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ASC
-
GREECE,
PART
III
SYS/84-03-10
SYSTEM
DESCRIPTION
Page
ASC GREECE
AUTOMATIC MESSAGE AND DATA SWITCHING CENTRE
DOC. NO. ASC/8020/PRP/001 ISSUE 1
PART III
SYSTEM DESCRIPTION
SUBMITTED TO: HELLENIC REPUBLIC
MINISTRY OF COMMUNICATION
CIVIL AVIATION AUTHORITY
SUPPLY DIVISION
1, VASILEOS GEORGIOU AVENUE,
HELLINICON, ATHENS
IN RESPONSE TO: TENDER NO. EX22/1983
PREPARED BY: CHRISTIAN ROVSING A/S
SYSTEMS DIVISION
LAUTRUPVANG 2
2750 BALLERUP
DENMARK
PRINCIPLE CONTACT: Gert Jensen, Systems Division
Manager
Telex Denmark 35111 cr dk
Telephone: 02 65 11 44
…0e…c…0f… Christian Rovsing A/S - 1984
This document contains information proprietary to Christian
Rovsing A/S. The information, whether in the form of
text, schematics, tables, drawings or illustrations,
must not be duplicated or used for purposes other than
evaluation, or disclosed outside the recipient company
or organisation without the prior, written permission
of Christian Rovsing A/S.
This restriction does not limit the recipient's right
to use information contained in the document if such
information is received from another source without
restriction, provided such source is not in breach
of an obligation of confidentiality towards Christian
Rovsing A/S.
T̲A̲B̲L̲E̲ ̲O̲F̲ ̲C̲O̲N̲T̲E̲N̲T̲S̲
Page
1 SYSTEM DESCRIPTION .............................
2
2 FUNCTIONAL CAPABILITIES .......................
10
2.1 SYSTEM OVERVIEW ...........................
10
2.1.1 ASC Functions .........................
11
2.1.2 Communications ........................
12
2.2 SYSTEM DESIGN CONSIDERATIONS ..............
13
2.3 HUMAN FACTORS CONSIDERATIONS ..............
17
2.3.1 Operations ............................
17
2.3.2 Maintenance ...........................
17
3 HARDWARE .......................................
18
3.1 INTRODUCTION ...............................
18
3.1.1 Overview ...............................
19
3.1.2 ASC System .............................
20
3.1.3 Potential ASC Maintenance System .......
24
3.2 CR80 PROCESSING ELEMENT ....................
26
3.2.1 The Processor Units (PU) ...............
26
3.2.2 The Channel Units (CU) .................
27
3.2.3 Bus Structure ..........................
30
3.3 WATCHDOG COMPUTER ..........................
32
3.4 CR80 PACKAGING .............................
34
3.5 PERIPHERAL SYSTEMS .........................
38
3.5.1 The Disc System ........................
38
3.5.2 The Communication System ...............
40
3.5.2.1 C/AFTN Lines and Telex Accesses ....
40
3.5.2.2 CBI and CIDIN Lines ................
40
3.6 TERMINAL EQUIPMENT .........................
41
3.6.1 Visual Display Units ...................
41
3.6.2 High Speed Printers BP 900 .............
41
3.6.3 Matrix Printer .........................
42
3.6.4 Papertape Reader and Punch .............
42
3.7 POWER SYSTEM ...............................
43
1̲ ̲ ̲S̲Y̲S̲T̲E̲M̲ ̲D̲E̲S̲C̲R̲I̲P̲T̲I̲O̲N̲
According to the requirements expressed in the technical
specifications (part 3) the total ASC will be delivered
in the three phases. In addition a hardware and software
maintenance system is offered as an option.
The physical configuration of the switch is illustrated
in figure 1-1.
the switch consist of the following components:
- ASC CR80 computer system with CPUs, Memory, Line
Interfaces, patchpanel and Disc drives.
- Uninter optional uptable power system with frequency
and voltage-control, battery and generator.
- Visual display units for the operational and technical
control positions.
- Papertape reader and punch.
- High Speed printer.
The second phase would only require the following additions:
- 1 Crate for the additional line interfaces.
- Line interfaces for the specified number of CBI,
CBI/MET lines.
- Modems for the lines.
The third phase would require the following additions:
- Line interfaces for the specified number of CIDIN
lines.
