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<concept id="GUID-A3449F37-89BB-5208-8FD5-F4DF73F7E71A" xml:lang="en"><title>System

Startup Overview</title><prolog><metadata><keywords/></metadata></prolog><conbody>

<section id="GUID-C41A0540-2C28-4CCC-B8AA-8236C68CEB18"><title> Configuring and Controlling a device's boot process </title> <p>Whenever

a Symbian device is powered up a number of things have to happen before it

is ready to be used. A number of processes and applications have to be started

and certain tasks performed. </p> <p>The System Starter and its related components

control the startup process. This guide describes what the System Starter

does and how it may be configured. Configuration is the responsibility of

device manufacturers. A manufacturer may choose to enable operators, third

parties and users to extend the startup configuration. </p> <p>There are numerous

considerations when configuring device startup. These include: </p> <ul>

<li id="GUID-5BA1769D-D1FC-59A4-87F6-30D031443CD9"><p>which processes, tasks

and applications are required, </p> </li>

<li id="GUID-48D7345B-0D3B-5ADA-A646-A3DAC85FE4F5"><p>the sequence of, and

inter-dependencies between, activities, </p> </li>

<li id="GUID-9C7A919A-8C67-5DC0-BDD8-D1DC12AE0636"><p>the user experience, </p> </li>

<li id="GUID-9F2C5CCC-EAD6-5AD6-8B85-7EB459F385BA"><p>the impact on manufacturing

and testing, </p> </li>

<li id="GUID-7212D20D-2A6C-51BC-A3B4-23FAF4CA5EC0"><p>operators' customisation

requirements, </p> </li>

<li id="GUID-1D75BFB9-9E0C-5E60-8473-278D3ABCF7B7"><p>users' customisation

requirements, </p> </li>

<li id="GUID-41225C9C-047B-59BF-A670-0981A73BF6FC"><p>what to do when something

goes wrong </p> <p>and </p> </li>

<li id="GUID-5E519AE8-3268-5C2B-A623-2E99229947F8"><p>aftermarket applications </p> </li>

</ul> <p><b>Processes and Applications </b> </p> <p>In the interest of readability

this document frequently<b> uses the terms application and process interchangeably</b>.

Unless specifically stated otherwise you may assume that the term used refers

to both. </p> </section>

<section id="GUID-528B2FD1-7233-413A-81C8-5064095135AB"><title>Static Startup Configuration</title> <p>The System Starter

is automatically invoked as part of the boot process once the file system

has been mounted. It works by processing a list of instructions in sequence.

The list is referred to as a Static Startup Configuration, or SSC. In practical

terms the SSC is defined in a resource file and is built into the ROM. </p> <p>A

fundamental feature of the SSC is that it allows the start up procedure to

be optimised. Though the commands are processed in sequence their effect is

to perform tasks not only in <b>sequence</b> (wait for the application or

process to initialise before continuing) but also in <b>parallel</b> (do not

wait for initialisation) and <b>at the optimum time</b> (wait until conditions

are right). </p> <p>For further information on the contents of an SSC see: </p> <ul>

<li id="GUID-1F8911D9-F92B-5A4F-8548-942842A7ED2A"><p><xref href="GUID-57F38146-1DA3-5657-ADF4-76DF740363C5.dita">Static

Startup Configuration</xref>  </p> </li>

</ul> <p>Though an SSC cannot be changed, a number of SSCs may be included

in a ROM. This allows a device to be started with one of a number of different

configurations, i.e. to be booted into different <b>modes</b>. </p> <ul>

<li id="GUID-92E0E027-8A4F-55A5-AC48-4252164E2E77"><p>The mode determines

which SSC the System Starter uses to start the system. Symbian has defined

(and reserved) a number of Startup Modes (for test and reference purposes):

Full, Emulator, Emergency, Battery charge & Test. Device manufacturers

may use their own startup modes and reserve their own unique range of values

by sending an email to the Device Services package mailing list (<xref href="mailto:td-os_base_services-dev@lists.symbian.org" scope="external">td-os_base_services-dev@lists.symbian.org</xref>)

specifying: </p> <ol id="GUID-E4D9A3AB-4BD5-5E5E-8B70-8E6435842F06">

<li id="GUID-9F4658CA-4DCE-5E88-91FC-AE0F3CA65997"><p>the device manufacturer

name </p> </li>

<li id="GUID-AA1CC293-099A-5534-BA71-3EEE6691BE53"><p>the number of start-up

mode ranges required (each range has 32 values)</p> </li>

</ol> </li>

</ul> <p>SSC files are named <filepath>SCCForStartupModeN.rss</filepath> where

N is the number of the mode. The method of selecting the mode, and therefore

the SSC file, for each startup is defined by the licensee. </p> <p>The degree

to which an SSC can control and optimise the boot process is further enhanced

by the concepts of <b>Startup States</b> and <b>Staged Startup</b>. </p> <p><b> Startup States</b> </p> <p>An SSC is divided into a series of states which

follow each other sequentially. Those described here are defined by Symbian.

