Over the past decade, higher network bandwidths and processing power has resulted in a significant increase in the demand placed on storage requirements. Plunging storage media costs and the mission-critical nature of data have both spurred the implementation of redundant data storage, or better known as storage replication to ensure higher availability of reliability of stored data.

Another important concept which has evolved alongside storage replication is storage virtualization. Simply put, storage virtualization allows a user or an application to access a storage volume as if it were connected physically to the host computer or server, where in fact, the physical storage device is residing on a set of one or more network connected servers.

Typically, storage virtualization is achieved using one of three implementations, namely host-based, storage device based and network based. Host-based virtualization has been around in operating systems for a long time. To illustrate with a simple example, a single 2 TB hard drive can be partitioned into multiple logical or virtual drives of smaller sizes. Users and applications utilize the logical drive as if it were an actual physical storage device. The operating system or host handles and interprets the I/O requests which are translated to the physical level.

Storage device based virtualization is best explained with RAID devices where a set of physical devices can present themselves as a single abstracted storage location to the host computer or server. Besides virtualization, disk arrays can also provide cloning, snapshots and remote replication.

Network based is the third and most popular implementation of storage virtualization, and is achieved using high availability storage software. In this implementation, existing server and network resources are utilized to create networked SAN typically utilizing iSCSI or FC or Fibre Channel technologies. Fibre Channel technology requires storage servers to be connected using dedicated Fibre cabling which is expensive but guarantees high data throughput. iSCSI Storage is the more popular implementation which is also known as SCSI over IP. This technology allows organizations to leverage existing server and network infrastructure to create highly available and reliable Storage Area Networks or SANs.

StarWind Software is the developer and vendor of StarWind 5.0, an SAN Software utilizing iSCSI Storage that turns any industry-standard server into a highly reliable and highly available enterprise-class SAN or centralized storage. StarWind 5.0 works extremely well as a centralized storage system for Server applications such as Microsoft SQL Server, Oracle, Microsoft Exchange Server, Microsoft Sharepoint Server or any other data-driven server application.

Additionally, StarWind 5.0 is also well suited for use in conjunction with application server virtualization platforms such as VMWare, Microsoft Hyper-V R2, creating robust, high-availability virtual servers, minimizing downtime and maximizing productivity.

On either implementation scenarios, users are provided with an entire suite of features which include Synchronous Data Mirroring, Automatic Failover, Failback with Fast Synchronization, Remote/Asynchronous Replication, CDP & Snapshots, Server Clustering and Thin Provisioning.

If you would like to maximize your IT infrastructure utilizing iSCSI Storage, StarWind 5.0 from StarWind Software is your platform of choice for high availability storage software.

To download a trial copy and to obtain additional information, visit StarWind Software.

If you have been a Windows application developer for the past 10 years, you would remember that when building a small, desktop sized application database driven application, perhaps the only viable option for a database would have been the Microsoft Jet Engine, which is what Microsoft Access is based upon. It used to get the job done, but with multiple users, the typical problem was that since it was file-based, the database would get corrupted as multiple simultaneous record updates took place.

Then at the turn of the century, along came a well-kept secret, the free Microsoft Desktop Engine, also known as MSDE 2000. This was essentially a scaled down version of the SQL Server 2000, with a size limit of 2GB. Microsoft did not over-advertize this database, and it did not even come with its own Management Tool. So you either had to use Microsoft Access as a front end (yes its possible, we will cover this in another post), or you had to purchase a third party tool such as MSDE Manager by Vale Software. This allowed many people to develop desktop and web applications on the Windows platform, with a more reliable database.

Subsequently, Microsoft a similarly scaled down version of the SQL Server 2005 database and branded it as Express. So it was called Microsoft SQL Server 2005 Express edition. This worked just as well as the MSDE 2000, and was also Vista compatible, in addition to having a larger data limit of 4 GBs. These two factors moved a large number of developers to switch from MSDE 2000 to MS SQL 2005 Express edition.

Currently, SQL Server 2008 Express edition is the latest free database offering from Microsoft. It comes with many more features compared with the humble MSDE 2000, including its own Management Tool, reporting, and full-text search. To obtain a copy of this database, head over to : The SQL Server 2008 Express homepage.

