IMA

Question 1

problems with cassical / federated avionics

Answer 1

• crosslinking to add new system
• supplier making hardware and software (not specialist in both)
• a lot of diff hardware and software on aircraft that is proprietary. -> high mantenence effort.
• cross-computer links and proprietary -> diff for maintenence
• hardware and software no abstractino -> more expensive with obsolescnce (can have to requalify system)
• supplier insentive to ned to do maintenence

Question 2

goals of IMA

Answer 2

• reduce number of controllers
• reduce obscolencence costs via OS
• standard API for all software
• standard hardware platform. (reduce maintenance costs. )

Question 3

what is IMA?

Answer 3

integration of software onto shared hardware

Question 4

describe the IMA cabinet concept? (beoing)

common computing resource is cabinet

Answer 4

chassis with backplane data bus and
CPM (computer processing unit with Ram, CPU, application software)
power
IOM (input output modules)

Question 5

IMA cabinet concept advantages

Answer 5

• strictly modular and scalable (maximum modularity and scalability)
• easy to replace module (each hardware is LRU - line replacable unit) to it is heavier
• can have third party IOM
• reduce CPU needs to do redundant signal procesing

(addidional delay on backplane bus)

Question 6

what does a B-777 IMA cabinet (CCR -common computing resource) contain

Answer 6

2 x cabinet switch
8 x general processing module
2 x graphics generator
2 x power conditioning unit

Question 7

what does the AFDX topology contain for the IMA cabinet concepts

Answer 7

2 x CCR common computing resource
6 x remote switches
21 x remote data concentrators

Question 8

what are the components of the Integrated LRU IMA Platform

Answer 8

CPU board (CPU and RAM including software applications)
power board
I/O board (signal processing -data busses, analog, discrete)

all in a metal housing

Question 9

CPOIM communication

Answer 9

• CPIOMS communicate via AFDX network

- board communicate via USB (airbus EYY) or PCI (thales deihl)

Question 10

CPIOM advantages

Answer 10

powerful CPU-> up to 23 apps
compact and lightweight
can build various kinds of CPIOMS

Question 11

CPIOM disadvantages

Answer 11

• if board breakes, entire LRU needs to be replaced.
• moderatey scalable
• 3rd party I?O requires qualification of entire CPIOM
• high deegree of CPU/ I?O integration effort

Question 12

what are the seven CPIOMs and what do they do?

what else links to ADCN

Answer 12

CPIOM A - pneumatic
B - Aircon
C - cockpit and flight controls
D - air ground data link
E  - electrical 
F - fuel
G - landing gear

IOM -for IO without AFDX connection

Question 13

who builds each CPIOM

Answer 13

airbus EYY -> C, D,
Thales Deihl -> A, B, E, F, G

THales Deihl supplies OS for alles

Question 14

what does a CPIOM contain?

Answer 14

• firmware
• OS
• config tables
• system applications
• ATAxx applicatinos

Question 15

what does firmware do?

Answer 15

makes CPIOM operable

• to load OS
• basic data loading

Question 16

what is OS job

Answer 16

• separate hardware + software (abstraction -> good for obsolescence)
• partitioning (OS has DAL of highest user -> separates user time so they can each have lower DAL runnning on same OS)
• ensure segregation of OS from applications (scheduling, mom managemnet, IO handling)

Question 17

how is memory organized

Answer 17

-each app has its own memory and own independent access to it

module area
partition area
supervised are
user area

Question 18

what is NVM and how is it organized

Answer 18

non-volatile memory (won’t erase in no power mode)

each applicatino has some

Question 19

how is I/O handled?

Answer 19

The OS stores io data in driver lanes

samples are updated either via sampling (continuous replacement) or queuing (sequential transition)

Question 20

job of API

Answer 20

makes requests from application to OS resources

Question 21

describe the OS configuration

what is usage domain

Answer 21

static, determined at time of compile/design (based on many rules)
-verifyed by DO 178 to DAL A (global and local)

usage domain is set of possible configurations

Question 22

what measures can be taken if bite detects an error?

Answer 22

• error stored in NVM
• software restart
• hardware restart
• LRU shut down and redundant system takes over.

Question 23

what is additional job of R-BITE

Answer 23

confirm and correlate errors reported by system BITES of IMA resources. Reports to CMS

can get no fault found errors

Question 24

what are the levels of BITE in IMA

Answer 24

application BITE : software reports to system BITE

System BITE: reports to CMS and RBITE

RBITE: correlates error. Reports to CMS

Question 25

what is purpose of ISDL and limitations?

Answer 25

IS: monitor resources from outside computer DL: load software onto coputers -> slow (must be doen in 15 min bc it is done through OMT which is avionics domain to avionc network (ADCN) and must go through SCI which checks packet wise

Question 26

what is SNMP and MIB

Answer 26

the checking of errors in translation through AFDX network are stored in MIB (management information base). Small Network Management PRotocol is used to quired results. This is a task of the AFDX Central Network BITE

Question 27

What is the job of monitoring?

Answer 27

continuously monitors CPIOM functions (memory segregation, watchdog timer, I/O communication hardware errrors.) reports to BITE. (does actual checking of functions. BITE reports to CMS and doing of appropriate actions)

Question 28

what does system supplier normally issue along with system for qualification

Answer 28

Declaration of design and performance. (fully certified system complying with all DO 178

Question 29

new qualification relationships

Answer 29

see pic

Question 30

what are the goals for software qualification

Answer 30

- dont have to qualify entire unit - change of software should not require change of any other software qualification - independent dqualification

Question 31

what are prerequisites for goals of software qualification to be achieved

Answer 31

1) segregation of all software even in cases of shared resources 2) even for arbitrary configuration

Question 32

what is incremental qualification

Answer 32

certify parts of IMA, not whole

Question 33

what is "usage domain"

Answer 33

set of valid configurations rules of dependencies of commonly used resources defines max and min values, dependencies, compiler settinds.. by IMA moule suplier necessary so others can maek independent software

Question 34

which document outlines IMA qualification process?

Answer 34

DO 297 -> references DO 178 and DO 254