Paging, Segmentation, Virtual Paging, and Virtual Segmentation

Introduction

It has long been a problem in the program memory location whose size exceeds the available memory. We assumed an active part in the process of segmenting a programmer and software downloads. It was proposed to shift the problem to the computer. The development of computer architectures has led to considerable complication of the memory organization, respectively, more complex and expanded operating system tasks of memory management (Silberschatz, 42). One of the major improvements of architecture is the emergence of virtual memory (virtual memory).

Each computer has some physical memory, which is the memory you put into the computer. That may be 128MB or 512MB or 2GB or whatever. The 32-bit computer processors have the ability to access much more memory than just 128MB. They can address 4GB. And the 64-bit processors can access much more than that. In a multi-tasking operating system, one of the jobs of the operating system is to load programs into memory and assign to each program a huge memory space. You open a small program, and it suddenly gets to use 4GB of RAM. Even if the program doesn't use that much memory, technically it could use up to 4GB of RAM. And on a 64-bit machine, it's much more than that. With virtual memory is usually solved two problems. First, the virtual memory address space allows much greater than the capacity of physical memory a particular computer (Bic, 25). In accordance with the principle of locality for real-world programs do not usually need to place them in physical memory as a whole. Here in this paper we are going to focus on paging, virtual paging, segmentation and virtual segmentation. On the other hand we are going to discuss its advantages, disadvantages plus its implementation.

Discussion

Paging

Paging is a virtual memory management scheme where the physical memory is divided into fixed sized blocks called frames and the virtual memory is divided into fixed sized blocks as well called as pages. Whenever a program has to be loaded into the memory, pages are loaded into the frames.

Segmentation

It is another scheme of implementing virtual memory. Here the logical address space is collection of segments. If you've done some coding in assembly then there is a provision of different segments like CODE Segment, DATA Segment, and STACK etc (Deitel, 181). Now these segments aren't fixed sized blocks like pages and aren't necessarily contiguously allocated. Such a scheme is much more preferred by programmers as they can put in any amount of code in CODE Segment, declare any number of variables in DATA Segment and like that. If a reference is required then all that needs to be done is to find the offset and SEGMENT name.

Virtual paging

Virtual memory paging is a technique of real memory management that allows the operating system provides the software itself and the user address space larger than the real or physical memory. Virtual memory is usually (but not necessarily) is implemented using paging. In paging, the least significant bits ...