CCNAs and CCNA candidates hear it all the time: ??Get some hands-on experience??. From my personal experience climbing the Cisco certification ladder, I can tell you firsthand that there is no learning like hands-on learning. No simulator in the world is going to give you the experience you will get cabling and configuring your own routers.
Whenever I mention this to one of my students, they always say it costs too much. The truth is, it is cheaper now to build your own CCNA and CCNP lab than it has ever been. The secret? Used routers.
The word ??used?? turns off a lot of people; not many of us buy used computers or used servers. Cisco routers, though, are robust; I personally own a Cisco 4000 router that I use as a Frame Relay switch in my lab that I??ve had for about four years, and I??ve never had a problem with it.
The good news for current CCNA and CCNP candidates interested in building their own labs is that used Cisco equipment has never been more plentiful or cheaper. eBay is a good way to get an idea of what??s out there and what the prices are, but you don??t have to assemble your lab one piece at a time. Many ebay vendors who sell used Cisco equipment sell ready-made CCNA and CCNP labs for one price, including cables.
I asked one major vendor of CCNA and CCNP labs, www.ciscokits.com, what the most common questions are regarding building your own Home lab. Here??s what they had to say:
Why do I need real routers instead of a simulator?
You need a physical router as the simulators just don??t have the ability to give you the ??hands on?? you need to see what happens when you disconnect a cable or put a cable in the wrong location. You will come to find quite quickly that mistakes you make on Router 1 are affecting Router 5 all because you did not screw in a cable properly. No simulator can simulate that.
How many routers do I need?
Two routers really are required to see if anything works. If you have a very limited budget, you can receive value from only purchasing a single router over working with a simulator. However, you will not be able to see the main thing we are trying to accomplish. The propagation of route tables! The only way you can see if your configurations work, is to have at least two routers. Therefore, I strongly recommend that you purchase a dual router kit that comes with all the accessories you need. Otherwise you can spend days trying to find all the little extra pieces you need to get your lab up and running.
Do I need a switch?
Well, it is nice to have. However, with only about 2 questions on the test dedicated to ??hands on?? switch knowledge, if you have to skimp on something, skimp on the switch.
What routers and switches should I buy?
Choices, choices, choices! Which 2500/2600 router do I pick? I will list some pros and cons of each router below, along with current prices (note that prices are generally lower if you buy a dual router kit instead of a single router):
1) Cisco 2501 Router with 16 MB Flash/16MB DRAM $94.99. The cheapest introduction router, and it can support a vast majority of the commands that you will need to learn for your CCNA test. All 2500 routers that we will discuss come with a minimum of two serial ports and an Ethernet port. You will need to add a transceiver to this unit to convert the Ethernet AUI port to an RJ-45 style Ethernet port.
2) Cisco 2503 Router with 16 MB Flash/16MB DRAM $119.99. This is the same as a Cisco 2501, except it adds an ISDN port so you can complete all your ISDN commands for the CCNA test. You will need to add a transceiver to convert the Ethernet AUI port to an RJ-45 style Ethernet port.
3) Cisco 2505/2507 with 16 MB Flash/16MB DRAM $109.99. The same as a Cisco 2501 except it has a built-in 8 or 16 port hub so you do not have to purchase a transceiver.
4) Cisco 2514 Router with 16 MB Flash/16MB DRAM $149.99. This router is the same as a Cisco 2501 except instead of one Ethernet port you have two. You may ask, what is the big deal? Well, you can use this as your Cable Modem/DSL Modem router. Now you can test your ability to setup a firewall and router in a live environment on the Internet. Lots of fun! You will need to add two transceivers to convert the Ethernet AUI ports to an RJ-45 style Ethernet ports.
5) Cisco 2520 Router with 16 MB Flash/16MB DRAM $119.99. This is the same as a 2503 but it also adds two more serial ports so you can use this as a frame relay switch later in your CCNA studies. It costs the same as a 2503, so this is a great money saving
tip.
6) Cisco 2612 Router with 32 DRAM and 8 MB Flash $199.99. This is a modular router unlike any of the 2500 series routers. So the big benefit of this is you can buy extra modules to add functionality such as more serial ports, ISDN ports, Ethernet ports, WICs and such. However, due to the flexibility you will pay a bit more. One day it is a frame relay switch, the next it is your ISDN router. In the long run it will be cheaper than purchasing a bunch of dedicated routers for each discipline you want to learn.
