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Computer files are the most basic unit of data that users can store on a disk. Every program, image, video, song and document is stored as a file. this slide describes the concept about files
This presentation gives a basic introduction to files as a Data Structure. Physical Files and Logical Files are covered. Files as a collection of records and as a stream of bytes are talked about. Basic operations in files are explained. C syntax is given. Types of files are briefly talked about.
Concept of computer files for Grade 12 learnerswellingtonoboh
Computer files are the most basic unit of data that users can store on a disk. Every program, image, video, song and document is stored as a file. this slide describes the concept about files
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Improve speed and performance of informix 11.xx part 2am_prasanna
A presentation deck, that takes a deep dive on configuration parameters of IBM Informix database server, enhancing the Performance and thus boosting the speed with which, one can work with Informix DB. The presentation is split into two parts, i.e Part 1 and 2
The biggest headine at the 2009 Oracle OpenWorld was when Larry Ellison announced that Oracle was entering the hardware business with a pre-built database machine, engineered by Oracle. Since then businesses around the world have started to use these engineered systems. This beginner/intermediate-level session will take you through my first 100 days of starting to administer an Exadata machine and all the roadblocks and all the success I had along this new path.
Beyond php - it's not (just) about the codeWim Godden
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Most PHP developers focus on writing code. But creating Web applications is about much more than just wrting PHP. Take a step outside the PHP cocoon and into the big PHP ecosphere to find out how small code changes can make a world of difference on servers and network. This talk is an eye-opener for developers who spend over 80% of their time coding, debugging and testing.
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Beyond php - it's not (just) about the codeWim Godden
Most PHP developers focus on writing code. But creating Web applications is about much more than just wrting PHP. Take a step outside the PHP cocoon and into the big PHP ecosphere to find out how small code changes can make a world of difference on servers and network. This talk is an eye-opener for developers who spend over 80% of their time coding, debugging and testing.
Avoiding Chaos: Methodology for Managing Performance in a Shared Storage A...brettallison
Scope - The primary focus of this presentation is on the methodology we use for managing performance in a very large shared Storage Area Network environment with a Primary focus on Distributed Systems and IBM Enterprise Storage Server. The focus on this presentation is methodology and NOT measurement. There are numerous excellent presentations already out there on measurement. However, there are several references in the back of the presentation to measurement tools.
Why You Should Replace Windows 11 with Nitrux Linux 3.5.0 for enhanced perfor...SOFTTECHHUB
The choice of an operating system plays a pivotal role in shaping our computing experience. For decades, Microsoft's Windows has dominated the market, offering a familiar and widely adopted platform for personal and professional use. However, as technological advancements continue to push the boundaries of innovation, alternative operating systems have emerged, challenging the status quo and offering users a fresh perspective on computing.
One such alternative that has garnered significant attention and acclaim is Nitrux Linux 3.5.0, a sleek, powerful, and user-friendly Linux distribution that promises to redefine the way we interact with our devices. With its focus on performance, security, and customization, Nitrux Linux presents a compelling case for those seeking to break free from the constraints of proprietary software and embrace the freedom and flexibility of open-source computing.
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End to end testing is a critical piece to ensure quality and avoid regressions. In this session, we share our journey building an E2E testing pipeline for GridMate components (LWC and Aura) using Cypress, JSForce, FakerJS…
PHP Frameworks: I want to break free (IPC Berlin 2024)Ralf Eggert
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This talk is aimed at encouraging a more independent approach to using PHP frameworks, moving towards a more flexible and future-proof approach to PHP development.
Transcript: Selling digital books in 2024: Insights from industry leaders - T...BookNet Canada
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Link to video recording: https://bnctechforum.ca/sessions/selling-digital-books-in-2024-insights-from-industry-leaders/
Presented by BookNet Canada on May 28, 2024, with support from the Department of Canadian Heritage.
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GDG Cloud Southlake #33: Boule & Rebala: Effective AppSec in SDLC using Deplo...James Anderson
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The software team must secure its software delivery process to avoid vulnerability and security breaches. This needs to be achieved with existing tool chains and without extensive rework of the delivery processes. This talk will present strategies and techniques for providing visibility into the true risk of the existing vulnerabilities, preventing the introduction of security issues in the software, resolving vulnerabilities in production environments quickly, and capturing the deployment bill of materials (DBOM).
