Artesyn ATCA-9405 Installation and Use (May 2014) - Manual (Page 114)

Intelligent Peripheral Management Controller
ATCA-9405 Installation and Use (6806800M71G) 114
8.3 Firmware Architecture
The IPMC and MMC firmware basically consists of three major parts:
 Boot loader
 Hardware Abstraction Layer (HAL)
 Application Layer
The boot loader maintains redundant copies of the firmware in flash. Each time the IPMI
firmware is upgraded, a redundant copy of the current IPMI firmware is made in flash.
The Hardware Abstraction Layer (HAL) initializes H8S/ATMEL and makes all preparations
necessary for running code written in C. The time management facility of the HAL provides a
means for measuring time and detecting timeout conditions. The device drivers are
responsible for implementing high-level interfaces to the hardware.
The Application layer is implemented as a multi threaded application. The main thread reads
incoming messages/events from various inbound queues, processes these messages/events,
and produces outgoing traffic to appropriate hardware interfaces.
The IPMC implements a number of subsidiary threads in addition, to serve RTM module
discovery and e-keying management.