Notes, summaries, assignments, exams, and problems for Computers

1. What is a Public Blockchain?

Public blockchains are open networks that allow anyone to participate. This permissionless nature means anyone can join the network and read, write, or participate in the blockchain.

Public blockchains are decentralized, meaning no single entity controls the network. Data on a public blockchain is secure because it is virtually impossible to modify or alter data once validated on the blockchain.

Features of Public Blockchains:

• High Security: Secured by mining and the 51% rule.
• Open Environment: Open for anyone to join.
• Anonymous Nature: Participants can remain anonymous, enhancing privacy.
• No Regulations: No strict regulations on platform usage.
• Full Transparency: The ledger is publicly viewable, ensuring transparency.

PL/SQL

PL/SQL is a procedural language designed specifically to embrace SQL statements within its syntax. PL/SQL program units are compiled by the Oracle Database server and stored inside the database. And at run-time, both PL/SQL and SQL run within the same server process, bringing optimal efficiency. PL/SQL includes procedural language elements like conditions and loops. It allows declaration of constants and variables, procedures and functions, types and variable of those types and triggers. It can support Array and handle exceptions (runtime errors).

Differences between SQL and PL/SQL

• SQL is a single query that is used to perform DML and DDL operations.
• PL/SQL is a block of codes that used to write the entire program blocks/ procedure/ function,

Data Storage Conversion:

• 1 gigabyte (GB) equals 1,024 megabytes (MB).
• 1 megabyte (MB) equals 1,024 kilobytes (KB).
• To convert gigabytes to kilobytes, multiply by 1,024 twice. For example: 1 GB = 1,024 MB * 1,024 KB = 1,048,576 KB.
• To convert gigabytes to megabytes, multiply by 1,024. For example: 1 GB = 1,024 MB
• To convert 20 megabytes to bytes: 20 MB = 20 * 1,024 KB * 1,024 bytes = 20,971,520 bytes
• To convert 2 gigabytes to kilobytes: 2 GB = 2 * 1,024 MB * 1,024 KB = 2,097,152 KB

Example: SHKRONJA A has a value of 1010, B - 1011, C - 1100, D - 1101, E - 1110, F - 1111.

Binary Number Representations

There are three main ways to represent signed numbers in binary:

1. Signed Magnitude

• Positive Numbers: Standard binary representation.
• Negative Numbers: The

Adding Files

/usr/src/test_kernel/SystemCalls/test_call.c: Creates sys call pointer, Exports the pointer so that syscall module can access it, Define sys call wrapper. /usr/src/test_kernel/SystemCalls/Makefile: obj-y :=test_call.o compiles files directly into kernel.

Modifying Files

/usr/src/test_kernel/SystemModule/syscallModule.c: Holds module code, Implements sys call behaviour Registers syscall pointer to the proper syscall handler. /usr/src/test_kernel/SystemModule/Makefile obj-m :=syscallmodule.o Compiles file as a module.

/usr/src/test_kernel/arch/x86/entry/syscalls/syscall_64.tbl: Add system call to the table. /usr/src/test_kernel/include/linux/syscalls.h: Define the sys call prototype. /usr/src/test_kernel/Makefile: Add the SystemCalls... Continue reading "Adding Files, Modifying Files, Readers-Writers, Deadlock Prevention, Kernel and User Spaces, Cache Misses, TLB Lookups, Disk Access" »

Mechatronics engineers are responsible for designing mechanical equipment. Combining their knowledge of computer, mechanical, and electrical engineering, they develop various automated products, such as cameras, cars, and aircraft. The engineering process typically involves designing and assembling components, testing products in development, making improvements, and evaluating finished products. Engineers must also assess equipment and publish reports outlining production factors, such as practical use, safety, and cost.

Work Areas:

• Electronics Development Unit
• Software Development Unit
• Project Management Unit
• Biomechanical Development Unit including our Mechanical Shop and Scientific Glassblower

Mechanical Engineer Job Duties:

• Evaluates mechanical

10LayerModelSecurity,10Security policies and mandates.9,Oversight of end-to-end processes to ensure compliance with enterprise security policies. Audit trails for the threads.8Security roles and responsibilities. Standard security practices as they relate to activities and exchanges. Security Architecture. Personnel security requirements. 3.10. Management7Application service security (e.g., integrity of the service and application code) and content security (e.g., security labels). Security of user access to IT. Privilege management. 6Framework service security (e.g., integrity of the service and application code of the framework). Content security labeling service and label checking service. Software-based content encryption/decryption services... Continue reading "Layered Security Model and IT Infrastructure Best Practices" »

Module 9: Firebase Application

Realtime Database

A cloud-hosted database. Data is stored as JSON and synchronized in real-time to every connected client. Provides easy-to-use services for authentication (email/password, 3rd-party providers like Google/Facebook).

Cloud Firestore

A flexible and scalable database for mobile, web, and development. It offers synchronization, offline support, and ACID transactions.

Cloud Functions

...

Hosting

CSS/JavaScript

Cloud Storage

Provides robust, secure file uploads and downloads for Firebase apps.

Module 10: UML Diagrams

Structural Diagrams

• Class Diagram: Shows class hierarchy, fields/attributes, and relevant methods.

How to Read

• Visibility:
  • +: Public
  • -: Private
  • #: Protected (accessed only by child classes)
• Relationships:

Annotation Elements

Used to notate and clarify the information presented.

Annotate Ribbon

Buttons: Aligned, Linear, Angular, Radial, Diameter, Arc Length, Spot Elevation, Spot Coordinate, Spot Slope, Detail Line, Region, Component, Revision Cloud, Detail Group, Insulation, Text, Check Spelling, Find/Replace, Tag By Category, Tag All, Beam Annotations, Multi-Category, Material Tag, Area Tag, Room Tag, Space Tag, View Reference, Tread Number, Keynote, Duct Legend, Pipe Legend, Color Fill Legend, and Symbol.

Annotate Ribbon Tab

Panels: Dimension, Detail, Text, Tag, Color Fill, and Symbol.

Application Menu

File access and management tools are grouped in this menu. This menu is designated by the large ‘R’ in the top left corner of the Revit screen.... Continue reading "Revit Elements and Tools: A Comprehensive Dictionary" »

Advantages of E-Governance

• Improves delivery and efficiency of government services.
• Improved government interactions with business and industry.
• Citizen empowerment through access to information.
• More efficient government management

Features of PHP

• Simple: It is very simple and easy to use, as compared to other scripting languages.
• Interpreted: It is an interpreted language, i.e. there is no need for compilation.

Supported Datatypes in PHP

• String: A string is a sequence of characters. A string can be any text inside quotes. You can use single or double-quotes.
• Integer: An integer data type is a non-decimal number between -2,147,483,648 and 2,147,483,647.
• Float (floating point numbers): A float (floating-point number) is a number with a decimal point or

Acid Rain: Concurrency-Related Attacks in Database-Backed Web Applications

Motivation:

• 12 popular self-hosted e-commerce applications (deployed over 2M websites, representing over 50% of all e-commerce websites)
• 22 critical ACIDRain attacks identified and verified
• Flexcoin -> Bankrupted

Problem Definition:

An application is vulnerable if:

• Anomalies Possible: Under concurrent API access, the application may exhibit behaviors (i.e., anomalies) that could not have arisen under serial execution.
• Sensitive Invariants: The anomalies arising from concurrent access lead to violations of application invariants.

Solution:

• Execute API calls against a live application and database to generate a (possibly sequential) trace of database activity.
• Analyze the trace