sudo apt-get update失败的
> W: Failed to fetch
> http://dell.archive.canonical.com/updates/dists/trusty-dell-biz-vivid-skl/Release.gpg
> Unable to connect to dell.archive.canonical.com:http:
>
> W: Failed to fetch
> http://dell.archive.canonical.com/updates/dists/trusty-dell-dino2/Release.gpg
> Unable to connect to dell.archive.canonical.com:http:
>
> W: Failed to fetch
> http://dell.archive.canonical.com/updates/dists/trusty-dell/Release.gpg
> Unable to connect to dell.archive.canonical.com:http:
>
> W: Failed to fetch
> http://dell.archive.canonical.com/updates/dists/trusty-dell-biz-vivid-skl/public/binary-amd64/Packages
> Unable to connect to dell.archive.canonical.com:http:
>
> W: Failed to fetch
> http://dell.archive.canonical.com/updates/dists/trusty-dell-biz-vivid-skl/public/binary-i386/Packages
> Unable to connect to dell.archive.canonical.com:http:
>
> W: Failed to fetch
> http://dell.archive.canonical.com/updates/dists/trusty-dell-biz-vivid-skl/public/i18n/Translation-en_US
> Unable to connect to dell.archive.canonical.com:http:
>
> W: Failed to fetch
> http://dell.archive.canonical.com/updates/dists/trusty-dell-biz-vivid-skl/public/i18n/Translation-en
> Unable to connect to dell.archive.canonical.com:http:
>
> W: Failed to fetch
> http://dell.archive.canonical.com/updates/dists/trusty-dell-dino2/public/binary-amd64/Packages
> Unable to connect to dell.archive.canonical.com:http:
>
> W: Failed to fetch
> http://dell.archive.canonical.com/updates/dists/trusty-dell-dino2/public/binary-i386/Packages
> Unable to connect to dell.archive.canonical.com:http:
>
> W: Failed to fetch
> http://dell.archive.canonical.com/updates/dists/trusty-dell-dino2/public/i18n/Translation-en_US
> Unable to connect to dell.archive.canonical.com:http:
>
> W: Failed to fetch
> http://dell.archive.canonical.com/updates/dists/trusty-dell-dino2/public/i18n/Translation-en
> Unable to connect to dell.archive.canonical.com:http:
>
> W: Failed to fetch
> http://dell.archive.canonical.com/updates/dists/trusty-dell/public/binary-amd64/Packages
> Unable to connect to dell.archive.canonical.com:http:
>
> W: Failed to fetch
> http://dell.archive.canonical.com/updates/dists/trusty-dell/public/binary-i386/Packages
> Unable to connect to dell.archive.canonical.com:http:
>
> W: Failed to fetch
> http://dell.archive.canonical.com/updates/dists/trusty-dell/public/i18n/Translation-en_US
> Unable to connect to dell.archive.canonical.com:http:
>
> W: Failed to fetch
> http://dell.archive.canonical.com/updates/dists/trusty-dell/public/i18n/Translation-en
> Unable to connect to dell.archive.canonical.com:http:
>
> W: Failed to fetch
> http://oem.archive.canonical.com/updates/dists/trusty-oem-sp1/Release.gpg
> Unable to connect to oem.archive.canonical.com:http:
>
> W: Failed to fetch
> http://oem.archive.canonical.com/updates/dists/trusty-oem/Release.gpg
> Unable to connect to oem.archive.canonical.com:http:
>
> W: Some index files failed to download. They have been ignored, or old
> ones used instead.
看来我需要添加 ppa 存储库。
能否请你帮忙？