I am pleased to finally report that the Centos release of Redhats 5.3 has been built and is available for download from http://www.centos.org/

The highlights of this release can be found at the following URL: http://www.redhat.com

The main areas of interest in my opinion excluding critical secirty fixes are:

• Updated hardwaresupport support for the new Intel Core i7 (Nehalem) chips
• Beefed up virtualiseation support increasing CPU and Ram limits of Virtual machines.
• Inclusion of the fully open sourced OpenJDK. This makes Red Hat Enterprise Linux 5.3 the first enterprise-ready solution with a fully open source Java stack when combined with JBoss Enterprise Application Platform.

For those who already have Centos 5.2 installed you can simply receive the update via Yum.

Before you do the following, check that  you do not have 3rd party repo's and the Centos-testing repo enabled.

You can display the currently enabled repo's using the following command.

$ yum repolist

Then as root at the prompt type:

$ yum update

When stress testing our loadbalancer, i was unable to get more than 20 reliable ssh connections. The following error would be reported.

ssh_exchange_identification: Connection closed by remote host

The resolution for this is quite simple.

Edit the /etc/ssh/sshd_config file and increase the MaxStartups. On my server i set this to 200.

Edit /etc/sysctrl.conf and add the following line:

net.core.netdev_max_backlog = 3000

Then apply this change:

# sysctl -p

In this article Barry Mavin, CEO and Chief Software Architect for Recital, details how to use the Client Drivers provided with the Recital Database Server to work with local or remote server-side OLE DB data sources.

Overview

The Recital Universal .NET Data Provider provides connectivity to the Recital Database Server running on any supported platform (Windows, Linux, Unix, OpenVMS) using the RecitalConnection object.

The Recital Universal JDBC Driver provides the same functionality for java applications.

The Recital Universal ODBC Driver provides the same functionality for applications that use ODBC.

Each of the above Client Drivers use a connection string to describe connections parameters.

The basic format of a connection string consists of a series of keyword/value pairs separated by semicolons. The equal sign (=) connects each keyword and its value.

The following table lists the valid names for keyword/values.

To connect to a server-side OLE DB data source, you use the gateway=value key/value pair in the following way.

gateway=oledb:oledb_connection_string_on_server

You can find examples of connection strings for most ODBC and OLE DB data sources by clicking here.

Example in C# using the Recital Universal .NET Data Provider:

////////////////////////////////////////////////////////////////////////
// include the references below
using System.Data;
using Recital.Data;
 
////////////////////////////////////////////////////////////////////////
// The following code example creates an instance of a DataAdapter that 
// uses a Connection to the Recital Database Server, and a gateway to
// the SQL server Northwind database. It then populates a DataTable 
// in a DataSet with the list of customers. The SQL statement and 
// Connection arguments passed to the DataAdapter constructor are used 
// to create the SelectCommand property of the DataAdapter.
public DataSet SelectCustomers()
{
	string gateway = "oledb:Provider=sqloledb;Initial Catalog=Northwind;
		Data Source=localhost;Integrated Security=SSPI";
	RecitalConnection swindConn = new 
		RecitalConnection("Data Source=localhost;gateway=\""+gateway+"\");
	RecitalCommand selectCMD = new 
		RecitalCommand("SELECT CustomerID, CompanyName FROM Customers", swindConn);
	selectCMD.CommandTimeout = 30;
	RecitalDataAdapter custDA = new RecitalDataAdapter();
	custDA.SelectCommand = selectCMD;
	swindConn.Open();
	DataSet custDS = new DataSet();
	custDA.Fill(custDS, "Customers");
	swindConn.Close();
	return custDS;
}

Example in Java using the Recital Universal JDBC Driver:

////////////////////////////////////////////////////////////////////////
// standard imports required by the JDBC driver
import java.sql.*;
import java.io.*;
import java.net.URL;
import java.math.BigDecimal;
import Recital.sql.*;
 
////////////////////////////////////////////////////////////////////////
// The following code example creates a Connection to the Recital 
// Database Server, and a gateway to the SQL server Northwind database. 
// It then retrieves all the customers.
public void SelectCustomers()
{
    // setup the Connection URL for JDBC
	String gateway = "oledb:Provider=sqloledb;Initial Catalog=Northwind;
		Data Source=localhost;Integrated Security=SSPI";
	String url = "jdbc:Recital:Data Source=localhost;gateway=\""+gateway+"\";
	// load the Recital Universal JDBC Driver
	new RecitalDriver();
 
	// create the connection
	Connection con = DriverManager.getConnection(url);
	// create the statement
	Statement stmt = con.createStatement();
	// perform the SQL query
	ResultSet rs = stmt.executeQuery("SELECT CustomerID, CompanyName FROM Customers");
	// fetch the data
	while (rs.next()) 
	{
		String CompanyID = rs.getString("CustomerID");
		String CompanyName = rs.getString("CompanyName");
		// do something with the data...
	}
    
	// Release the statement
	stmt.close();
	
	// Disconnect from the server
	con.close();
}

In this article Barry Mavin, CEO and Chief Software Architect for Recital provides details on how the Recital Database Server can be used to provide a solution for Universal Data Integration.