7) Cisco 1912 or 1924 Switch with Enterprise software $109.99. This is a good low cost switch.. The only draw back is it is a 10 MB switch except for the two 100 MB uplink ports. Not a big deal since you have 10 MB routers.
8) Cisco 2912 or 2924 Switch with Enterprise software $249.99. This switch will run all the current commands needed for the test and is a full 100 MB switch.
And should you desire to sell your lab after you complete your certification, you can either negotiate a price with the vendor who sold it to you, or you can sell it yourself on ebay. It??s my experience that 95% of candidates who earn their CCNA go on to pursue their CCNP within one year, though, so don??t sell it too quickly.
In the end, you spend only a few hundred dollars, and you gain invaluable experience and knowledge that will help you both in your certification quest and your job performance. Having been there, I can tell you that you will learn much more from actually configuring and cabling your own equipment than you ever will from any simulation of the real thing.
To your success,
Chris Bryant, CCIE (TM) #12933, has been active in the Cisco certification community for years. He has written several books that have helped CCNA candidates around the world achieve the coveted CCNA certification, including several concentrating on binary math conversions and subnetting questions that the average CCNA candidate will need to answer on their CCNA exams
2008年6月25日星期三
4 Computer Money-saving Tips
Tip #1 -- Rebates:A rebate is not always a bargain. Computers with rebates are often close to being discontinued. You may pick up a good deal or purchase technology that's about to become yesterday's news. What's more, stores will often package computers with a bunch of free items to make it look like you're getting more value. Chances are the extras are either poor quality or items you're unlikely to use. Also, they're counting on you to not redeem your rebate, a very common occurrence.
Tip #2 -- Extended Service Warrantees:Buyer Beware! They're a gamble, but not always a bad idea. If you're purchasing a laptop and you plan to travel a lot, an extended warranty that covers replacement of the monitor/display can be a good gamble. Replacing a display can cost $400-$600, making the warranty worthwhile. On the other hand, if you plan on buying the warranty for routine maintenance; save your money. Oftentimes it can take weeks for the store to send your PC out for service.
Also, remember the store where you purchased your computer does not always do warranty work during the first year, instead you may have to ship it directly to the manufacturer. In general, extended warranties cover electronics [things you can't see]. They don't usually cover physical damage. Most extended warranties have large gray areas, leaving the warranty provider a lot of room to reject claims.
Tip #3 -- Monitors:Don't throw away your monitor if it's still working properly. Instead, keep it and save a chunk of money by just replacing your old CPU [computer tower]. Monitors last much longer than CPUs and the technology is usually compatible between your old monitor and the new CPU. However, if you're dissatisfied, then monitors, keyboards and mouses are the three tools to spend extra money on, since you use them every day!
Tip #4 -- networking:How are you connecting to the Internet? If you're using a high speed Internet connection, such as cable broadband or DSL, you'll want to make sure you have a network card built into your system. If you have a wireless network at Home or at the office, save money and installation time by buying the wireless card built right into the computer.
About the Author
Tip #2 -- Extended Service Warrantees:Buyer Beware! They're a gamble, but not always a bad idea. If you're purchasing a laptop and you plan to travel a lot, an extended warranty that covers replacement of the monitor/display can be a good gamble. Replacing a display can cost $400-$600, making the warranty worthwhile. On the other hand, if you plan on buying the warranty for routine maintenance; save your money. Oftentimes it can take weeks for the store to send your PC out for service.
Also, remember the store where you purchased your computer does not always do warranty work during the first year, instead you may have to ship it directly to the manufacturer. In general, extended warranties cover electronics [things you can't see]. They don't usually cover physical damage. Most extended warranties have large gray areas, leaving the warranty provider a lot of room to reject claims.
Tip #3 -- Monitors:Don't throw away your monitor if it's still working properly. Instead, keep it and save a chunk of money by just replacing your old CPU [computer tower]. Monitors last much longer than CPUs and the technology is usually compatible between your old monitor and the new CPU. However, if you're dissatisfied, then monitors, keyboards and mouses are the three tools to spend extra money on, since you use them every day!
