Technical Interview Questions » Operating System Interview Questions

How to identify the difference between the kernel object and user object?

admin — Sun, 19 Aug 2007 05:37:51 +0000

The easiest way to determine whether an object is a kernel object is to examine the function that creates the object. Almost all functions that create kernel objects have a parameter that allows you to specify security attribute information.

Which is the data member common to all the kernel object and what is the use of it?

admin — Sun, 19 Aug 2007 05:37:31 +0000

The usage count is one of the data members common to all kernel object types

How does the kernel object outlive the process that created it?

admin — Sun, 19 Aug 2007 05:37:11 +0000

If your process calls a function that creates a kernel object and then your process terminates, the kernel object is not necessarily destroyed. Under most circumstances, the object will be destroyed; but if another process is using the kernel object your process created, the kernel knows not to destroy the object until the other process has stopped using it

How owns the Kernel Object?

admin — Sun, 19 Aug 2007 05:36:48 +0000

Kernel objects are owned by the kernel, not by a process

If we cannot alter these Kernel Object structures directly, how do our applications manipulate these kernel objects?

admin — Sun, 19 Aug 2007 05:36:28 +0000

The answer is that Windows offers a set of functions that manipulate these structures in well-defined ways. These kernel objects are always accessible via these functions. When you call a function that creates a kernel object, the function returns a handle that identifies the object.

User can access these kernel objects structures?

admin — Sun, 19 Aug 2007 05:36:07 +0000

Kernel object data structures are accessible only by the kernel

What is a kernel object?

admin — Sun, 19 Aug 2007 05:35:48 +0000

Each kernel object is simply a memory block allocated by the kernel and is accessible only by the kernel. This memory block is a data structure whose members maintain information about the object. Some members (security descriptor, usage count, and so on) are the same across all object types, but most are specific to a particular object type. For example, a process object has a process ID, a base priority, and an exit code, whereas a file object has a byte offset, a sharing mode, and an open mode.

What are kernel objects?

admin — Sun, 19 Aug 2007 05:35:27 +0000

Several types of kernel objects, such as access token objects, event objects, file objects, file-mapping objects, I/O completion port objects, job objects, mailslot objects, mutex objects, pipe objects, process objects, semaphore objects, thread objects, and waitable timer objects.

What is fragmentation? Different types of fragmentation?

admin — Sun, 19 Aug 2007 05:34:22 +0000

Fragmentation occurs in a dynamic memory allocation system when many of the free blocks are too small to satisfy any request. External Fragmentation: External Fragmentation happens when a dynamic memory allocation algorithm allocates some memory and a small piece is left over that cannot be effectively used. If too much external fragmentation occurs, the amount of usable memory is drastically reduced. Total memory space exists to satisfy a request, but it is not contiguous. Internal Fragmentation: Internal fragmentation is the space wasted inside of allocated memory blocks because of restriction on the allowed sizes of allocated blocks. Allocated memory may be slightly larger than requested memory; this size difference is memory internal to a partition, but not being used

What is hard disk and what is its purpose?

admin — Sun, 19 Aug 2007 05:33:56 +0000

Hard disk is the secondary storage device, which holds the data in bulk, and it holds the data on the magnetic medium of the disk.Hard disks have a hard platter that holds the magnetic medium, the magnetic medium can be easily erased and rewritten, and a typical desktop machine will have a hard disk with a capacity of between 10 and 40 gigabytes. Data is stored onto the disk in the form of files.