The database is powerful enough to handle most desktop and workgroup applications. The good thing is that if you start off with the Express edition and find that you need a more robust database, you can easily switch to the one of the many versions of the full-fledged SQL Server 2008. Click here for a full comparison of all the versions of SQL Server 2008, including the free Express edition.

Just a word of advise, SQL Server 2008 Express edition starts in a “lockdown” mode. To prevent security risks, you will need to enable any features which you need on the server. Even simple network access within a local area network is disabled. Its designed to work only in Shared Memory mode when first installed. To get access to the server over TCP/IP, you will need to fire up the SQL Server Configuration Manager. Under SQL Server Services, first make sure that the SQL Server Browser service is running. Next, expand the SQL Server Network Configuration, and under Protocols for SQLEXPRESS, right click on TCP/IP and click on Enable. Now, double click on TCP/IP and under the IP addresses tab, you will see all the IP address which are associated with your server. Make sure you change those which you need to Enable and Active. Phew talk about lockdown security. If you still cannot access your SQL Server, you may also want to enable the NetBIOS protocol on your network connection, and also Enable the Named Pipes protocol in your Protocols for SQL Express.

Hopefully these steps you help you save some frustration in connecting to your SQL Server 2008 Express edition. Would love to hear from your on your experiences.

Once that list loaded, it took equally long to show a list of subfolders within a particular folder I double-clicked on. This kept happening until I reached the folder in which I wanted to save my file.

It would take about a minute or two for the screen to display the contents of each subfolder. Frustrated by the delay, I did a quick search on Google and discovered that the delay can be caused by network drives which are not currently available.

I then realized the source of my problem. I had recently purchased a HP Color LaserJet CP1518ni color laser printer, which comes with a built-in memory card reader. The printer driver had automatically created a mapped network drive to the card reader on my computer with the drive letter X:.

Each time I would explore the folders on my computer through the file save dialog box, it would try to connect to the network drive. This was the cause of the delays! I right clicked on the mapped network drive and clicked on Disconnect, and voila, the file save as dialog box begun working speedily again.

Hopefully this will help you save time and frustration if you ever come across this problem. By the way the HP Color LaserJet CP1518ni is an excellent color laser printer which I purchased for RM 1200 from Sri Computers in Low Yat Plaza.

I have experimented with a few Draft-N wireless routers from Level One and Belkin and have discovered they stop short of delivering the promised range on the box especially in multi-storey houses and buildings.

The Linksys WRT54GX on the other hand is able to broadcast a strong signal through several concrete walls despite being placed in less-than-perfect locations, such as below staircases and nooks and corners.

This router has given me excellent service all these years, with hardly any need for power-cycling or resetting, while being paired with a simple TMNet Billion modem. So recently when this router began giving me some trouble I immediately took a trip to Low Yat to purchase a new unit of this exact model, given its reliability in the past. My trip turned out to be a disappointment when I found out this model had been discontinued and replaced with N routers. Given my not-so-fantastic experience with Level One and Belkin N routers, I decided to give the Linksys N routers a skip and went home and decided to perform a thorough examination of the router to determine what was wrong.

Upon further checking, I discovered the router was working well when I connected to it through a wired connection, but the wireless portion was not working altogether. In fact, it was worse, the status screen on the web interface indicated there was no wireless module installed at all. The wireless light on the router failed to come on as well. I decided to upgrade the firmware to version 2.00.20 and it was still the same. Every setting seemed correct and I was beginning to wonder if the wireless module had malfunctioned.

That’s when I performed a search on Google for “WRT54GX wireless MAC missing”. It is amazing what the correct keywords can do for a query. It can really mean a world of difference between getting the results you need and sifting through pages after pages of irrelevant results.

Anyway, the search results lead me to this page on the Linksys forums which was a post by hameluck from the United States with the exact same problem I was facing!

The best part was that he had discovered a solution to the problem, and the reason why the wireless module was not working was that the wireless daughter card in the modem had become loose from its connector. Without wasting anytime, I unscrewed the device and sure enough I saw that the wireless card had become loose from its connector. I pushed it back in, powered the router back on and voila! the wireless module was functional again.

