Report On Palm OS

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Report On Palm OS 

• Ancita J.Vaz
• ID999291975
• EMAILvazanci_at_iit.edu
•  
•  

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1. INTRODUCTION

• The Palm OS is the standard for handheld
  computing, a new form of computing focused on
  helping you manage and access all the information
  in your life, at any time, in any location.
• Palm Powered handhelds are the way that everyone
  can manage personal information, work with
  corporate applications and data, and mine the
  richness of the web.
• They have by far the most users, the most
  software programs, the most hardware options, and
  the most manufacturers and yet are still the
  simplest handhelds to learn and use.

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The reasons for the popularity of the Palm OS
are

• The most software
• One of the best features of this is the huge
  range of software programs you can run on them.
• The most hardware optionsThey are designed to
  be wearable , small and lightweight and can be
  easily expandable
• The most manufacturers
• The Palm OS is an open standard, licensed to
  many manufacturers like Handspring, Motorola,
  IBM, Kyocera, Nokia, Samsung, Sony, Symbol,
  Franklin Covey, and TRG.

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2.THE PALM OS PLATFORM
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The Palm OS platform consists of five primary
components

• 1.Palm OS software
• 2.Reference hardware design
• 3.HotSync conduit data synchronization
  technology for one-button synchronization
• 4.Platform component tools including an API
  that enables developers to write applications
• 5.Software interface capabilities to support
  hardware add-ons

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In Depth

• Device applications such as HTML-based web
  clipping applications allow websites to deliver
  compressed information to users in under 10
  seconds, on average.
• Graffiti power writing software allows users to
  quickly and accurately enter information into
  their handheld devices.
• System libraries let developers easily extend the
  functionality of the Palm OS.
• An internal software map of how the hardware
  works, the hardware abstraction layer gives
  developers the flexibility to modify the Palm OS
  without having to rewrite code each time a change
  is made.
• Localization architecture makes it easy to
  localize an application by putting all
  localizable data into an overlay file.
• The application interface makes it easy to access
  a function or launch an application by pushing a
  clearly labeled onscreen button instead of
  navigating through a menu.
• Intelligent compression formats the most
  important information for display on a single
  screen, visible without scrolling

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2.OVERVIEW OF OS

• PalmOS actually includes a preemptive
  multitasking microkernel . Each PalmOS
  application has one PilotMain which receives all
  events for the application, and decides how to
  route them. One task runs the user interface.
  Other tasks handle things like monitoring input
  from the tablet. The user interface permits only
  one application to be open at a time.In the
  following sections we discuss the OS in detail.

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The Memory Architecture

• Hardware Overview
• The Memory Manager
• The Dynamic Heap
• The Data Manager
• The Storage Heap(S)

• Preferences
• File Streams
• Features
• Memory Reset
• Storing Data

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 Hardware Overview 

• All Palm OS memory is considered part of
  a card. RAM and ROM coexist on the same card.The
  OS can support multiple cards in a device,
  theoretically up to 256 cards
• ROM -- Contains the operating system,
  built in applications, and default databases. ROM
  sizes to date vary from 512K to 2M.
• RAM -- Contains add-on applications,
  system preferences, user data, and run time
  storage. RAM sizes to date vary from 128K to 2M.
  Palm OS can currently support up to 12M of RAM on
  a single memory card

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Memory Cards

• Each card that includes ROM has a header with the
  manufacturer, name, a 4 byte signature, a
  version, and a list of the size and offset of
  each block of RAM or ROM on the card.
• All RAM is considered one store, and ROM is
  considered another store, and the OS assumes a
  maximum of 2 stores per card. A store is a
  largely invisible abstraction that is simply a
  container for an identifier, a list of heaps, and
  a database directory. The store header helps
  determines the validity of RAM on a given card.
• Macintosh Simulator has a second card which
  contains the application code and resources. This
  second card aids in simulating the separation of
  RAM and ROM of an actual device.

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Memory Partitioning

• The RAM and ROM are further divided into
  heaps, with a small amount of RAM that is not in
  any heap reserved for low memory globals, store
  headers, and the like. The memory is used for
  various OS subsystems and also contains the trap
  dispatch table. Applications should not read or
  write this memory directly. Palm OS instead
  provides documented APIs to access many of these
  values.
•  

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The Memory Manager 

• The subsystem that is responsible for managing
  allocations from a heap is called the Memory
  Manager. All three heaps dynamic, storage, and
  ROM, are controlled by the same memory manager.
  Memory manager structures are described in
  MemoryPrvNew.h. The applications typically only
  use the Memory Manager APIs directly to access
  the dynamic heap. The Data Manager APIs provide
  high level access to the storage heap data, and
  the ROM heaps are not normally used directly by
  an application.