Tip #4 -- networking:How are you connecting to the Internet? If you're using a high speed Internet connection, such as cable broadband or DSL, you'll want to make sure you have a network card built into your system. If you have a wireless network at Home or at the office, save money and installation time by buying the wireless card built right into the computer.
About the Author
Is DVD Storage An Attractive Alternative For Your Computer Backup?
If you have a computer for Home use or for your Business and don't take comprehensive backup for full protection then you are in the danger-zone. Maybe you do not take any backup at all.
You can find in Windows a basic backup utility which are installed during the installation.
I should say for all Windows?,but in fact it is not included during the installation of Windows XP Home Edition.
It is as if Microsoft thinks that data protection is not necessary for Home computers and computers used by small Businesses.
It is true that hard drives are becoming less prone to hard disk crashes.
But, if you consider not only hard disk crashes, but also virus infection, theft plus other treats, then you realize the importance of implementing a full-proof backup strategy for your computer.
Today many computers are equipped with a DVD burner, yet most do not use it to manage their vital data backup. The amount of data you can store on a single DVD is several Giga Byte.
There are many types of backup you can make.
Here are the steps that I take myself to fully secure my data against data loss:
1. Disk image backup. I use a disk image backup software and make a complete image backup of the disk on consecutive DVDs.
I also create an emergency rescue CD. If I have a hard disk crash I'll use this emergency CD to boot from.
But, first I have to install and setup a new hard disk that is working. Then I can recreate the data directly back from this backup stored on the DVDs.
This work is made fast and without the need to spend time installing both the operation system and the backup software. Everything is instead copied directly into the hard disk from the DVD's.
2. Full hard disk backup.
I also use a data backup software and create a full backup of the hard disk on consecutive DVD's.
This is a standard disk backup. With this backup I'm able to restore any files and/or folders. I can also move the data to another computer.
3. Regular scheduled backup of files and folder.
Here I use the same software product I use for the full disk backup. I make with this software regular schedule backups of the files and folders I work with. In my case they include My Documents, Outlook emails and other files that are modified over time.
I do this by keeping a permanent rewritable DVD inside the DVD burner. I then rotate a number of DVD's for this purpose so I can keep copies away from the computer.
Whenever I install important new programs from the Internet or I make other major changes to my system I'll also create a new disk image backup and a full hard disk backup.
You should use a DVD burner that is built for rewritable DVDs. Unfortunately there are several competing DVD standards on the market. The DVD-R, DVD-R and DVD-RAM standards supports DVDs which only can be written to once and can't be reused and those standards should be avoided. The DVD player should instead support at least one rewritable DVDs standard.
Either DVD-RW or DVD+RW.
Conclusion:
I use regular schedule backup to backup the data files I work with on a daily basis.
I'll make a disk image backup so that in case of a hard disk failure I will be back in Business fast.
I also create a full disk backup so that I will be able to restore individual files or folders. It makes it also possible to move the data
to another computer.
Per Strandberg specializing in data security and data storage and have a site about data backup technology
You can find in Windows a basic backup utility which are installed during the installation.
I should say for all Windows?,but in fact it is not included during the installation of Windows XP Home Edition.
It is as if Microsoft thinks that data protection is not necessary for Home computers and computers used by small Businesses.
It is true that hard drives are becoming less prone to hard disk crashes.
But, if you consider not only hard disk crashes, but also virus infection, theft plus other treats, then you realize the importance of implementing a full-proof backup strategy for your computer.
Today many computers are equipped with a DVD burner, yet most do not use it to manage their vital data backup. The amount of data you can store on a single DVD is several Giga Byte.
There are many types of backup you can make.
Here are the steps that I take myself to fully secure my data against data loss:
1. Disk image backup. I use a disk image backup software and make a complete image backup of the disk on consecutive DVDs.
I also create an emergency rescue CD. If I have a hard disk crash I'll use this emergency CD to boot from.
But, first I have to install and setup a new hard disk that is working. Then I can recreate the data directly back from this backup stored on the DVDs.
This work is made fast and without the need to spend time installing both the operation system and the backup software. Everything is instead copied directly into the hard disk from the DVD's.
