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Explain the difference between microkernel and macro kernel?
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.
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What is multi tasking, multi programming, multi threading?
Multi programming: Multiprogramming is the technique of running several programs at a time using timesharing.It allows a computer to do several things at the same time. Multiprogramming creates logical parallelism. The concept of multiprogramming is that the operating system keeps several jobs in memory simultaneously. The operating system selects a job from the job pool and starts executing a...
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Give a non-computer example of preemptive and non-preemptive scheduling?
Consider any system where people use some kind of resources and compete for them. The non-computer examples for preemptive scheduling the traffic on the single lane road if there is emergency or there is an ambulance on the road the other vehicles give path to the vehicles that are in need. The example for preemptive scheduling is people standing in queue for tickets.
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Different types of Real-Time Scheduling?
Hard real-time systems – required to complete a critical task within a guaranteed amount of time.Soft real-time computing – requires that critical processes receive priority over less fortunate ones.
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What is DRAM? In which form does it store data?
DRAM is the Hershey's chocolate of readable/writable memory: it's not the best, but it's cheap, does the job, and is available almost everywhere you look. DRAM data resides in a cell made of a capacitor and a transistor. The capacitor tends to lose data unless it's recharged every couple of milliseconds, and this recharging tends to slow down the performance of DRAM compared to speedier RAM types....
00elton00
- Aug 5th, 2007
DRAM forms the Physical Memory of the PC. The process of recharging described in the earlier post is know as a Refreshing Cycle.
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Deadlock Detection-Algorithm Usage?
->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.
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What Location(on hard disk) for the default port numbers in NT based system?
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What is Dispatcher?
->Dispatcher module gives control of the CPU to the process selected by the short-term scheduler; this involves:Switching contextSwitching to user modeJumping 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.
pbchaudhari
- Aug 15th, 2007
The short-term scheduler (also known as the dispatcher) decides which of the ready, in memory processes are to be executed (allocated a CPU) next, following a clock interrupt, an IO interrupt, an op...
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Differentiate between RAM and ROM?
Semiconductor memories are of two types: RAM (random access memory) and ROM (read only memory).RAM is a read/write memory. Information can be written into and read from a RAM. It is volatile memory.It stores information so long as power supply is on. ROM is permanent type memory. Its contents are not lost when power supply goes off. the user cannot write into a ROM.Its contents are decided by...
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Condition for deadlock occurrence?
Deadlock can arise if four conditions hold simultaneously.Mutual exclusion: only one process at a time can use a resource.Hold and wait: a process holding at least one resource is waiting to acquire additional resources held by other processes.No preemption: a resource can be released only voluntarily by the process holding it, after that process has completed its task.Circular wait: ...
Sandhya.Kishan
- Jun 1st, 2012
The condition for the occurrence of deadlocks are Mutual Exclusion: At least one resource must be non-shareable.[1] Only one process can use the resource at any given instant of time. Hold and Wait ...
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What is the important aspect of a real-time system or Mission Critical Systems?
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...
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What is cache memory?
Cache memory is random access memory (RAM) that a computer microprocessor can access more quickly than it can access regular RAM. As the microprocessor processes data, it looks first in the cache memory and if it finds the data there (from a previous reading of data), it does not have to do the more time-consuming reading of data from larger memory.
thukral.rahul
- Jan 12th, 2010
A Cache is a fast memory (generally SRAMS) that is genearally installed between the main memory and disk to reduce the transfer rate and access time disparities.
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Differentiate between Complier and Interpreter?
An interpreter reads one instruction at a time and carries out the actions implied by that instruction. It does not perform any translation. But a compiler translates the entire instructions.
Sandhya.Kishan
- Apr 23rd, 2012
The compiler converts a high level language instruction into into machine language where as an interpreter converts the high level instruction into some intermediate form and after that, the instructi...
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What are different tasks of Lexical Analysis?
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
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Why paging is used?
Paging is solution to external fragmentation problem which is to permit the logical address space of a process to be noncontiguous, thus allowing a process to be allocating physical memory wherever the latter is available.
Sandhya.Kishan
- Apr 23rd, 2012
Paging is a process of dividing the memory into equal sized logical blocks.When any page is required the operating system searches for that page in the secondary memory and copies that page to the mai...
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What are the main difference between Micro-Controller and Micro- Processor?
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)...
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What is Context Switch?
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...
Sandhya.Kishan
- Apr 23rd, 2012
Context switching is a process of storing and restoring the state of the CPU So that the execution of the process can be resumed from the same point where it had been switched. There are 3 situations ...
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