Speakers:
Bob Boule
Robert Boule is a technology enthusiast with PASSION for technology and making things work along with a knack for helping others understand how things work. He comes with around 20 years of solution engineering experience in application security, software continuous delivery, and SaaS platforms. He is known for his dynamic presentations in CI/CD and application security integrated in software delivery lifecycle.
Gopinath Rebala
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Welcome to UiPath Test Automation using UiPath Test Suite series part 5. In this session, we will cover CI/CD with devops.
Topics covered:
CI/CD with in UiPath
End-to-end overview of CI/CD pipeline with Azure devops
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In this work, we equipped AFL, a popular fuzzer, with DIAR and examined two critical Linux libraries -- Libxml's xmllint, a tool for parsing xml documents, and Binutil's readelf, an essential debugging and security analysis command-line tool used to display detailed information about ELF (Executable and Linkable Format). Our preliminary results show that AFL+DIAR does not only discover new paths more quickly but also achieves higher coverage overall. This work thus showcases how starting with lean and optimized seeds can lead to faster, more comprehensive fuzzing campaigns -- and DIAR helps you find such seeds.
- These are slides of the talk given at IEEE International Conference on Software Testing Verification and Validation Workshop, ICSTW 2022.
UiPath Test Automation using UiPath Test Suite series, part 4DianaGray10
Welcome to UiPath Test Automation using UiPath Test Suite series part 4. In this session, we will cover Test Manager overview along with SAP heatmap.
The UiPath Test Manager overview with SAP heatmap webinar offers a concise yet comprehensive exploration of the role of a Test Manager within SAP environments, coupled with the utilization of heatmaps for effective testing strategies.
Participants will gain insights into the responsibilities, challenges, and best practices associated with test management in SAP projects. Additionally, the webinar delves into the significance of heatmaps as a visual aid for identifying testing priorities, areas of risk, and resource allocation within SAP landscapes. Through this session, attendees can expect to enhance their understanding of test management principles while learning practical approaches to optimize testing processes in SAP environments using heatmap visualization techniques
What will you get from this session?
1. Insights into SAP testing best practices
2. Heatmap utilization for testing
3. Optimization of testing processes
4. Demo
Topics covered:
Execution from the test manager
Orchestrator execution result
Defect reporting
SAP heatmap example with demo
Speaker:
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DevOps and Testing slides at DASA ConnectKari Kakkonen
My and Rik Marselis slides at 30.5.2024 DASA Connect conference. We discuss about what is testing, then what is agile testing and finally what is Testing in DevOps. Finally we had lovely workshop with the participants trying to find out different ways to think about quality and testing in different parts of the DevOps infinity loop.
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Clients don’t know what they don’t know. What web solutions are right for them? How does WordPress come into the picture? How do you make sure you understand scope and timeline? What do you do if sometime changes?
All these questions and more will be explored as we talk about matching clients’ needs with what your agency offers without pulling teeth or pulling your hair out. Practical tips, and strategies for successful relationship building that leads to closing the deal.
In his public lecture, Christian Timmerer provides insights into the fascinating history of video streaming, starting from its humble beginnings before YouTube to the groundbreaking technologies that now dominate platforms like Netflix and ORF ON. Timmerer also presents provocative contributions of his own that have significantly influenced the industry. He concludes by looking at future challenges and invites the audience to join in a discussion.
Epistemic Interaction - tuning interfaces to provide information for AI supportAlan Dix
Paper presented at SYNERGY workshop at AVI 2024, Genoa, Italy. 3rd June 2024
https://alandix.com/academic/papers/synergy2024-epistemic/
As machine learning integrates deeper into human-computer interactions, the concept of epistemic interaction emerges, aiming to refine these interactions to enhance system adaptability. This approach encourages minor, intentional adjustments in user behaviour to enrich the data available for system learning. This paper introduces epistemic interaction within the context of human-system communication, illustrating how deliberate interaction design can improve system understanding and adaptation. Through concrete examples, we demonstrate the potential of epistemic interaction to significantly advance human-computer interaction by leveraging intuitive human communication strategies to inform system design and functionality, offering a novel pathway for enriching user-system engagements.