Licencees may add or insert further states by defining them and including

them in an SSC. The Symbian defined states have a certain significance: </p> <ul>

<li id="GUID-4C3113C7-CFAF-59AE-A271-51424F6B2478"><p> <b>The Critical Static

State:</b> This is when the essential ROM based components are started. Nothing

started in this state relies on anything outside the ROM. </p> </li>

<li id="GUID-56754FF8-08A4-56BE-A4C2-A8F2A25AE738"><p> <b> The Critical Dynamic

State:</b> This is when essential non-ROM based components and components

which use non-ROM based files are started. </p> </li>

<li id="GUID-804244EC-006E-5216-B286-D9FC6B9495EA"><p> <b> The Non-critical

State:</b> Components started here are not essential for the basic functionality

of the device. i.e. the phone will be 'up and running' before these components

are started. </p> </li>

</ul> <p><b>Staged

Startup</b> </p> <p>A further level of startup control and configuration can

be achieved using Staged Startup. This technique enables components to perform

their initialisation procedure as separate stages - essential earlier, non-essential

later. This enables further reduction of the effective boot time. </p> <p>Applications

must be <b>Staged Startup Aware (SSA)</b> to take advantage of the staged

startup facilities. They must register with the Starter so that they can receive

state-change notifications. An SSA application may perform a <b>stage</b> of

its startup during each SSC <b>state</b>. </p> <p>Staged startup subdivides

each state into five ordered domains: Kernel, Base, OS Services, Application

Services and UI Framework (these correspond to the <xref href="GUID-98E4DFEE-D7FA-581B-A56C-89797890D418.dita">Symbian

OS System Model</xref>). Each SSA component associates itself with a domain

according to its location in the System Model. Within each state the domains

are processed sequentially. This allows application dependency to be accommodated

without individual applications having to manage these dependencies. </p> </section>

<section id="GUID-F58AE201-31BF-4E36-96B6-50D61A53B9CA"><title>Dynamic Startup Configuration (DSC) </title> <p>All of the

components included in the Static Startup Configuration are present for the

life of the device. Components installed after the ROM has been built, or

after the device has been shipped, may also be started during boot by being

added to a Dynamic Startup Configuration (DSC). </p> <p>One or more DSCs may

be included at various points in an SSC. </p> <p>A run-time API allows entries

to be added to and deleted from a DSC. This means that aftermarket applications,

updates and patches can be inserted automatically on installation, over the

air by a Network Operator, or by the user. </p> <ul>

<li id="GUID-84D36270-880B-56F4-BBD9-5C80F9DA1BEF"><p><xref href="GUID-E3941FAF-988E-5FB3-8E62-84E192E41EA1.dita">How

to use the DSC API</xref>  </p> </li>

</ul> </section>

<section id="GUID-D6D28700-0BAD-4F88-8CE9-2E0330233468"><title>Specifying action on failure </title> <p>Though system startup

is an automatic process, things can go wrong. In some cases the device can

continue to function if a component fails to start, in others it cannot. Applications

can fail to start or fail after they have started for a variety of reasons.

Symbian OS provides mechanisms for detecting and handling failure. </p> <p>When

an application is started using an SSC or a DSC several parameters must be

specified in its resource. These include: </p> <ul>

<li id="GUID-4DC8B8DA-FA50-57E9-B1FD-B60991C927C1"><p>a startup method (<codeph>EFireAndForget</codeph>, <codeph>EWaitForStart</codeph>, <codeph>EDeferredWaitForStart</codeph>) </p> </li>

<li id="GUID-8236B8FB-CDD9-544A-91FA-F53231EDEDAF"><p>the number of retries

(attempts to start the application) </p> </li>

<li id="GUID-A9EA3792-BA99-59C8-8AE1-40A34CFAC095"><p>a timeout period (after

which an EWaitForStart startup will be considered to have failed) </p> </li>

<li id="GUID-F9CEA642-4140-5430-9092-C5B70BE9B691"><p>a restart action (<codeph>EIgnoreProcessFailure</codeph>, <codeph>ERestartOS</codeph>, <codeph>ERestartOSWithMode</codeph> - the action to be taken in the event of failure

to rendezvous or failure while running normally.) </p> </li>

<li id="GUID-F737C84D-3BAB-5256-858E-4D9EF9C0AB19"><p>a restart mode (the

phone might restart in a 'Safe Mode', for instance) </p> </li>

<li id="GUID-2030D3D4-D1C6-5E80-B75E-F8F656CA5168"><p>whether to initiate

monitoring after the component has made its rendezvous. </p> </li>

</ul> <p>If, after the <b>timeout period</b> the application has not made

its rendezvous, the OS can make further attempts to start it. If, after the <b>number

of retries</b> specified, it has not succeeded it will take the specified <b>restart

action</b>. If the restart action is <codeph>ERestartOS</codeph> or <codeph>ERestartOSWithMode</codeph> it

will shut down the device and restart it (in the second case in the <b>restart

mode</b> specified). If <b>monitoring</b> is enabled the System Monitor will

continue to monitor the process after a successful rendezvous and, if it stops

unexpectedly at any time, will re-use the same configuration information and

act accordingly. </p> <ul>

<li id="GUID-64BFBF8C-3279-5DE5-9350-19DB7FD5D481"><p><xref href="GUID-4E195F2A-78AE-5664-A115-AD65BF457AB1.dita">How

to use the System Monitor</xref>  </p> </li>

</ul> <p>Note that processes or threads declared 'System Critical' use an

aternative monitoring mechanism, which pre-dates the System Monitor, to restart

the OS when they fail (see <xref href="GUID-B0E661BC-4058-3256-B9C3-5A4FD52F6DE5.dita#GUID-B0E661BC-4058-3256-B9C3-5A4FD52F6DE5/GUID-AF3E8BE4-FE65-3CCE-8B5A-6C4585BEA2EC"><apiname>RThread::SetCritical()</apiname></xref>). The

System Monitor offers two significant advantages: the ability to restart the

process without restarting the OS and the option of restarting in a specified

mode. </p> </section>

</conbody></concept>