- Modems for the lines.
The communication line configuration is defined in
the two figures 1-3 and 1-4. Figure 1-3 shows the required
lines for HCAA in the three phases both initial e.g.
provided in the phases and as a possible maximum.
Figure 1-4 shows the actual number of lines and the
possible expansions based on the hardware connectivity
available in the phases. It must be noted that the
available maximum line capacity is above the requirements
of HCAA.
The costing tables call for a tape system for the long
term (30 days) storage of messages; the system offer
a more modern cost effective solution, a dual set of
disc drive with removable disc cartridges, which can
contain messages for a longer time period than tape
and provide for direct access to the individual messages.
Should the customer desire a tape drive system, this
can be delivered instead.
Figure 1-1
ASC Configuration
The possible hardware and software maintanance system
can consist of the following as illustrated in figure
1-2:
- ASC Maintenance CR80 computer system with CPU,
Memory, Line interfaces, and Disc drive.
- Visual display unit for the SW/HW maintenance control.
- Printer.
Figure 1-2
ASC HW/SW Maintenance System Configuration
The software for the ASC consists of the following
components in phase 1:
- XAMOS operating system.
- Application software for the Conventional AFTN
Switching function.
The software for phase 2 consists of the following
additional component:
- Application software for the CBI and CBI/MET chart
processing.
The phase 3 consists of the following component:
- Application software for the CIDIN packet switching
function.
- Network management software for the CIDIN packet
switching.
The software configuration is described in details
in part II, chapter 2.2.
PHASE 1 PHASE 2 PHASE
3
Lines Required Initial Maximum Initial Maximum
Initial maximum
̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲
̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲
Conventional
AFTN lines 55 80
Telex accesses 8 12
CBI lines 4 18
CBI/MET lines 0 6
CIDIN lines 4 12
̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲
̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲
Figure 1-3 Required ASC Communication lines
Phase 1 Phase 2 Phase 3
̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲
̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲
Lines on ASC Initial Additional Initial Additional Initial Additional
̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲
̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲
Conventional
AFTN lines 92 as required
Telex acceses
CBI lines 4 28 (1)
CBI/MET lines 0 60 (2)
CIDIN lines 24 (1)
4 56 (2)
̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲
̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲ ̲
(1) Based on a maximum speed of 4800 Baud per line.
(2) Based on a maximum speed of 1200 Baud per line.
(3) Capacity shared between phase 2 & 3.
Figure 1-4 Available ASC Communication Lines.
The additional lines are over and above the initial
lines. The additional lines are calculated based on
the hardware connectivity available in the phase.
2̲ ̲ ̲F̲U̲N̲C̲T̲I̲O̲N̲A̲L̲ ̲C̲A̲P̲A̲B̲I̲L̲I̲T̲I̲E̲S̲
2.1 S̲Y̲S̲T̲E̲M̲ ̲O̲V̲E̲R̲V̲I̲E̲W̲
The ASC provides a complete facility for fast reliable
and flexible distribution, management and control of
the AFTN traffic.
The ASC will meet all requirements for speed, capacity,
reliability and expandability.
The system can manage a significant number of incoming
and outgoing messages per hour. Availability is ensured
by the flexibility and modularity of the system, which
provides easy and fast maintenance, as well as implementation
of fault-tolerancy and dualization of modules.
F̲e̲a̲t̲u̲r̲e̲s̲
o M̲o̲r̲e̲ ̲r̲e̲l̲i̲a̲b̲l̲e̲ ̲c̲o̲m̲m̲u̲n̲i̲c̲a̲t̲i̲o̲n̲ through computer control,
equipment dualization and system redundancy.
o H̲i̲g̲h̲e̲r̲ ̲s̲u̲r̲v̲i̲v̲a̲b̲i̲l̲i̲t̲y̲ through alternative paths
and automatic rerouting.
o T̲i̲g̲h̲t̲e̲r̲ ̲c̲o̲n̲t̲r̲o̲l̲ through centralized computer coordination,
supervisor visibility, and automatic collection
of statistics and status information.
o O̲p̲e̲r̲a̲t̲i̲o̲n̲a̲l̲ ̲s̲i̲m̲p̲l̲i̲c̲i̲t̲y̲ through automatic distribution,
and minimum operator intervention.
