Practical ,Transparent Operating System Support For SuperpagesNadeeshani Hewage
Discussion of the paper by authors : Juan Navarro, Sitaram Iyer, Peter Drusche, Alan Cox
Paper: Practical ,Transparent Operating System Support For Superpages
Practical ,Transparent Operating System Support For SuperpagesNadeeshani Hewage
Discussion of the paper by authors : Juan Navarro, Sitaram Iyer, Peter Drusche, Alan Cox
Paper: Practical ,Transparent Operating System Support For Superpages
Memory management is the process of controlling and coordinating a computer's main memory. It ensures that blocks of memory space are properly managed and allocated so the operating system (OS), applications and other running processes have the memory they need to carry out their operations.
AWS re:Invent 2016| DAT318 | Migrating from RDBMS to NoSQL: How Sony Moved fr...Amazon Web Services
In this session, you will learn the key differences between a relational database management service (RDBMS) and non-relational (NoSQL) databases like Amazon DynamoDB. You will learn about suitable and unsuitable use cases for NoSQL databases. You'll learn strategies for migrating from an RDBMS to DynamoDB through a 5-phase, iterative approach. See how Sony migrated an on-premises MySQL database to the cloud with Amazon DynamoDB, and see the results of this migration.
Java one2015 - Work With Hundreds of Hot Terabytes in JVMsSpeedment, Inc.
Presentation Summary: By leveraging on memory mapped files, the Chronicle Engine supports large maps that easily can exceed the size of your server’s RAM, thus allowing application developers to create huge JVM:s where data can be obtained quickly and with predictable latency. The Chronicle Engine can be synchronized with an underlying database using Speedment so that your in-memory maps will be “alive” and change whenever data changes in the underlying database. Speedment can also automatically derive domain models directly from the database so that you can start using the solution very quickly. Because the Java Maps are mapped onto files, the maps can also be shared instantly between several JVM:s and when you restart a JVM, it may start very quickly without having to reload data from the underlying database. The mapped files can be hundreds of terabytes which has been done in real world deployment cases.
Goals
make allocation and swapping easier
Make all chunks of memory the same size
call each chunk a “PAGE”
example page sizes are 512 bytes, 1K, 4K, 8K, etc
pages have been getting bigger with time
we’ll discuss reasons why pages should be of a certain size as the week progresses.
Memory management is the process of controlling and coordinating a computer's main memory. It ensures that blocks of memory space are properly managed and allocated so the operating system (OS), applications and other running processes have the memory they need to carry out their operations.
AWS re:Invent 2016| DAT318 | Migrating from RDBMS to NoSQL: How Sony Moved fr...Amazon Web Services
In this session, you will learn the key differences between a relational database management service (RDBMS) and non-relational (NoSQL) databases like Amazon DynamoDB. You will learn about suitable and unsuitable use cases for NoSQL databases. You'll learn strategies for migrating from an RDBMS to DynamoDB through a 5-phase, iterative approach. See how Sony migrated an on-premises MySQL database to the cloud with Amazon DynamoDB, and see the results of this migration.
Java one2015 - Work With Hundreds of Hot Terabytes in JVMsSpeedment, Inc.
Presentation Summary: By leveraging on memory mapped files, the Chronicle Engine supports large maps that easily can exceed the size of your server’s RAM, thus allowing application developers to create huge JVM:s where data can be obtained quickly and with predictable latency. The Chronicle Engine can be synchronized with an underlying database using Speedment so that your in-memory maps will be “alive” and change whenever data changes in the underlying database. Speedment can also automatically derive domain models directly from the database so that you can start using the solution very quickly. Because the Java Maps are mapped onto files, the maps can also be shared instantly between several JVM:s and when you restart a JVM, it may start very quickly without having to reload data from the underlying database. The mapped files can be hundreds of terabytes which has been done in real world deployment cases.
