电子邮件附件 解码
If you are using a locally installed mail client, you may have noticed that the size of an email seems to be a bit larger than the files you have attached to it. Why is that and is it a cause for concern? Today’s SuperUser Q&A post has the answer to a confused reader’s question.
如果您使用的是本地安装的邮件客户端，则可能已经注意到，电子邮件的大小似乎比您所附加的文件大一些。 为什么会这样，这值得关注吗？ 今天的“超级用户问答”帖子回答了一个困惑的读者的问题。
Today’s Question & Answer session comes to us courtesy of SuperUser—a subdivision of Stack Exchange, a community-driven grouping of Q&A web sites.
今天的“问答”环节由SuperUser提供，它是Stack Exchange的一个分支，该社区是由社区驱动的Q＆A网站分组。
问题 (The Question)
SuperUser reader arc_lupus wants to know why the size of his email is larger than its attached files:
超级用户阅读器arc_lupus想知道为什么他的电子邮件的大小大于其附件的大小：
When attaching files to email, I have noticed that Mozilla Thunderbird calculates the total size of the resulting email as much larger than the files I have attached.
在将文件附加到电子邮件时，我注意到Mozilla Thunderbird计算出的结果电子邮件的总大小比我附加的文件大得多。
Here is a recent example: two images, one at 13 MB and the other at 3.6 MB, approximately 17 MB in total, and there were four lines of text. Mozilla Thunderbird then asked me if I really wanted to send an email with a total size of 22 MB.
这是一个最近的示例：两张图像，一个图像为13 MB，另一图像为3.6 MB，总共约17 MB，并且有四行文本。 Mozilla Thunderbird然后问我是否真的要发送总大小为22 MB的电子邮件。
Where is that difference in size coming from? Having 5 MB of text sounds like a bit much.
大小差异来自何处？ 拥有5 MB的文本听起来有点像。
Why would the size of an email be larger than its attached files?
为什么电子邮件的大小大于附件的大小？
答案 (The Answer)
SuperUser contributor David Schwartz has the answer for us:
超级用户贡献者David Schwartz为我们提供了答案：
Your data was 17 MiB, there are 1024 KiB in a MiB, 1024 B in a KiB, and 8 bits in a byte. So that is a total of 142,606,336 bits.
您的数据是17 MiB，MiB中有1024 KiB，KiB中有1024 B，字节中有8位。 因此，总共有142,606,336位。
Base 64 encoding encodes every 6 bits as a separate byte, so we need about 23,767,722 bytes. Dividing by 1024 twice gives us a total of 22.67 MiB. So that is where the 22 MiB comes from.
Base 64编码将每6位编码为一个单独的字节，因此我们需要约23767722个字节。 除以1024两次得到的总数为22.67 MiB。 这就是22 MiB的来源。
Email is a pretty old technology and does not assume an 8-bit clean pipe.
电子邮件是一项相当古老的技术，并不假定使用8位纯净管道。
Have something to add to the explanation? Sound off in the comments. Want to read more answers from other tech-savvy Stack Exchange users? Check out the full discussion thread here.
有什么补充说明吗？ 在评论中听起来不错。 是否想从其他精通Stack Exchange的用户那里获得更多答案？ 在此处查看完整的讨论线程 。
翻译自: https://www.howtogeek.com/278737/why-is-the-size-of-my-email-larger-than-its-attached-files/
电子邮件附件 解码