Android is a brand new platform for mobile phones, and has been created from scratch specifically for this purpose. This means that it is a ‘modern’ system that does not suffer from any legacy issues, and has taken the best ideas from various other projects to build a system that is arguably better than any of the other, competing, systems. Thus, for example, it uses the Java language as the development language, but has rejected the rest of the Java ecosystem. Specifically it uses a completely new virtual machine (Dalvik) which is redesigned with mobiles in mind – and has a number of very interesting design decisions that we will discuss. Similarly, the Android application framework represents a departure from the traditional way of doing things, and has a learning curve, but once you get used to it, it is great, especially for allowing different apps to share data, code, and in general co-operate. We will explore and discuss this and various other design decisions in Android. This talk can serve as your introduction to “”What is Android”", and more importantly, “”Why is Android”"

1. Why is Android the way it is ... Navin Kabra [email_address]

4. B.Tech, IIT-Bombay

7. http://punetech.com/navin

9. Email: [email_address]

12. Also: HTC, Motorola, Intel, T-mobile, TI, Samsung

14. Java programming language

15. OpenGL graphics

16. Android’s own app development framework Photo Credit:Android Home by Unnamed 102 (via wikipedia)

21. Optimized for low-memory requirements

29. Activities

30. Intents

31. Content Providers

33. Each activity independently invokable

35. Show email list

36. Create an email

42. Level of indirection between app & data storage

44. (By the way, SQLite is in-built)

47. No standard Java libraries

48. No JCP (Java community process)

49. No Java license

50. No JARs (i.e. no byte-code compatibility)

53. “ Bionic” – customized, partial libc implementation

54. Only 200k (half of glibc)

55. Designed for low CPU devices

58. Touch, but not multi-touch (yet)

60. CPU: 250-500MHz

61. Bus: 100MHz

62. Data-cache: 16-32K

64. High-level startup takes up another 20MB

65. System library takes up another 10MB

66. Only 10MB available for apps

68. Language and region

69. screen orientation: port, land, square

70. screen pixel density: 92dpi, 108dpi,

71. touchscreen type: notouch, stylus, finger

72. keyboard: keysexposed, keyshidden, keyssoft

73. primary input type: nokeys, qwerty, 12keys

74. primary navigation method: nonav, dpad, trackball, wheel

75. screen dimensions: 320x240, 640x480

76. sdk version: v1 (1.0), v2 (1.1), v3(1.5)

78. remove features (simplicity)

79. ease of use (user interaction design)