4. Definitions
Seek time
– Average time to move the read-write head
Rotational delay
– Average time for the sector to move under the
read-write head
Transfer
– Time to read a sector and transfer the data to
memory
5. More Definitions
Logical Record
– The data about an entity (a row in a table)
Physical Record
– A sector, page or block on the storage medium
Typically several logical records can be
stored in one physical record.
7. Heap File
ID Company Industry Symbl. Price Earns. Dividnd.
1767 Tony Lama Apparel TONY 45.00 1.50 0.25
1152 Lockheed Aero LCH 112.00 1.25 0.50
1175 Ford Auto F 88.00 1.70 0.20
1122 Exxon Oil XON 46.00 2.50 0.75
1231 Intel Comp. INTL 30.00 2.00 0.00
1323 GM Auto GM 158.00 2.10 0.30
1378 Texaco Oil TX 230.00 2.80 1.00
1245 Digital Comp. DEC 120.00 1.80 0.10
Tony Lama was the first record added,
Digital was the last.
8. Heap File Characteristics
Insertion
– Fast: New records added at the end of the file
Retrieval
– Slow: A sequential search is required
Update - Delete
– Slow:
Sequential search to find the page
Make the update or mark for deletion
Re-write the page
9. Sequential (Ordered) File
ID Company Industry Symbl. Price Earns. Dividnd.
1122 Exxon Oil XON 46.00 2.50 0.75
1152 Lockheed Aero LCH 112.00 1.25 0.50
1175 Ford Auto F 88.00 1.70 0.20
1231 Intel Comp. INTL 30.00 2.00 0.00
1245 Digital Comp. DEC 120.00 1.80 0.10
1323 GM Auto GM 158.00 2.10 0.30
1378 Texaco Oil TX 230.00 2.80 1.00
1480 Conoco Oil CON 150.00 2.00 0.50
1767 Tony Lama Apparel TONY 45.00 1.50 0.25
11. Sequential File Characteristics
Older media (cards, tapes)
Records physically ordered by primary key
Use when direct access to individual records
is not required
Accessing records
– Sequential search until record is found
Binary search can speed up access
– Must know file size and how to determine mid-
point,
12. Inserting Records in SAM files
Insertion
– Slow:
Sequential search to find where the record goes
If sufficient space in that page, then rewrite
If insufficient space, move some records to next
page
If no space there, keep bumping down until space is
found
– May use an “overflow” file to decrease time
13. Deletions and Updates to SAM
Deletion
– Slow:
Find the record
Either mark for deletion or free up the space
Rewrite
Updates
– Slow:
Find the record
Make the change
Rewrite
14. Binary Search to Find GM
(1323)
ID Company Industry Symbl. Price Earns. Dividnd.
1122 Exxon Oil XON 46.00 2.50 0.75
1152 Lockheed Aero LCH 112.00 1.25 0.50
1175 Ford Auto F 88.00 1.70 0.20
1231 Intel Comp. INTL 30.00 2.00 0.00
1. 1245 Digital Comp. DEC 120.00 1.80 0.10
3. 1323 GM Auto GM 158.00 2.10 0.30
2. 1378 Texaco Oil TX 230.00 2.80 1.00
1480 Conoco Oil CON 150.00 2.00 0.50
1767 Tony Lama Apparel TONY 45.00 1.50 0.25
Takes 3 accesses as opposed to 6 for linear search.
15. Indexed Sequential
Disk (usually)
Records physically ordered by primary key
Index gives physical location of each record
Records accessed sequentially or directly
via the index
The index is stored in a file and read into
memory when the file is opened.
Indexes must be maintained
16. Indexed Sequential Access
Given a value for the key
– search the index for the record address
– issue a read instruction for that address
– Fast: Possibly just one disk access
18. Inserting into ISAM files
Not very efficient
– Indexes must be updated
– Must locate where the record should go
– If there is space, insert the new record and
rewrite
– If no space, use an overflow area
– Periodically merge overflow records into file
19. Deletion and Updates for ISAM
Fairly efficient
– Find the record
– Make the change or mark for deletion
– Rewrite
– Periodically remove records marked for
deletion
20. Use ISAM files when:
Both sequential and direct access is needed.
Say we have a retail application like Foley’s.
Customer balances are updated daily.
