[ros-kernel] Disk layout continued

[Robert K. <ro...@ko...>]

Hi, I'd like to warm up the theme about Directory structure and multiple
installations, again.

Hyper and I had a discussion in this context, and I want to give us a base
via posting it.
Conclusion up to now is:
-very different views for some ss
-multiple distinct installations should be possible on one partition but
cause dir-inconsistency (who has the true view)

Let's start clearing this problem.,


do you think we should continue that discussion about directory structure?

NonVolatil: yes
KJK::Hyperion: I have five queued messages
maybe we should ask first :-)
NonVolatil: I think we should define the structure as early as possible
and diverge the sturcute to have no overfilled dirs
*** KJK::Hyperion signed off at Wed Apr 24 21:38:43 2002.
*** KJK::Hyperion signed on at Wed Apr 24 21:38:53 2002.
KJK::Hyperion: yes, I agree
the earlier, the better
KJK::Hyperion: about Unix dirs...
I think they *really* should stay in the disk root. All systems with a
POSIX subsystem (MacOS/X, QNX, BeOS) do that, I don't see why we have to
differ
NonVolatil: here agein
KJK::Hyperion: heh
NonVolatil: moment I have a call......
KJK::Hyperion: that's ok
NonVolatil: Here I am again. Female phone partners never find an end
KJK::Hyperion: hehehehehehehehe
how true
NonVolatil: what now............
NonVolatil: I don't want to pollute the root
KJK::Hyperion: the root is no-one's land
NonVolatil: This is one of the advances of NT over OS/2 for example. You
can install multiple installations on one parttion
NonVolatil: W2k gave this adv. away in some parts
NonVolatil: AND I want to have a subdir for each sub system, also win32
KJK::Hyperion: Win32 can, by design, be installed everywhere
Unix systems cannot. They have a rigid structure, and more important
there's no way to determine dynamically the location of directories
NonVolatil: thats ok and unchangeable. But with virtual dirs there is a
possibility to locate the real dirs under the OS' dir
KJK::Hyperion: virtual directories are an administration and programming
hell
NonVolatil: i don't think so
NonVolatil: 'cos a programmer of a certain ss knows what he knows
KJK::Hyperion: they introduce yet another special file system object, for
example
NonVolatil: not needed
*** Error while sending IM: Rate to client
NonVolatil: for example NT's os2 ss does souch a thing with CONFIG.SYS
NonVolatil: The os2 ss creates a virtual config.sys form a key in the
registry.
KJK::Hyperion: this is hideous
NonVolatil: So every NT installation has its own config.sys - which was
the intention
NonVolatil: hideous?
KJK::Hyperion: horrible
KJK::Hyperion: what path has this fake config.sys?
NonVolatil: X:\
NonVolatil: ?
NonVolatil: I know...you are imaging yourself a posix only version
KJK::Hyperion: do they take in account all the possible paths?
X:\dir\..\config.sys? X:\config.sys.? X:\dir1\dir2\..\..\config.sys?
NonVolatil: OS/2's config.sys resides in the boot drives root
KJK::Hyperion: what if some program reads it with an "indirect" path like
those? do you have to check every damn file open?
NonVolatil: whats an indierect path?
KJK::Hyperion: the dot and double-dot entries, for example
NonVolatil: the ss's open implementation has to monitor if a special file
is opened and treat that differently.  - Its possible but hard
KJK::Hyperion: X:\..\..\dir\.\dir2\..\.\..\config.sys....

this is the same as X:\config.sys
NonVolatil: oh, yes, they are
NonVolatil: I don't know if it is possible in nt
NonVolatil: but it is pain
KJK::Hyperion: with a little sacrifice no more problems
NonVolatil: Its difficult if you think of a posix or os2 only version. But
this would mean that you can boot different systems with win32 but the
other ss remain the same - or even more evil refuse to function in the
other version
KJK::Hyperion: there's another problem with the "every SS has its root"
approach. That they cannot work together
NonVolatil: was it you who told us about the other POSIX 2 compiant ss
taken by M$
NonVolatil: if they share the same root ?
KJK::Hyperion: if they share the same root, file paths can be exchanged
freely with little or no processing required
NonVolatil: what do you mean with  that?
KJK::Hyperion: POSIX+ for example already accepts both the backslash and
forward slash as path separator. A path like \home\hyperion\desktop is
both a valid Win32 and a valid POSIX path
NonVolatil: lets talk baout your ss. which dirs are required?
KJK::Hyperion: technically, none. Only the root and /tmp. But for an
usable system, it needs /bin, /dev, /etc, /lib and /sbin. For full FHS
compliance, /boot, /home, /mnt and /opt are also required
KJK::Hyperion: and /usr, and /var, by the way
NonVolatil: tmp and usr may share the root. the others I think not
NonVolatil: dev may exist but be 'filled' by the ss
KJK::Hyperion: why not? I can guarantee you that it poses no problem at
all for existing programs
NonVolatil: The parallel install thing.
 And, as you said, other ss that use the same names
KJK::Hyperion: no other subsystem uses these names
NonVolatil: I can imagine a carbon ss. This will have tmp as darwin has
one
KJK::Hyperion: Darwin is Unix
NonVolatil: yes and so it requires different usr var etc etc.
NonVolatil: I don't like this either
KJK::Hyperion: but Carbon doesn't define standard directories
NonVolatil: Do you know MacOS? I don't
NonVolatil: But take for example the Cocoa API
*** Error while sending IM: Rate to client
KJK::Hyperion: A bit. It has directories like System, Applications, and a
few others. I think, apart from System, that other directories have no
special meaning
NonVolatil: is this for os X true, too?
KJK::Hyperion: yes. The root is something like this:
/bin
/etc
/lib
...
/Applications
...
NonVolatil: so darwin+MacOS
KJK::Hyperion: it's just that /bin, /etc, /lib, etc. are hidden
KJK::Hyperion: yes. They effectively have four concurrent subsystems:
POSIX, Carbon (old Mac), Cocoa (NeXTStep) and Aqua (new Mac)
KJK::Hyperion: and they use a single root
NonVolatil: ? I thought Carbon are old but  improved binarys. They use
Aqua for display. Cocoa are native apps and they use also Aqua for
display. Aqua is not a subsystem
KJK::Hyperion: Aqua is the subsystem, the display is called Quartz
and to support the old Mac they both have an emulation subsystem with
binary compatibility (Classic) and a native subsystem with source
compatibility (Carbon)