Goals
make allocation and swapping easier
Make all chunks of memory the same size
call each chunk a “PAGE”
example page sizes are 512 bytes, 1K, 4K, 8K, etc
pages have been getting bigger with time
we’ll discuss reasons why pages should be of a certain size as the week progresses.
HEAP SORT ILLUSTRATED WITH HEAPIFY, BUILD HEAP FOR DYNAMIC ARRAYS.
Heap sort is a comparison-based sorting technique based on Binary Heap data structure. It is similar to the selection sort where we first find the minimum element and place the minimum element at the beginning. Repeat the same process for the remaining elements.
Sachpazis:Terzaghi Bearing Capacity Estimation in simple terms with Calculati...Dr.Costas Sachpazis
Terzaghi's soil bearing capacity theory, developed by Karl Terzaghi, is a fundamental principle in geotechnical engineering used to determine the bearing capacity of shallow foundations. This theory provides a method to calculate the ultimate bearing capacity of soil, which is the maximum load per unit area that the soil can support without undergoing shear failure. The Calculation HTML Code included.
Cosmetic shop management system project report.pdfKamal Acharya
Buying new cosmetic products is difficult. It can even be scary for those who have sensitive skin and are prone to skin trouble. The information needed to alleviate this problem is on the back of each product, but it's thought to interpret those ingredient lists unless you have a background in chemistry.
Instead of buying and hoping for the best, we can use data science to help us predict which products may be good fits for us. It includes various function programs to do the above mentioned tasks.
Data file handling has been effectively used in the program.
The automated cosmetic shop management system should deal with the automation of general workflow and administration process of the shop. The main processes of the system focus on customer's request where the system is able to search the most appropriate products and deliver it to the customers. It should help the employees to quickly identify the list of cosmetic product that have reached the minimum quantity and also keep a track of expired date for each cosmetic product. It should help the employees to find the rack number in which the product is placed.It is also Faster and more efficient way.
Understanding Inductive Bias in Machine LearningSUTEJAS
This presentation explores the concept of inductive bias in machine learning. It explains how algorithms come with built-in assumptions and preferences that guide the learning process. You'll learn about the different types of inductive bias and how they can impact the performance and generalizability of machine learning models.
The presentation also covers the positive and negative aspects of inductive bias, along with strategies for mitigating potential drawbacks. We'll explore examples of how bias manifests in algorithms like neural networks and decision trees.
By understanding inductive bias, you can gain valuable insights into how machine learning models work and make informed decisions when building and deploying them.
Online aptitude test management system project report.pdfKamal Acharya
The purpose of on-line aptitude test system is to take online test in an efficient manner and no time wasting for checking the paper. The main objective of on-line aptitude test system is to efficiently evaluate the candidate thoroughly through a fully automated system that not only saves lot of time but also gives fast results. For students they give papers according to their convenience and time and there is no need of using extra thing like paper, pen etc. This can be used in educational institutions as well as in corporate world. Can be used anywhere any time as it is a web based application (user Location doesn’t matter). No restriction that examiner has to be present when the candidate takes the test.
Every time when lecturers/professors need to conduct examinations they have to sit down think about the questions and then create a whole new set of questions for each and every exam. In some cases the professor may want to give an open book online exam that is the student can take the exam any time anywhere, but the student might have to answer the questions in a limited time period. The professor may want to change the sequence of questions for every student. The problem that a student has is whenever a date for the exam is declared the student has to take it and there is no way he can take it at some other time. This project will create an interface for the examiner to create and store questions in a repository. It will also create an interface for the student to take examinations at his convenience and the questions and/or exams may be timed. Thereby creating an application which can be used by examiners and examinee’s simultaneously.
