Re: FileSystem Question
On 07/03/07 08:20, Douglas Allan Tutty wrote:
On Mon, Jul 02, 2007 at 09:39:32PM -0500, Ron Johnson wrote:
On 06/29/07 17:54, Douglas Allan Tutty wrote:
It sounds like the Log File System (LFS) that NetBSD is working on, or
the database-style of a mainframe where every 'file' is really a record
in a database where back copies are maintained until the space is
needed.
No. It is file versioning, which OpenVMS has had since the late
1970s.
That's what I meant by "database-style of a mainframe". It may not be
an actual database built on-top of a filesystem, but the ideas behind it
are the same.
Well, actually, no. The ideas behind databases and file versioning
are totally different.
Extremely useful, for every reason that OP mentioned.
I agree. How does one implement it under *NIX? I've only _needed_ it a
couple of times and used Postgresql to do it. Having it available
simply would be useful and I would use it more. Under postgres, I had a
python CLI or dialog front-end. Ask for a copy of the file (default to
the most recent version) and you get a file to edit. Post that file
back to the system and it gets assigned a new version number that
integrates it into the version tree. I.e. if the current version was 3
and I requested version 2 to edit, when posted it became version 2.1.
The files existed in a directory in the user's home directory and it was
up to the user to not go and edit a file directly.
That sounds like a revision "tracking" system.
[snip]
Ron, from what I've read over the years, there are a lot of features
from the mainframe world that would be very useful in the NIX world.
Someone here with experience in both said that the mainframes were only
useful now for large batch jobs; that as servers it was cheaper to use
NIX boxes. That may or may not be so but there's a lot we can learn
from the mainframe world. However, for those of us who haven't had the
priveledge of experiencing that world, it remains viewed 'as through a
mirror dimly'.
OpenVMS has a lot of mainframe features, but it's still a time-
sharing system, just like Unix, but *not* like the mainframe.
Mainframes *do* excel at record-oriented COBOL batch jobs, but they
are also great at on-line systems with staggering numbers of
concurrent users. This is because the machine only "sees" terminal
activity when a user XMITs a block/screen of data. (Web forms are a
pale imitation of CICS.)
--
Ron Johnson, Jr.
Jefferson LA USA
Give a man a fish, and he eats for a day.
Hit him with a fish, and he goes away for good!
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