Re: Switching from CVS to GIT

Date: Mon, 15 Oct 2007 00:45:47 +0100 (BST)
From: Johannes Schindelin <redacted>
cc: Alex Riesen <redacted>, ae@op5.se, tsuna@lrde.epita.fr, 
    git@vger.kernel.org, make-w32@gnu.org

The problem is that on Windows, you cannot keep a file open and delete it 
at the same time.

That is no longer true, for quite some time.  NT4 and later versions
support that almost exactly like Posix filesystems.

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- no acceptable level of performance in filesystem and VFS (readdir,
  stat, open and read/write are annoyingly slow)

With what libraries?  Native `stat' and `readdir' are quite fast. 
Perhaps you mean the ported glibc (libgw32c), where `readdir' is indeed 
painfully slow, but then you don't need to use it.

No, native.

Once you experienced the performance of git on Linux, then rebooted into 
Windows on the same box, you will grow a beard while waiting for trivial 
operations.

Maybe GIT assumes too much about `readdir' and `stat', and should
refactor its code into better abstractions.

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- it is the only OS in the world with multi-root (/a/b/c and /a/b/c
  can be not the same, depending on what current "drive" is)

So what? on Unix "a/b/c" can be not the same.  Both cases are simply not 
complete file names, that's all.  No one said there must be a single 
root for all volumes, it's the Posix jingoism creeping in again.

I think Alex means this: you can have C:\a\b\c and D:\a\b\c.  So depending 
on which drive you are, you mean one or the other.  Just comparing the 
paths is not enough.

What _I_ meant is that the C: part is part of the full file name,
exactly like the leading / is on Unix.

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- No real "mmap" (which kills perfomance and complicates code)

You only need mmap because you are accustomed to use it on GNU/Linux.

Yes.  And we rely on the performance very much.

There's no need for mmap to get memory performance, except if sbrk and
friends are too slow.