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Information Markup Language

Table of Contents | Chapter 1 | Chapter 2 | Chapter 3

1. Introduction

1.1 Simputer

The Simputer is a low-cost, multi-lingual, mass access device, currently under development. The Information Markup Language is the primary format of the content accessed by the Simputer. Hence the specification of IML is intimately tied to the system architecture of the Simputer and its application environment. Details of the Simputer's hardware and software architecture can be found on The Simputer website .

The Simputer is a handheld device with the following features:

  • A (320x240) LCD panel which is touch enabled.
  • A speaker, microphone and a few keys.
  • A soft-keyboard.
  • A stylus as the pointing device.

The display resolution is much smaller than the usual desktop monitor, but much higher than the usual wireless devices (cell phones, pagers etc).

The OS for the Simputer is linux. It is designed so that linux is to be started up infrequently (at the time of battery change for example), but the Simputer is in a low-power mode during the times it is not in use. When the Simputer is 'powered on', the user is presented with a screen having several icons (similar to the Palm home screen). The following kinds of usage are available in the Simputer:

  • Information access.
  • Computation.
  • Transaction processing.
  • Internet access.

1.2 Goals of IML

The design goal of the user interface of the Simputer is to make it usable by people who may not be literate. Thus, use of simple icons to be selected by pointing with a stylus and text-to-speech output in the local language are the two primary means of communication. Text entry is to be through a soft-keyboard and by a novel system of character input called tapAtap. The user is not expected to be familiar with the currently widespread user interface paradigm (windows, slidebars and pull-down menus). The notion of opening and closing various applications for various purposes (editors, browsers, mailer etc.) and maintaining several windows are also complicated for the naive user.

Hence, it is essential that for the general user, a single consistent interface be presented for handling the applications of the Simputer. For obvious reasons, a browser-like interface is expected to meet such requirements of simplicity and consistency.

1.2.1 The History of IML

The Information Markup Language (IML) evolved from the need to simplify content presentation on Simputer-like devices. During spring 1999, a primitive markup language called IML was specified and a simple browser was implemented using perl/Tk. (This work is reported in the Master's project work of Arun and Ganguly, July 1999).

Some sample applications like calendar, diary and a pygmy banking application were created for access from the basic IML browser. However, this version of IML was very primitive and required every application programmer to create user-interface widgets using perl/Tk, thus drastically curtailing the choices available for application development.

During the spring of 2000, with the design of the simputer further along, only the name IML was retained, the language was redesigned from scratch, and the current version of IML, brought out.

1.2.2 Why not WML?

The Wireless markup language (WML), the emerging standard for wireless devices, was initially considered as a candidate for the Simputer. However, this was given up quite soon. The reason is that WML caters to one extreme of device capabilities, while HTML caters to the other. There is a clear space between these two extremes that correspond to the space of handheld PCs like the Simputer: adequate processing power, reasonable display resolution and size, flexibility in terms of connectivity (modem/ethernet/wireless/infrared). Thus IML is positioned to cater to devices in this range. In other words, IML is not restricted to the Simputer, even though the Simputer architecture is the starting point for its evolution.

Thus IML's features are a superset of that of WML. Unlike HTML and WML, there is no provision for a script language. The primary reason is that with Simputer-like devices, the focus is on server-side processing and hence it is unnecessary to restrict the languages that can be used for such processing.

For the FAQ on IML and the Simputer: The Simputer FAQ.

1.2.3 Requirements for Simputer Markup

The requirements of the markup language is to serve as the information content vehicle for the Simputer. We will discuss IML with reference to the Simputer, having the understanding that IML is applicable to a range of Simputer-like devices.

1.2.4 Design Goals of IML

  • Simplicity
  • Open standard
  • Accessible to devices of all kinds on the Internet
  • Ability to interoperate with HTML and WML
  • Simplicity of browser

1.3 The Role of IML on the Web

Content in IML will be created primarily by applications that are tailored to the Simputer. However, existing Internet and Wireless content, including HTML and WML will be converted to IML by various servers. Since IML is designed for devices that are more capable than wireless devices, WML content can be easily accessed by IML-enabled devices.

IML is designed in such a way that Simputers communicate with all other entities using IML as the only medium of communication.

Table of Contents | Chapter 1 | Chapter 2 | Chapter 3

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