o E̲a̲s̲i̲e̲r̲ ̲e̲x̲p̲a̲n̲s̲i̲o̲n̲ through flexible, common and interchangeable
hardware/software modules.
o M̲e̲s̲s̲a̲g̲e̲ ̲S̲w̲i̲t̲c̲h̲i̲n̲g̲. Store and forward switching
of messages.
o E̲x̲p̲a̲n̲s̲i̲o̲n̲ ̲F̲e̲a̲t̲u̲r̲e̲s̲. Fully dualized system with
n+1 redundancy.
o G̲r̲e̲a̲t̲e̲r̲ ̲e̲f̲f̲i̲c̲i̲e̲n̲c̲y̲. Faster delivery and higher
throughput through real-time multiplexed use of
network facilities.
The ASC consist of the following main elements.
o Flexible modern circuit connections to international,
local and domestic circuits.
o Store and forward CR80 computer system.
o Terminal positions with VDU and printer for system
supervision and message corrections.
The ASC CR80 store and forward message switch can be
implemented both as a single system and as a fully
fault tolerant dualized system. The proposal describes
both systems. The differences in the two solutions
is limited to the internal hardware structure and modules,
which results in the higher availability and fast performance
of the dualized system. The configurations for the
two systems are shown in chapter 3. The availability
features described in the following sections can not
always be fully exploited in the single system.
2.1.1 A̲S̲C̲ ̲F̲u̲n̲c̲t̲i̲o̲n̲s̲
The functional aspects of the ASC comprise three principal
functions:
o The message switch
o The Supervisor/Operator interface
o Statistic and Reporting.
The message switch implements all essential functions
for automatic storing and forwarding of messages. This
includes line handling, processing of input signals,
output processing, routing and queueing, and message
storage and retrieval.
The supervisor/operator interface implements a user
friendly man-manchine interface, enabling human intervention
and control, where necessary. The supervisor function
can due to safe operations only be allowed at one position
at a time; examples of the supervisor capabilities
are routing table changes and allocation of functions
to the other position. The operator function includes
the reject message processing and can be done at the
same position as the supervisor or at both positions,
if required.
Finally, facilities are provided to produce required
statistic reports, and log/printouts used to evaluate
functioning of the ASC and ensure optimum performance.
2.1.2 C̲o̲m̲m̲u̲n̲i̲c̲a̲t̲i̲o̲n̲s̲
The baseline system is designed for the specified initial
capacity of phase 1. But due to the modular design
of the hardware is it possible to expand to virtually
any number of circuits, not only the indicated increase
in international, local, and domestic circuits, but
also with multiple channels on individual circuits.
The line interface hardware is general purpose and
also used in the communications systems for Air Canada
and American Airlines. It can accommodate much higher
transmission speeds; the Line Terminating Unit (LTU),
which handles four circuits is designed for 9600 baud.
The line interface hardware is capable of operating
with full duplex, half duplex and simplex lines.
The modular design of not only hardware but also software
facilitates expansions and extendability. The software
modules used for the ASC are from the same baseline
as the Air Canada and American Airlines communications
software which is employing CCITT X.25 packet switching
up to OSI level 3. The external network environment
accommodates the SITA, ARINC, and CNT networks.
The migration to the future CIDIN* network with the
expected level 3b and level 4 will not pose any problems
and off-the-shelf software will be available from the
present CHRISTIAN ROVSING A/S projects.
* CIDIN: Common ICAO Data Interchange Network
2.2 S̲Y̲S̲T̲E̲M̲ ̲D̲E̲S̲I̲G̲N̲ ̲C̲O̲N̲S̲I̲D̲E̲R̲A̲T̲I̲O̲N̲S̲
The many functional and operational features inherent
in the CR80 computer systems for ASC go beyond the
mere physical size variations and expansion options.
The computer family is designed for high reliability,
high flexibility systems, such as communications processors,
front-end processors, data concentrators and packet-switched
networks.
Flexible variation in the size and structure of the
CR80 systems are permitted by the unusual degree of
hardware and software modularity. The hardware essentially
consists of fast transfer buses joined to each other
by adapters which allow units on one bus to access
those on another. Dualization at the internal level
and multiple redundancy at the system level provide
a CR80 hardware architecture which is exploited by
the XAMOS software operating system and programs to
survive operational failure of individual components.
o Distributed processing throughout the CR80 computer
family
- Multiple Central Processors
- Multiple CPU's in Central Processors
- Individual Microprocessors in each Peripheral
Controller Module
- Fast separate processor for Interrupt Preprocessing
and Data Channel management.