Examination System is very useful for Teachers/Professors. As in the teaching profession, you are responsible for writing question papers. In the conventional method, you write the question paper on paper, keep question papers separate from answers and all this information you have to keep in a locker to avoid unauthorized access. Using the Examination System you can create a question paper and everything will be written to a single exam file in encrypted format. You can set the General and Administrator password to avoid unauthorized access to your question paper. Every time you start the examination, the program shuffles all the questions and selects them randomly from the database, which reduces the chances of memorizing the questions.
Welcome to WIPAC Monthly the magazine brought to you by the LinkedIn Group Water Industry Process Automation & Control.
In this month's edition, along with this month's industry news to celebrate the 13 years since the group was created we have articles including
A case study of the used of Advanced Process Control at the Wastewater Treatment works at Lleida in Spain
A look back on an article on smart wastewater networks in order to see how the industry has measured up in the interim around the adoption of Digital Transformation in the Water Industry.
Forklift Classes Overview by Intella PartsIntella Parts
Discover the different forklift classes and their specific applications. Learn how to choose the right forklift for your needs to ensure safety, efficiency, and compliance in your operations.
For more technical information, visit our website https://intellaparts.com
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Saudi Arabia stands as a titan in the global energy landscape, renowned for its abundant oil and gas resources. It's the largest exporter of petroleum and holds some of the world's most significant reserves. Let's delve into the top 10 oil and gas projects shaping Saudi Arabia's energy future in 2024.
Pile Foundation by Venkatesh Taduvai (Sub Geotechnical Engineering II)-conver...
Enabling the Duo-phase Data Management to Realize Longevity Bit-alterable Flash Memory.pptx
1. Enabling the Duo-phase Data
Management to Realize Longevity
Bit-alterable Flash Memory
Speaker: Po-Chuan Chen
2. Table of contents
• Abstract
• Introduction
• Background & Motivation
• Flash memory
• Bit-alterable flash memory
• Related works
• Duo-Phase Data Management Scheme
• Bit-count Regulator
• Hot-page monitor
• Data placement strategy
• Duo-phase G.C.
• Algorithm for operations
• Memory footprint analysis
• Further discussions
• Evaluation
• Conclusion
3. Abstract
• Bit-alterable flash memory is a cutting-edge technology that enables a
novel operation, called page-level erase operation.
• But it introduces a new wear-leveling problem that flash pages within
the same block will receive different program/erase (P/E) cycles
during runtime.
4. About this paper
• A duo-phase data management scheme considering the page-level
wear-leveling issue.
• This mechanism simultaneously cares about page- and block-level
wear-leveling issues.
5. Introduction
• Bit-alterable flash memory, might totally avoid the live-page-copying
overhead because of the enabled page level erase operation.
6. Page level wear-leveling issue
• Because some flash pages within the bit-alterable flash memory will
be frequently erased by page level erase operations for avoiding
copying live pages.
• So, the frequently-erased flash pages will reach the limited number of
erase cycles soon.
7. A duo-phase method
Bit-count regulator
Hot-page monitor
Data placement strategy
Duo-phase garbage collector
8. Contribution
• The pioneer to propose a complete solution for the page-level wear-leveling
issue with the bit-alterable flash memory.
• A lightweight solution for FTL management.
(193.52KB size for 128 GB flash memory)
• It can prolong the lifetime of bit-alterable flash memory by 1.5 to 1.9 times.
9. Table of contents
• Abstract
• Introduction
• Background & Motivation
• Flash memory
• Bit-alterable flash memory
• Related works
• Duo-Phase Data Management Scheme
• Bit-count Regulator
• Hot-page monitor
• Data placement strategy
• Duo-phase G.C.
• Algorithm for operations
• Memory footprint analysis
• Further discussions
• Evaluation
• Conclusion
10. The differences between a conventional and bit-alterable flash memory.
It doesn’t need to copy valid pages anymore.
This is because the bit-alterable flash memory
can simultaneously modify multiple
selected bits in a flash page
to support a page erase operation
12. Related Works
• For bit-alterable flash memory, about the page-level and block-level
management, some researchers just claimed that the traditional FTL
can resolve the related issue. But actually it can’t.
