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The post Best Java IDE’s for Linux Developers first appeared on Tecmint: Linux Howtos, Tutorials & Guides .

Brief: This article guide highlights the most widely used Java IDEs for developing Java applications. Java is a high-level, object-oriented, and general-purpose programming language that is widely used to build robust and secure web

The post Best Java IDE’s for Linux Developers first appeared on Tecmint: Linux Howtos, Tutorials & Guides.

Learn the OSI model in 5 minutes Anamika Tue, 10/04/2022 - 03:00

The Open Systems Interconnection (OSI) model is a standard for how computers, servers, and people communicate within a system. It was the first standard model for network communications and was adopted in the early 1980s by all major computer and telecommunications companies.

The OSI model provides a universal language for describing networks and thinking about them in discrete chunks, or layers.

Layers of the OSI model

The model describes the seven layers through which computer systems communicate over a network.

1. Application layer
2. Presentation layer
3. Session layer
4. Transport layer
5. Network layer
6. Data link layer
7. Physical layer

Each of these layers has its own way of working, with its own set of protocols that distinguish it from the others. This article provides a breakdown of the layers one by one.

Application layer

The application layer is implemented in software. It is the layer used to interact with applications.

Consider the example of sending a message. The sender will interact with the application layer and send the message. The application layer sends the message to the next layer in the OSI Model, the presentation layer.

Presentation layer

The data from the application layer is forwarded to the presentation layer. The presentation layer receives the data in the form of words, characters, letters, numbers, and so on, and converts them into machine representable binary format. This process is known as translation.

At this stage, ASCII characters (American Standard Code for Information Interchange) are converted into Extended Binary Coded Decimal Interchange Code (EBCDIC). Before the converted data goes further, it also undergoes encoding and encryption processes, using the SSL protocol for encryption and decryption.

The presentation layer provides abstraction and assumes that the layers following it will take care of the data forwarded to them from this layer. It also plays a role in compression of the data. The compression can be lossy or lossless, depending on various factors beyond this article's scope.

Session layer

The session layer helps in setting up and managing connections. The main work of this layer is to establish a session. For example, on an online shopping site, a session is created between your computer and the site's server.

The session layer enables the sending and receiving of data, followed by the termination of connected sessions. Authentication is done before a session is established, followed by authorization. Like the previous layers, the session layer also assumes that, after its work is done, the data will be correctly handled by the subsequent layers.

More on edge computing Understanding edge computing Why Linux is critical to edge computing eBook: Running Kubernetes on your Raspberry Pi Download now: The automated enterprise eBook eBook: A practical guide to home automation using open source tools eBook: 7 examples of automation on the edge The latest on edge Transport layer

The transport layer manages data transportation and its own set of protocols for how data will be transferred. The data received here from the session layer is divided into smaller data units called segments. This process is known as segmentation. Every segment contains the source's and destination's port numbers and a sequence number. Port numbers identify the application on which the data needs to be sent. Note that the data is transferred in chunks. The sequence numbers are used to reassemble the segments in the correct order.

The transport layer takes care of the flow control, or the amount of data transferred at a given time. It also accounts for error control, such as data loss, data corruption, and so on. It makes use of an error-detecting value known as a checksum. The transport layer adds a checksum to every data segment to check whether the sent data is received correctly. Data is then transferred to the network layer.

Network layer

The network layer helps communicate with other networks. It works to transmit received data segments from one computer to another located in a different network. The router lives in the network layer.

The function of the network layer is logical addressing (IP Addressing). It assigns the sender's and receiver's IP addresses to each data packet to ensure it is received at the correct destination. The network layer then routes the data packets. Load balancing also happens in the network layer to make sure that no overloading takes place. Next, the data is transported to the data link layer.

Data link layer

The data link layer allows direct communication with other devices, such as computers and hosts.

It receives data packets containing the IP addresses of the sender and receiver from the network layer and does the physical addressing, assigning the media access control (MAC) addresses of the sender and receiver to a data packet to form a frame.

Physical layer

This layer consists of all the hardware and mechanical elements of a system, including the configuration of wires, pins, adapters, and so forth. The data received here by the preceding layers is in the form of 0s and 1s. The physical layer converts this data and transports it to local media via various means, including wires, electrical signals, light signals (as in optical fiber cables), and radio signals (as in WiFi).

Note that the physical layer works at the receiver's end and transports the received signal to the data link as a frame (by converting it back to bits). The frame is moved to the higher layers, and ultimately the required data is received at the application layer, which is the software.

Conclusion

The OSI model is helpful when you need to describe network architecture or troubleshoot network problems. I hope this article gave you a clearer understanding of the elements this model. 

Get the basics of the Open Systems Interconnection (OSI) framework for conceptualizing communication within a computer system.

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5 new improvements in Apache ShardingSphere Yacine Si Tayeb, PhD Tue, 10/04/2022 - 03:00

Apache ShardingSphere, a powerful distributed database, recently released a major update to optimize and enhance its features, performance, testing, documentation, and examples. In short, the project continues to work hard at development to make it easier for you to manage your organization's data.