Usually sequential access is more efficient for
batch updates.
But we may need direct access to answer
customer questions about balances.
21. Direct or Hashed Access
A portion of disk space is reserved
A “hashing” algorithm computes record
address
Hashing
Algorithm
455-72-3566
Address
Overflow
376-87-3425
Address
22. Hashed Access Characteristics
No indexes to search or maintain
Very fast direct access
Inefficient sequential access
Use when direct access is needed, but
sequential access is not.
23. Secondary Indexes
Provide access via non-key attributes
Three data structures discussed here:
– Linked lists: embedded pointers
– Inverted lists: cross-index tables
– B-Trees
24. Simple Linked List: Oil Industry
Head: 1122
ID Company Industry Symbl. Price Earns. Dividnd. Next Rec.
1122 Exxon Oil XON 46.00 2.50 0.75 1378
1152 Lockheed Aero LCH 112.00 1.25 0.50
1175 Ford Auto F 88.00 1.70 0.20
1231 Intel Comp. INTL 30.00 2.00 0.00
1245 Digital Comp. DEC 120.00 1.80 0.10
1323 GM Auto GM 158.00 2.10 0.30
1378 Texaco Oil TX 230.00 2.80 1.00 1480
1480 Conoco Oil CON 150.00 2.00 0.50 -null-
1767 Tony Lama Apparel TONY 45.00 1.50 0.25
25. Ring: Oil Industry
Conoco points to the head of the list.
Head: 1122
ID Company Industry Symbl. Price Earns. Dividnd. Next Rec.
1122 Exxon Oil XON 46.00 2.50 0.75 1378
1152 Lockheed Aero LCH 112.00 1.25 0.50
1175 Ford Auto F 88.00 1.70 0.20
1231 Intel Comp. INTL 30.00 2.00 0.00
1245 Digital Comp. DEC 120.00 1.80 0.10
1323 GM Auto GM 158.00 2.10 0.30
1378 Texaco Oil TX 230.00 2.80 1.00 1480
1480 Conoco Oil CON 150.00 2.00 0.50 1122
1767 Tony Lama Apparel TONY 45.00 1.50 0.25
26. Types of List
Non-dense: Few records (Oil stocks)
Dense: Many or all records (Symbol)
Two-way: Next and Prior pointers
Multi-list: Many lists on the same record
type
27. Processing with Lists
Assume an Oil industry list and the query:
SELECT * FROM STOCKS
WHERE INDUSTRY = “Oil” AND EARNINGS > 2.50
Fetch head of oil industry list.
Until Next Record Pointer = -null-
Fetch oil industry record.
If Earnings > 2.50, include on output list.
End Until.
28. Problems with lists
Difficult to maintain
Broken pointer chains
Inefficient to search dense lists for one or a
few records
31. Select * From Stocks Where Earnings > 2.00
and Dividends < 0.60
Earnings Dividends
Values Occurrences Values Occurrences
1.25 1152 0.00 1231
1.50 1767 0.10 1245
1.70 1175 0.20 1175
2.00 1231, 1480 0.25 1767
2.10 1323 0.30 1323
2.50 1122 0.50 1152
2.80 1378 0.75 1122
1.00 1378
Only one record must be fetched !
32. B-Trees
Hierarchical (tree) structure
Balanced
– all paths from top to bottom the same length
Consist of:
– Index Set: Indexed access for the key field
– Sequence Set: Sequential access for the key field
33. A B-Tree of Order 3 and Height 2 for Stock Symbol
Number of levels in the index set
Number of values per level minus 1
Level O Index
Index Symbol Key Index Symbol Key Index Symbol Key
11 F 1175 12 TONY 1767 13
Index 11 Index 12 Index 13
Symbol Key Symbol Key Symbol Key
CON 1480 GM 1323 TX 1378
DEC 1245 INTL 1231 XON 1122
LCH 1152
Sequence Set
CON 1245 DEC 1420 F 1175
GM 1323 INTL 1231 LCH 1152
TONY 1767 TX 1378 XON 1122
34. Summary
Three file organizations
– Heaps
– Sorted
Sequential Access Method
Indexed Sequential Access Method
– Direct Access Method
Three data structures for secondary keys
– Linked lists, Inverted lists, B-trees