macbook air 501 是 64 位还是 32 位？ 我应该选择哪个版本的Eclipse？

Question

The information from "unname -a" tells that it is i386. But I found that some applications in the Activity Monitor are with types "Intel 64". What's more, the System Profiler says:64-bit Kernel and Extensions, no. So, which version of Eclipse should I choose, 64-bit or 32-bit?

Answer 1

The same of Java, try

java -version

32-bit:

java version "1.6.0_26"
Java(TM) SE Runtime Environment (build 1.6.0_26-b03)
Java HotSpot(TM) Client VM (build 20.1-b02, mixed mode, sharing)

64-bit:

java version "1.6.0_20"
Java(TM) SE Runtime Environment (build 1.6.0_20-b02)
Java HotSpot(TM) 64-Bit Server VM (build 16.3-b01, mixed mode)

Answer 2

I usually use sysctl :

bash$ /usr/sbin/sysctl hw.cpu64bit_capable
hw.cpu64bit_capable: 1
bash$

You don't really care about the hardware though. Eclipse cares about which java you are running. rekin's answer for Eclipse.

Note: I added this answer just in case anyone stumbles across this in the future.

Answer 3

See the nice article Booting into 64-bit mode (Snow Leopard) on how to test whether your machine is 64-bit capable and how to boot into 64-bit mode, if you wish to.

The interesting part:

With 32-bit firmware, you cannot boot into 64-bit kernel; it's not possible.

To determine if your Mac has 32-bit or 64-bit firmware, copy/paste the following command shown in red into Terminal (Terminal is found in the /Applications/Utilities folder):

llcMP:~ lloyd$ ioreg -l -p IODeviceTree | grep firmware-abi
    | |   "firmware-abi" = <"EFI64">

As shown above, the firmware-abi has the value EFI64, indicating that my Mac Pro is 64-bit capable. If it reads EFI32, then your Mac cannot be booted into a 64-bit kernel.

Edit: Since the original color is lost, the command one has to copy and paste in the terminal is: ioreg -l -p IODeviceTree | grep firmware-abi ioreg -l -p IODeviceTree | grep firmware-abi