Makes it easy to point different subdomain to different servers. Since each subdomain "can" have a different IP address. But different subdirectories cannot have different IP addresses without first going to a central server than then being proxied to another server.
Also, allows you have have different features like SSL certificates depending on the subdomain. Again, this is not possible with subdirectories.
Apart from the technical reason, there might be cosmetic reasons.
-- Edward Alfert http://www.rootmode.com/ Multiple Domain Hosting and Reseller Hosting Plans Coupon Code (Recurring $5/month Discount): newsgroup
> not know much about subdomains, it appears that the first address simply > redirects to the second and third.
First of all - every domain is a sub domain of it's parent (except for root )
Secondly, a sub domain can be a stand alone seperate entity with or without and connection to the directory structure below domain - in fact a sub domain can be located on a different machine located anywhere.
The word folder is a windows peculiarity and has no ;real' significance to the web. You need to think in terms of directories, below or above the domain root (or sometines called doc root). while a sub-domain located on the parent domains machine can use a sub-directory it is more usual for the sub domain to have its own 'doc root' and tree structure. This way it could be moved easily to another location/machine without any need for major surgery.
A sub directory as in domain/sub/ is everything a sub domain is not. It is dependant on the domain tree to exist it cannot be located on another machine It is an integeral part of the parent and subject to the permissions / restrictions of the parent (within allowable modifications:-) Its location is static
> Makes it easy to point different subdomain to different servers. Since > each subdomain "can" have a different IP address. But different > subdirectories cannot have different IP addresses without first going to a > central server than then being proxied to another server.
"subdirectories can not have IP addresses.
> Also, allows you have have different features like SSL certificates > depending on the subdomain. Again, this is not possible with > subdirectories.
???
> Apart from the technical reason, there might be cosmetic reasons.
-- There are 10 types of people in this world Those that understand binary and those that don't
> First of all - every domain is a sub domain of it's parent > (except for root )
> Secondly, a sub domain can be a stand alone seperate entity > with or without and connection to the directory structure > below domain - in fact a sub domain can be located on a > different machine located anywhere.
> The word folder is a windows peculiarity and has no ;real' > significance to the web. You need to think in terms of > directories, below or above the domain root (or sometines > called doc root). while a sub-domain located on the parent > domains machine can use a sub-directory it is more usual for > the sub domain to have its own 'doc root' and tree > structure. This way it could be moved easily to another > location/machine without any need for major surgery.
> A sub directory as in domain/sub/ is everything a sub domain > is not. > It is dependant on the domain tree to exist > it cannot be located on another machine > It is an integeral part of the parent and subject to the > permissions / restrictions of the parent (within allowable > modifications:-) > Its location is static
Oh my, HERE we go again, and please don't get me started ;o) -- There are 10 types of people in this world Those that understand binary and those that don't
Sure it can. Even on a machine at the end of the world.
>>It is an integeral part of the parent and subject to the >>permissions / restrictions of the parent (within allowable >>modifications:-) >>Its location is static
Not true, when it's a link, you can move it everywhere, other disc, other machine, other universe, other operating system.
> Sure it can. Even on a machine at the end of the world.
> >>It is an integeral part of the parent and subject to the > >>permissions / restrictions of the parent (within allowable > >>modifications:-) > >>Its location is static
> Not true, when it's a link, you can move it everywhere, other disc, > other machine, other universe, other operating system.
Whhhaaaatttt!!!! If a directory is located on another machine how can it be a sub directory of one else where? A sub-directory by definition is a directory below a directory in the 'machines' hierarchal tree. If it is elsewhere then it is a sub-directory of another machine where ever it is.
I am looking forward to your response on this one.
>>Sure it can. Even on a machine at the end of the world.
>>>>It is an integeral part of the parent and subject to the >>>>permissions / restrictions of the parent (within
> allowable
>>>>modifications:-) >>>>Its location is static
>>Not true, when it's a link, you can move it everywhere,
> other disc,
>>other machine, other universe, other operating system.
> Whhhaaaatttt!!!! If a directory is located on another > machine how can it be a sub directory of one else where?
It's a feature that has been supported by *nix for many years.
> A > sub-directory by definition is a directory below a directory > in the 'machines' hierarchal tree. If it is elsewhere then > it is a sub-directory of another machine where ever it is.
> I am looking forward to your response on this one.
With NFS (Network Filesystem) you can mount a directory, on a computer in say Mexico, *under* a directory of a machine in say, the Netherlands.
Let's call the first directory mexico, the second one netherlands, which contains rotterdam.html, and that the cwd is mexico, i.e.