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Heap Allocations

• The Memory Manager allows clients to allocate two
  types of memory, movable chunks and fixed chunks,
  more commonly called handles and pointers.
• The terms "pointer" and "handle" normally refer
  to the 4-byte variable that references memory,
  rather than to memory itself. One main
  distinction between pointers and handles is that
  pointers stay at a fixed address as long as they
  exist.
• Handles can be moved in the heap at virtually any
  time, and so must be locked down before they can
  be used. The memory manager is free to move
  unlocked handles around in memory, which is may
  do to reduce fragmentation and service other
  allocation requests.
• By convention, movable chunks are kept near the
  beginning of the heap, at lower addresses. Fixed
  chunks are kept at the end of the heap, at higher
  addresses. This is done to facilitate heap
  compaction.

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Heap Structure

• Header. Each heap has a header with a heap ID,
  status flags, the heap size, and the master
  pointer table..
• Master Pointer Table. The master pointer table is
  a dynamically-built table of persistent handles
  which map to the location for each chunk.
• Chunks. The remainder of the heap consists of the
  three kinds of chunks (free, movable, and fixed.)
  
• Terminator. Essentially a zero-length chunk, only
  4 bytes wide, used to detect the end of the heap
  when iterating through chunk by chunk. 

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• The chunk header always contains the size of the
  chunk, in bytes, and a flag that identify a chunk
  as free or allocated, and an owner ID. For
  allocated chunks, a size adjust may be stored
  which defines "pad" bytes at the end of the chunk
  which are not considered part of the allocation.
  This allows the memory manager to keep track of
  very small runs of bytes which could not
  otherwise be used. Chunks are always immediately
  next to each other, so every chunk in the heap
  can be found by starting at the first chunk and
  offsetting by the chunks size to find the next
  chunk. Chunks can be split and combined as
  necessary to accommodate memory manager
  operations.

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• Allocating and Managing The Free List
• When an allocation is made, a large enough free
  chunk is located by walking the heap from the
  beginning. If the chunk is large enough to
  accommodate the request and still have free space
  left over, it is split and a new smaller free
  chunk is created. If it is not large enouh for
  this extra chunk, the whole free chunk is used.
  When a chunk is released, it is simply marked as
  free.
• Heap Compaction
• The goal of compaction is to coalesce all the
  free memory into a single contiguous chunk so
  that a large allocation can be made. The memory
  manager compacts the heap by moving unlocked
  movable chunks down (to lower addresses) to fill
  in the free spaces. When a fixed or locked chunk
  is encountered, the memory manager searches the
  rest of the heap for the largest unlocked movable
  chunk that can fit into the space remaining below
  the fixed or locked chunk.
• Memory Manager Protection
• Write protection is in effect on the storage
  heap(s) and is enforced by setting the hardware
  chip selects to mark that memory as read only. In
  order to write to a protected heap, the memory
  manager first acquires the semaphore to ensure
  that no other task is modifying memory manager
  structures. It then disables task switching and
  enables hardware write permission to the
  protected area.

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The Dynamic Heap

• On a card with RAM, the first RAM heap,
  (typically heap 0,) is used as the dynamic heap.
  The size of the dynamic heap varies from device
  to device, and in general has gotten larger as
  newer devices are introduced. Dynamic heap space
  is possibly the most valuable resource for Palm
  OS developers, and should be used sparingly. The
  devices that run the 1.0 release have only 32K of
  dynamic heap. Devices that run 2.0 have either
  32K or 64K of dynamic heap, however on the 64K
  devices 32K is reserved for TCP/IP use, so the
  space available for other purposes is still only
  32K. 3.0 devices to date have 96K of dynamic
  heap, still with 32K reserved for TCP/IP. The
  dynamic heap is intended to be used as temporary
  storage for all run time operations on a given
  device. Data in the dynamic heap is not preserved
  across reset.

