In the given presentation, process overview,process management scheduling typesand some more basic concepts were explained.
Kindly refere the presentation.
In the given presentation, process overview,process management scheduling typesand some more basic concepts were explained.
Kindly refere the presentation.
Provides a simple and unambiguous taxonomy of three service models
- Software as a service (SaaS)
- Platform as a service (PaaS)
- Infrastructure as a service (IaaS)
(Private cloud, Community cloud, Public cloud, and Hybrid cloud)
Virtual Memory
• Copy-on-Write
• Page Replacement
• Allocation of Frames
• Thrashing
• Operating-System Examples
Background
Page Table When Some Pages Are Not in Main Memory
Steps in Handling a Page Fault
Distributed Operating System,Network OS and Middle-ware.??Abdul Aslam
Define Distributed Operating System, Network Operating System and Middle-ware? Differentiate between DOS, NOS and Middle-ware? Define the goals of each? ???
n computer operating systems, demand paging is a method of virtual memory management. In a system that uses demand paging, the operating system copies a disk page into physical memory only if an attempt is made to access it and that page is not already in memory
Provides a simple and unambiguous taxonomy of three service models
- Software as a service (SaaS)
- Platform as a service (PaaS)
- Infrastructure as a service (IaaS)
(Private cloud, Community cloud, Public cloud, and Hybrid cloud)
Virtual Memory
• Copy-on-Write
• Page Replacement
• Allocation of Frames
• Thrashing
• Operating-System Examples
Background
Page Table When Some Pages Are Not in Main Memory
Steps in Handling a Page Fault
Distributed Operating System,Network OS and Middle-ware.??Abdul Aslam
Define Distributed Operating System, Network Operating System and Middle-ware? Differentiate between DOS, NOS and Middle-ware? Define the goals of each? ???
n computer operating systems, demand paging is a method of virtual memory management. In a system that uses demand paging, the operating system copies a disk page into physical memory only if an attempt is made to access it and that page is not already in memory
Class lecture by Prof. Raj Jain on Storage Virtualization. The talk covers Disk Arrays, Data Access Methods, SCSI (Small Computer System Interface), Advanced Technology Attachment (ATA), ESCON and FICON, Fibre Chanel, Fibre Channel Devices, Fibre Channel Protocol Layers, Fibre Channel Flow Control, Fibre Channel Classes of Service, What is Storage Virtualization?, Benefits of Storage Virtualization, Virtualizing Storage, RAID Levels, Nested RAIDs, Synchronous vs. Asynchronous Replication, Virtual Storage Area Network (VSAN), Physical Storage Network, Virtual Storage Network, SAN vs. NAS, iSCSI (Internet Small Computer System Interface), iFCP (Internet Fiber Channel Protocol), FCIP (Fibre Channel over IP), FCoE (Fibre Channel over Ethernet), Virtual File Systems. Video recording available in YouTube.
Virtualization is the creation of a virtual (rather than actual) version of something, such as an operating system, a server, a storage device or network resources.
This slides will provide viewers a complete understanding of all the different virtualization techniques.
The main reference for the presentation is taken from Mastering cloud computing By Rajkumar Buyya.
a glance on memory management in operating system.
this note is useful for those who are keen to know about how the OS works and a brief explanation regarding several terms such
-paging
segmentation
fragmentation
virtual memory
page table
to A Level A2 Computing students, this light note may be helpful for your revision
Abhaycavirtual memory and the pagehit.pptxwemoji5816
in this ppt we are learning about the concept of the virtual memory incomputer science with the help of which we run large program in less primary memory
Virtual memory is a memory management capability of an OS that uses hardware and software to allow a computer to compensate for physical memory shortages by temporarily transferring data from random access memory (RAM) to disk storage.
Unit 8 - Information and Communication Technology (Paper I).pdfThiyagu K
This slides describes the basic concepts of ICT, basics of Email, Emerging Technology and Digital Initiatives in Education. This presentations aligns with the UGC Paper I syllabus.
Model Attribute Check Company Auto PropertyCeline George
In Odoo, the multi-company feature allows you to manage multiple companies within a single Odoo database instance. Each company can have its own configurations while still sharing common resources such as products, customers, and suppliers.
2024.06.01 Introducing a competency framework for languag learning materials ...Sandy Millin
http://sandymillin.wordpress.com/iateflwebinar2024
Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
The Art Pastor's Guide to Sabbath | Steve ThomasonSteve Thomason
What is the purpose of the Sabbath Law in the Torah. It is interesting to compare how the context of the law shifts from Exodus to Deuteronomy. Who gets to rest, and why?
