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NTFS file system

NTFS is a flexible and powerful file system built, on an elegantly simple file system model. The most noteworthy feature of NTFS include . 1. Recoverability:-   high on the list of requirements for the new w2k file system was the ability to recover from file system crashes  and disk failure. In the event of such the failure, NTFS is able to reconstruct disk volumes and return them to a consistent state. It does this by using a transaction processing model for changes to the file system; each significant change is treat as an atomic action that is either entirely performed or not performed at all. Each transition that was in process at the time of a failure is subsequently backed out or brought to completion. In addition, NTFS uses redundant storage for critical file system data, So that failure of a disk sector does not cause of the loss of the data describing the structure and status of the file system. 2. Security: - NTFS uses the w2k object model to enforce security. An
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How to protect CPU

we must prevent a user program from getting stuck in an infinite loop or not calling system services, and never returning control to the operating system. This goal is achieved by using timer.   A timer can be set to interrupt the computer after a specified period. The period may be fixed or variable, A variable timer generally implemented by a fixed rate clock and a counter. The operating system sets the counter. Every time the clock ticks, the counter is decremented. When the counter reaches 0, an interrupt occurs. For example, a 10-bit counter with a 1 milisecond clock allows interrupt at intervals from 1 milisecond to 1024 miliseconds, in step of 1 milisecond.Before turning control to the user, the iperating system ensures that the timer is set to interrupt. If the timer intrrupts, control transer automatically to the operating system, which may treat the interrupt as a fatal error or may give the program more time. obviously, instruction that modify the operation of the tim
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WHAT IS SPOOLING AND BUFFERING

Spooling:-                                A spool is a buffer that holds output for a device, such as a printer, that cannot accept interleaved data streams. Spooling is the process in which jobs from the to the disk and the location of that card in the disk is recorded in a table by the operating system. When that job is required for execution, it is read from the disk . Similarly, when job required a printer for output a line, that particular line is copied onto the disk and system buffer, and at the completion of job output is read from disk and printed by the printer. Some devices, such as tape drive and printer, cannot useful multiplex the I/O request of multiple concurrent applications. Spooling is one way that OS can coordinate concurrent output. Another way to deal with concurrent dives access is for provide ding explicit facilities for coordinating some OS provided support it is called spooling. Buffering:-                                  A buffer is a me
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What is file system? and types.

A file system is a collection of files. It consists of two words file and system. The word 'file' signifies a bunch of data put some where. But the important question is where? If, for example, in a library the librarian stars keeping the books in a disorganized fashion, it will be very difficult to find a book later on. This is where 'system' come in - instead of just throwing the data to the device. We generalize and construct a system that virtualizes a nice and ordered structure in which we can arrange our data in much the same way as books are arranged our data in much  be same make it easy for us to update and maintain our data. A file is a named collection of information that recorded on secondary storage. From user's perspective, a file is the smallest allotment of logical secondary storage. It means that data  cannot be written to secondary storage unless they are within  a file. Commonly, or binary. In general, a file represent programs and data. D
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Service of Operating system

SERVICE OF OPERATING SYSTEM:- 1.Input/Output Operation:-                                                                      A running program may require I/O. this I/O may involve a file or an I/O device. For efficiency and protection, users usually cannot control devices directly. Generally, the program that require I/O, specifies only a function the rest of the work is handled by operating system. 2.Works as a Resource Allocator:-                                                                                         When multiple users are logged on the system or multiple jobs are running at the same time, resources must be allowed to reach them. Various types of resources are managed by operating system. Some may have special allocation code, whereas others may have much more general request release code. 3.File-system Manipulation:-                                                                             Programs need to read and write files. Program
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Operating system defination and types

An operating system may be viewed as an organized collection of software extensions of hardware, consisting of control routines for operating system a computer and for providing an environment for execution of programs. Other programs rely on facilities provided by the operating system to gain  access to computer system  such as files and input/output devices. Programs usually invoke services of the operating system by means of operating system call. Types of operating system:-  Microsoft :-   1. window XP                       2. window vista                       3. window 7                       4. window 8                       5. window 8.1                       6. window 10 etc. Linux/Unix:-    1.redhat                          2.kali5.                          3. parrot                          4.ubuntu etc. various types of operating system:- Desktop system  Multiprocessor system Clustered system  Handheld system Real-time system
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Android information

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San Francisco is to home to technology. Now it's home to perhaps the most technologically-advanced house, too. Inside a new store on Fourth Street stands a mockup of a Victorian-style house, Complete with gingerbread trim and a three-panel bay window but made entirely out of acrylic. There's nursery, in which visitors can trigger a morning routine that's homey and alie n all at once. A projected silhouette of a baby in an acrylic crib awakes. A onesie outfitted with sensors, from the startup Memo, detects the movement and alerts a mother's phone in the adjacent room. A shimmering white stream of data visualizes the connection. Andr oid Developer story. Zabob Studio and Buff Studio reach global useh0rs with Google Play. South Korean Games developers zabob Studio and Buff Studio are start-ups seeking to become major Players in the global mobile industry. Established in 2013, Zabob Studio was set up by know Dae-hyeon and his wife in 2013. This couple-run bu
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