http://www.pendrivelinux.com/
Simple and yet powerful, it helps you to put a Linux distribution that you like on a USB thumbdrive. This is good for system recovery, emergency bootup, etc.
Highly recommended.
It's great for these days when USB thumbdrives are cheap and highly portable, a handy boot disk shall be great. It won't occupy much space as well.
Thursday, August 12, 2010
Wednesday, July 28, 2010
Amazon and foreign currency
I just realized that Amazon offered to pay in HKD (or your native currency) instead of USD, this seems to be very convenient at the first glance, but the evil is in the detail.
Yes, they will charge you HKD (or your native currency) and you will know the exact amount that you will have to pay very clearly. However, if you do a simple exercise with a calculator, you will immediately know that it's not going to be a good deal. I suggest you to try it out yourself.
I would advise you to use USD for the payment, and your credit card will do the conversion for you. The exchange rate of bank is far more reasonable in my experience.
Yes, they will charge you HKD (or your native currency) and you will know the exact amount that you will have to pay very clearly. However, if you do a simple exercise with a calculator, you will immediately know that it's not going to be a good deal. I suggest you to try it out yourself.
I would advise you to use USD for the payment, and your credit card will do the conversion for you. The exchange rate of bank is far more reasonable in my experience.
Paypal currency switching
I've some paypal balance in USD. Transfering it to the local bank would not incur a charge but the exchange rate is pretty bad. Therefore, it makes more sense to use it to buy something else.
Today, I tried to buy something in GBP, however, paypal would not allow me to use my paypal balance in USD. After some google work, I realize that if the amount to be paid is more than your balance would allow, it will not let you use the balance but instead, it will charge completely by the credit card!
To solve this problem, I asked the vendor to separate the paypal request into two parts. The first part is less than my paypal balance, so that paypal would allow me to use my existing balance. And the second part is to use credit card.
Quite simple, but of course, since there's a currency switching, I expect poor exchange rate again.
Today, I tried to buy something in GBP, however, paypal would not allow me to use my paypal balance in USD. After some google work, I realize that if the amount to be paid is more than your balance would allow, it will not let you use the balance but instead, it will charge completely by the credit card!
To solve this problem, I asked the vendor to separate the paypal request into two parts. The first part is less than my paypal balance, so that paypal would allow me to use my existing balance. And the second part is to use credit card.
Quite simple, but of course, since there's a currency switching, I expect poor exchange rate again.
Tuesday, July 13, 2010
Great freeware video tools
If you want to do one of the followings, you might want to have a look on a freeware tool.
It allows you to do the above easily, and for inserting a video clip in PowerPoint slide, it helps by converting your existing clip to wmv, which I found is the best for PowerPoint purpose.
- Download video from youtube
- Insert video clip in your PowerPoint slide
- Convert videos from one format to another
- Simple video manipulations
- and more!
It allows you to do the above easily, and for inserting a video clip in PowerPoint slide, it helps by converting your existing clip to wmv, which I found is the best for PowerPoint purpose.
Tuesday, June 8, 2010
Broadband via Mobile Phone Network
A few months ago, I found that my Internet connection failed. After many different investigation, it was found that the cable was broken by the renovation work down stair. After millions of negotiation, the broadband provider agreed to lay the cable for me again but we had a very hard time to do that on the original trunking. After that, my internet connection becomes very unstable all the time.
Finally, I decided to switch to a wireless based solution. It provides broadband services via 3G mobile phone network, and it also provides conventional home telephone service as well. What they provided is a wireless gateway, which sits in the middle of the 3G network, and on the other hand, to provide internet services via LAN or Wi Fi.
The good thing about this technology is that, you don't have to lay any cable. There're virtually "nothing" to fix in case of network failure, except that small wireless gateway. The speed of the internet might vary over the day, it could go really fast like my last ISP (based on Cable TV network), or quite slow... but it's still fast enough for youtube, etc.
For me, stability is more important than speed. And I found it hard when the network had problem, you have to stay at home, to wait for the technician to come and fix the whole thing for you, and that requires a lot of waiting and negotiation. Troublesome enough for me.
I guess that I will stay with this kind of service. And another good thing about this service is that, you can move your house without re-apply another service. Mobile phone network can reach any places virtually these days, so it sets the internet and your home phone free.
Tuesday, May 25, 2010
DIY Macro Filter
I've a 70mm f=500mm (astronomical grade) objective sitting idle from a finished experiment, so I was always thinking how could I use it in the best way.
When I heard that a macro filter is just an optical lens to bring the focus point closer, I begin to think that it might be just a converging lens! For example, if you have a 500mm focal length lens, if your subject is at 500mm from this objective, parallel ray will go out from the other side of the lens. Yes, parallel ray, that means, if your camera lens will focus at infinity, it will accept parallel ray! In that case, if my lens would focus as close as 1 meter, if I add this f=500mm lens in front of it, it will focus as close as, at least, 500mm now.
To do that, I will only need to buy a suitable threaded ring and stick it in the lens cell like the following:
So now I can put it on and take it off easily, and the result:
Not bad, right?
When I heard that a macro filter is just an optical lens to bring the focus point closer, I begin to think that it might be just a converging lens! For example, if you have a 500mm focal length lens, if your subject is at 500mm from this objective, parallel ray will go out from the other side of the lens. Yes, parallel ray, that means, if your camera lens will focus at infinity, it will accept parallel ray! In that case, if my lens would focus as close as 1 meter, if I add this f=500mm lens in front of it, it will focus as close as, at least, 500mm now.
To do that, I will only need to buy a suitable threaded ring and stick it in the lens cell like the following:
So now I can put it on and take it off easily, and the result:
Not bad, right?
Network Convergence
We have the following networks:
1. telephone (fax)
2. television
3. internet
4. mobile phone
Telephone Company: ADSL is to use the telephone network for internet connection, and to go a step further, video on demand can be made to work with ADSL. In that sense, the telephone network is now to provide TV, internet as well.
Cable TV: Cable modem is to use the cable TV network for internet connection, and voice over IP can be made to put telephone services on the same network. In that sense, the cable TV network is now to provide TV, telephone and Internet.
Mobile Network: Recently, I've subscribed a service which is based on mobile phone network to provide internet access, as well as conventional telephone service. It's not very fast, but then I believe it's fast enough for most people. Of course, it can support video on demand as well.
Who will win finally in the war of network convergence? Personally, I think Internet will rule in the form of optical fibre services provider since it's fastest and thus it can provide all sorts of services nicely, and the second candidate should be the mobile phone network, since nothing else could replace it.
1. telephone (fax)
2. television
3. internet
4. mobile phone
Telephone Company: ADSL is to use the telephone network for internet connection, and to go a step further, video on demand can be made to work with ADSL. In that sense, the telephone network is now to provide TV, internet as well.
Cable TV: Cable modem is to use the cable TV network for internet connection, and voice over IP can be made to put telephone services on the same network. In that sense, the cable TV network is now to provide TV, telephone and Internet.
Mobile Network: Recently, I've subscribed a service which is based on mobile phone network to provide internet access, as well as conventional telephone service. It's not very fast, but then I believe it's fast enough for most people. Of course, it can support video on demand as well.
Who will win finally in the war of network convergence? Personally, I think Internet will rule in the form of optical fibre services provider since it's fastest and thus it can provide all sorts of services nicely, and the second candidate should be the mobile phone network, since nothing else could replace it.
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