Category: Technology

  • DVD-R and DVD+R Explained

    I have recently began archiving my digital pictures and videos, and would eventually begin archiving film, slides and other photographs. The collection and space requirements will be quite large as there is much to back up. I have decided to archive it all to multiple DVD discs. This got me to thinking about which discs to use for my archiving. Obviously, I want good quality discs (please read How Long Will a CD-R last? for more details) but I then thought about the two competing DVD standards: DVD-R and DVD+R.

    I decided to research the two formats and determine which one I should choose for archiving. I explain my findings in this post.

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  • AOL Users – Multiple IP Addresses

    A few days ago I was in a forum and someone mentioned that they noticed a discrepancy in their Web server logs. A visitor to their Web site was an AOL user, but they appeared to be making several requests from different IP addresses.

    If you are on dialup, you will probably get a different IP address each time you connect to your ISP, however, it won’t change as long as up don’t log off. How did the AOL user have multiple IP addresses even if they didn’t log off? I will explain that phenomenon in this post.

    AOL Proxy Servers

    Unlike regular dialup users, AOL users don’t get assigned an IP address that will show up in a Web server’s log file. This is because when an AOL user makes a request over the Internet; the request goes through what is known as a proxy server.

    A proxy server is a server that acts as an intermediary between a user and the Internet. This allows an enterprise to control security, caching and provide administrative support. The proxy server is the access point to the Internet from the internal network of an enterprise.

    How does this relate to AOL users? When a user connects to AOL, they receive an IP address from AOL. When they make a request to a Web site, the request is sent to the proxy server. The server then sends the request to the respective Web server. By this time the request has the IP address of the proxy server, and not of the AOL user.

    The Web server completes the request and sends the information back to the IP address of the proxy server. The proxy server then determines which user requested the data, and then forwards the information to the AOL user.

    If the AOL user makes another request, it can be sent to a different proxy server with a different IP address. The Web server will then receive a request from the same user, but this time the IP address will associated with the new proxy server. In this scenario, the AOL user has made two requests to the same Web server, but from two different IP addresses.

    Issues with AOL Proxy Servers

    There have been some issues related to the AOL proxy servers and AOL users. One issue is that Webmasters can’t get accurate data about their Web traffic. Usually, Web traffic data uses the IP address to determine unique users. If you get one user requesting data through multiple proxy servers, each with their own IP address, your Web data may indicate more users.

    Another issue has to do with the actual IP addresses themselves. Many times a Web site might prevent traffic from a specific IP address from accessing their site. If a Web site bans an IP address from one of the proxy servers, any requests by AOL users that are sent through that proxy server won’t be able to access the Web site. This has frustrated many AOL users in the past.

    Summary

    Since AOL uses proxy servers to connect their users to the Internet, you may see multiple IP address from a single user in your Web logs. Each request from an AOL user can come from a different IP address depending on which proxy server the request is sent through. Besides the skewed Web stats from the multiple IP addresses, AOL users can be frustrated if a Web site has banned any traffic from one of the proxy server’s IP address.

  • What is a Device Driver?

    You have probably connected several devices to your computer, a printer, scanner, or digital camera, and sometimes Windows would recognize the device without difficulty. Other times, however, the device was now recognized by Windows, and you couldn’t use the device.

    The reason Windows couldn’t recognize the device was because it didn’t have a device driver for it. This is required by all devices that are connected to your computer, both internal and external. In this post, I will describe what a device driver is, as well as what it does.

    Interacting with Hardware

    There are many types of hardware that you can connect to your computer. Hardware such as video or sound cards are connected directly to the motherboard inside of your case, while printers and scanners are connected externally into one of the ports. The problem is how does an operating system know how to talk to the hardware if it is all different. Answer: through the use of device drivers.

    A device driver, or just driver, is a computer program that allows software interact with hardware. Typically, the software that talks to the device driver is the operating system, such as Windows. Essentially, the driver is an instruction manual that provides information to the operating system on how to communicate and use the device.

    Installing Device Drivers

    If the operating system needs to use a driver to talk to a device, how is the driver installed? There are many ways a driver is installed.

    If the device you are connecting is older than the version of Windows, chances are that Windows already contains the necessary driver. Once you connect your device, then Windows will detect it and install the drivers automatically. You may be prompted to insert the Windows CD/DVD.

    Most devices also include a CD that includes such things as applications and manuals. Also on the CD are drivers for specific operating systems that you can install. These drivers should be installed if the operating system is older than the device. Since the device wasn’t around when the operating system was created, then it obviously wouldn’t have the drivers. Follow the instructions included with your device to install the drivers.

    You can also navigate to the vendor’s Web site of your device online and download any updated drivers. Once downloaded you just run the application and the drivers are installed.

    It is important to keep your device drivers updated as they may help fix any issues you may be having. Sometimes Windows Update will install an updated driver. You can also go to the vendor’s Web site and see if they have a new driver available for download.