Reliability, which is increasingly becoming of concern
in real-time and distributed network applications,
is achieved in the CR80 computer systems by applying
unique architectural concepts. The CR80 hardware/
-software architecture treats all multiprocessors as
equal elements not absolutely dedicated to a specific
role. Fault tolerance and backup are achieved through
an n+1 redundance scheme without preassignment of system
functions to specific processors. This is in marked
contrast to the more common rigid dualized configurations
often encountered in dedicated applications with on-line
master/slave arrangements, or off-line backup with
switchover facility.
o Fault Tolerancy
- No-break computing supported by numerous unique
hardware, software and maintenance features
to achieve mean time between system failures
in the order of years.
- Multiple Central Processor incorporation of
Peripheral Controller modules providing alternative
processing paths.
- Economic N+1 Central Processor redundancy.
- Economic N+1 Communication Interface redundancy.
- Dual Powering of Peripheral Controller modules
safeguards against single power failures.
- Redundant Fan Units ensure sufficient cooling
of equipment in the event of Fan breakdown
or failure in a mains phase supply.
- Short mean time to repair ensured by major
system components exchangeable from the front
with no cable detachment or special tools needed.
- Extensive Quality assurance and control program
during design and production for achieving
and maintain the CR80 high level of module
reliability.
- Maintenance and Configuration Processor subsystem
supervises Power Supply voltages and environmental
conditions and provides reconfiguration of
the computer in response to errors reported
by on-line diagnostics, self-checks and status
reporting.
Coupled with reliability is maintainability. The CR80
computer system family offers a very advanced concept
of on-line serviceability and extendability. It offers
an integral maintenance and configuration processor
for system supervision and unattended operations.
o On-line serviceability and extendability
- Computers partioned in self sustained physical
subunits complete with power supply and cooling.
- Physical subunits galvanically isolated from
each other and interconnected via high speed
dual or multiple redundant long distance data
highways, omitting ground loops normally limiting
size and on-line extension of computer systems.
- All major modules, inclusive the power supplies
and Fan Units, are insertable and exchangeable
from the front without special tools.
- On-line exchange and addition of modules without
power down provided by electronic power switches
and bus high impedancing circuitry in the individual
modules.
- Extensive individual module self test at power-on
provides immediate visual indication to operator
of hardware status.
- Wide range of maintenance and diagnostic programs.
- Early warning of error prone conditions and
preventive fault correction made possible by
the Maintenance and Configuration microcomputer
monitoring power supply voltages and environmental
conditions of subunits.
o Maintenance and Configuration Processor
- Stand-alone system Watchdog microcomputer monitors
equipment status through physical sensing.
- Voltage variations of power supplies monitored
with A/D converters.
- Fault Tolerancy computer reconfigurations,
based on accumulated on-line diagnostics, selfchecks
and status reporting.
- Distributed monitoring and control of all computer
subunits through separate redundant, galvanically
isolated connections.
- Fail-safe switch-over to manual set-up of configuration
in case of error in the Maintenance and Configuration
Processor itself.
- Manages the economic N+1 redundancy switch-over
of communications lines.
o Extensive use of LSI technology
- High equipment density achieved by use of RAM's,
PROM's, CPU's, USART's, FIFO's, Programmable
Logic Arrays and microprocessors.
- Low power consumption, allowing for forced
air cooling of even the largest computer configurations.
- Very low space requirements of packed computers.
- High speed based on Schottky-TTL technology.
o Powerful CPU utilized
- Microcycle time 250 nanoseconds.
- 16 bit instructions.
- Internal pipe lining.
- Instruction prefetch.
- Comprises dual Arithmetic and Logic Units allowing
up to 3 operand arithmetic operations to be
executed simultaneously.
- Extensive error checking with roll-back allowing
instruction reexecution.
- Designed for multi CPU, multiprocessor environment.
- Non-mapped and mapped virtual memory capability.
- Field exchangeable single unit.
