Operating Systems

The feudal system was a hierarchical social and economic structure that dominated medieval Europe, characterized by the exchange of land for military service. In this system, kings granted large estates to nobles (lords) in return for loyalty and soldiers, while peasants or serfs worked the land in exchange for protection and a place to live. This arrangement created a rigid class system, with the monarch at the top, followed by nobles, knights, and peasants. The feudal system declined with the rise of centralized monarchies, trade, and urbanization.

In operating systems and other multithreaded, event-driven, or low-level software, it is possible to have event-handling or interrupt-handling code that is called every time an event or interrupt is triggered by hardware or software. If an event triggers a call to the handler, then the code will context switch to "enter" that method. Once in the method, suppose that it accesses a set of static structures in memory, so that they can be modified (like a counter or a routine that reads and updates the data). Now, suppose that another thread or process triggers an event to call the same method. This will enter the same handler method at the same time (a reentrant block of code). Well, while the first method is still accessing the static memory location, the second thread/process will be entering the same method to do the same thing, and they will attempt to modify the same area of memory at the same time. This is called a race condition. In order to prevent this from happening, memory management in the OS kernel should "lock" the memory location so that no other processes can overwrite that memory at the same time. They will encounter the lock and will either wait until the locked memory has been unlocked by the first routine, or they will exit. Typically, if locks are not accounted for, and two threads are dependent upon each other, a deadlock condition can also be reached, which freezes the system.

Ø In a paging system, programs and data stored on disk are divided into equal, fixed sized blocks called pages, and main memory is divided into blocks of the same size called frames. Exactly one page can fit in one frame.

Physical memory is divided into parts called FRAME and logical memory is divided into parts called PAGE.

because the process holding the spinlock would do nothing (thus wasting CPU cycles) when it is allocated the CPU. It is better to put it in the sleep state (that is putting the process in the waiting queue). As soon as the process is wakened up (by some other process/thread invoking "signal/wake" on it) it is put in the "ready" queue when it runs as soon as the CPU is assigned to it.

on multiprocessor systems, it's generally better to "spin" because it is assumed that the running process on the other processor will release the lock pretty soon (thus it can release the lock and still continue running while your thread/process is getting a hold of the lock).

for better explanation check out "Operating System Concepts" by Silberchatz,

also Cornell University slides on Operating Systems Course are pretty useful as well.

The king of Spain in the 15th century installed it to get tax money from the Indians in present day Mexico and southern America

try links on qnxforum.com

It is called multi-tasking or multiple use.

Write a monitor solution to the Readers/Writers problemWrite a monitor solution to the Readers/Writers problem

Var directory is a sub directory of the root directory,

The system writes data during process of its operation.

"Yes, actually if you have all the required materials to do it. It is quite affordable and will save you a lot of money to install the Sky system yourself."

Unisys Corporation (Unisys) is a worldwide information technology (IT) company.

The Company provides a portfolio of IT services, software and technology. It

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moving doors

Your ugly as hell

Don't tell me what to do.

No, there should be no problem as long as you have enough room on your hard disk to run these three OS's. 160GB or less would be too small for Windows Vista and Windows 7 to run fast. I wouldn't recommend it but it does work.

Hope this helps!

1. The OS has to keep track of the main memory address space allocated to each process so that a process does not affect or harm other processes data. This is a necessay , for example, a virus may try to destroy or modify other process data.

2. Switching from one process to another process leads to time overhead, this requires storing the current register values and loading the register values of the next process from its PCB(program Control Block).

3. If a running process requires large space in memory then other processs needs to be dumped back to hard disk which again leads to time overhead.

For more information mail to: akhilanger@gmail.com

The droop also known as the steady-state guarantees all generation in a system to settle at a unique operating point

Stay right where you are and you're doing both! You are occupying a particular space at a particular point in time.

A GUI contains visual objects like buttons, windows , cursor and all. It is used to make using your computer more friendly. You don't need to have technical knowledge to use a GUI.

Material Requirements Planning(MRP) helps production managers plan and schedule the purchase of raw materials and component parts for manufacturing facilities. They are driven by outstanding orders or foretasted orders or both together.

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