Re: [ros-kernel] Re: File system struct - ENOUGH ALREADY

[Casper H. <ch...@us...>]

tir, 2002-04-30 kl. 14:53 skrev Frank D. Engel, Jr.:
> > Why is this a better layout than that on my Windows NT partition?
> 
> For a single-drive, mini-system without the need for advanced I/O
> optimizations...  it's not.

How could the Windows layout prevent you from optimizing I/O?

> 
> But, if you are dealing with a large system, having many drives, and
> attempting to seamlessly integrate those drives into a cohesive, usable
> layout... it can be significantly better.
> 
> Software is typically stored in /usr, /bin, /opt, and /sbin.  IRIX, for
> example, has /bin as a symlink to /usr/bin.  /usr is a good candidate
> for a mount point to a large parition on a separate drive.  Another
> good candidate is home directories (/home under Linux; /export/home
> under Solaris -- server-side; /usr/people under IRIX; etc.)  This is
> where the documents are stored.  Additionally, moving /tmp to a
> separate partition (or better yet to swap space, as in Solaris), can
> help to prevent users from flooding the boot device with large files,
> adding to the system's stability.
> 

You can also use quotas to prevent flooding of a system. This way you
get more control and it is definitely easier to change quotas than
resizing partitions in case you need more disk space.

> On the other hand, a single-user, home system can put all of these onto
> a single partition, allowing space to be managed much more easily.  If
> a second drive is added, with a new partition for, say, home
> directories...
> 
> 1. make the partition(s)
> 2. mkfs the partition(s)
> 3. shutdown now  (to single-user mode, after warning users)
> 4. mount the partition on, say, /mnt/temporary
> 5. mv /home/* /mnt/temporary
> 6. umount /mnt/temporary
> 7. mount /dev/newpartition /home
> 8. adjust fstab
> 9. telinit 5  (or 3)
> 
> This gives *NIX systems a LOT more flexibility when it comes to disk
> management.  And, the above procedure does not break existing software,
> or require reinstallations...
> 
> Try moving a large app between drives under Windows...
> This changes the path, often requiring a reinstall, or some messy
> registry edits.
> 
> > /mnt/cdrom
> > 
> > better than
> > 
> > D:
> > 
> > for accessing my CD-ROM?
> 
> Once more, what if you add another drive, and your drive letter
> changes?  Some of those games might not work anymore until you
> reinstall them!

If I want a partition to have a specific drive letter I would go into
disk management in control panel and change the drive letter. If I want
the partition to not have a drive letter, I could mount it in an NTFS
directory. If I have two partitions but want only one drive letter for
them both, I could use a software RAID driver.

Why would you move your applications manually? The Windows NT policy in
this area is to keep applications in the Program Files directory. Try
moving samba on linux. The location of smb.conf is generally hardcoded
in the program, so moving it will render it unusable. On my Mandrake
installation it is located in /etc/samba, but I've seen it in /etc,
/usr/local/samba, and /usr/local/lib too.

> 
> > Your arguments:
> > "The Win32 "standard" for filesystem structure is hardly the "best".
> > Drive letters are hardly the best way to identify devices."
> > are not good enough for me to agree with you.
> 
> Does it make a little more sense now?
> 
> > Yes, NT is not a microkernel. NT has microkernel principals in it's
> > design, but it is not a true microkernel because it is comercially
> > impractical. AKAIK, no comercial operating systems implement a true
> > microkernel design. Since someone claim that MS says it is, I would
> 
> The BeOS used a true microkernel.  And, it was BLAZING fast.  (I think
> you can still DL the personal edition for free from cNet.)  Much of
> POSIX, FAST, GUI-based, FAST, easy to work with, FAST, fun, FAST...

I think your FAST key is stuck ;o)

> 
> > be
> > glad if someone would post a link to some official statement from MS,
> > because I have never heard them say this. The only information I have
> > about this is from Inside Microsoft Windows 2000 published by
> > Microsoft
> > Press.
> 
> 
> http://www.microsoft.com/technet/treeview/default.asp?url=/TechNet/prodtechnol/ntwrkstn/reskit/archi.asp
> 
> M$ refers to NT as having a "modified" microkernel architecture, as
> opposed to a "pure" microkernel architecture.

And they are right.