Personal Digital Assistant

A personal digital assistant (PDA), to German " personal digital assistant " is a compact, portable computer, which is in addition to many other programs (eg, word processing ) used primarily for personal calendar, and task management.

It is operated via a touch-sensitive LCD display. Many PDAs also dominate a handwriting recognition. Beginning of the 1990s, Apple used for its newly introduced Newton MessagePad first time the term PDA. Since the late 1990s, the name in the German language was often used synonymously for all small portable computer.

Today, classic PDAs play virtually no role in the market, they are replaced by smartphones, which have the additional features of mobile phones and tablet computers with larger screens and more computing power. These devices usually have a mobile internet access.

T -Mobile calls its smartphones based on PDA as MDA - Mobile Digital Assistant.

  • 5.1 Operating Systems

History

Electronic Organizer, which emerged in the development of programmable calculators were only conditionally suitable for mobile use due to the mandatory bulky keyboard. Therefore Developed Electronic Organizer who also have a touch screen, this enabled interactive display control inputs with a fingertip or with a special pen with a rounded tip. This eventually followed by the development of a new generation of extremely compact organizer which (with a few function keys) completely renounced a conventional keyboard, the PDA.

In 1992, with the Zoomer the first PDA. This was developed by Palm and sold by Tandy and Casio. 1993 followed with the AT & T EO440 and 880, 600 and Amstrad PenPad Newton MessagePad Apple the first wave of PDAs.

In March 1996, the company U.S. Robotics brought small and very successful devices under the name Pilot ( later Palm) out. Here the term palmtop can be located. In relation to the concept laptop for portable personal computer, the palmtop is a portable PDA for Palm ( Palm engl. For palm) and refers to the brand Palm (see above, Pilot or Palm Pilot).

The transition from the present PDA Smartphone represents the product placed on the market in December 2004, HTC Magician ( XDA mini), which was finally completed with the release of the iPhone in June 2007.

Technical Basics

PDAs are usually equipped with a rapid-start the operating system. The operating system, the most important settings and personal information such as date and contact information will only be stored in the RAM memory. Therefore, PDAs are never completely shut down, but only in the standby mode ( standby mode engl. ) was added. They therefore continue to consume even in the " off" state current, albeit very little. This has the advantage that the user interface is available immediately after turning on the PDA. However, this is connected with the great disadvantage that the battery is drained slowly even when the PDA. If it is empty, the operating system and all data (including address, scheduling, and contact information ) as well as individual settings are deleted and have to be recovered long after restart.

Therefore modern PDAs have next to the main battery via a separate backup battery ( engl. backup battery), actually a battery. After the complete discharge of the main battery, while making it no "normal operation" possible, but the battery powered RAM further comprising current and thus ensures over a prolonged period, all data stored therein. To avoid that this also emptied sooner or later, they will be charged over and over again during normal charging or by the main battery. An alternative way to avoid data loss when tank is empty, the use of flash ROM memory, so that all data is retained even after power supply failure in the device (eg Palm Tungsten | e2)

Furthermore, a PDA now has additional built ROM memory modules or slots for external memory cards, for example, in the SD format. There, the user can save permanently without risk of loss due to " blackout " their own applications or data, such as MP3 audio files.

Telematics in PDAs deals with the networking of PDAs.

Usage

The most important applications on a PDA are summarized under the term PIM software and are usually supplied as standard with the PDA. These include, for example, address book, scheduler, calendar, memo pad, task scheduler, email and project management. In most current devices other applications such as word processing, spreadsheet, calculator (office programs) and games are integrated. Most of today's PDAs also allow playback of music (MP3) and videos as well as the recording of spoken notes and sounds. Software for various and very specific situations is playable example from the Internet and rechargeable via cable (USB or serial) or wirelessly via infrared or Bluetooth interface in the PDA. Using these interfaces, you can connect a PDA with a suitable mobile phone and access the Internet about this.