2.3 H̲U̲M̲A̲N̲ ̲F̲A̲C̲T̲O̲R̲S̲ ̲C̲O̲N̲S̲I̲D̲E̲R̲A̲T̲I̲O̲N̲S̲
The system is designed to comply with modern man-machine
interface practice and with due considerations to operators
and maintenance personnel for minimal training, operational
knowledge, minimal computer system knowledge, and user
error tolerance. The system is also designed for unattended
operations to the widest possible extend. The primary
fields where human factors have been considered are
in operations and in maintenance.
2.3.1 O̲p̲e̲r̲a̲t̲i̲o̲n̲s̲
The system have been designed for operators with little
or no knowledge of computers by providing menu driven
function selection, both for the supervisory functions,
for the Message correction functions and for training.
Furthermore, where input is allowed or requested to
the operator the data is checked in type, range and
legality to the extent possible. The updates to the
tables are validated where possible and critical input
data must be validated by the operator after injection.
2.3.2 M̲a̲i̲n̲t̲e̲n̲a̲n̲c̲e̲
The system has been constructed for fast maintenance
with minimum training. The fault finding is heavily
supported by visual aids in the form of control LEDs
on all modules and by on-line and off-line diagnostic
programs.
The capability for on-line maintenance is described
in the preceeding section, section 2.2.
3̲ ̲ ̲H̲A̲R̲D̲W̲A̲R̲E̲
3.1 I̲N̲T̲R̲O̲D̲U̲C̲T̲I̲O̲N̲
The CR80 product line is extremely versatile. The computer
system for ASC is the very flexible and modular CR80
computer, which has been used in many military and
commercial projects.
CR80 modules can be configured to meet specific costumer
requirements or delivered in standard configurations.
The configurations encompass a broad range of physical
characteristics to meet the requirements of the smaller
stand-alone user and those of the largest multi-installation
network applications. The configurations offer
- a 80:1 range in processing power utilizing one
CPU or up to 16 interconnected multiprocessors
with a maximum of 5 CPUs each, providing instruction
rates of 0.6 mips to 30 mips.
- a 1000:1 range in memory capacity from 512 kilobytes
to 512 megabytes.
- a 400:1 range in connectivity through Peripheral
Controllers accommodating a variety of terminations
with as many as 960 peripherals or up to 4096 communication
lines.
Flexible variation in the size and structure of the
CR80 systems are permitted by the unusual degree of
hardware and software modularity. The hardware essentially
consists of fast transfer buses joined to each other
by adapters which allow units on one bus to access
those on another. Dualization at the internal level
and multiple redundancy at the system level provide
a CR80 hardware architecture which is exploited by
the XAMOS software operating system.
Reliability is achieved in the CR80 computer systems
by applying unique architectural concepts. The CR80
hardware/software architecture treats all multiprocessors
as equal elements not absolutely dedicated to a specific
role. Fault tolerance and backup are achieved through
a redundancy scheme without preassignment of system
functions to specific processors.
3.1.1 O̲v̲e̲r̲v̲i̲e̲w̲
The CR80 System can consist of the following elements
depending on requirements:
o Processing Elements (PE), i.e.
- Processing Units (PU)
- Channel Units (CU)
o Watchdog Computer
o Peripheral Equipment, e.g.
- Disc systems, tape systems, relational database
systems, communication lines, and communication
systems.
o Terminal Equipment, e.g.
- Alphanumeric displays, graphic displays, printers,
...
The ASC hardware for both the single and the dualized
system consists of the following main elements:
* CR80 single or dualized system
* Disc drives
* CR-comfort VDUs
The single and dual system are described in the next
paragraphs, the remaining hardware elements, which
are common for the two solutions are described in section
3.5 to 3.7.
3.1.2 A̲S̲C̲ ̲S̲y̲s̲t̲e̲m̲
The single system for the ASC configuration of the
message switch consists of the following main CR80
modules:
. a Processing Unit with 2 single CPUs and 1.5 Mbytes
of RAM
. a Channel Unit with 2 mirrorred disc controllers
and line interfaces to communication lines, VDUs
and printer.
. A channel unit with n + 1 redundant line interfaces
to the CBI communication lines (phase 2) and the
communication CIDIN lines (phase 3).
The line interfaces (LTUS) are identical for the
3 phases.