Overview

The Recital Database Server handles universal cross-platform data access to a wide range of data sources. The database server natively handles full remote SQL data access to Recital, Visual FoxPro, FoxPro, FoxBASE, Clipper and older dBase data. Using Bridges, it handles full remote SQL data access to C-ISAM and OpenVMS RMS. Using gateway connections, it handles full remote SQL data access to Oracle, MySQL, PostgreSQL, SQL Server, server-side ODBC, server-side JDBC and server-side OLE DB data sources. With its ability to access data using server-side ODBC, JDBC and OLE DB drivers from clients on all supported operating systems (Windows, Linux, Unix, OpenVMS), the Recital Database Server is an ideal Data Integration Solution for applications of all sizes and complexity.

Universal Data Integration Solutions

There are several ways in which data may be accessed by the Database Server.

Table 1:

Client Universal Data Access solutions for accessing local or remote data.

Table 2:

Windows Server Universal Data Access solutions accessible from any remote client running on Windows, Linux, Unix or OpenVMS:

Table 3:

Linux and Unix Server Universal Data Access solutions accessible from any remote client running on Windows, Linux, Unix or OpenVMS:

Table 4:

OpenVMS Server Universal Data Access solutions accessible from any remote client running on Windows, Linux, Unix or OpenVMS:

Supported Data Sources

Native Data Access

The Recital Database Server has native built-in support for the following data sources:

• Recital
• Visual FoxPro
• FoxPro
• FoxBASE
• Clipper
• dBase

You can setup tables to work with using the Database Administration Tool in Recital Enterprise Studio.

Bridges

Using Bridges, you can access the following data sources as if they were standard Recital/FoxPro tables:

• CISAM
• OpenVMS RMS

You can setup bridges using the Database Administration Tool in Recital Enterprise Studio.

Gateways/Connections

Using Gateways, you can transparently access the following local or remote data sources:

• Recital
• Oracle
• ODBC (Server-side ODBC data sources)
• JDBC (Server-side JDBC data sources)
• OLEDB Use this to connect to SQL Server and other Windows OLE DB data sources)
• MySQL
• PostgreSQL

Remote Data Object functions

Recital 10 includes a complete and robust set of data source independent functions for accession MySQL, Oracle, DB2 and Postgres. This article explains how to use them.

Client Data Access drivers

Included with the Recital Database Server are three Client drivers. These Client drivers can access any data sources supported by the Recital Database Server. They are not restricted to accessing only Recital data. They can be used to access server-side ODBC, JDBC and OLE DB data sources also.

Recital Universal .NET Data Provider

Use this client driver when building .NET applications with Visual Studio .NET. A data provider in the .NET Framework serves as a bridge between an application and a data source. A data provider is used to retrieve data from a data source and to reconcile changes to that data back to the data source.

Key features of the Recital Universal .NET Data Provider:

• Fully Internet enabled
  The Recital Universal .NET Data Provider works across the internet providing access to a wide range of data sources located on remote servers running Windows, Linux, Unix and OpenVMS.
• SQL Server compatible
  The Recital Universal .NET Data Provider is plug compatible with the .NET Framework SQL Server Data Provider.
• Cross-platform Data Integration
  Using the Recital Universal .NET Data Provider, you can connect to remote Windows, Linux, Unix or OpenVMS servers and access any data source supported by the Recital Database Server.
• Managed code
  The Recital Universal .NET Data Adaptor written in C# is 100% .NET Framework managed code.
• Runs on Windows Mobile
  The Recital Universal .NET Data Adaptor runs under the .NET Compact Framework on Windows Mobile.

Recital Universal JDBC Driver

The JDBC API is the industry standard for database-independent connectivity between the Java programming language and a wide range of databases. The JDBC API provides a call-level API for SQL-based database access. JDBC technology allows you to use the Java programming language to exploit "Write Once, Run Anywhere" capabilities for applications that require access to enterprise data.

Key features of the Recital Universal JDBC Driver:

• Fully Internet enabled
  The Recital Universal JDBC driver works across the internet providing access to a wide range of data sources located on remote servers running Windows, Linux, Unix and OpenVMS.
• JDBC 3.0 API
  The Recital Universal JDBC driver supports the JDBC 3.0 API.
• Pure Java Type 3 Driver
  The Recital Universal JDBC driver is a 100% pure Java Type 3 driver.
• Full Access to Metadata
  The JDBC API provides metadata access that enables the development of sophisticated applications that need to understand the underlying facilities and capabilities of a specific database connection.
• Cross-platform Data Integration
  Using the Recital Universal JDBC driver, you can connect to remote Windows, Linux, Unix or OpenVMS servers and access any data source supported by the Recital Database Server.
• No Installation
  A pure JDBC technology-based driver does not require special installation; it is automatically downloaded as part of the applet that makes the JDBC calls. The Recital Universal JDBC Driver is 100% java.

Recital Universal ODBC Driver

Connect to remote data from Microsoft Office or other applications that support ODBC data access. The Recital Universal ODBC Driver is also available for Linux and Unix.

Key features of the Recital Universal ODBC Driver:

• Fully Internet enabled
  The Recital Universal ODBC driver works across the internet providing access to a wide range of data sources located on remote servers running Windows, Linux, Unix and OpenVMS.
• Works with Crystal Reports
  The Recital Universal ODBC driver supports the SQL syntax generated by Crystal Reports.
• Works with Microsoft Office
  The Recital Universal ODBC driver works with Microsoft Office products.
• Works with PHP on Linux
  The Recital Universal ODBC driver is available for Linux and works with PHP.