As mentioned above, the router is placed below a staircase and despite all the concrete, it is still able to send a strong signal across an entire double storey house, right up to the very corners of the house. Despite all the marketing hype, I have yet to see an 802.11n router perform as well as this router can.

So, when a visitor or a client drops by the office and would like to hook up to the WiFi to check his/her email, a potential security risk is created. The risk is not only limited to malicious users with the intention to abuse network resources, it could also cause viruses to creep into the company’s network over the wireless connection.

Now consider a scenario of someone who would like to share their broadband connection at home with the people living around the block, much like a neighborhood hotspot. Despite the noble intention, a huge security risk is created if they were to allow anyone to access their network.

So the question now becomes how to go about sharing a single broadband connection wirelessly, while maintaining the security and integrity of the network? When I came across this need some time ago, I searched high and low on the Internet without much help.  After a bit of experimenting, I discovered the perfect solution to this problem, and is known as Double NAT.

The first thing that has to happen is that you will need two WiFi routers. The reason for this is that you want to ensure your internal network is secure and accessible only to people whom you specifically allow. The other WiFi router will serve as your Public Hotspot. You can even choose to leave this unencrypted if you want to allow anyone at all to use your wireless connection.

Next, you would set up each WiFi router with different SSIDs, so that they serve as distinct wireless networks. It is highly recommended to encrypt your primary (or internal WiFi) connection with WPA, you may even choose to hide the SSID if its purely for internal use and you do not intend to make your internal WiFi discoverable.

Also ensure that the two routers are on different channels so that their signals do not interfere with each other (especially if they are going to be placed within each other’s wireless range). Next, set the LAN IP addresses of both these routers to different subnets. For example, if your primary WiFi router’s IP address is in the range of 192.168.0.xxx, you could set up your secondary WiFi router in the range or 192.168.1.xxx. Finally, ensure that the DHCP server function on both routers is enabled.

Usually, in a typical PPPoE setup, the WiFi router is connected to the ADSL modem on the “WAN” or “Internet” port. The WiFi router is then configured to ‘dial’ the PPPoE connection using a username or password. In this scenario, we are going to extend this network setup by linking the “WAN” port of the second WiFi router to a vacant “LAN” port on the primary WiFi router.

The Internet connection of the second WiFi router should be configured not as PPPoE, but with DHCP, usually with a setting called “Obtain an IP address automatically from my ISP”, or “Dynamic IP address”. Using the IP address ranges in the example above, with this setup, the primary WiFi router will assign an IP address in the range of 192.168.0.xxx to the WAN port of the secondary router, while the secondary router will further assign IP address in the range of 192.168.1.xxx to its clients.

Therefore, you have effectively separated the two wireless networks on different subnets using different encryption keys, while sharing the same broadband connection.

While some people feel that this approach (known as Double NAT) is not good, I personally have set this up in two different locations with perfect results. The wireless clients on the secondary WiFi are able to run all Internet-enabled applications such as Skype, MSN Messenger and the like in addition to surfing the web and accessing emails without any problems or extra configuration.

What this means is that if you have subscribed to a Personal Streamyx account, or a Business Broadband (SOHO Package), you may experience problems with sending out emails with the default settings of port 25, especially if you are sending out emails using your own domain name. If your customers frequently complain of not receiving your emails, this could be a tell tale sign. Users who are using their Streamyx email accounts may not be affected (example@streamyx.com) by this, since it involves emails on hosted domains (eg info@hosteddomain.com).

Personally, I experienced problems with sending out emails from my locally hosted and foreign hosted domains on port 25 and that is when I discovered this countermeasure by TM Net. In my case, my host Webserver has provided an alternative port, 587 for SMTP and this works much more reliably compared to port 25 (since TM Net is performing heavy filtering on this port). Therefore, it is advisable to contact your web host to find out if they have any alternative ports you can use for SMTP, especially if you experience slowness in sending emails.

If your web host does not have an alternative port, you can try TM Net’s suggested solution, which is to use smtp-proxy.tm.net.my as the SMTP server in place of your hosted domain name (eg mail.hosteddomain.com). For more information on how to set this up for your email clients, refer to this website : http://webmail.tm.net.my/info/proxy.html