Figure 3.1.2-1
ASC Phase 1 system
* possible extension
The possible fully dualized store and forward message
switch consists of the following main CR80 modules:
. 2 Processing Units, each with two CPUs and 2 x
512 Kbytes of RAM
. 1 Channel Unit with dual bus and duplicated disc
controllers and n+1 redundant line interfaces to
communication lines and VDUs
. 1 Watchdog computer to automatically control the
configuration and to switch PU or line interfaces.
. A channel unit with n + 1 redundant line interfaces
to the CBI communication lines (phase 2) and the
communication CIDIN lines (phase 3).
The line interfaces (LTUS) are identical for the
3 phases.
The configurations are illustrated in figure 3.1.2-1
and 3.1.2-2. The functioning of the Processing Units
and the Channel Unit is described in section 3.2, the
Watchdog computer in 3.3 and the packaging in 3.4.
Figure 3.1.2-2
ASC phases 1.2 & 3 system
* possible extensions
3.1.3 P̲o̲t̲e̲n̲t̲i̲a̲l̲ ̲A̲S̲C̲ ̲M̲a̲i̲n̲t̲e̲n̲a̲n̲c̲e̲ ̲S̲y̲s̲t̲e̲m̲
The single system for the maintenance configuration
of the message switch consists of the following main
CR80 modules:
. a Processing Unit with a single CPU and 1.5 Mbytes
of RAM
. a Channel Unit with disc controller and line interfaces
to communication lines, VDU and printer.
The configuration is illustrated in figure 3.1.3-1.
The functioning of the Processing Units and the Channel
Unit is described in section 3.2, the Watchdog computer
in 3.3 and the packaging in 3.4.
Figure 3.1.3-1
Potential ASC Maintenance System Configuration
3.2 C̲R̲8̲0̲ ̲P̲R̲O̲C̲E̲S̲S̲I̲N̲G̲ ̲E̲L̲E̲M̲E̲N̲T̲
A CR80 Processing Element (PE) comprises Processing
Units (PUs), Channel Units (CUs), and a supporting
bus structure, providing the user(s) with a virtual
memory multiprogram/multiprocessor computing system.
3.2.1 T̲h̲e̲ ̲P̲r̲o̲c̲e̲s̲s̲o̲r̲ ̲U̲n̲i̲t̲s̲ ̲(̲P̲U̲)̲
The PU is a multiprogrammable multiprocessor consisting
of up to 5 Central Processor Units, CPUs, utilizing
virtual memory and demand paging.
The PU is highly flexible, allowing selection of modules
to meet specific requirements. The modules are interfaced
via a dual bus structure for reduction of bus contention
as shown in figure 3.2.1-1.
Figure 3.2.1-1
Processor Unit
3.2.2 T̲H̲E̲ ̲C̲H̲A̲N̲N̲E̲L̲ ̲U̲N̲I̲T̲S̲ ̲(̲C̲U̲)̲
The Channel Units contain the CR80 I/O controller modules
for interfacing towards peripheral equipment, communication
lines etc. The CU has an internal single or dual transfer
bus structure. The dualized structure ensures that
no single failure can stop operation of more than one
I/O controller as shown in figure 3.2.2-1.
Figure 3.2.2-1
The transfer buses, data bus A and data bus B, are
connected to two different PU's to ensure continuous
access to the controller modules. The characteristics
of data bus A and data bus B correspond to the internal
buses of the PU.
The CIA-modules constitute the interface between the
word oriented internal transfer buses and the byte
oriented data channels.
The I/O controller modules are all based on the same
principle for interfacing to the Channel Unit bus structure
and for the external interfaces as illustrated in figure
3.2.2-2. They exist in two versions, for single and
for dual bus.
Figure 3.2.2-2
Channel Unit Interface
The interface to the CR80 system employs a multiported
RAM memory through which the data is exchanged. The
program for the CPU of the controller module is either
resident in PROM chips or is downloaded from the CR80.
The DISK CTRL and PARALLEL CTRL modules employ PROM's
while the Line Termination Modules (LTU) used for control
of communication lines, terminals etc., are loaded
with programs from the CR80, meaning that different
protocols can be supported without hardware changes.
The physical interfaces to the peripherals, communication
lines etc., are adapter modules located at the rear
of the CU Crate. For interfacing to a communication
line, a line interface adapter module (LIA) is available.
An optional version of this module is able to select
a spare LTU module to be used instead of a failing
module. The spare LTU can be backup for a number of
active LTU's (n out of n+1 redundancy).
