Mobile Operating Systems Lesson 04 PalmOS Part 2

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2 PalmOS Memory Support Assumes that there is a 256 MB memory card(s) The card RAM, ROM, and flash memories A memory card logical hexadecimal addresses from 00000h to 3FFFFh Oxford University Press All rights reserved. 2

3 PalmOS Memory Support RAM for stacks of processes and for the global variables in the running processes of the application(s) ROM or flash for permanent resident application programs and OS Flash used for storage of non-volatile data Oxford University Press All rights reserved. 3

6 Memory A dynamic heap (within 96 kb for PalmOS 3.x) of application process stacks (3kB) TCP/IP stack (32 kb) OS functions stack, applications and OS functions dynamic-memory spaces, system global variables (2.5 kb Application global variables Oxford University Press All rights reserved. 6

7 Direct memory address spaces in card Used instead of allocated dynamic memory buffers for the I/O port devices (e.g., LCD display, keypad input, and modem I/Os) Oxford University Press All rights reserved. 7

9 File manager Manages each file as a database which has multiple records and information fields Each record attributes protected record, deleted record (similar to deleted file), locked record (in use by application process or OS), and updated record Deleted record attribute helps in data recovery by a recovery program Oxford University Press All rights reserved. 9

10 The info fields of each record Record ID and record attributes Info fields about the file have (i) name, (ii) file attributes, (iii) version of application database, (iv) modification number (number of times modified) and access counter for number of times accessed), and (v) file local ID Oxford University Press All rights reserved. 10

11 File Local ID In place of several characters requiring several bytes The file local ID a number used to identify the file locally when an application is running Oxford University Press All rights reserved. 11

12 File ID A local file sorting table uses the file local ID to sort the file in the required order For example, the ordering may also be based on the time and date of the last modification made in the file Oxford University Press All rights reserved. 12

15 Protocols Connection management (CM) protocol modem manager (MM) Serial link protocol (SLP) interacts with SM to transmit the data to PC A device receives the data from the other end through serial manager and SLP, MM, or CM Oxford University Press All rights reserved. 15

16 Communication Protocols MM for deploying a dial up-modem CM carries out exchanges for establishing connection, baud rate selection, and finding version number SLP for packet communication on serial line Oxford University Press All rights reserved. 16

17 Communication Protocols A desktop link protocol (DLP) transmits data to PADP when serial device is sending data to PC and receives data from PADP when serial device is receiving data from the PC Oxford University Press All rights reserved. 17

19 IrDA Asynchronous serial (115 kbps) Synchronous serial communication (1.152 or 4 Mbps) Exchange manager as session layer and IrDA library functions (for IrDA protocol layers) at lower level Oxford University Press All rights reserved. 19

20 Exchange manager Enables data interchange directly without HotSync Exchange manager and application use a set of launch codes to generate appropriate events Oxford University Press All rights reserved. 20

21 Network library functions TCP/IP network library functions (for UDP and TCP) to send stack to a net protocol stack (NPS) and provides a socket API Berkeley Socket APIs also supported Uses HTTP/HTTPS net library for Internet connectivity Oxford University Press All rights reserved. 21

22 Application Development Method Corresponding to each event, there is an event handler Application development means defining additional events and coding for the corresponding handlers Oxford University Press All rights reserved. 22

23 Application Development Method An application can be assumed to be divisible into sub-applications a m to a n 1 along with the existing event handlers a 0 to a m 1 Assume that a i runs on the events e i An event e i polled at a sleep interval of t i 1 in an infinite while loop Oxford University Press All rights reserved. 23

Application on PalmOS platform as event driven number of

26 Application Development Packages Supports development packages Palm SDK (software development kit) and CDK (conduit development kit) A conduit is a path Oxford University Press All rights reserved. 26

27 CDK conduit of Palm Provides a two-way path for data exchanges and synchronization between a desktop PC application (for Windows or Solaris) and the applications running on a device Oxford University Press All rights reserved. 27

28 Summary PalmOS Memory management Partitioning Communication APIs Network Library Functions Application Development Method Application Development Packages Oxford University Press All rights reserved. 28

Palm Platform Hardware Intro to the Palm OS and application programming

Palm Platform Hardware Intro to the Palm OS and application programming Total memory (RAM/ROM) originals had only 128 Kb currently average is 4 Mb (max. 8Mb) 32 bit addresses 8, 16 & 32 bit data types