Recital Web Getting Started
Recital is a dynamic programming language with an embedded high performance database engine particularly well suited for the development and deployment of high transaction throughput applications.
The Recital database engine is not a standalone process with which the application program communicates. Instead, the Recital database is an integral part of any applications developed in Recital.
Recital implements most of the SQL-99 standard for SQL, but also provides lower level navigational data access for performing high transaction throughput. It is the choice of the application developer whether to use SQL, navigational data access, or a combination of both depending upon the type of application being developed.
The Recital database engine, although operating as an embedded database in the user process, multiple users and other background processes may access the same data concurrently. Read accesses are satisfied in parallel. Recital uses automatic record level locking when performing database updates. This provides for a high degree of database concurrency and superior application performance and differentiates the Recital database from other embeddable databases such as sqlite that locks the entire database file during writing.
Key features of the Recital scripting language include:
- High performance database application scripting language
- Modern object-oriented language features
- Easy to learn, easy to use
- Fast, just-in-time compiled
- Loosely-typed
- Garbage collected
- Static arrays, Associative arrays and objects
- Develop desktop or web applications
- Cross-platform support
- Extensive built-in functions
- Superb built-in SQL command integration
- Navigational data access for the most demanding applications
- Scripting language is upward compatible with FoxPRO
Key features of the Recital database include:
- A broad subset of ANSI SQL 99, as well as extensions
- Cross-platform support
- Stored procedures
- Triggers
- Cursors
- Updatable Views
- System Tables
- Query caching
- Sub-SELECTs (i.e. nested SELECTs)
- Embedded database library
- Fault tolerant clustering support
- Chronological data versioning with database timelines
- Optional DES3 encrypted data
- Hot backup
- Client drivers for ODBC, JDBC and .NET
sernet.de maintain the latest Samba releases in a yum repository, allowing for an easy and painless install or upgrade of Samba on your yum based Linux distribution.
To install the latest available Samba execute the following commands at the shell:
# cd /etc/yum.repos.d # wget http://ftp.sernet.de/pub/samba/experimental/centos/5/sernet-samba.repo # yum install samba
To upgrade an existing Samba install:
# cd /etc/yum.repos.d # wget http://ftp.sernet.de/pub/samba/experimental/centos/5/sernet-samba.repo ## Note: edit sernet-samba.repo and add the line "gpgcheck=false" otherwise ## it will not install as it is not signed
# yum update samba
Note: These steps will install the very latest build available at sernet.de.
If you require a less bleeding edge version of Samba, use the "tested" repo. This can be found at the following URL: http://ftp.sernet.de/pub/samba/tested/rhel/5
VMware products, such as ESX, Workstation, Server, and Fusion, come with a built-in VNC server to access guests.
This allows you to connect to the guest without having a VNC server installed in the guest - useful if a server doesn't exist for the guest or if you need access some time when a server would not work (say during the boot process). It's also good in conjunction with Headless Mode.
The VNC server is set up on a per-VM basis, and is disabled by default. To enable it, add the following lines to the .vmx:
RemoteDisplay.vnc.enabled = "TRUE" RemoteDisplay.vnc.port = "5901"
You can set a password with RemoteDisplay.vnc.key; details for how to calculate the obfuscated value given a plaintext password are in Compute hashed password for use with RemoteDisplay.vnc.key.
If you want more than one VM set up in this manner, make sure they have unique port numbers. To connect, use a VNC client pointing at host-ip-address:port. If you connect from a different computer, you may have to open a hole in the OS X firewall. If you use Leopard's Screen Sharing.app on the same computer as Fusion, don't use port 5900 since Screen Sharing refuses to connect to that.
If you have software packages which you wish to share with others or simply between your own personal machines, a neat and easy solution is to create your own YUM repository and provide your .repo file for download.
YUM is by far the easiest method of installing software on Red hat, Centos and Fedora. Not only does it mean you don't need to trawl the web looking for somewhere to download the packages, YUM does a great job of satisfying any package dependencies. As long as the required packages are available in the enabled repositories on your system, YUM will go out and get everything you need.
To create your own YUM repository, you will need to install the yum-utils and createrepo packages:
yum install yum-utils createrepo
yum-utils contains the tools you will need to manage your soon to be created repository, and createrepo is used to create the xml based rpm metadata you will require for your repository.
Once you have installed these required tools, create a directory in your chosen web server's document root e.g:
mkdir -p /var/www/html/repo/recital/updates
Copy the rpm's you wish to host into this newly created directory.