• And the page-level wear-leveling issue is still an unsolved and urgent
problem since the bit-alterable flash memory can support page-level
erase operations.
13. Page-level wear-leveling issue
The main problem for this study is how
to achieve page-level wear-leveling
inside a flash block with a nearly-zero
performance overhead
and small memory footprint.
14. Some challenges
A lightweight method should be developed for achieving page-level
wear-leveling in a flash block.
Hot pages should be monitored and processed for avoiding accumulating
erase counts on these flash pages.
A new garbage collection mechanism which choosing the appropriate
victim flash block with the considerations of both performance efficiency
and flash memory lifetime.
15. Table of contents
• Abstract
• Introduction
• Background & Motivation
• Flash memory
• Bit-alterable flash memory
• Related works
• Duo-Phase Data Management Scheme
• Bit-count Regulator
• Hot-page monitor
• Data placement strategy
• Duo-phase G.C.
• Algorithm for operations
• Memory footprint analysis
• Further discussions
• Evaluation
• Conclusion
16. Overview
1. A bit counter as a regulator to
count the number of page-level
erase operations on flash pages.
2. The hot-page monitor will
allocate iron-hot flash pages
for icy-cold data
3. Data placement strategy
within the proposed duo-phase
scheme will cope with all write
requests from the host system
side or garbage collection (GC)
processes.
4. Specialized garbage collector
dedicates on victim selection
and inner/inter block wear-
leveling issues.
(a page or block-level erase
operation for reclaiming invalid
spaces)
17. Bit-count Regulator
• Goal :
It helps the proposed scheme to identify hot flash pages by using few bits.
• Method :
With the bit-count regulator, the number of page-level operations per
flash page will be represented by a few bits stored in the spare area of
the flash page.
18. Hot-page monitor
• Goal :
A hot-page monitor that maintains some iron hot flash pages.
• Method :
It needs , an urgent list to keep the information of iron hot flash pages;
and is enlisted in the hot page monitor. (insertion/deletion)
So, the duo-phase data management scheme has the ability to store
icy cold data into iron hot flash pages.
19. Data placement strategy
• Goal :
To place data into the right flash page space.
• Method :
The duo-phase scheme classified free flash blocks into six different
lists according to its program/erase cycle (young/old) and the MSB
information of the free page within the block (1/0/mixed).
Old
Young
20. When new data write
• Based on the free list design, the data placement strategy will allocate
free spaces to all new written/updated data by finding the free flash
page in the order from P6 to P1 (young to old).
21. When garbage collection
• Categorizing the garbage collection (GC) data into two types:
Old and new data.
• Allocating the free space for the old GC data by checking the free pages
in the urgent list.
• If no free pages are in the urgent list, the data placement strategy will
allocate the space for old GC data by checking free lists in the order
from P1 to P6 (old to young), it can cool down hot flash pages.
22. Duo-phase GC
• Goal :
Try to solve the page-level wear-leveling issue
• Method :
The duo-phase scheme includes a duo-phase garbage collector that can
select the most performance-efficient way to do garbage collection,
considering the inner-block wear-leveling issue.
(performance-oriented victim selector / a page-level wear-leveling strategy)
23. Performance-oriented Victim Selection
• Based on the latencies of page-level and block-level garbage
collection processes.
• If the threshold is positive, choosing block-level GC, otherwise
choose page-level GC
T_Eb : block erase latency
T_Cp : the latency of copying a valid page
N_Valp : the number of valid pages
T_Ep : page erase latency
N_Ialp : the number of invalid pages
24. Calculating efficiency
• Equation 2 presents how to evaluate the efficiency of a garbage
collection process when a block-level GC operation is selected.
• While a flash block is reclaimed its invalid spaces by a page-level GC
operation, the performance efficiency of the flash block can be
estimated by Equation 3.
