Linus Torvalds (torvalds@linux-foundation.org) on 1/26/09 wrote:
---------------------------
>Howard Chu (hyc@symas.com) on 1/25/09 wrote:
>>TruePath (truepath@infiniteinjury.org) on 1/25/09 wrote:
>>>
>>>Is it simply inertia that favors the traditional unix file
>>>abstraction or some disadvantage that isn't occurring to me?
>>
>>I think it's simply recognizing that no matter how many
>>record-oriented facilities you provide, there will always
>>be an application developer who wants something else.
>>
>>Therefore, leave it to userland implementation and keep
>>the base system generic.
>
>Exactly. The reason the "stream of bytes" is so powerful
>is because you can build any abstraction on top of it, and
>it doesn't cause problems when you copy things around.
>
>People should think about (and shudder) filesystems
>like the VMS one, where if you downloaded a file over FTP,
>it simply stopped working - because you lost the metadata.
>Or remember all the MacOS issues? What a disaster!
>

In fact, downloading a _text_ file over FTP to/from VMS works just fine. Last time I tried to do the same with binary files there were issues but I used _very_old_ version of VMS (about 5.3, when AFAIR VAX is supported up to version 7.1, IPF and Alpha are currently in 8.something).

>We don't use FTP any more, but HTTP byte-serving isn't
>really any different. Do you really want to live in a world
>where simple generic applications like scp/rsync etc no
>longer work, because your files aren't just streams of
>bytes any more?

Well, I don't know much about VMS, but supposedly backup command takes care of that sort of issues.
And, of course, even on Linux/Unix/Windows world to transfer things around people much more often rely on tar+zip or version control than on binary copy.

BTW, I don't say that file systems that know too much about the files they are storing are preferable, not at all. I fully agree that streams of bytes as an interface between application and file system make more sense in most cases. Just want to point out that the problems created by higher-level abstraction, at least in particular case of VMS are not nearly as serious as you presented them. I'd imagine that were VMS remaining a popular desktop OS mere 5-7 years more than it happened in reality those problems would be solved in a ways so transparent to the end users that nobody (except a few developers) would pay attention that there were problems.


>
>Hint: if you answered 'yes' to the question above, just
>get yourself sterilized now.
>
>Do your fancy stuff on top of the simple file abstraction.
>Sure, it results in mistakes like xml, but the alternatives
>are worse.
>
>Linus