The next step is to create the xml based rpm metadata. To create this use the createrepo program we installed earlier.
At the shell type the following command:
createrepo -v -s md5 /var/www/html/repo/recital/updates
This will create the required metadata in the repodata directory of your /var/www/html/repo/recital/updates directory.
root@test repodata]# ls -l rwotal 44 -rw-r--r-- 1 root root 28996 Jan 13 21:42 filelists.xml.gz -rw-r--r-- 1 root root 284 Jan 13 21:42 other.xml.gz -rw-r--r-- 1 root root 1082 Jan 13 21:42 primary.xml.gz -rw-r--r-- 1 root root 951 Jan 13 21:42 repomd.xml
To do a final consistency check on your repository run the following command:
verifytree /var/www/html/repo/recital/updates
We now have a fully functioning YUM repository for our hosted rpm packages.
The next process is to create a .repo file in the client systems /etc/yum.repos.d directory.
Navigate to the /etc/yum.repos.d directory on your system as root.
Using your preferred text editor to create the .repo file. In this example I will call it recital.repo.
Now paste in the following lines:
[Recital] name=Recital Update Server baseurl=http://ftp.recitalsoftware.com/repo/recital/updates enabled=1 gpgcheck=1
Once that is saved, at the shell prompt on the same machine (YUM client system).
$ yum repolist Loaded plugins: presto, refresh-packagekit repo id repo name status Recital Recital Update Server enabled: 1 adobe-linux-i386 Adobe Systems Incorporated enabled: 17 fedora Fedora 12 - i386 enabled: 15,366
As you can see the Recital repo is now being picked up and we have access to all the packages it is hosting.
See how easy that was!
Key features of the Recital scripting language include:
What are the key feature of the Recital database?
- High performance database application scripting language
- Modern object-oriented language features
- Easy to learn, easy to use
- Fast, just-in-time compiled
- Develop desktop or web applications
- Cross-platform support
- Extensive built-in functions
- Superb built-in SQL command integration
- Navigational data access for the most demanding applications
- For building shared libraries on the MAC the following need to be set
-
- The shared library file extension should be .dylib
- The compile flag is -dynamic
- For accessing the shared libraries at runtime
-
- DYLD_LIBRARY_PATH needs to be set to the location of the shared libraries
- Useful utilities for shared library support
-
- The following command will display the table of contents of the dynamically linked library
otool -TV sharedlibraryfile.dylib
Many motherboards nowadays have integrated gigabit ethernet that use the Realtek NIC chipset.
The Realtek r8168B network card does not work out of the box in Redhat/Centos 5.3: instead of loading the r8168 driver, modprobe loads the r8169 driver, which is broken as can be seen with ifconfig which shows large amounts of dropped packets. A solution is to download the r8168 driver from the Realtek website and install it using the following steps:
Check whether the built-in driver, r8169.ko (or r8169.o for kernel 2.4.x), is installed.
# lsmod | grep r8169
If it is installed remove it.
# rmmod r8169
Download the R8168B linux driver from here into /root.
Unpack the tarball :
# cd /root
# tar vjxf r8168-8.012.00.tar.bz2
Change to the directory:
# cd r8168-8.012.00
If you are running the target kernel, then you should be able to do :
# make clean modules
# make install
# depmod -a
# insmod ./src/r8168.ko (or r8168.o in linux kernel 2.4.x)
make sure modprobe knows not to use r8169, and that depmod doesn’t find the r8169 module.
# echo "blacklist r8169" >> /etc/modprobe.d/blacklist
# mv /lib/modules/`uname -r`/kernel/drivers/net/r8169.ko \ /lib/modules/`uname -r`/kernel/drivers/net/r8169.ko.bak
You can check whether the driver is loaded by using the following commands.
# lsmod | grep r8168
# ifconfig -a
If there is a device name, ethX, shown on the monitor, the linux driver is loaded. Then, you can use the following command to activate it.
# ifconfig ethX up
After this you should not see any more dropped packets reported.
Usually, you do not need to setup an email server under Linux. Most GUI email clients support Gmail POP3 and IMAP configurations. But, how do you send mail via the standard /usr/bin/mail user agents in a shell script? Programs such as sendmail / postfix / exim can be configured as a gmail smarthost but they are largely overkill for this use. The ssmtp program is a neat utility that does just that for you via gmail.