1. SQL audit for data sharding

The problem: When a user executes an SQL query without the sharding feature in large-scale data sharding scenarios, the SQL query is routed to the underlying database for execution. As a result, many database connections are occupied, and businesses are severely affected by a timeout or other issues. Worse still, should the user perform an UPDATE/DELETE operation, a large amount of data may be incorrectly updated or deleted.

ShardingSphere's solution: As of version 5.2.0, ShardingSphere provides the SQL audit for data sharding feature and allows users to configure audit strategies. The strategy specifies multiple audit algorithms, and users can decide whether audit rules should be disabled. SQL execution is strictly prohibited if any audit algorithm fails to pass.

Here's the configuration of an SQL audit for data sharding:

rules:
- !SHARDING
  tables:
    t_order:
      actualDataNodes: ds_${0..1}.t_order_${0..1}
      tableStrategy:
        standard:
          shardingColumn: order_id
          shardingAlgorithmName: t_order_inline
      auditStrategy:
        auditorNames:
          - sharding_key_required_auditor
        allowHintDisable: true
  defaultAuditStrategy:
    auditorNames:
      - sharding_key_required_auditor
    allowHintDisable: true  auditors:
    sharding_key_required_auditor:
      type: DML_SHARDING_CONDITIONS

Given complex business scenarios, this new feature allows you to dynamically disable the audit algorithm by using SQL hints so that partial business SQL operations can be executed.

ShardingSphere has a built-in DML disables full-route audit algorithm. You can also implement a ShardingAuditAlgorithm interface to gain advanced SQL audit functions:

/* ShardingSphere hint: disableAuditNames=sharding_key_required_auditor */ SELECT * FROM t_order;2. SQL execution process management

The ShardingSphere MySQL database provides a SHOW PROCESSLIST statement, allowing you to view the currently running thread. You can kill the thread with the KILL statement for SQL that takes too long to be temporarily terminated.

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(Duan Zhengqiang, CC BY-SA 4.0)

The SHOW PROCESSLIST and KILL statements are widely used in daily operation and maintenance management. To enhance your ability to manage ShardingSphere, version 5.2.0 supports the MySQL SHOW PROCESSLIST and KILL statements. When you execute a DDL/DML statement through ShardingSphere, ShardingSphere automatically generates a unique UUID identifier and stores the SQL execution information in each instance.

When you execute the SHOW PROCESSLIST statement, ShardingSphere processes the SQL execution information based on the current operating mode.

If the current mode is cluster mode, ShardingSphere collects and synchronizes the SQL execution information of each compute node through the governance center and then returns the summary to the user. If the current mode is the standalone mode, ShardingSphere only returns SQL execution information in the current compute node.

You get to determine whether to execute the KILL statement based on the result returned by SHOW PROCESSLIST, and ShardingSphere cancels the SQL in execution based on the ID in the KILL statement.

More on data science What is data science? What is Python? How to become a data scientist Data scientist: A day in the life What is big data? Whitepaper: Data-intensive intelligent applications in a hybrid cloud blueprint MariaDB and MySQL cheat sheet Latest data science articles 3. Shardingsphere-on-cloud

Shardingsphere-on-cloud is a project of Apache ShardingSphere providing cloud-oriented solutions. Version 0.1.0 has been released, and it has been officially voted as a sub-project of Apache ShardingSphere.

Shardinsphere-on-cloud will continue releasing configuration templates, deployment scripts, and other automation tools for ShardingSphere on the cloud.

It will also polish the engineering practices in terms of high availability, data migration, observability, shadow DB, security, and audit, optimize the delivery mode of Helm Charts, and continue to enhance its cloud-native management capabilities through Kubernetes Operator. There are already introductory issues in the project repository to help those interested in getting Go, Database, and Cloud up and running quickly.

4. Access port

In version 5.2.0, ShardingSphere-Proxy can monitor specified IP addresses and integrate openGauss database drivers by default. ShardingSphere-JDBC supports c3p0 data sources, and a Connection.prepareStatement can specify the columns.

5. Distributed transaction

The original logical database-level transaction manager has been adjusted to a global manager, supporting distributed transactions across multiple logical databases. XA transactions are now automatically managed by ShardingSphere, which removes the XA statement's ability to control distributed transactions.

Use ShardingSphere for distributed data

ShardingSphere supports multiple databases, and each improvement takes more work off your hands. The establishment of the shardingsphere-on-cloud sub-project shows ShardingSphere's commitment to being cloud-native. The greater ShardingSphere community welcomes anyone interested in Go, databases, and the cloud to join the shardingsphere-on-cloud sub-project!

The article was first published on Medium.com and has been republished with permission.

ShardingSphere supports multiple databases, and each improvement in the 5.2.0 release takes more work off your hands.

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