1. Java Ring
What is Java Ring ?
The Java Ring is a stainless-steel ring, 16-millimeters (0.6 inches) in diameter that houses
a 1-million-transistor processor, called an iButton
The Java Ring is a tiny wearable computer with 134kilobytes of RAM.
RAM has 6KB of data memory and to 32KB 0f program memory
6KB may not sound like much, but it is 20 percent more memory
than the first computer ever used .
Even 6 K is enough to hold our secret codes, our credit card
numbers, our driver license, other wallet contents, and even some electronic cash. The
ring can also store a few important URLs.
The Java Ring is a wearable computer that can be used to authenticate users to services
on the Internet. A user only has to push the ring on his finger on a Java Ring reader for
about a second.
The key issue about a wearable computer is not whether it is a ring
or another form factor: the deciding point is that we will always
have it with us. Many aspects of computing change once there
is no need to go to a special room to get at the computer.
INSIDE JAVARING
A Java Ring is a finger ring that contains à
JAVA VIRTUAL MACHINE
134KB RAM
32KB ROM
REAL TIME CLOCK
IBUTTON
BLUE DOT RECEPTOR
JAVA VIRTUAL MACHINE
JVM is the piece of software that recognises java language and translate into byte code,
which is used by system connected to java ring via reader.
134KB of RAM
It is used to store program and data. The NVRAM offers high R/W speed and also
provides temper resistance through instantaneous clearing of all memory when tempering
is detected.
Energy provided by lithium backup preserves complete state of machine when java ring
is disconnected from user
Performs garbage collection to deal with the objects which are out of scope and recycle
memory. Applets can be loaded or unloaded from java iButton

2. 32KB of ROM
Special kind of operating system called E-commerce based on java and JVM is stored in
the ROM. This is because it is not supposed to be altered by the user. Operating system
handles all operations happening in iButton.
REAL TIME CLOCK
It gives exact time of the day. It can run up to 10 years by energy provided by lithium
backup. Processor clock frequency is not constant and cannot be determined by external
means.
The jewel of the Java Ring is the Java iButton
The iButton is a computer chip enclosed in a 16mm thick stainless steel can. Because of
this unique and durable container, up-to-date information can travel with a person or
object anywhere they go. Designed to be fully compatible with the Java Card 2.0 standard
the processor features a high-speed , large RAM and ROM memory capacity, and an
unalterable real-time clock. It is small and portable enough to attach to a key fob, ring,
watch, or other personal items.
Types of iButtons
• Memory iButton
• Java-powered cryptographic iButton
• Thermochron iButton
iBUTTON COMPONENTS
Can :
It is an electronic communications
interface. Each can has a data contact,
called the 'lid', and a ground contact,
called the 'base'. Each of these contacts
is connected to the silicon chip inside.
Grommet :
The two contacts are separated by a polypropylene grommet .Information is transferred
between iButton and a PC with a momentary contact, at up to 142K bits per second.
To do that one presses iButton to the Blue Dot receptor, a $15 pipeline into PC. The Blue
Dot sticks to any convenient spot on the front of a PC and is cabled to the serial or
parallel port in the back.
By simply touching the iButton to the two contacts described
above ,we can communicate with it through our 1-Wire protocol.

3. The 1-Wire interface has two communication speeds: standard
mode at 16kbps, and overdrive mode at 142kbps
Information is transferred between an iButton and a PC with a
momentary contact at up to 142kbps. We simply need to touch our
iButton to a Blue Dot receptor or other iButton probe, which is
connected to a PC.
Blue Dot Receptor
The R/W operation in java ring is done by blue dot receptor provided by RS232 serial
port adapter. DS1402D-DR8 is a 1-wire network cable designed to connect to any serial
or USB 1-wire port that has up to two buttons simultaneously.
Information is transferred between an iButton and a PC with a momentary contact, at up
to 142kbps.We just need to touch our iButton to a Blue Dot receptor or other iButton
probe, which is connected to a PC.
The Blue Dot receptor is cabled to a 1-wire adapter that is attached to the PC’s serial or
parallel port.
Each receptor contains two Blue Dots to accommodate instances where multiple iButtons
are required to complete a transaction.
TMEX RUNTIME ENVIRONMENT(RTE)
A layer of software is required to interface iButtons to computers and produce the desired
information in the desired format.
For all iButtons ,iButton-TMEX is a software platform on which to build applications.
TMEX’s architecture follows the International Standards Organization(ISO) reference
model of Open System Interconnection (OSI), a protocol with seven layers denoted as
Physical, Link, Network,Transport,Session , Presentation, and Application.
iButton Viewer
With the TMEX Windows installations we get the iButtons Viewer, an application for
exploring iButton features from our PC.
iButton Viewer automatically finds iButtons on our system and displays their serial
numbers with a description of relevant features and menu options
Java Virtual Machine
Automatic garbage collection for efficient reuse of memory space.
Add or delete applets in a secure manner to update applications.

4. Java-accessible unique 64 bit registration number supplements IP addresses to make the
intermittent network of roaming iButtons globally addressable.
Security in Java Ring
Confidential data is stored in Non Volatile RAM memory.
Barrier substrate and triple layer technique deny unauthorized access to NVRAM
confidential data.
If any unauthorized access penetrates the two layers, its detected by security processor
and data is erased immediately. This is called as Rapid Zeroization.
The communication between iButton and outside world is limited to single line, provides
security against hard ware attacks.
Processor clock frequency is not constant and cannot be determined by external means
Applications
Some of the applications of Java ring are in:
e-banking to get the account balance of customer.
Configuring our car components according to preferences.
Opening door to prevent entry of unauthorized users.
The Java Ring, therefore, is simply the latest and most complex descendant of a long line
of products that have proven themselves to be highly successful in the marketplace. With
its stainless steel armour, it offers the most durable packaging for a class of products that
likely will suffer heavy use and abuse as personal possessions. The iButton form factor
permits attachment to a wide variety of personal accessories that includes rings,
watchbands, key fobs, wallets, bracelets, and necklaces, so the user can select a variation
that suits his or her lifestyle.