CSE 334: Pervasive Computing
Dept. of Computer Science & Engineering
Daffodil International University
Lecture- 2: Information Access Devices
Content
Topics of Discussion
• Handheld Computers
• Sub-Notebooks
• Phones
Handheld Computers
Handheld computers comprise the largest group of Internet connectable pervasive devices. They are small, lightweight, and fit into
pockets. A stylus is used to tap on a touch screen to activate applications or enter data. Currently two major operating systems are applied
on handheld devices: Palm OS and Windows CE.
Palm OS-Based Devices :
Palm os was developed by Palm Computing, a subsidiary of
3COM. It is the best-known and most popular operating system for handheld devices, having a market share of about 70 percent. Palm OS based devices are manufactured by Palm or other companies, like Symbol, IBM, and Handspring, which licensed the operating system and sell devices on their own.
The renown Palm 111 models were launched in 1998. They in- Some Polm OS cluded infrared communication, version 3.0 of Palm OS and 2 MB devices
of memory. The newer Palm IIIx has 4 MB of memory and an improved display. The heart of the Palm IIIx is a Motorola Dragonball
EZ processor, which is more power efficient and opens the way for
the use of less expensive memory upgrades.
Palm OS-Based Devices
Windows CE-Based Handheld Computers
Windows CE is the second major operating system for handheld computers, taking almost the remaining rest of the market share.
Windows CE has been developed by Mierosoft and is applied by manufacturers like Casio, HP, and Compaq.
Computer platform to mobile computers. Users should be able to do the same things in the same way on any computer alike device - as far as such is possible under the given constraints of form factors and reduced processing power. Windows CE provides the same consistent look and feeI. both on the common PC and on the smaller
Handheld
From the Mierosoft perspective, a handheld is nothing else than a
miniaturized PC! This philosophy is reflected by terms as PocketPC,
Palmheld PC, and Handheld PC.
Windows CE-Based Handheld
Computers
Sub-Notebooks
In terms of size, weight, processing power, and functionality, subnotebooks
are somewhere in between a handheld device
and a regular notebook. Most of a handheld computer's characteristics
are valid for sub-notebooks too. But they have more memory, more CPU power and they provide a reasonable screen as well.
Additionally, they have a small keyboard, making data entry much
easier - a significant advantage, in case a lot of text has to be typed
in. Although sub-notebooks won't fit into pockets anymore, they are
still highly portable and a bit lighter than full-sized notebooks.
The
main differences to regular notebooks are that the sub-notebooks have much less computing power, cost less and that they are intended
for mobile usage.
But being less convenient to carry around than a handheld and having less functionality than notebooks, makes the sub- notebook
dass not very popular for a broad audience.
Sub Notebook
EPOC is a versatile operating system designed far usage in various
mobile devices. Beside sub-notebooks, it is also applied far phones.
EPOC has been developed by the Symbian consortium, founded by
Ericsson, Motorola, Nokia, and Psion. EPOC based sub- notebooks
are available as MC218 from Ericsson, Oregon Scientific's OsariS,
and Psion's 5mx Pro (Figure 2.7), Series 7, and revo EPOC-Based Sub-Notebooks
Windows CE-Based Sub-Notebooks
Major device manufacturers for Windows CE sub-notebooks are HP Qornada 820) and Compaq (Aero 8000) - both are using version
2.11 ofthat operating system. Version 3.0 is not yet available for that dass of devices
Windows
CE handhelds feature a PC Card slot far various peripherals like wireless communication adapter, modems, and many more.
Phones
Modern phones create a high demand for new pervasive technologies.
They have evolved from a simple person-to-person voice interface
to powerful network clients. F ancy computing features like tiny
hard disks and voice recognition are condensed into a tiny shell dissolving
the demarcation to handheld organizers. Today, address books, calendar, memos, and games are state of the art applications,
which are no longer restricted to high-end phones.
Cellular Phones
The diversity of cellular phones is incredible; their functionality too:
the endless list of features gets longer every day. There are manifold
games, fancy form factors, built-in FM radio, and even PIM functionality.
The operating systems used in cellular phones are quite manifold too. Mostly proprietary systems like RTOS from Siemens
or GEOS from Geoworks are used. Others like EPOC are applied
by several companies.
GSM
Global System for Mobile Communication (GSM) is the accepted de facto standard for mobile wireless communication. A
dense net of GSM base stations has been established by numerous
telecommunication providers throughout more than 100 countries.
Each station feeds the digital signals from cellular phones within its
reach into the worldwide telephone network. The standard ensures
interoperability from a technical point of view : all information required for user
identification and authentication as well encryption of the communication
is stored on a smart card, which is plugged into every phone.
The so called Subscriber Identity Module (SIM) functions as a secure
token..
CDMA/TDMA
In North America and parts of Asia wireless communication providers
operate networks based on several other digital standards.
Among these, Code Division Multiple Access (CDMA) is today's
most common one. It also allows a secure communication using an encoding key, which is sent along with the voice data. Time
Division
Multiple Access (TDMA) is a competing standard, which works similar to CDMA, but has an improved bandwidth.
Thank you!
