Top Microsoft Windows Interview Preparation Guide

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Waiting state

A microcontroller is by definition a is a computer on a chip. It includes all the necessary parts (including the memory) all in one IC. You just need to apply the power (and possibly clock signal) to that device and it starts executing the program programmed to it. A microcontroller generally has the main CPU core, ROM/EPROM/EEPROM/FLASH, RAM and some necessary functions (like timers and I/O controllers) all integrated into one chip. The original idea behind the
microcontroller was to limit the capabilities of the CPU itself, allowing a complete computer (memory, I/O, interrupts, etc) to fit on the available silicon real estate.
Microcontrollers are typically used where processing power isn't so important. More important are generally compact construction, small size, low power consumption and that those chips are cheap. For example controlling a microwave oven is easily accomplished with the smallest of microcontrollers. There is countless number of small
electronic devices which are nowadays based on microcontroller. A modern home can include easily tens or hundreds of microcontrollers, as almost every modern device which has electronics have a microcontroller (or more than one) inside.
Microprocessor is generally just the CPU core itself, although nowadays it might have some accessory parts also integrated to the same chip

Specification of the task
Design of algorithms
Implementation (coding)
Testing and debugging
Maintenance and evolution of the system
Obsolescence

A real time operating system has well defined fixed time constraints. Process must be done within the defined constraints or the system will fail. An example is the operating system for a flight control computer or an advanced jet airplane. Often used as a control device in a dedicated application such as controlling scientific experiments, medical imaging systems, industrial control systems, and some display systems.Real-Time systems may be either hard or soft real-time.

Hard real-time:
Secondary storage limited or absent, data stored in short term memory, or read-only memory (ROM) Conflicts with time-sharing systems, not supported by general-purpose operating systems.

Soft real-time:
► Limited utility in industrial control of robotics
► Useful in applications (multimedia, virtual reality) requiring advanced operating-system features.

A real time process is a process that must respond to the events within a certain time period. A real time operating system is an operating system that can run real time processes successfully

THere is two solutions:

1. Restore from last back.

2. User Recycler folder. Start-->RUN-->type c:recycler --> type FTYPE

Micro-Kernel:
A micro-kernel is a minimal operating system that performs only the essential functions of an operating system. All other operating system functions are performed by system processes.

Monolithic:
A monolithic operating system is one where all operating system code is in a single executable image and all operating system code runs in system mode.

Main memory:
only large storage media that the CPU can access directly.

Secondary storage:
extension of main memory that provides large nonvolatile storage capacity.

Scheduling is the activity of the deciding when process will receive the resources they request.

FCFS:
FCSFS stands for First Come First Served. In FCFS the job that has been waiting the longest is served next.

Round Robin Scheduling:
Round Robin scheduling is a scheduling method where each process gets a small quantity of time to run and then it is preempted and the next process gets to run. This is called time-sharing and gives the effect of all the processes running at the same time

Shortest Job First:
The Shortest job First scheduling algorithm is a nonpreemptive scheduling algorithm that chooses the job that will execute the shortest amount of time.

Priority Scheduling:
Priority scheduling is a scheduling method where at all times the highest priority process is assigned the resource.

TASK :
A Particular Work to be Done is known as TASK

PROCESS :
one or more PROCESS will be required to complete a task.

► Amoeba
► WinNT
► Minix

Deadlock is a situation where a group of processes are all blocked and none of them can become unblocked until one of the other becomes unblocked. The simplest deadlock is two processes each of which is waiting for a message from the other.