$ ls mexico netherlands $ cd netherlands $ ls rotterdam.html
It is similar to mounting 5 different harddiscs under mount, and call them hd1 t/m hd5, i.e.
$ ls /mnt h1 h2 hd3 hd4 hd5
mnt is not a special directory with magic. You can simply create a directory:
/home/john/htdocs/pictures-of-mexico
and mount a 200 GB harddisc as 'pictures-of-mexico'. *nix program will "see" pictures-of-mexico as a subdir of htdocs, even if the physical location is another harddisc. Apache has no problem with this set up, and that is a good thing :-D. If you have hot swappable harddiscs, it means you can create an entire new subdir by just plugging in a harddisc, and mounting it under a directory, without turning the computer off.
With NFS (Network File System), the 200 GB harddisc can be in an other computer.
> Sure it can. Even on a machine at the end of the world.
>>>It is an integeral part of the parent and subject to the >>>permissions / restrictions of the parent (within allowable >>>modifications:-) >>>Its location is static
> Not true, when it's a link, you can move it everywhere, other disc, > other machine, other universe, other operating system.
> (sorry for piggybacking)
What? I didn't write any of that
-- There are 10 types of people in this world Those that understand binary and those that don't
>>Sure it can. Even on a machine at the end of the world.
>>>>It is an integeral part of the parent and subject to the >>>>permissions / restrictions of the parent (within allowable >>>>modifications:-) >>>>Its location is static
>>Not true, when it's a link, you can move it everywhere, other disc, >>other machine, other universe, other operating system.
>>(sorry for piggybacking)
> What? I didn't write any of that
I apologised for the piggybacking :-D. I didn't see the original message, or overlooked it so I piggybacked yours. The > level shows that I reply to Bill.
>>>Sure it can. Even on a machine at the end of the world.
>>>>>It is an integeral part of the parent and subject to the >>>>>permissions / restrictions of the parent (within allowable >>>>>modifications:-) >>>>>Its location is static
>>>Not true, when it's a link, you can move it everywhere, other disc, >>>other machine, other universe, other operating system.
>>>(sorry for piggybacking)
>> What? I didn't write any of that
> I apologised for the piggybacking :-D. I didn't see the original > message, or overlooked it so I piggybacked yours. The > level shows that > I reply to Bill.
Hoy, no offense. I am attacked here on a regular basis (not that it means anything to me). Just didn't want to get the shaft for starting something here, especially since I do a good job of getting myself in trouble all on my own. If everyone helped me get in trouble here.....Well I just can't imagine what that would bring ;o)
-- There are 10 types of people in this world Those that understand binary and those that don't
John Bokma wrote: > With NFS (Network Filesystem) you can mount a directory, on a computer > in say Mexico, *under* a directory of a machine in say, the Netherlands.
True, though once mounted, the directory in Mexico becomes effectively part of the computer in the Netherland's file system. The bits aren't physically copied over, but the files may be considered to exist in the Netherlands.
> >>Sure it can. Even on a machine at the end of the world.
> >>>>It is an integeral part of the parent and subject to the > >>>>permissions / restrictions of the parent (within
> > allowable
> >>>>modifications:-) > >>>>Its location is static
> >>Not true, when it's a link, you can move it everywhere,
> > other disc,
> >>other machine, other universe, other operating system.
> > Whhhaaaatttt!!!! If a directory is located on another > > machine how can it be a sub directory of one else where?
> It's a feature that has been supported by *nix for many years.
> > A > > sub-directory by definition is a directory below a directory > > in the 'machines' hierarchal tree. If it is elsewhere then > > it is a sub-directory of another machine where ever it is.
> > I am looking forward to your response on this one.
> With NFS (Network Filesystem) you can mount a directory, on a computer > in say Mexico, *under* a directory of a machine in say, the Netherlands.
> Let's call the first directory mexico, the second one netherlands, which > contains rotterdam.html, and that the cwd is mexico, i.e.
> $ ls mexico > netherlands > $ cd netherlands > $ ls > rotterdam.html
> It is similar to mounting 5 different harddiscs under mount, and call > them hd1 t/m hd5, i.e.
> $ ls /mnt > h1 h2 hd3 hd4 hd5
> mnt is not a special directory with magic. You can simply create a > directory:
whoot!!! you say???? Think about it! Yes, I know about NFS - I have been working with *nix since before you were born!
There are three reasons why what you say is crapola.
1. We were talking about sub-domains, sub-directories on the net in relation to a web server. Not networked machines on a lan 2. Without a persistant link the sub-directory would no longer be mounted so could only exist on another machine for a short while. 3. If the link is persistant then the two machines are considered as one and the idea the sub-directory is on two seperate machines no longer applies.
