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Random rumbling during our journey through the E-Learning wonderLand - by Albert Ip (Fablusi P/L)
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Posted by
Albert Ip
at
10:06 am
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Labels: technology
I read with horror how a chief technical officer at APConnections publish an article with misinformation (i guess the aim is to convince users not to use BitTorrent).
Here is what I disagree; [My comments in square brackets like this]
First of all, lets look behind the scenes at how BitTorrent can affect a large ISP's network.
Torrents create thousands of connections. If you use a BitTorrent program on your laptop and attempt to download content (music, movies, et cetera), your computer will locate and find as many sources of this specific content as possible and download from all sources simultaneously. [true]
Conceptually, this is like simultaneously downloading separate chapters in a book from different sources, and then putting the chapters back together on your computer when the downloads complete. Your motivation is time; downloading all the chapters simultaneously is much faster than downloading them in sequence. [good conceptualisation]
In addition to looking for multiple sources for a single file, BitTorrent clients allow the user to attempt more than one file download at a time. [that's the beauty of BT!] This behavior further multiplies the number of active connections from your computer to the Internet. The amount of concurrent connections generated by one home user to the Internet can reach into the thousands. [Untrue! Most torrent client sets the TOTAL connections to around 400] Compare that number of connections with somebody who passively browses the web, and perhaps runs an AIM messenger client on their home computer; their connection total would not exceed fifteen or so at any moment in time.
But multiple connections generate tremendous overhead for a provider, too. [FALSE]
Each connection from your computer across the Internet must be accounted for [???] in various switching points (routers) in order for the data to flow. [OK, data packets go through] You can imagine these switching points as little traffic police standing at the intersection of a street during a 5K road race telling the runners where to turn. Now imagine thousands of races running all over the city at one time; each starting and terminating at a different location. Obviously the traffic cops would get overwhelmed and have to restore some order, like making sure organizers did not run their races all at the same time. [Bad conceptualisation. The effectiveness of Internet traffic is based on packet switching. That means that each packet may traffic from source to destination on different paths. The little traffic police at the switch does not care whether this packet is for the same connection to the last packet. Each packet is routed on path depending on the current traffic situation. CONNECTIONS do NOT increase any workload for the traffic police. The amount of traffic DOES!] In a nutshell, that is one of the motivations for a service provider to try and limit torrents. [I don't think the motivation is because of number of connections. Rather it is more related to the AMOUNT of traffic] The spontaneous and overwhelming number of connections they can create can overwhelm their circuits.
Where do all these BitTorrent files come from? Who is serving up this content?
When you set up a BitTorrent client and start downloading files you also unwittingly become a BitTorrent host/server. Any file you download to your computer can also be sent to other users while your BitTorrent program is active. [True]
From a content provider perspective there is great value in having your data hosted by millions of home users connected by BitTorrent; they can reduce your distribution costs. A content provider that distributes content from servers hosted on their private servers would be charged accordingly for the amount of data uploaded from their hosts. By using a BitTorrent model for distribution, however, a content provider becomes a parasite on third party sites allowing them to replicate and distribute content like a benevolent virus. [Bad comparison and deliberately biased against bitTorrent! Are you saying that you are objecting your users to host home-base smaill web servers. They are serving content as well. When a user connects to a website, the initiation is also out-going traffic! Again, a packet is a packet and is a packet. To the ISP, except for accounting purposes, incoming or outgoing packets should be treated the same and have similar load on routers.]
So who is absorbing the distribution cost when a content provider distributes their data by releasing it into the BitTorrent cloud? [Good questions, but it should be asked from an accounting point of view rather than technical.]
The additional cost of delivering BitTorrent content is essentially shouldered by the major ISPs who likely did not account for this traffic overhead when building out their networks. [No!, ISP do NOT have another additional cost except users are actually requesting the ISP to meet the sale agreement. For unlimited quota plan, most ISP will offer different prices based on different speed limits. So users using BT only INCREASE the amount of traffic, which is agreed in the price. For limited quota plan, BT users are godsend. They need more traffic and you have a great reason to ask them to upgrade! Another point to note, once a physical link is built (eg an optical fibre) the cost of running the fibre is small compared with the capital investment. Amount of traffic does NOT have any effect on running cost! Quota is a mechanism in accounting!]
Posted by
Albert Ip
at
11:35 pm
1 comments
Labels: technology
This is how I get 4 screens for a workhorse computer and optional control on my second laptop.
Configuration:
Workhorse laptop is running Windows XP and a low-cost laptop running Windows Vista Basic Home (This Vista laptop is basically useless except I need it for testing.)
I have two old monitors. So each laptop gets a secondary display. Via the windows display property, I extended my desktop to these secondary display.
Now, on my workhorse, I have two screens. On the vista, I also have two screens.
But I want to have 4 screens for my workhorse when I am not testing using the idling vista. If I can control the vista from my workhorse, then I don't need to move my hand to the vista's keyboard. (BTW, my workhorse has an external keyboard and mouse which make editing so much easier!)
I bought Mirror Pro from Maxivista.com. (I am upgrading from a previous version, so I am paying only half price. If you don't need desktop mirroring, you can opt for the Professional. I would not suggest you to go for the Standard version!)
Install the software on my workhorse. During installation, it will prompt you for generation of client viewer. I asked for two client viewers.
Copy both client viewers to the vista and install both. Configure one of the client viewer to link to the laptop's primary screen and the other to its secondary screen.
From my workhorse computer, activate extended screens of both Maxivista viewers. I can see the background of the vista changed to the workhorse background. Open the workhorse display property and move the screens to their correct positions.
Viola! I use 4 screens at the same time. Optionally, I can control the vista using Maxivista too! Sometimes, finding the cursor from these many screen estate can be difficult. I use a custom set of cursors (brighter and bigger!) to help with my failing eye-sight!
This software solution requires both computer connected to a network, which is my case anyway.
There is no additional hardware and less cable than using KVM switch.
This is a printScreen of my current desktop.
Posted by
Albert Ip
at
11:08 am
0
comments
Labels: technology
