Operating Systems 1. Memory Management Following is the independent, separate co

Question

Operating Systems

1.Memory Management

Following is the independent, separate concern components of Memory Management:

1) Translate logical addresses to Physical addresses

Describe the component’s responsibility and provide an example of an implementation of that component.

Follow this Format:

For example, within the Memory Management component, separating the capability to translate logical addresses to physical addresses is one separate area of concern. This component is typically a hardware component (the MMU) manufactured to support a very specific architecture, such as the ARM Architecture (page 387) with 4-KB and 16-KB, or 1-MB and 16-MB pages for a 32-bit address. Fixing a bug, or upgrading the address translation algorithm version is confined to the MMU and the OS component, isolating this concern from other parts of the OS.

Explanation / Answer

MEMORY MANAGEMENT :

Primary Memory alludes to a physical memory that is the inside memory to the PC. The word principle is utilized to recognize it from outer mass stockpiling gadgets, for example, plate drives. Fundamental memory is otherwise called Smash. The PC can change just information that is in principle memory. In this way, every program we execute and each document we get to must be duplicated from a capacity gadget into principle memory.

Every one of the projects are stacked in the primary memeory for execution. Here and there total program is stacked into the memory, yet a few times a specific part or routine of the program is stacked into the primary memory just when it is called by the program, this instrument is called Dynamic Stacking, this upgrade the execution.

Additionally, now and again one program is subject to some other program. In such a case, as opposed to stacking all the needy projects, CPU connects the needy projects to the primary executing program when its required. This system is known as Powerful Connecting.

Swapping :

A procedure should be in memory for execution. Be that as it may, now and then there isn't sufficient principle memory to hold all the at present dynamic procedures in a timesharing framework. In this way, abundance process are kept on circle and got to run progressively. Swapping is the way toward acquiring each procedure in primary memory, running it for some time and afterward returning it to the circle.

Contiguous Memory Allocation :

In contiguous memory allocation each process is contained in a single contiguous block of memory. Memory is divided into several fixed size partitions. Each partition contains exactly one process. When a partition is free, a process is selected from the input queue and loaded into it. The free blocks of memory are known as holes. The set of holes is searched to determine which hole is best to allocate.

Memory Protection :

Memory protection is a phenomenon by which we control memory access rights on a computer. The main aim of it is to prevent a process from accessing memory that has not been allocated to it. Hence prevents a bug within a process from affecting other processes, or the operating system itself, and instead results in a segmentation fault or storage violation exception being sent to the disturbing process, generally killing of process.

Memory Allocation :

Memory allocation is a process by which computer programs are assigned memory or space. It is of three types :

First Fit :

The first hole that is big enough is allocated to program.

Best Fit :

The smallest hole that is big enough is allocated to program.

Worst Fit :

The largest hole that is big enough is allocated to program.

Fragmentation :

Fragmentation occurs in a dynamic memory allocation system when most of the free blocks are too small to satisfy any request. It is generally termed as inability to use the available memory.

In such situation processes are loaded and removed from the memory. As a result of this, free holes exists to satisfy a request but is non contiguous i.e. the memory is fragmented into large no. Of small holes. This phenomenon is known as External Fragmentation.

Also, at times the physical memory is broken into fixed size blocks and memory is allocated in unit of block sizes. The memory allocated to a space may be slightly larger than the requested memory. The difference between allocated and required memory is known as Internal fragmentation i.e. the memory that is internal to a partition but is of no use.

Paging :

A solution to fragmentation problem is Paging. Paging is a memory management mechanism that allows the physical address space of a process to be non-contagious. Here physical memory is divided into blocks of equal size called Pages. The pages belonging to a certain process are loaded into available memory frames.

Page Table :

A Page Table is the data structure used by a virtual memory system in a computer operating system to store the mapping between virtual address and physical addresses.

Virtual address is also known as Logical address and is generated by the CPU. While Physical address is the address that actually exists on memory.

Segmentation :

Segmentation is another memory management scheme that supports the user-view of memory. Segmentation allows breaking of the virtual address space of a single process into segments that may be placed in non-contiguous areas of physical memory.

Segmentation with Paging :

Both paging and segmentation have their advantages and disadvantages, it is better to combine these two schemes to improve on each. The combined scheme is known as 'Page the Elements'. Each segment in this scheme is divided into pages and each segment is maintained in a page table. So the logical address is divided into following 3 parts :

PARTITIONING IN A MEMORY MANAGEMENT SYSTEM ;

Partitions help enable users to divide a computer hard drive into different drives or different portions for a number of reasons. For example, allowing multiple operating systems to run on the same device.

Different types :

There are also dozens of different partition types. Below is a listing of some of these partitions with a brief description. While all of these partitions are available, they may not be available in your partition utility.

Information about creating, deleting (unpartition), or otherwise using fdisk to manipulate partitions can be found on our fdisk overview.

Hope you got the answer ;

If you have any further doubts or queries please inform me through comments .

• AIX Partition (Boot)

• Partition used with the AIX operating system.

• Boot Partition

• As defined by Microsoft a boot partition is a partition that contains the files required for a system startup. Also see: System Partition

• BSD/OS Partition (OpenBSD)

• Partition used with the BSD operating system.

• DOS (12-bit, 16-bit) Partition

• Partition used with older versions of MS-DOS.

• DOS Extended Partition

• Partition that is extended from one or more of the original MS-DOS partitions.

• DRDOS (Hidden, Secured)

• Partition used with the DR. DOS operating system.

• Extended Partition

• Partition that is extended from one or more of the primary partitions.

• Hibernation Partition

• Partition used with older hibernation programs.

• HPFS Partition (OS/2 IFS)

• Partition used with IBM OS/2 and Microsoft NT 3.x

• Linux (Linux native, Linux swap, Linux extended, ext2fs)

• Partition used with various variants of the Linux operating systems.

• MINIX

• Partition used with the MINIX operating system.

• NON-DOS Partition

• When using Microsoft fdisk a NON-DOS partition indicates a partition that is not native to the Microsoft operating system. For example, this could be a Linux partition.

• NEC DOS

• Partition used with the old NEC DOS variant.

• NEXTSTEP

• Partition used with the Nextstep operating system.

• Novell Netware

• Partition used with the Novell Netware operating system.

• NTFS

• Partition used with Microsoft Windows NT 4.x, Windows 2000 and Windows XP.

• Partition Magic (PowerQuest)

• Partition created using the Partition Magic utility by PowerQuest.

• PC-ARMOUR

• Partition created by the PC ARMOUR security utility. When created this partition is commonly protected by a password.

• Primary

• In a Microsoft operating system the Primary Partition commonly refers to the main or first partition used for the Microsoft operating system.

• Solaris X86

• Partition used with the Sun Solaris X86 platform operating system.

• System Partition

• As defined by Microsoft a system partition is a partition that contains the system32 directory. Also see: Boot Partition

• Tandy DOS

• Partition used with the old Tandy DOS variant.

• Unix System V (SCO, IRIX, ISC, Unix, UnixWare, etc...)

• Partition used with various Unix operating systems.

• VMWare (VMWare Swap)

• Partition used by VMWare.

• XENIX (XENIX /usr)

• Partition used with the Xenix operating system.

Related Questions

Navigate

• Browse (All)
• Browse O
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.