Not only is the internal bus structure dualized, the
power input is also taken from two separate sources
to ensure that a failure in one power source cannot
stop the CU from operating.
3.2.3 B̲U̲S̲ ̲S̲T̲R̲U̲C̲T̲U̲R̲E̲
A CR80 computing system is organized around several
buses, which are described in this section.
The interconnections of the different buses and units
are shown schematically in figure 3.2.3-1.
Figure 3.2.3-1
CR80 Bus Structure
Internal in a Processing Unit two buses are available
for data transfer. Electrically and functionally they
are identical, the only differences are related to
the type of module which are connected to them.
To the Processor Bus, the CPU's and Memory are connected,
and to the Channel Bus, DMA modules and memory are
connected.
The two buses are located on each motherboard, mounted
in the back of the PU-Crate.
Internal in a Channel Unit two buses are used for data
transfer, Data Bus A and Data Bus B. The buses are
identically, and further use the same signals as the
Processor and Channel Buses. These two buses are located
on each motherboard, mounted in the rear of the CU-crates.
The Data Channel is a flat cable bus connecting the
buses of a PU (Processing Bus and Channel Bus) with
one of the Data Buses of each CU.
This is done by means of the Data Channel interface
modules (MAP-MIA), CIA-A & CIA-B.
The Configuration Control Bus is used in the Watchdog
Subsystem. The traffic on the configuration control
bus are directives from the Watchdog about switching
of LTU's and information to the Watchdog concerning
the Crate Power Supply Voltage Levels. Also automatic
switch-over between active and stand-by processor are
performed and monitored by the watchdog.
3.3 W̲A̲T̲C̲H̲D̲O̲G̲ ̲C̲O̲M̲P̲U̲T̲E̲R̲
The Watchdog computer, also called the Maintenance
and Configuration Processor (MCP) system, consists
of standard CR80 modules used in the monitoring and
control of the total CR80 system. As for the main elements,
PUs and CUs, the MPC can be configured to suit specific
requirements over and above the standard watchdog functions
shown here. The normal watchdog system structure employed
in the dualized ASC is shown in figure 3.3-1.
Figure 3.3-1 Watchdog System
The WD-CPU is the central Maintenance and Configuration
Processor receiving status and control messages from
the CR80 Processing Elements through its dual interfaces
to PE's of the CR80 system.
The WCA (Watchdog CPU Adapter) constitutes the interface
between the WD CPU and the configuration Bus and the
four available V24 communication ports. The V24 ports
are used for possible connection of one or two system
consoles and for connection to a communication port
for remote maintenance and diagnostics of the CR80
system.
The Daisy Chained Configuration Bus is a dualized serial
communication path between the WCA and the connected
CCA's (Crate Configuration Adapters). The CCA is a
standard CR80 adapter module designed for monitoring
and control of the PU and CU Crates. The functions
available are: monitoring of the DC voltages, switching
of LIA-S modules (switching a spare LTU to the lines
instead of a defect module), and monitoring of digital
and analogue inputs, and control of digital outputs.
The WD CPU and the WD Panel Controller utilize alternative
paths of the serial configuration bus for control and
monitoring of the attached crates and associated modules.
The serial configuration bus is therefore redundant,
with different parts of it being used in AUTO and MANUAL
mode.
A fail safe circuit is implemented between the WD CPU
and the WD Panel Controller, which performs automatic
switching to the manual settings of the WD Panel in
case of WD CPU failure or service. Similarly, replacement
of the WD Panel Controller can be done with the system
online and under control of the WD CPU.
Crates under control of the MCP system is galvanically
isolated by optocouplers from the serial configuration
bus and can be removed from the operational configuration
bus without electrical interference with the remaining
part of the system.
3.4 C̲R̲8̲0̲ ̲P̲A̲C̲K̲A̲G̲I̲N̲G̲
As for the processing system design, great emphasis
has been put on failure tolerance and modularity of
the packaging, cooling and Power Supply subsystems.
The CR80 modular fault tolerant computer system is
assembled using standard modules (printed circuit cards)
housed in Processor Units and Channel Units (Card Cages).
The Units are interfaced by galvanically isolated transfer
buses, structured as shown below (figure 3.4-1) and
described in the following.