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Dynamic Heap Contents

• Global data for the operating system This
  includes things like font tables, kernel data,
  event queues, kernel and interrupt stacks, kernel
  structures, and everything necessary to maintain
  operating system services.
• TCP/IP stack When TCP/IP was added, an
  additional 32K of dynamic heap was made available
  to accommodate the TCP/IP stack.
• Library data Like the TCP/PI stack, the serial,
  IR, and other libraries use some dynamic heap
  memory for their buffers and state when they are
  in use.  
• Application UI data structures Things like
  windows, forms, fields, tables, bitmaps behind
  windows, etc. created by the various Palm OS
  services at the request of a running application.
  
• Buffers Space for pen strokes, key presses,
  system events, serial manager data, video memory,
  etc.
• Application global variables These are loaded
  when application is loaded. By convention they
  are based on the A5 register and can not move or
  change size while the application is running. 
• Application constant data Most compilers by
  default generate code to store things like
  strings and array initializers with the globals.
• Application stack Used for parameters and return
  addresses for both application functions and
  called system functions.

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Memory Ownership

• Each chunk in the dynamic heap has an owner.
  When a chunk is allocated, the memory manager
  assigns that chunk the ownerID of the running
  application. The ownerID does not uniquely
  identify any application, rather it is assigned
  from a small pool (currently 16) when an app
  starts, and the ID is reclaimed and reused when
  the app exits. This owner ID is primarily used to
  clean up any left over chunks when an application
  exits. On app exit, the system frees all chunks
  with the owner ID of the (no longer) running
  application.

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The Data Manager 

• Palm OS Databases
• Palm OS divides databases
  into two major categories record and resource
  databases.. Record databases access records by an
  index or a unique ID, can sort records by a key
  field, and data can be retrieved either directly
  using the index or via a search on the unique ID
  or key. Resource databases index resources by a
  4-byte resource type and a 2-byte resource ID,
  and resources are retrieved using the type/id
  combination.
• Records and Record Databases
• Record databases are most
  common for data storage, as they are more
  structured than resource databases. The system
  provides more management functionality for record
  databases than for resource databases.The system
  can spread records among all storage heaps on the
  same store
• Resources and Resource Databases
• Resource databases can be
  used for free-form storage. The system provides
  management of resource ID's and of resource types
  but nothing beyond that, so resource databases
  have lower overhead than record databases. They
  provide a natural way for storing static
  heterogeneous data

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• The Storage Heap(s)
• The storage heap is used for persistent storage.
  Unlike the dynamic heap, storage heap memory is
  not cleared when the device is reset, and has
  additional protections against inadvertent
  overwriting. All persistent user applications and
  data is kept in the storage heap, in one form or
  another.
• Preferences
• The OS provides two databases that can be used to
  store small amounts of data for an application
  that is not associated with a particular
  application database. These provide good places
  to store things like user display choices, high
  score..
• File Streams
• New in the 3.0 release is an API to access data
  using streaming operations such as open, close,
  read, write, and seek. This API allows access to
  data streams larger than 64K in size. The data
  streams can be temporary or permanent.
• Features
• The OS provides an API for storing and retrieving
  small (4 byte) amounts of data that do not
  persist across resets, called features. Each
  feature is identified by a 4 byte creatorID and a
  2 byte index. Features were intended to allow the
  OS, libraries, and extensions to "publish"
  information about what they support and their
  version

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• Memory Reset
• A reset is normally performed by sticking a
  bent-open paper clip or equivalent poking device
  into a small hole in the back of the device and
  pressing a button known as the "reset switch." A
  soft reset clears all of the low memory globals
  and dynamic heap. A hard reset is performed by
  pressing the reset switch while holding down the
  power key. A confirmation message is displayed,
  asking the user to confirm the deletion of all
  data.
• Storing Data
• The data can be stored in
• Global Variables
• Stack
• Dynamic Heap
• Application Resources
• Record Databases
• AppInfo Data in a Database
• Unsaved Preferences Database
• Saved Preferences Database
• File Streams
• Features and Feature Pointers

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• EVENTS
• A Palm OS application is
  event-driven. Events arrive, like pen down or key
  down, and your application responds to them. Some
  events are handled by your application others
  are handled by the operating system. Once your
  application begins, it enters an event loop,
  repeatedly getting, then handling an event.
• FORMS AND
  CONTROLS
• The Palm OS has built-in support
  for various controls and for managing forms.
  Forms are similar to windows on a desktop
  operating system. Because of the simpler user
  interface on the Palm OS, only one form is active
  even though several forms may be displayed. The
  Palm OS provides a rich API for forms that
  includes many user-interface elements.
• 
  COMMUNICATIONS 
• The Palm OS supports a variety
  of communication methods. Current communication
  protocols are
• Serial communication.
• TCP/IP with a socket interface.
• Infrared. Low-level infrared support is via IrDA
  (Infrared Data Assocation).

