External Drive Talk

External hard drives are a very useful tool in your arsenal of PC peripherals.  They are useful for hosting your backup files (See Backup, Backup, BACKUP!) and when your main PC drive is starting to run out of space.  Certain types of external drives can be used for central storage of your music and/or family photos.

There are two types of external drive connections.  One type is via USB, SATA or Firewire, where basically the drive is connected directly to your PC, while the other type is via ethernet or wireless connection to your internal home network. 

If you connect a USB drive to your computer, you can expect theoretical speeds at 12Mbps with USB 1.1 and 480Mbps with USB 2.0.  Firewire is rated 786 Mbps (Firewire 800) theoretical.  SATA can get you much higher data speeds, which can go higher than 1.5Gbps.  Again, all these are theoretical rates, actual rates are affected by many factors - even temperature!  But again, these types of connections are just direct to your computer alone.

If you read my previous blog Kilo, Mega or Giga Speed, you'll get an idea about Internet connection speed.  Internet connection speed is typically slower than local network speed.  Most of today's PC's have Gigabit speed ethernet cards built-in, and therefore you can assume connection speeds at 1Gbps theoretical.  What you get actually is affected by the same factors affecting Internet connection speed. 

Connecting an external drive to your local network is very useful because you can share music files, photos, and other files with all the other computers on your network.  Contrasting that with a directly connected external drive you get sole use of the drive.  Each type of drive connection has it's place. 

At the request of a relative, I want to focus a little on a network connected external drive.  No matter which type you get, you want to remember the old addage, "A chain is only as strong as it's weakest link".  Or, by changing the words a little bit, "Your network speed is only as fast as the slowest device."  Lets say you have a Gigabit speed network card built in to your PC, and you went out and bought a discounted network external drive that has only a 100Mbps network connection.  You've effectively slowed down your network by connecting a slower device.  Many consumer grade wireless routers do not have Gigabit ethernet connectors simply because at the time of this writing, you can't get wireless speeds to go that fast, nor can you get (home) Internet speeds that fast.  So there isn't a need to put Gigabit speed ethernet ports on the wireless router.  So if you use your wireless router as the main point of connection between your PC and the external drive, and the wireless router has 100Mbps ethernet ports, then you are limiting the speed which you can write and read your data from the drive. 

Here's what I do.  I use what is called a Gigabit network switch.  You can purchase multiple port Gigabit switches which you can use to connect all your internal network devices.  Forgive the cheesy illustration, but this is basically how I have my network. 

Connect the Gigabit switch to all of your internal devices and then to the router/firewall.  Be aware, that if you are going to try to access files from the network attached external drive over a wireless connection, you have to think about the old addage I wrote about above.  At the time of this writing, gigabit speeds over (home) wireless devices has not yet been attained, so your wireless connection will be the "weakest link" when you are trying to copy files to or from the external drive.  Just to give you an idea, wireless connections can range from 11Mbps to above 54Mbps depending on what type of wireless protocol is being used by your wireless router and wireless network card in your PC.

With this information, I hope you are able to build your own little digital home empire! 

Kilo, Mega or Giga Speed

If there is one thing that seems to baffle people about their connection to the Internet, it's the mysterious concept of connection speed.   Your ISP sold you a connection to the Internet at a certain speed.  Maybe you didn't really care what the speed was when you bought your Internet connection, or maybe you did.  I live in a city that has a technically advanced ISP who sells a whopping 60Mbps option.  Unfortunately, they also limit or "cap" the amount of Internet data I use.  Whether you still have a modem with your screeching 56Kbps connection or you have cable at great speeds like my provider sells, at some time or another the question of actual speed seems to come to the surface.

Connection speed is generally measured in bps or (b)its (p)er (s)econd.  So when you see Kbps, that means Kilobits per second or thousand bits per second.  And if you see Mpbs, that means Megabits per second or million bits per second.  Gbps means Gigabits per second or billion bits per second.  At the time of this writing, I have not yet seen Tbps or Terabits per second which is trillion bits per second.

Lets create a hypothetical ISP customer named - eh.. Ken Shnayal.  Mr. Shnayal calls up his ISP and gets a blazing 10Mbps connection.  They come out and install the service by connecting directly to his primary computer and verifying that it meets standards.  Yay!  Mr. Shnayal is so happy.  He starts to try out his new found connection by going to Netflix and watching his favorite old movies.  All is going well.

Mr. Shnayal decides that he wants to join the wireless world and buys a fancy-dancy wireless router.  Wow!  Wireless freedom!  He finds out that he can hardwire connections to the back of the wireless router as well as enjoy wireless connections.  Suddenly Mr. Shnayal sees all sorts of opportunities to connect all kinds of devices wirelessly as well as via ethernet (using a wire).  During all of his excitement, he starts to notice that things aren't going as fast as they used to.  The Netflix movies are pausing and buffering and some sites seem to be really slow when loading.  So, Ken decides to go on a fact-finding mission.  He finds a 10 MB Adobe PDF online from his community college web site and clicks on it to see how long it takes to download.  It should take a second right?  But the file takes almost 12 seconds!  WHAT???  Mr. Shnayal calls his ISP demanding some kind of fix.  So, the Internet cable guy comes out and moves the Internet connection directly back to the original computer on which it was installed and retries the same test with the 10MB PDF with Ken watching over his shoulder.  The file downloads in 9 seconds and the repair guy says, "Ok!  We are done here."  Mr. Shnayal is confused, so the Internet cable guy explains.  "There is a difference between 10 Megabits and 10 Megabytes.  A bit is the most basic piece of information used by a computer.  A bit can either be 0 or 1.  Whereas a byte is made up of eight bits."  (The reason for this will be the subject of a future blog entry).  So the connection that Mr. Shnayal bought is rated as 10 megabits per second, but it can also be considered a 1.2 mega bytes per second connection.  So when you divide the 10MB file by 1.2, you come up with  8.33 seconds.  So the file should have transfered in 8.33 seconds in an ideal world.  9 seconds would actually be a reasonable rate of transfer.  So what happened when he saw it go up to 12 seconds?  Most likely the problem came from having the data go through his fancy-dancy wireless router.

So we come to the whole point I'm trying to make.   The Internet is made up of all kinds of devices all over the world from manufacturers all over China - er - the world.  In my experience, you will see degradation in your Internet connection originating from consumer grade networking components.  Once I bought a wireless router from a popular manufacturer as it was claiming all sorts of features that I wanted.  I brought it home and noticed an instant performance decrease.  I called my ISP and wanted to blame them because I had just spent all this money on this new fancy-dancy wireless router and how could that be at fault?  Well, it turned out that it wasn't the wireless router, but the compatibility of the wireless network card in my laptop and the wireless router.  Sure enough, the purchase of a new wireless card proved to be the answer.  In reality 12 seconds difference from the theoretical 8.33 seconds it should have taken is not that bad.

There are many other external factors to Internet connection speed as well.  Things like the load on a site or load on a certain network "path" can cause a slowdown situation as well, sometimes only momentary.

Here's what I do.  I use the site http://www.speedtest.net/  This is a really cool graphical site that can identify where you are on a map and provides you with nearby testing locations from which you can obtain speed statistics.  Sometimes your ISP has their own speed test site about which you will only discover if you call them about it.

Bottom line - if you are a stickler for the speed, you need to do some research and pick good networking components.  Be ready to pay a little more now and again for higher performance, and coming up with good compatibility combinations.

Happy speed testing!