Re: Shock and Awe

Matthew T. Russotto wrote:
In article <LbmMh.18106$O_5.15491@trnddc03>,
Wes Groleau <groleau+nntp@xxxxxxxxxxxxx> wrote:
Matthew T. Russotto wrote:
It is. But modifying a file the way prebinding does is not the same
as deleting one and putting a new one in its place.
Changing bytes IN an open file is absurd!

Without some method of keeping changes coherent, it is. But it can be
quite useful if such methods exist.

In a multiuser database system, there is a reason for it, and extensive
code to keep it from causing problems. When you are merely recompiling or tweaking an executable, make a new version and delete the old when
it is free.

Even Windows is smart enough to resist that.

Only Windows, so far as I know.

Windows is not the only system that has file locking.

Now, if you want real fun, try changing a running application by
modifying the file on disk, then forcing the app to be paged out.

In the versions of Solaris that I worked with in the 1990s, you
don't really modify a file on disk. You write a new version and
tell the OS to delete the old one. Which it does when there are
no file descriptors using it. Until then, the processes owning
those file IDs continue to use the old version for paging or whatever.

I believe this is true of other Unix variants. It should be true
for HFS+ but apparently it is not. BUG.

--
Wes Groleau
----
The man who reads nothing at all is better educated
than the man who reads nothing but newspapers.
-- Thomas Jefferson
.

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