...And if I was a total non-techy, the below message would have made me
run away screaming, and never want to jailbreak. <grin>. Seriously
Joseph, sometimes you have to keep it simple, sort of like on the
Braille Sense list. In short, non-techy terms, jailbreaking allows you
to add tweaks or features or abilities to the iPhone which normally
can't be done.
--
Raul A. Gallegos
Why do we press harder on a remote control when we know the batteries
are almost dead?
Home Page: http://raulgallegos.com
Twitter: https://twitter.com/rau47
Facebook: http://facebook.com/rgallegos74
On 6/11/2012 3:32 AM, Joseph Lee wrote:
Hi,
To explain jailbreaking, I think we need to visit operating system
security and user levels. But first:
Yes - jailbreaking and unlocking are two different things. Jailbreaking
means using some OS exploit to run programs using a different user's
privilege, whereas unlocking means allowing a device to be used on any
carrier (as many phones are locked to specific carriers).
Now onto the subject at hand:
There are at least two user modes under Unix (which is the basis for iOS
and Mac OS X and other OS's such as Linux): root and normal user. The
root is the user which has total control ovth files and programs on
Unix, such as program installation, file system modification and so on.
Many Unix systems run in normal user mode for most of the time - and iOS
follows this.
Under iOS, there are two users defined (although it may not appear to be
so): root and mobile. Root is the admin account while mobile is the
regular user mode of the iOS. What dailbreak does is it changes the
running mode of the iDevice to that of root mode where the device user
has total control over files and programs on an iDevice. This allows
installation of apps not authorized by Apple and to perform other things
such as modifying how the device works by using tweaks and changing files.
But you may ask, "how can I access my iDevice from my computer?" This is
where SSH (Secure Shell) comes in. This is a terminal environment where
a computer can access another computer over it network. A good example
is remote website administration from a home computer. In order for
this to work, the target device must be told to accept "incoming" SSH
connections (in this case, by jailbreaking it and installing OpenSSH).
From the local computer (the one which will be accessing the iDevice),
the user needs to know the IP address of the iDevice, its root userdayn
and password (by %default, it is "root" for user"^n and "allpine" for
password; it is recommended to change the password). Because we're
using root user mode,
be careful about what you do with file system in iDevice - one wrfg
change and it requires restore via iTunes, which installs "regular"
firmware instead of jailbroken firmware.
Finally, let us investigate how jailbreaking is even possible. Operating
systems, like any programs, contains well-known bugs and opportunities
for programmers to mess around with it (at least through bugs and
programs). For example, there was a bug fix release by Apple last year
because some PDCF documents made the device unstable, which was used by
jailbreak programmers (this is callbed "exploit," that of using a bug to
mess around in an OS). So in order for jailbreak to work, programmers
need four things: the exploitable bug itself in a device firmware, a
modified firmware that allows root control of a device, a way of
transfering this new firmware and making it permanent (called
"untethered jailbreak"). First, the programmers find out the exploit in
a firmware, prepares a new (modified or unlocked) firmware that be^akes
advantage of the exploit and makes it availible to others. Then the
jailbreak package connects to the iDevice (mostly via iTunes connection)
and embbeds the newly modified firmware to the device's memory. Then it
does some modifications to make this patch permanent unless restoration
via iTunes occurs, at which point the jailbreak will be undone by
flashing the
official firmware from Apple.
Hope this helps.
Cheers,
Joseph
----- Original Message -----
From: "Arnold Schmidt" <arno...@mindspring.com
To: <viphone@googlegroups.com
Date sent: Mon, 11 Jun 2012 02:57:52 -0400
Subject: Jail Breaking, What Does This Mean?
Being new, I ask: I think jail breaking a phone means that one can
install apps onto it that are not approved by apple. What is ssh? Most
importantly, will this void my warranty, or will apple deny me updates
because they think I have an illegal phone? I do not think one can get
updates for an unlocked phone, I may not be correct about that. And I
assume that jail breaking and unlocking are not the same. Thanks for
clarification.
Arnold Schmidt
--
You received this message because you are subscribed to the "VIPhone"
Google Group.
To search the VIPhone public archive, visit
http://www.mail-archive.com/viphone@googlegroups.com/.
To post to this group, send email to viphone@googlegroups.com.
To unsubscribe from this group, send email to
viphone+unsubscr...@googlegroups.com.
For more options, visit this group at
http://groups.google.com/group/viphone?hl=en.
--
You received this message because you are subscribed to the "VIPhone" Google
Group.
To search the VIPhone public archive, visit
http://www.mail-archive.com/viphone@googlegroups.com/.
To post to this group, send email to viphone@googlegroups.com.
To unsubscribe from this group, send email to
viphone+unsubscr...@googlegroups.com.
For more options, visit this group at
http://groups.google.com/group/viphone?hl=en.