► Selects from among the processes in memory that are ready to execute, and allocates the CPU to one of them.
► CPU scheduling decisions may take place when a process:
1.Switches from running to waiting state.
2.Switches from running to ready state.
3.Switches from waiting to ready.
4.Terminates.
► Scheduling under 1 and 4 is nonpreemptive.
► All other scheduling is preemptive.

diskcopy
Java Thread States

Distribute the computation among several physical processors.
Loosely coupled system each processor has its own local memory; processors communicate with one another through various communications lines, such as high-speed
buses or telephone lines
Advantages of distributed systems:
► Resources Sharing
► Computation speed up load sharing
► Reliability
► Communications

► Interrupt transfers control to the interrupt service routine generally, through the interrupt vector, which contains the addresses of all the service routines.
► Interrupt architecture must save the address of the interrupted instruction.
► Incoming interrupts are disabled while another interrupt is being processed to prevent a lost interrupt.
► A trap is a software-generated interrupt caused either by an error or a user request.
► An operating system is interrupt driven.

► When, and how often, to invoke depends on:
How often a deadlock is likely to occur?
How many processes will need to be rolled back?

► If detection algorithm is invoked arbitrarily, there may be many cycles in the resource graph and so we would not be able to tell which of the many deadlocked processes ?caused? the deadlock.

The purpose of the lexical analyzer is to partition the input text, delivering a sequence of comments and basic symbols. Comments are character sequences to be ignored, while basic symbols are character sequences that correspond to terminal symbols of the grammar defining the phrase structure of the input

Switching the CPU to another process requires saving the state of the old process and loading the saved state for the new process. This task is known as a context switch. Context-switch time is pure overhead, because the system does no useful work while switching. Its speed varies from machine to machine, depending on the memory
speed, the number of registers which must be copied, the existed of special instructions(such as a single instruction to load or store all registers).

Unix and Windows use completely different paradigms for run-time loading of code. Before you try to build a module that can be dynamically loaded, be aware of how your system works.

In Unix, a shared object (.so) file contains code to be used by the program, and also the names of functions and data that it expects to find in the program. When the file is joined to the program, all references to those functions and data in the file's code are changed to point to the actual locations in the program where the functions and data are placed in memory. This is basically a link operation.

In Windows, a dynamic-link library (.dll) file has no dangling references. Instead, an access to functions or data goes through a lookup table. So the DLL code does not have to be fixed up at runtime to refer to the program's memory; instead, the code already uses the DLL's lookup table, and the lookup table is modified at runtime to point to the functions and data.

In Unix, there is only one type of library file (.a) which contains code from several object files (.o). During the link step to create a shared object file (.so), the linker may find that it doesn't know where an identifier is defined. The linker will look for it in the object files in the libraries; if it finds it, it will include all the code from that object file.

Dispatcher module gives control of the CPU to the process selected by the short-term scheduler; this involves:
Switching context
Switching to user mode
Jumping to the proper location in the user program to restart that program
Dispatch latency ? time it takes for the dispatcher to stop one process and start another running.

Dynamic Loading:
► Routine is not loaded until it is called
► Better memory-space utilization; unused routine is never loaded.
► Useful when large amounts of code are needed to handle infrequently occurring cases.
► No special support from the operating system is required implemented through program design.
Dynamic Linking:
► Linking postponed until execution time.
► Small piece of code, stub, used to locate the appropriate memory-resident library routine.
► Stub replaces itself with the address of the routine, and executes the routine.
► Operating system needed to check if routine is in processes? memory address.
► Dynamic linking is particularly useful for libraries.
Overlays:
► Keep in memory only those instructions and data that are needed at any given time.
► Needed when process is larger than amount of memory allocated to it.
► Implemented by user, no special support needed from operating system, programming design of overlay structure is complex.

Main component of operating system are kernel and shell.

Shell is a interface between application program and kernel whenever application program wants some work to be done It contacts kernel and kernel inturn perform work with the help of device drivers .thus we can say kernel is an interface between hardware and shell.

Kernel uses device drivers to control microcontroller card of peripheral device and inturn work is being accomplished.

application program -> [shells ->kernel ->device driver -> controller card -> physical hardware]

Active is a centralize directory database it's provide single point of administration
what is DHCP
dynamic host configuration protocol
it is one of the network service which is provides the ip address dynamically to the DHCP client
it give ip address automatically to the client
WHAT IS DNS
do mine naming service
it provide ip to host and host to ip