Perhaps you need to go back and read the OP - get what you want to say into context?
>>With NFS (Network Filesystem) you can mount a directory, on a computer >>in say Mexico, *under* a directory of a machine in say, the Netherlands.
> True, though once mounted, the directory in Mexico becomes effectively > part of the computer in the Netherland's file system. The bits aren't > physically copied over, but the files may be considered to exist in the > Netherlands.
So a directory can be on a different machine. The visitor can not see this.
>>> With NFS (Network Filesystem) you can mount a directory, on a computer >>> in say Mexico, *under* a directory of a machine in say, the >>> Netherlands.
>> True, though once mounted, the directory in Mexico becomes effectively >> part of the computer in the Netherland's file system. The bits aren't >> physically copied over, but the files may be considered to exist in the >> Netherlands.
> So a directory can be on a different machine.
It's a question of semantics -- I wouldn't say the directory was on a different machine as it appears as part of one filesystem.
Bill Logan wrote: > "John Bokma" <postmas...@castleamber.com> wrote in message
[ NFS ]
> whoot!!! you say???? > Think about it! Yes, I know about NFS - I have been working > with *nix since before you were born!
Don't be fooled by my good looks ;-D
> There are three reasons why what you say is crapola.
I can think of one, your lack (again) of understanding.
> 1. We were talking about sub-domains, sub-directories on the > net in relation to a web server. Not networked machines on a > lan
That doesn't matter. sub-domains can be put on several machines in a LAN, behind a firewall. Same can be done with NFS. There is no difference here.
> 2. Without a persistant link the sub-directory would no > longer be mounted so could only exist on another machine for > a short while.
So, what's the problem there? If a machine that hosts a subdomain loses its connection, it's gone too.
> 3. If the link is persistant then the two machines are > considered as one and the idea the sub-directory is on two > seperate machines no longer applies.
A machine is normally defined as running one copy of the kernel image. But you probably don't know that. So it's not a machine. What you say is that the Internet is one machine, because all computers are connected.
> Perhaps you need to go back and read the OP - get what you > want to say into context?
I proved that the statement: a subdir has to be on the same machine, is false.
> > "John Bokma" <postmas...@castleamber.com> wrote in message
> [ NFS ]
> > whoot!!! you say???? > > Think about it! Yes, I know about NFS - I have been working > > with *nix since before you were born!
> Don't be fooled by my good looks ;-D
> > There are three reasons why what you say is crapola.
> I can think of one, your lack (again) of understanding.
> > 1. We were talking about sub-domains, sub-directories on the > > net in relation to a web server. Not networked machines on a > > lan
> That doesn't matter. sub-domains can be put on several machines in a > LAN, behind a firewall. Same can be done with NFS. There is no > difference here.
If you want to talk about sub-domains - there is a huge difference. Now sub-domains definately do not need to be on the same machine, or connected in any way to the parent domain (apart from in the zone file:-)
> > 2. Without a persistant link the sub-directory would no > > longer be mounted so could only exist on another machine for > > a short while.
> So, what's the problem there? If a machine that hosts a subdomain loses > its connection, it's gone too.
The big difference is that a sub-directory 'belongs' to the domain that owns the parent directory. If the sub-directory, (housed on a different machine) is lost, part of the web site is lost with it. Also, if the machine housing the parent directory goes down, the sub-directory and all it contains is also not accessable. (through the parent directory)
A sub domain is a stand alone entity (that may or may not have connections -links to the parent domain. If the sub domain is on another machine and the parent domain is not accessable the sub domain will still be accessable if the other machine is up.
> > 3. If the link is persistant then the two machines are > > considered as one and the idea the sub-directory is on two > > seperate machines no longer applies.
> A machine is normally defined as running one copy of the kernel image. > But you probably don't know that. So it's not a machine. What you say is > that the Internet is one machine, because all computers are connected.
The internet has been likened to a giant computor made up of all the connected cpu's so yes, - while connected. Otherwise, what would you call a sub-directory on a second drive (that contains no kernal img) yet is accessable to the 1st?
> > Perhaps you need to go back and read the OP - get what you > > want to say into context?
> I proved that the statement: a subdir has to be on the same machine, is > false.
Physically, yes, but in practical terms - and that is what matters - it is like proving man can go to the moon. True, but not much use to those of us who want to go there.
What is the value in being able to put a sub-directory anywhere if it is not able to function as a sub-directory whenever the machine it's parent is on needs too?
