一种趋势是千真万确的，不会改变的，那就是便携式系统在不断地缩小。即使很多器件的外形因数已达到无法进一步缩小的程度，机壳内众多的子系统还是能变得更小一些的。例如，一些最新潮的无线电话小巧玲珑，再缩小的话，使用时就会感到不舒服。但设备提供的功能数量还能增加。 A trend is true, will not change, that is, portable systems are constantly shrinking. Even though the form factors of many devices have reached the point where they can not be further reduced, many of the subsystems in the enclosure can be made smaller. For example, some of the latest wave of wireless phones are smaller and smaller, and uncomfortable to use. However, the number of functions provided by the device can also be increased.