Quantum Computing – The Next Tech Revolution Technology has evolved rapidly over the last few decades—from bulky mainframe computers to powerful smartphones in our pockets. Yet, despite these advances, traditional computers are approaching their physical limits. This is where quantum computing enters the scene, promising to revolutionize the way we process information and solve complex problems. What Is Quantum Computing? Quantum computing is a new paradigm of computing that uses the principles of quantum mechanics, a branch of physics that explains how matter and energy behave at the smallest scales. Unlike classical computers, which use bits that represent either 0 or 1, quantum computers use qubits. Qubits can exist in multiple states simultaneously, thanks to a property called superposition. Additionally, qubits can be interconnected through entanglement, allowing them to share information instantaneously. These unique properties give quantum computers immense computational power....
Virtual Memory
* Virtual memory is a characteristics of an operating system that allows a computer to be adept to compensate shortages of physical memory by transferring pages of data from random access memory to disk storage
* In practice, most real processes do not require all their pages, or at least not all at once, for several reasons:
• Error handling code is not required unless that specific error occurs, some of which are quite rare.
• Arrays are often over-sized for worst-case schemes, and only a small fraction of the arrays are actually used in practice.
• Definite features of definite programs are rarely used, such as the routine to balance
the federal budget.
*The potential to load only the portions of processes that were actually needed (and only when they were needed) has several benefits:
•Programs could be written for a much longer address space(virtual memory space) than physically exists on the computer.
• Because each process is only using a fraction of their overall address space, there is more memory left for other programs, increasing CPU utilization and system throughput.
• Small I/O is needed for swapping in and out of RAM, speeding things up.
* Figure below shows the general layout of virtual memory, which can be much longer
than physical memory:
Fig: Diagram showing virtual memory is larger than physical memory
* Figure below conveys virtual address space, which is the programmer’s logical view of process memory storage. The actual physical layout is managed by the process's page table.
* Note that the address space shown in Figure is sparse - A great hole in the middle of the address space is never used, unless the stack and/or the heap grow to fill the hole.
Fig: Virtual address space
* Virtual memory also permits the sharing of files and memory by multiple processes, with several benefits:
• System libraries can be divided by mapping them into the virtual address space of more than one process.
• Processes can also divides virtual memory by mapping the same block of memory to more than one process.
• Process pages can be divided during a fork( ) system call, eliminating the need to
copy all of the pages of the actual(parent) process.