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4.THE HANDHELD DEVICE 

• The handheld device is one part of the Palm
  application.Some of its prominent parts are
• Screen The touch sensitive screen is 160 by 160
  pixels.
• Writing Area Here ís where you will enter text
  using either GraffitiÆ, a simplified script, or
  an on-screen keyboard. Hardware Buttons These
  buttons launch the four main applications.
•  Scroll Buttons These buttons page up or down.
• Power This button turns your Palm device on or
  off. Holding it down for at least two seconds
  toggles the backlighting.
• Silkscreen Buttons Tap these buttons to use
  them.

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5. OVERVIEW OF CONDUITS

• The second part of the Palm application is the
  desktop connection. Because Palm devices act as
  an extension of the desktop, it is crucial that
  information be easily exchanged. Conduits are the
  mechanism for doing this.A conduit is code on the
  desktop that is called during a HotSync
  synchronization to manage the flow of information
  to and from databases on the handheld. Conduits
  register the database or databases for which they
  are responsible . Each database should have only
  one conduit responsible for it.Conduits) are
  created using Conduit Development Kits for
  Windows (C/C), Mac OS (C/C), or Java.

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6.HANDHELD DEVELOPMENT

• For the development of the handheld portion of
  your Palm application, you can write code on
  Windows 95/98/NT, Unix, or Macintosh platforms.
  Palm's official development environment,
  CodeWarrior, is available for both Windows and
  Macintosh. POSE is the application which is a
  further development of Copilot. It serves as a
  replacement for an actual Palm OS device while
  you do development. Because it can load a ROM
  image from disk, it usefully emulates different
  versions of the Palm OS

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7.The features of Palm OS version 4.0

• The newest Palm OS operating system, version
  4.0, supports the growing expansion opportunities
  and includes convenient new features such as
• Enhanced Security You can put an automatic lock
  on your handheld, assign a password and encrypt
  sensitive data to keep information safe
• View and Clear Multiple Alarms - Go to one place
  to view all the Alarms you have set. Clear
  multiple alarms with a single tap.
• Set Silent Alarms - If you're in meetings you can
  set vibrating or LED/flashing light alarms on
  your m500 or m505 handheld. You can still choose
  to play a tune if that's your preference.
• 65,000 Color Support - View email, spreadsheets,
  eBooks, video clips and photos in brilliant color
   
• Easier Data Entry - You can now use the on-screen
  keyboard and Graffiti writing at the same
  time.Switch back and forth without changing
  screens.
• Wireless Internet and eMail access You can
  install the included Mobile Connectivity Software
  on your Palm m500 or m505 handheld and use it to
• get information from your favorite websites
• send and receive email
• send short messages to other Palm handheld users
  or GSM phones worldwide.

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8.USES OF PALM OS 

• Early applications included an address book, a
  date book, to-do list and memo pad. This
  information can be transferred directly from/to
  your desktop databases by synchronizing.  
• Further advances included development
  environments for creating your own
  applications. 
• Then came the development of enterprise database
  applications, spreadsheets, text and word
  processors.  
• Recent hard and software additions allow
  reliable, secure, and cost effective enterprise
  wireless wired communications using a Palm.
  communication using radio frequency (Palm VII
  and web clipping).
• Data entry on the Palm is not simply entering
  character by character in a field (although it
  can be), but tends to be pick from a menu list,
  click on an icon, enter the first few characters
  and the rest fills itself in etc.
• A lot of the power of the Web with its point and
  click methodology applies here.
• The business case must be analyzed carefully or
  you may end up with another novelty application
  (or worse, an application slower and more complex
  than the desktop version).

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9.What Palm OS Devices Don't Have and Why?

• Almost more important than what Palm OS devices
  have is what they lack. No Palm OS device has
• A keyboard
• Full text recognition
• An industry-standard PC card slot
• A powerful processor
• Adding any of these features requires changing
  the magic combination of speed, size, and price
  that has made the Palm devices so popular. By
  removing both the keyboard and any real way of
  handling text input in quantity, Palm Computing
  kept its focus on what kind of device it was
  providing. Palm devices don't have a card slot,
  because they couldn't do it and keep the device
  small and cheap. Palm did install a nonstandard
  memory card to give users the ability to upgrade
  the functionality.