Operating System (Os) Characteristics - Ingenico IWL220 Technical Manual

The bootstrap very briefly takes control of the terminal following each powering up to
perform the initialization and the self-test. Then it automatically runs the OS which in turn
starts the applications manager.
Thus the Bootstrap provides the following functionalities:
Memory and checksum self-test;
Local download of the OS if absent;
OS authenticity check and start-up.
6.4.2.

Operating system (OS) characteristics

The OS is downloaded (locally or remotely) into the memory. It is upgradeable. After a few
fractions of a second following powering up, it takes control. It checks the presence,
integrity and authenticity of the system components and application present in the
terminal.
The maintenance subsystem takes control in the following cases:
if no authentic application is present;
or if a manual action by the operator is made when powering up;
or if it is activated by application.
The maintenance subsystem ensures, among other things, the downloading of the
applications.
The OS ensures the start of the multitask core and then runs of the application by making a
set of services available to them:
Multitask management: Availability of a pre-emptive real-time environment, based
on interruptions, events and mail boxes. This management enables simultaneous
processing, which improves the terminal's performance.
Input/output management: This is carried out under interruptions, generally in
buffered mode. Thus, the applications developer enters a "conventional" C context.
System alarms management: Certain incidents (e.g. swipe card reading error)
detected by the OS are recorded. They can be used later by the maintenance
subsystem during remote or local diagnostics.
Application alarms management: A number of incidents detected by the
applications can be saved by the OS at their request. This recording is used later as
in the case of system alarms.
Application isolation management: The OS provides the mechanisms described in
the section on software isolation and memory protection. Between software
isolation is managed by an MMU (Memory Management Unit).
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