## 讓 Windows 2000/XP/Vista 與 Server 2003/2008 能夠更新的軟體

Hacker News 上看到「Legacy Update」這個網站：

Legacy Update: Fix Windows Update on Windows XP, Vista, Server 2008, 2003, and 2000

## 0.1 + 0.2 = 0.30000000000000004

Your language isn't broken, it's doing floating point math. Computers can only natively store integers, so they need some way of representing decimal numbers. This representation comes with some degree of inaccuracy. That's why, more often than not, .1 + .2 != .3.

It's actually pretty simple. When you have a base 10 system (like ours), it can only express fractions that use a prime factor of the base. The prime factors of 10 are 2 and 5. So 1/2, 1/4, 1/5, 1/8, and 1/10 can all be expressed cleanly because the denominators all use prime factors of 10. In contrast, 1/3, 1/6, and 1/7 are all repeating decimals because their denominators use a prime factor of 3 or 7. In binary (or base 2), the only prime factor is 2. So you can only express fractions cleanly which only contain 2 as a prime factor. In binary, 1/2, 1/4, 1/8 would all be expressed cleanly as decimals. While, 1/5 or 1/10 would be repeating decimals. So 0.1 and 0.2 (1/10 and 1/5) while clean decimals in a base 10 system, are repeating decimals in the base 2 system the computer is operating in. When you do math on these repeating decimals, you end up with leftovers which carry over when you convert the computer's base 2 (binary) number into a more human readable base 10 number.

## VM Import：把 VMware Image 直接丟到 AWS EC2 上面跑...

You can start importing 32 and 64 bit Windows Server 2008 SP2 images right now (we support the Standard, Enterprise, and Datacenter editions).