Today my colleague told me that his 13" macbook pro (2009 ver.) cannot boot up with black screen. After taking a look, I found that it even gives out crazily annoying beep sound continuously (beep-beep-beep, halt, beep-beep-beep, halt, ......). I have not met that before and turned to Google for help. After some looking and trying (at some time I thought it is because a disc stuck in the drive), finally I found a few sources all point out that the 3-beep sound means "bad memory". The colleague then tried taking the two 1-GB RAM in and out to test and BINGO! The problem was caused by one single faulty RAM! So I will know what to do if any of my machine gives me that sound......
Update: One of my friends told me just now those beep sounds are called "beep code" and their meanings are dependent to different BIOS. A reference of Mac machines can be found here.
Update: Another reference in Wikipedia.
Thursday, October 14, 2010
Wednesday, October 13, 2010
Notes of differences between x86 and x64 on programming
Notes: For reference only, actual situation should be affected by CPU type, kernel, compiler, etc.
| Data Type | Ubuntu x86 | Ubuntu x64 | Win32 | MacOS 10.6 | SunOS 5.10 | MIPS | iOS |
|---|---|---|---|---|---|---|---|
| char | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
| short | 2 | 2 | 2 | 2 | 2 | 2 | 2 |
| int | 4 | 4 | 4 | 4 | 4 | 4 | 4 |
| long | 4 | 8 | 4 | 8 | 4 | 4 | 4 |
| long int | 4 | 8 | 4 | 8 | 4 | 4 | 4 |
| long long | 8 | 8 | 8 | 8 | 8 | 8 | 8 |
| float | 4 | 4 | 4 | 4 | 4 | 4 | 4 |
| double | 8 | 8 | 8 | 8 | 8 | 8 | 8 |
| long double | 12 | 16 | 8 | 16 | 16 | 8 | 8 |
| pointer | 4 | 8 | 4 | 8 | 4 | 4 | 4 |
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