2. Full hard disk backup.
I also use a data backup software and create a full backup of the hard disk on consecutive DVD's.
This is a standard disk backup. With this backup I'm able to restore any files and/or folders. I can also move the data to another computer.
3. Regular scheduled backup of files and folder.
Here I use the same software product I use for the full disk backup. I make with this software regular schedule backups of the files and folders I work with. In my case they include My Documents, Outlook emails and other files that are modified over time.
I do this by keeping a permanent rewritable DVD inside the DVD burner. I then rotate a number of DVD's for this purpose so I can keep copies away from the computer.
Whenever I install important new programs from the Internet or I make other major changes to my system I'll also create a new disk image backup and a full hard disk backup.
You should use a DVD burner that is built for rewritable DVDs. Unfortunately there are several competing DVD standards on the market. The DVD-R, DVD-R and DVD-RAM standards supports DVDs which only can be written to once and can't be reused and those standards should be avoided. The DVD player should instead support at least one rewritable DVDs standard.
Either DVD-RW or DVD+RW.
Conclusion:
I use regular schedule backup to backup the data files I work with on a daily basis.
I'll make a disk image backup so that in case of a hard disk failure I will be back in Business fast.
I also create a full disk backup so that I will be able to restore individual files or folders. It makes it also possible to move the data
to another computer.
Per Strandberg specializing in data security and data storage and have a site about data backup technology
Flash Memory, Part I: MMC and SD
MMC and SD
Flash memory is available in so many formats that it can be difficult to know what will work with any particular device. Devices such as MP3 players, PDAs, mobile phones, digital cameras, and personal computers can take advantage of flash memory to bolster their storage capacity, but selecting the right format may be easier said than done.
To try to address all of the common formats in one Tech Tip might be quite a read, so we're doing a two part series on Flash Memory. Part I of the Flash memory series will focus on two similar, very popular and generally interchangeable formats: MMC and SD.
The Basics
Before getting into the details, some background on each card may be appropriate. The letters 'MMC' stand for MultiMedia Card, which is a format that was developed jointly by SanDisk and Siemens in 1997. The letters 'SD' stand for Secure Digital, and this format is an improvement on the original MMC design, and was developed jointly by SanDisk, Matsushita Electronics (better known as Panasonic) and Toshiba.
Both formats are quite durable and the solid state (no moving parts) components are protected by a rigid plastic shell. The devices are generally unaffected by extreme temperatures, and should withstand a drop of 10 feet without experiencing any damage from shock.
Physical Features
Both MMC and SD flash memory units measure approximatly 24mm x 32mm x 2.1mm, about the size of a typical postage stamp, and weigh a mere 2 grams. This miniature footprint may make them about the easiest way to misplace your data, but also allows the devices that accept them to be smaller. Personal electronics are shrinking as they get more powerful, and the necessary accessories need to keep pace. Although they share the same basic form factor, MMC and SD cards can be distinguished by two physical features, a sliding tab and the number of connections.
When looking at an MMC or SD card so that the label is facing you, and the electrical connections are facing away from you, there will be a notch in the upper right corner of the card. From this point of reference there will be a small sliding tab on the left edge of an SD card, not found on an MMC card. Compare this 512MB MMC card with this 512MB SD card and you can see the difference if you look closely at the enlarged images. This tab slides into two positions, locked and unlocked. It allows the user to manually write protect the data on the card, which means with the tab in the locked position data can be read from the card, but nothing can be written to or erased from the card.
The other physical difference is on the backside of the card. An MMC card features seven electrical connections (small rectangular pads for data transfer and receiving power), whereas an SD card has nine.
* While there may be rare exceptions, for all practical purposes, SD & MMC cards may be used interchangeably on current devices, especially if they indicate "SD/MMC" compatibility.
Transfer Rate
SD and MMC cards are capable of similar data transfer rates, with a slight edge going to the SD cards. SD cards are now available with write speeds rated at 60x (9 MB/s) and read speeds rated at 66x (10 MB/s), while MMC transfer rates seem to peak at 9 MB/s in either direction. Not much of a difference and both are quite fast, but end user results will vary and may not reach these speeds in real world use, regardless of format chosen.
