相关疑难解决方法(0)

我想知道为什么upgrade有时不想升级系统的某些部分，而dist-upgrade确实如此。这是运行后的示例apt-get upgrade：

apt-get upgrade：

rimmer@rimmer-Lenovo-IdeaPad-S10-2:~$ sudo apt-get upgrade
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following packages have been kept back:
  linux-generic linux-headers-generic linux-image-generic
0 upgraded, 0 newly installed, 0 to remove and 3 not upgraded.

与apt-get dist-upgrade：

rimmer@rimmer-Lenovo-IdeaPad-S10-2:~$ sudo apt-get dist-upgrade
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Calculating upgrade... Done
The following NEW packages will be installed:
  linux-headers-3.0.0-13 linux-headers-3.0.0-13-generic
  linux-image-3.0.0-13-generic …

最近我在旧机器上安装了旧版本的 Ubuntu。每当我尝试安装任何软件时，都会收到一条错误消息，说找不到它：

$ sudo apt-get install vlc
Reading package lists... Done               
Building dependency tree       
Reading state information... Done    
E: Couldn't find package vlc