T_Eb : block erase latency
T_Cp : the latency of copying a valid page
N_Valp : the number of valid pages
T_Ep : page erase latency
N_Ialp : the number of invalid pages
N_IWLp : the number of pages used in
inner-block wear leveling strategy
25. Inner-block Wear-leveling Strategy
• The inner-block wear-leveling strategy will move data stored in the
flash page with MSB 0 to another free page with MSB 1.
N_Valp : the number of valid pages
N_Ialp : the number of invalid pages
N_MSB1 : the number of flash pages
whose MSB is 1
N_MSB0 : the number of flash pages
whose MSB is 0
N_IWLp : the number of pages used in
inner-block wear leveling strategy
Valid → Invalid / MSB 0 → MSB 1
26. Table of contents
• Abstract
• Introduction
• Background & Motivation
• Flash memory
• Bit-alterable flash memory
• Related works
• Duo-Phase Data Management Scheme
• Bit-count Regulator
• Hot-page monitor
• Data placement strategy
• Duo-phase G.C.
• Algorithm for operations
• Memory footprint analysis
• Further discussions
• Evaluation
• Conclusion
27. Operations of Duo-phase Data Management
• Algorithm 1 is data allocation process.
• Algorithm 2 summarizes the operations of a block-level garbage
collection process.
28. Data allocation
Check the request is “write”
Check the free space list from 6 → 1 (young to old)
The free page with MSB 0 will be firstly selected
(in block 5 ~ block 2)
After 3, if the block still has free pages, it won’t
be removed from free space list
But if no free space in the free space list,
the Algorithm will check urgent list, and it will
return the allocated block & page numbers
to the address translator
1
2
3
4
5
29. Data movement
If is the block level, it will move the valid data to the appropriate
pages according to the age of valid data.
If the valid data are young, treating as newly-written data.
Or old valid data will be copied to the old block; first check the
space maintained in the urgent list. If there are no free pages, it
will find a free space by searching the free space lists in the
order from 1 to 6.
Because of old data, the data movement process will firstly
select free pages with MSB 1 to be the destination for live-page
copying, while P2 or P5 is visited.
If it picks up a page-level garbage collection process, all invalid
pages will be erased at first, and the inner-block wear-leveling
process will be taken.
2
3
4
30. Memory footprint analysis
• Based on this case, the memory footprint is the sum of 128 KB
(derived from 32,768 × four bytes), 24 Bytes (derived from 6 × four
bytes), and 65.5 KB (derived from 8,389 × eight bytes).
• Compared with the capacity of flash memory, the memory footprint is
only 193.52 KB that is negligible.
N_B : the number of block
S_TS : the size of time stamp
S_P : the size of pointer
N_PU : the number of flash pages
S_UL : the size of urgent list
31. Further discussions
• Multi-level Cell Flash Memory (TLC/QLC locality)
• Multi-channel Flash Memory Drive (individual do GC in mlti-chip)
32. Table of contents
• Abstract
• Introduction
• Background & Motivation
• Flash memory
• Bit-alterable flash memory
• Related works
• Duo-Phase Data Management Scheme
• Bit-count Regulator
• Hot-page monitor
• Data placement strategy
• Duo-phase G.C.
• Algorithm for operations
• Memory footprint analysis
• Further discussions
• Evaluation
• Conclusion
36. Advanced analysis
• Page erase latency : stable & acceptable
• The number of bit in regulator :
The lifetime decrease as the number of bits in the
regulator counter increase because the gap
between the maximum and minimum erase count
in the same block become large.
• The 95/99th Percentile Latency :
the longest latency but acceptable
37. Conclusion
• This study is the first work to point out the page-level wear-leveling
issue with the bit-alterable flash memory.
• Proposing a novel data management solution, namely the duo-phase
data management scheme.
• The proposed data management scheme can extend the bit-alterable
flash memory lifespan by 1.5 to 1.9 times, compared with other
solutions.