SD and MMC cards should reference a speed as part of the technical specification, and it is an important thing to consider when shopping around. Lower speed cards are still commercially available, and can have an impact on the performance of digital cameras or other devices where speed may be critical. Each 'x' in the speed rating represents 0.15 MB/s, so if 45x compared to 66x doesn't sound like a big deal to you, maybe putting it in terms of 6.75 MB/s compared to 10 MB/s will. Instead of actual speed ratings, some manufacturers will use words like "High Speed" or "Ultra" when referring to the faster cards.
Note: Check the actual write speed specs of your device before purchasing "Ultra" or "High Speed' chips. You could be putting a Hemi engine in a AMC Gremlin. Don't spend the extra money if the camera does not support it.
Capacity
SD cards are readily available in sizes up to 1 GB, 2 GB models are starting to show up, and the SD Card Association states that models with up to 4 GB and 8 GB of storage capacity are also on the way. In contrast, MMC cards have a maximum capacity of 512MB, making the SD technology much more appealing.
Security
As mentioned in the physical features section above, SD cards offer the benefit of write protection. By 'locking' the card, a user can
be assured that the data is secure until they take the necessary step to un protect it. Fears of accidentally losing or changing data can be eliminated by using an SD card over an MMC card, thus improving the security of the data.
Another feature supported by SD, but not MMC, involves copyright protection. The SanDisk web site refers to this feature as "cryptographic security for protection of copyrighted data", and other locations reference it as DRM, or Digital Rights management. Basically, licensed content can be written to an SD card and it can not be executed except from that specific card.
Applications
In general, SD and MMC cards are interchangeable and either can be used in a compatible device. An SD card may generally cost more than an MMC card with the same capacity, but as seen in this Tech Tip, it does offer more for the money.
Many card readers are available for personal computers that promote the ability to read and write to a variety of common flash media formats. A 15-in-1 reader/writer, such as this one, can be made quite compact thanks in part to the fact that two of the 15, MMC and SD, can be read from the same slot on the device.
MP3 players generally come with a base amount of memory to store music files, but having an expansion slot allows users to increase the capacity, and play time, by adding flash memory of their choice. The Pogo RipFlash MP3 Player is such a device, providing 256MB onboard as well as an SD/MMC slot for easy expandability.
Mobile phones and PDAs can also take advantage of increased storage space thanks to flash memory slots. The Handspring Treo 600 is a combination phone/PDA that offers an SD/MMC slot for such convenience.
And of course, digital cameras use flash memory as their 'film', where larger and faster cards are always a welcome upgrade. odak DX7630 6.1MP 3x Optical Zoom 4x Digital Zoom Camera The 6.1 MegaPixel Kodak DX7630 could fill up the same SD/MMC card much faster than the 3.2 MegaPixel Umax AstraPix 640, but one of the great things about these cards is that the user can choose the size, as well as the quantity to have on hand, in order to suit their particular needs and budget.
One word of warning - be sure to check your device for the capacity of the card that it can handle. If your camera can handle only up to a 512 MB card, then using a 1 GB card in the camera will be pointless (depending on the device, some will not even be able to read the card, whereas others will only use up to the capacity that it is rated for. Either way, you want to make sure that you match the card properly to the device). So as always, check your product's manual to be sure that you buy memory that it can support.
Final Words
MMC and SD are two of the more commonly used formats of flash memory, but as mentioned, there are several others. Keep an eye out for next week's Tech Tip: Part II of the Flash Memory Series will address Compact Flash, Smart Media, Memory Stick, and xD formats.
Flash memory is available in so many formats that it can be difficult to know what will work with any particular device. Devices such as MP3 players, PDAs, mobile phones, digital cameras, and personal computers can take advantage of flash memory to bolster their storage capacity, but selecting the right format may be easier said than done.
To try to address all of the common formats in one Tech Tip might be quite a read, so we're doing a two part series on Flash Memory. Part I of the Flash memory series will focus on two similar, very popular and generally interchangeable formats: MMC and SD.
The Basics
Before getting into the details, some background on each card may be appropriate. The letters 'MMC' stand for MultiMedia Card, which is a format that was developed jointly by SanDisk and Siemens in 1997. The letters 'SD' stand for Secure Digital, and this format is an improvement on the original MMC design, and was developed jointly by SanDisk, Matsushita Electronics (better known as Panasonic) and Toshiba.
