes.
A __________ is a collection of similar records
The __________ level is the primary interface with the environment outside of the computer system.
_________ are used mostly in applications where timeliness of information is critical and where data are rarely processed exhaustively.
A _________ is a collection of related data.
The _________ is concerned with scheduling disk and tape accesses to optimize performance.
The term _________ refers to the logical structuring of the records as determined by the way in which they are accessed.
The most common form of file structure is __________ .
The _________ file exploits the capability found on disks to access directly any block of a known address.
A _________ is a contiguous set of allocated blocks.
A(n) __________ is a general model of access control as exercised by a file or database management system.
__________ represents an open file associated with a process.
A UNIX file system resides on a single logical disk or disk partition and is laid out with the following elements: superblock, inode table, data blocks, and __________ .
The __________ level provides a standard interface between applications and the file systems and devices that hold the data.
In the __________ form of file structure all records are of the same length, consisting of the same number of fixed-length fields in a particular order.
The essential aspects of a __________ are that the relationships that exist among elements of data are explicit and designed for use by a number of different applications.
The physical organization of the file on secondary storage depends on the blocking strategy and the __________ strategy.
__________ provides a general purpose record I/O capability and maintains basic data about files.
An _________ is a control structure that contains the key information needed by the operating system for a particular file.
An objective of the __________ is to meet the data management needs and requirements of the user, which include storage of data and the ability to perform related operations.
The __________ is responsible for all file I/O initiation and termination.
Because there is no structure to the _________ form of file organization, record access is by exhaustive search.
__________ are often used where very rapid access is required, where fixed-length records are used, and where records are always accessed one at a time.
Direct files (or Hashed files)
The ________ is a balanced tree structure with all branches of equal length, and has become the standard method of organizing indexes for databases.
Linux makes use of a __________ , which presents a single, uniform file system interface to user processes.
Virtual file system (VFS)
Three methods of file allocation commonly used are: chained, indexed and _________ .
A _________ is a collection of addressable sectors in secondary memory that an OS or application can use for data storage. |
The category of external devices are suitable for communicating with the computer user
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