Operation “Blue Star” is the only event in the history of Independent India where the state went into war with its own people. Even after about 40 years it is not clear if it was culmination of states anger over people of the region, a political game of power or start of dictatorial chapter in the democratic setup.
The people of Punjab felt alienated from main stream due to denial of their just demands during a long democratic struggle since independence. As it happen all over the word, it led to militant struggle with great loss of lives of military, police and civilian personnel. Killing of Indira Gandhi and massacre of innocent Sikhs in Delhi and other India cities was also associated with this movement.
The French Revolution, which began in 1789, was a period of radical social and political upheaval in France. It marked the decline of absolute monarchies, the rise of secular and democratic republics, and the eventual rise of Napoleon Bonaparte. This revolutionary period is crucial in understanding the transition from feudalism to modernity in Europe.
For more information, visit-www.vavaclasses.com
2. Virtual Memory
Memory virtualization is seen as virtual
memory, or swap, on servers and
workstations.
It enhances performance by providing greater
memory capacity, without the expense of
adding main memory.
Instead, a portion of a disk drive serves as an
extension of main memory.
A physical address is the actual memory
address of physical memory.
Page faults occur when a logical address
requires that a page be brought in from disk.
3. Virtual Memory
Main memory and virtual memory are divided into equal sized pages.
The entire address space required by a process need not be in memory
at once. Some parts can be on disk, while others are in main memory.
Further, the pages allocated to a process do not need to be stored
contiguously-- either on disk or in memory.
In this way, only the needed pages are in memory at any time, the
unnecessary pages are in slower disk storage.
4. Importance of Virtual Memory
When the computer runs out of physical
memory it writes what it needs to remember
to the hard disk in a swap file as virtual
memory.
If a computer running windows requires more
memory or RAM, then it is installed in the
system to run a program , it uses a small
section of hard drive for this purpose.
5. Example
A 16 MB program can run in 4 MB space by carefully choosing which 4 MB
to keep in memory at each instance, with pieces of the program being
swapped between disk and memory as needed.
6.
7. Demand Paged Virtual Memory
The fundamental approach in implementing virtual memory is paging.
To facilitate copying virtual memory into real memory, the operating
system divides virtual memory into pages, each of which contains a fixed
number of addresses.
To accomplish this, the virtual address is divided into two fields: A page
field, and an offset field.
The page field determines the page location of the address, and the offset
indicates the location of the address within the page.
8. The logical page number is translated into a physical page frame through a
lookup in the page table
Information concerning the location of each page, whether on disk or in memory,
is maintained in a data structure called a page table (shown below).
There is one page table for each active process.
Demand Paged Virtual Memory
9. Demand Paged Virtual Memory
When the pages are needed to
execute a particular program,
they are loaded.
Pages that are never accessed
are thus never loaded into the
memory.
This technique is known as
Demand paging.
10.
11. Internal Fragmentation
Paging is subject to internal fragmentation because a
process may not need the entire range of addresses
contained within the page. Thus, there may be many
pages containing unused fragments of memory.
12. Demand Segmented Virtual Memory
Memory is divided into variable length segments.
Each segment has a base physical address and length.
Used when insufficient hardware is there to implement demand paging.
Segment descriptor contains a valid bit to indicate whether the segment
is currently in memory.
If segment is in main memory, access continues,
If not in memory, segment fault occurs.
13. Demand Segmented Virtual Memory
A segment is located through its entry in a segment table, which contains
the segment’s memory location and a bounds limit that indicates its size.
After a page fault, the operating system searches for a location in memory
large enough to hold the segment that is retrieved from disk.
Each segment has a page table. This means that a memory address will
have three fields, one for the segment, another for the page, and a third for
the offset.
14. External Fragmentation
Both paging and segmentation can cause
fragmentation.
Segmentation is subject to external fragmentation,
which occurs when contiguous chunks of memory
become broken up as segments are allocated and
deallocated over time.
15. Thrashing
When the hard drive is being overworked by moving information between
the system memory and virtual memory excessively, thrashing is caused.
When the system doesn’t have enough memory, the system swap file is
not properly configured, or too much is running on the computer and it
has low system resources.
Thrashing is bad on a hard drive because of the amount of work the hard
drive has to do and if is left unfixed will likely cause an early failure of
the hard drive.
16. Advantages
More applications can run at once.
Larger applications can run with less real RAM without need to buy more
memory.
Allows speed gain when only a particular segment of the program is
required for the execution of the program.
This frees programmers from concern of memory limitations and helps
implementing multiprogramming environment.
17. Disadvantages
Applications may run slower.
It takes more time to switch between applications.
Less available hard drive space for the user’s use.
The possibility of Thrashing due to excessive Paging and Page faults