Both formats are quite durable and the solid state (no moving parts) components are protected by a rigid plastic shell. The devices are generally unaffected by extreme temperatures, and should withstand a drop of 10 feet without experiencing any damage from shock.
Physical Features
Both MMC and SD flash memory units measure approximatly 24mm x 32mm x 2.1mm, about the size of a typical postage stamp, and weigh a mere 2 grams. This miniature footprint may make them about the easiest way to misplace your data, but also allows the devices that accept them to be smaller. Personal electronics are shrinking as they get more powerful, and the necessary accessories need to keep pace. Although they share the same basic form factor, MMC and SD cards can be distinguished by two physical features, a sliding tab and the number of connections.
When looking at an MMC or SD card so that the label is facing you, and the electrical connections are facing away from you, there will be a notch in the upper right corner of the card. From this point of reference there will be a small sliding tab on the left edge of an SD card, not found on an MMC card. Compare this 512MB MMC card with this 512MB SD card and you can see the difference if you look closely at the enlarged images. This tab slides into two positions, locked and unlocked. It allows the user to manually write protect the data on the card, which means with the tab in the locked position data can be read from the card, but nothing can be written to or erased from the card.
The other physical difference is on the backside of the card. An MMC card features seven electrical connections (small rectangular pads for data transfer and receiving power), whereas an SD card has nine.
* While there may be rare exceptions, for all practical purposes, SD & MMC cards may be used interchangeably on current devices, especially if they indicate "SD/MMC" compatibility.
Transfer Rate
SD and MMC cards are capable of similar data transfer rates, with a slight edge going to the SD cards. SD cards are now available with write speeds rated at 60x (9 MB/s) and read speeds rated at 66x (10 MB/s), while MMC transfer rates seem to peak at 9 MB/s in either direction. Not much of a difference and both are quite fast, but end user results will vary and may not reach these speeds in real world use, regardless of format chosen.
SD and MMC cards should reference a speed as part of the technical specification, and it is an important thing to consider when shopping around. Lower speed cards are still commercially available, and can have an impact on the performance of digital cameras or other devices where speed may be critical. Each 'x' in the speed rating represents 0.15 MB/s, so if 45x compared to 66x doesn't sound like a big deal to you, maybe putting it in terms of 6.75 MB/s compared to 10 MB/s will. Instead of actual speed ratings, some manufacturers will use words like "High Speed" or "Ultra" when referring to the faster cards.
Note: Check the actual write speed specs of your device before purchasing "Ultra" or "High Speed' chips. You could be putting a Hemi engine in a AMC Gremlin. Don't spend the extra money if the camera does not support it.
Capacity
SD cards are readily available in sizes up to 1 GB, 2 GB models are starting to show up, and the SD Card Association states that models with up to 4 GB and 8 GB of storage capacity are also on the way. In contrast, MMC cards have a maximum capacity of 512MB, making the SD technology much more appealing.
Security
As mentioned in the physical features section above, SD cards offer the benefit of write protection. By 'locking' the card, a user can
be assured that the data is secure until they take the necessary step to un protect it. Fears of accidentally losing or changing data can be eliminated by using an SD card over an MMC card, thus improving the security of the data.
Another feature supported by SD, but not MMC, involves copyright protection. The SanDisk web site refers to this feature as "cryptographic security for protection of copyrighted data", and other locations reference it as DRM, or Digital Rights management. Basically, licensed content can be written to an SD card and it can not be executed except from that specific card.
Applications
In general, SD and MMC cards are interchangeable and either can be used in a compatible device. An SD card may generally cost more than an MMC card with the same capacity, but as seen in this Tech Tip, it does offer more for the money.
Many card readers are available for personal computers that promote the ability to read and write to a variety of common flash media formats. A 15-in-1 reader/writer, such as this one, can be made quite compact thanks in part to the fact that two of the 15, MMC and SD, can be read from the same slot on the device.
MP3 players generally come with a base amount of memory to store music files, but having an expansion slot allows users to increase the capacity, and play time, by adding flash memory of their choice. The Pogo RipFlash MP3 Player is such a device, providing 256MB onboard as well as an SD/MMC slot for easy expandability.