With increasing device performance also completely new uses are added. Thus PDAs can also use for mobile data collection or can replace usual standard mobile computer in certain scenarios. By the combination of Bluetooth or WLAN (WiFi) with a Voice-over- IP (VoIP ) client, it is possible to use a PDA as an IP telephone. PDAs also be used as navigation systems for some time. With the help of either external GPS receiver that can be connected via the serial port or via Bluetooth, or with an integrated GPS receiver, the PDA can determine its position accurately and be used with appropriate software and route planning. The user saves the cost of the still fairly expensive built- navigation computer in the vehicle. In addition, the navigation system is no longer tied to a motor vehicle and in addition to using with other vehicles (eg, bicycle) or hiking are used.

A great advantage of current PDAs is that they can be easily match with the PC. This balance is called synchronization, he was carried out with programs such as HotSync or ActiveSync. This can be backed up on the PC, for example, e- mails and addresses ( for example, from Microsoft Outlook, Notes etc. ) and appointments between the PDA and the computer replaced and all other databases. In this way, both devices bring each other up to date You can move your pre-defined Web pages from the Internet when synchronizing to the PDA and then read independently of the network connection ( so-called WebClipping, for example, Plucker, AvantGo or Mobipocket ).

Another great application is the industry here, for example, in logistics or as a mobile diagnostic systems. In these cases, it is mainly due to the presence of appropriate interfaces and often to greater robustness of the devices.

Based on the positive hardware features already mentioned, the multifunctional PDAs are also being increasingly used for "mobile learning" or M -learning in companies, universities and schools.

Connection and expansion options

With a variety of connectivity and expansion options can use PDAs for different applications. In addition to the classical field of appointment and address management is the creation of texts, using as an e -book reader, reference book, MP3 player, navigation system possible. Other applications include computer games, Internet use or the acquisition and display of digital photos.

Especially the last generation of PDAs is equipped with comfortable Internet browsers. It often is the Microsoft Internet Explorer in PocketPC format. For the use of the WWW to PDAs to be best prepared for cell phone displays pages. In essence, these are " stripped down " websites that fail to put up data intensive and thus are very quickly accessible with the available GPRS or EDGE bandwidth.

Expansion options or hybrid devices

  • Memory cards (Compact Flash ( CF), SD Memory Card, MiniSD, MicroSD, Multimedia Card (MMC), Memory Stick ), mainly for data backup and needed ' capacity expansion or for faster data transfer between PC and PDA, for example, for multimedia data.
  • Navigation aids (GPS ), for example GPS Springboard Module for the Handspring Visor or Garmin iQue360
  • External keyboards that can be connected via infrared or Bluetooth interface.
  • Mobile phone and PDA combined in one device
  • MP3 player Photo PDA (MP3 player, PDA and camera )
  • MP3 Photo Phone PDA (mobile phone, MP3 player, PDA and camera )

Connections

  • Infrared - wireless, optical transmitting data with invisible infrared light ( digital business cards, notes, or tasks to another device, which is located in the immediate vicinity).
  • Bluetooth - for wireless transmission ( wireless ) between two Bluetooth devices.
  • WLAN - wireless communication ( radio ) between multiple wireless - enabled devices and for integration into network infrastructure (Internet access, access to resources in local area networks ).
  • RS- 232 - for synchronization or for connecting GPS receivers, or RS232 -based measuring equipment. Thus, the PDA is used for diagnostic and configuration device in machine and plant engineering.
  • USB slave - wired synchronization with a PC.
  • USB Host - direct communication with other USB devices such as digital cameras, hard drives, USB flash drives, keyboards etc. So far have only a few devices (excluding HandheldPCs and PocketPCs ) this kind of connection.

Operating Systems

One of the first (1991 introduced ) was the HP95LX PDAs from Hewlett -Packard. The successor HP100LX and HP200LX were very popular devices. All three were based on the DOS operating system in conjunction with additional software from the Lotus 1-2-3 was the most efficient secure. Lotus 1-2-3 was then the most popular spreadsheet in DOS ( such as today Microsoft Excel under Windows ). A desktop spreadsheet in a palm-sized device was then a technological masterpiece and the first time allowed the use of extensive " worksheets " on the road.