    Summary

    Device drivers are used by the operating system to communicate with a piece of hardware. Anytime you install a new piece of hardware, you will also need to install the device driver associated with that hardware.

    There are many ways of installing the driver. The operating system can install the driver if it has one, install the driver from the CD that came with the device, or download the driver from the vendor’s Web site.

  • Digital Camera Memory Cards

    The digital camera has changed the way people take pictures. It is now easier to take a picture, decide if we want to keep it, and delete it if we don’t. Some cameras even allow you to apply effects to your pictures, such as colour replacing. How are digital cameras able to do this? Pictures are stored as files on a memory card that you load into your camera.

    There are many types of memory cards on the market today, and different digital cameras require different memory cards. Some cameras even allow you to use two types of memory cards. What is the difference between all the types, and which one is better? This post will describe the various popular memory types and discuss their differences.

    What is Flash Memory?

    Before we look at the various cards, it is important to understand what I mean I say flash memory. You may be familiar with computer memory (RAM) or hard drive space, which have been around for many years. Both of these storage mediums have their advantages and disadvantages. The RAM in your computer has no moving parts so it may not break as easily than a hard drive, but it is volatile, meaning that it won’t keep the data once the power is turned off. Hard drives are non-volatile, can hold enormous amounts of data, but they have many moving parts, that could easily break.

    Flash memory is non-volatile memory with no moving parts. They have been known to be durable even on some intense testing. The memory can be electrically erased and written to just like a hard drive, and very small physically. Although they don’t have the storage capacity of a hard drive, they are becoming larger each year.

    CompactFlash / MicroDrive

    The CompactFlash cards were once the most common flash cards used, however, that crown now belongs to the Secure Digital memory. CompactFlash is rather large at 3.3mm x 36.4mm x 42.8mm (thickness x length x width) for the Type I compared to the other memory cards. Type II cards are thicker at 5.0mm, but the length and width sizes are the same. Cameras that use Type I cannot use Type II, however, cameras that use Type II can use either.

    Some older cameras that use CompactFlash may not be able to use any size larger than 2GB. This is because CompactFlash uses FAT for sizes under 2GB, and FAT32 for any sizes above 2GB.

    Some cameras that accept CompactFlash Type II may also be able to use a MicroDrive. A MicroDrive is a small hard drive usually in sizes of 340MB and 1GB.

    Secure Digital (SD) / MultiMediaCard (MMC)

    This is perhaps the most common memory card in use today. They are much smaller (2.1mm x 32mm x 24mm) than the CompactFlash cards but have the same amount of storage space.

    Both the SD and MMC cards are almost identical in terms of size and look on the outside, but inside they are technically different. Although your digital camera may accept SD memory cards, it may not accept MMC cards as well.

    There are also miniSD cards on the market mostly used in MP3 players and mobile phones; I have yet to see any digital cameras that use this memory card. The miniSD is smaller than the SD card since it is only 1.4mm x 21.5mm x 20mm.

    Sony Memory Stick (MS)

    This type of memory card, or rather stick, was created by Sony in 1999 and is used in all of their Cybershot digital cameras as well as their digital video Handycams.

    The original blue Memory Stick was incredibly slow compared to today’s SD and CompactFlash cards. There have been several versions, or types of memory sticks developed by Sony over the years.

    There is the Memory Stick Select which allows you to select between 128MB and 256MB to make it compatible with older digital cameras. Next came the Memory Stick Pro that had a capacity up to 2GB. With the exception of the Cybershot F717, this Memory Stick was not compatible with any of the pre-2003 digital cameras. There is also a high speed Memory Stick Pro that is capable of transfer speeds of 80Mbps.

    xD-Picture Card (xD)

    The xD card was developed by Olympus and Fujifilm and is about the size of a postage stamp. Most Olympus digital cameras now use the xD card. There are currently two types of xD cards on the market: the M series and the H series.

    Not all cameras can accept both types of xD memory cards, so check your manual before purchasing an xD card. The H series cards are reported to be about 2-3 times faster than the M series.

    Summary

    There are many types of flash memory cards on the market to use with your digital camera. Any digital camera you purchase today will use one of the memory cards mentioned in this post. Always read your instruction manual that came with your camera to determine the exact memory card that you can use. As always, technology progresses, and there may be a time when the above memory cards will be replaced with something else. As long as you can keep taking pictures, you don’t need to worry about that, though.

  • Types of Digital Camera Batteries

    I mentioned in a previous post, About Digital Cameras, I mentioned that you should always buy two sets of rechargeable batteries. In this post I discuss the two most common rechargeable batteries used by digital cameras, although there are other types of rechargeable batteries on the market.

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  • How Long Will a CD-R Last?

    I recently wrote a post called Backing Up Digital Photos where I outlined the various backup media you can use. I discussed the advantages and disadvantages of the various media. After the post I decided to talk more about the longevity of a CD/DVD, since that is probably the most used media for backups.

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