Mobile phones and PDAs can also take advantage of increased storage space thanks to flash memory slots. The Handspring Treo 600 is a combination phone/PDA that offers an SD/MMC slot for such convenience.
And of course, digital cameras use flash memory as their 'film', where larger and faster cards are always a welcome upgrade. odak DX7630 6.1MP 3x Optical Zoom 4x Digital Zoom Camera The 6.1 MegaPixel Kodak DX7630 could fill up the same SD/MMC card much faster than the 3.2 MegaPixel Umax AstraPix 640, but one of the great things about these cards is that the user can choose the size, as well as the quantity to have on hand, in order to suit their particular needs and budget.
One word of warning - be sure to check your device for the capacity of the card that it can handle. If your camera can handle only up to a 512 MB card, then using a 1 GB card in the camera will be pointless (depending on the device, some will not even be able to read the card, whereas others will only use up to the capacity that it is rated for. Either way, you want to make sure that you match the card properly to the device). So as always, check your product's manual to be sure that you buy memory that it can support.
Final Words
MMC and SD are two of the more commonly used formats of flash memory, but as mentioned, there are several others. Keep an eye out for next week's Tech Tip: Part II of the Flash Memory Series will address Compact Flash, Smart Media, Memory Stick, and xD formats.
JVCs First Three-Layer Combo-Disc Blu-Ray / DVD
JVC developed and used a high-performance reflective film to produce this revolutionary three layer structure. The outer Blu-ray layer can be read by the blue light laser but it is transparent for the red light laser which therefore has access to the inner dual DVD layer.
The JVC disc sums 33.5 GB in total storage capacity of which: 8.5 GB are allocated to the standard video content; 25 GB hold high definition content.
JVC unveiled its intentions to promote its disc to the Blu-ray Disc Association, in the spring of 2005. Mass production will begin when BD-ROM players are available, early 2006. The combo disc will be available for a 30% higher price than standard DVDs.
The idea is to ease the transition among standard DVD and high definition discs. All big players on the DVD market, including JVC, expect SD and HD DVD to cohabit for a while.
At the beginning of this month, Toshiba and Memory-Tech were announcing their dual-layer DVD/HD DVD disk able to store both DVD and HD DVD content. The DVD layer had a 4.7 GB capacity, satisfying specification of current DVD discs, while the HD DVD layer could store 15 GB capacity.
At least with storing capacity, until now, JVC (Japan Victor Corporation) is the market leader. The company is currently working on a Blu-ray/ DVD combo ROM disc with even more storage capacity. This later disc will feature 50 GB of high definition data (BD format), stored on a dual layer and 8.5 GB of DVD dual layer structure.
Iulia Pascanu writes for http://www.dvdrecorders.ws where you can find more information about DVD recorders.
Please feel free to use this article in your Newsletter or on your website. If you use this article, please include the resource box and send a brief message to let me know where it appeared:
The JVC disc sums 33.5 GB in total storage capacity of which: 8.5 GB are allocated to the standard video content; 25 GB hold high definition content.
JVC unveiled its intentions to promote its disc to the Blu-ray Disc Association, in the spring of 2005. Mass production will begin when BD-ROM players are available, early 2006. The combo disc will be available for a 30% higher price than standard DVDs.
The idea is to ease the transition among standard DVD and high definition discs. All big players on the DVD market, including JVC, expect SD and HD DVD to cohabit for a while.
At the beginning of this month, Toshiba and Memory-Tech were announcing their dual-layer DVD/HD DVD disk able to store both DVD and HD DVD content. The DVD layer had a 4.7 GB capacity, satisfying specification of current DVD discs, while the HD DVD layer could store 15 GB capacity.
At least with storing capacity, until now, JVC (Japan Victor Corporation) is the market leader. The company is currently working on a Blu-ray/ DVD combo ROM disc with even more storage capacity. This later disc will feature 50 GB of high definition data (BD format), stored on a dual layer and 8.5 GB of DVD dual layer structure.
Iulia Pascanu writes for http://www.dvdrecorders.ws where you can find more information about DVD recorders.
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