Meanwhile, there are a number of different operating systems, which are used in PDAs.

The Newton used the Newton OS as the operating system, the first fully written in C operating system that was trimmed for low memory and CPU consumption.

With PEN / GEOS was released in 1992, a PC / GEOS for PDAs, handhelds and smartphones like the ZOOMER PDA, the HP OmniGO100/120 HandheldPC ( successor to the DOS HPxxx -LX series ) and the early Nokia Communicator Smartphone series, from the rise Nokia established the world market leadership.

The basis for the devices often offered under the heading of " Palm " Palm OS developed by the now independent company PalmSource.

The Psion EPOC operating system forms the basis for Symbian OS, which in smartphones such as Siemens SX1, Nokia 9210/9290/9300/9500, 7710, 3650/3660/7650/6260/6600/6630/6670/6680/7610/N70 / N90/N91/N95/N96, N -Gage, N -Gage QD, Sony Ericsson P800/P900/P910, Sendo X, Panasonic X700 and Motorola A925/A1000 is employed.

Another operating system for handheld computers is Linux. Meanwhile, there are several distributions, specifically customized to PDA version is OPIE, which is available at the moment for Sharp Zaurus, Siemens Simpad and HP iPAQ in multiple languages ​​free, and Maemo, which was developed by Nokia for the Nokia 770 and also at his successors N800 / N810 will be used.

More PDA grades are sold under the name Pocket PC and run under a particular version of Windows, the Windows CE or Windows Mobile.

In the meantime, have all current PDAs also have built-in or optional Java support (on Connected Device Configuration, CLDC or MIDP - based ), which is one of the most popular applications of embedded Java, in the case of Mobile Digital Assistants, ie mobile PDAs. Use the default Java version is an appeal to the COM interfaces for example GPS receiver not possible, so there are special versions of Java, such as EWE or their successors EVE.

Operating Systems

  • Newton OS, used by Apple
  • Apple iOS, a modified Mac OS X system from Apple for iPhone, iPad and iPod touch.
  • PEN / GEOS, established in 1993 in Casio Z- PDA " Zoomer ", and 1996 HP Omnigo100/120 and in other
  • Palm OS, mainly used by Palm Palm Tungsten series
  • Sony CLIE
  • Acer n series
  • Asus MyPal series
  • CASIO Cassiopeia
  • Fujitsu Siemens FSC Loox
  • HP Jornada
  • HP / Compaq iPAQ
  • HTC ( among others known by the XDA / MDA / VPA- series, which are offered as OEM products for German mobile network operators )
  • LG KS20
  • Icon
  • Toshiba Toshiba e400/e800
  • Axim x30
  • Axim x50 or x51
  • Axim x50v and x51v with VGA screen
  • HP / Compaq iPAQ
  • SHARP Zaurus
  • Simputer
  • Maemo for Nokia Internet Tablets
  • Openmoko
  • HTC Dream / G1
  • SHARP Zaurus SL -C3000, SL - C3100, SL - C3200
  • SHARP Zaurus SL -C3000, SL - C3100, SL - C3200
  • Psion revo, Series 3, Series 5 classic and mx, Series 7, Netbook, Siena
  • Ericsson MC218 (equivalent series 5 mx ) and R380 (Smartphone )
  • Oregon Scientific Osaris
  • Geofox One and Pro
  • Psion Teklogix Netbook per
  • HP600er series, and other older handhelds
Optical character recognition Sharp Wizard Booting Sleep mode Read-only memory M-Learning Hewlett-Packard Access Systems Americas EPOC (operating system) OPIE user interface Connected Limited Device Configuration Mobile Information Device Profile Pocket LOOX Jornada (PDA) Dell Android (operating system) NetBSD OpenBSD WebOS
372556
de