在實際開發中，有時需要考慮到兼容性問題，這兩個信息還是很有用的，我一般都是程序開始時讀取，存到公共變量裏。
#import "sys/utsname.h"
/*!
* get the information of the device and system
* "i386" simulator
* "iPod1,1" iPod Touch
* "iPhone1,1" iPhone
* "iPhone1,2" iPhone 3G
* "iPhone2,1" iPhone 3GS
* "iPad1,1" iPad
* "iPhone3,1" iPhone 4
* @return null
*/
- (void)getDeviceAndOSInfo
{
//here use sys/utsname.h
struct utsname systemInfo;
uname(&systemInfo);
//get the device model and the system version
NSLog(@"%@", [NSString stringWithCString:systemInfo.machine encoding:NSUTF8StringEncoding]);
NSLog(@"%@", [[UIDevice currentDevice] systemVersion]);
}