Figure 3.4-1
Units are housed in 19" Crates (Card Magazines) for
installation in standard 19" Racks, as shown overleaf
(figure 3.4-2). A Crate contains a 25 slot Front Magazine
for insertion of up to 17 Printed circuit card modules
and 2 Power Supply modules, the two upper rows of connectors
are each interconnected by multilayer printed circuit
buses, while the lower row of connectors is connected
individually via flatcables to corresponding connectors
in the Rear Magazine. The 19 slot Rear Magazine, which
can be pivoted down for access to Crate internal cabling,
holds controller Adapter modules providing the interface
and cabling to peripherals. Also a number of slots
is provided outside the rear Magazine, at the rear
of the crate for insertion of bus termination cards
and interface cards to the Data Channel bus. Keeping
all external cabling at the rear of the Crate, allows
all front modules (CPU, RAM, Peripheral Modules etc.),
inclusive the plug-in Power Supplies, to be exchanged
quickly without use of special tools.
Below each crate (PU or CU) in the CR80 system is installed
an exchangeable fan unit, which by forced air cools
the modules in the crate. To ensure continuous air
flow, the fan unit is redundantly constructed with
the airstream being provided by two sets of blowers,
each being powered from different mains phases, and
each with a capacity sufficient for cooling the entire
crate over a prolonged period of time. This ensures
the failure tolerance of the fan unit, both against
a Mains phase falling out and mechanical breakdown
of a blower.
One, or two power supply modules operating in parallel,
are installed, in each PU crate dependent of the required
power consumption. A power supply failure in the PU
will cause the PE to stop processing, but it will not
influence the system operation, as processing of the
failed PE will be taken over by the remaining operating
PE's.
In a dualized CU crate two Power Supplies are installed,
each backing up for the other in supplying the modules
power via two separate buses. This power scheme ensures
that a single power supply can fail without influencing
the operation of the modules in the CU crate due to
the special Power Supply ORing-circuit in each of the
modules. The power ORing-circuit contains a current
limiter which ensures that a short in a module will
not draw excess power from the power supplies, and
thereby interrupt the operation of other modules in
the crate.
A second function of the Power ORing-circuit is, in
combination with a slightly shorter pin in the interface
connector of any Peripheral Module and the buses, to
allow on-line replacement of a module in an operating
CU-crate. When a module is removed or inserted the
shortened pin will disconnect first and connect last.
This pin controls the current limiter in the Power
ORing-circuit and power to the module is therefore
removed, or applied, without spikes on crate-busses
during module exchange. Since the special bus driver/receivers
have high impedance against the buses, when the power
is removed, no interruption occurs in operation of
the Data busses during module exchange.
BIT (Built In Test) are found in most CR80 modules.
The test starts automatically when power is applied
to the module and lights the red TEST LED on the front
plate. When the internal test cycle lasting a few seconds
has been run through successfully, the TEST LED is
estinguished; therefore, on faulty modules the red
TEST LED will remain on.
Other built-in test functions, which are not destructive
to the normal module function, are used for error detection
by the CR80 on-line diagnostics during actual operation
of the computer.
Figure 3.4-2
CR80 Processor Unit & Channel Unit
3.5 P̲E̲R̲I̲P̲H̲E̲R̲A̲L̲ ̲S̲Y̲S̲T̲E̲M̲S̲
3.5.1 T̲h̲e̲ ̲D̲i̲s̲c̲ ̲S̲y̲s̲t̲e̲m̲
The disc-drives for the ASC is selected from the new
highly reliable compact disc-drives from CDC's range
of disc-drives, see illustration figure 3.5.1-1.
The disc-drives can be configured to run as mirrored
discs, with one disc backing up for the other. They
can also be configured for independent functioning.
The ASC system consists of 2 mirrored fixed discs,
FSD's, with 160 Megabytes capacity each; and two mirrored
removable discs, RSDs, with 80 Megabytes capacity each.
The fixed discs contain the communication software,
the tables, and the 1 hour short time buffering for
messages. The removable discs contain the long term
storage with the 30 day retention period being accomplished
by periodic disc exchange.
The ASC SW/HW maintenance system is equipped with one
RSD for software maintenance and hardware testing and
fault finding.
Figure 3.5.1-1
ASC Disc Drive System with 4 drives.
3.5.2 T̲h̲e̲ ̲C̲o̲m̲m̲u̲n̲i̲c̲a̲t̲i̲o̲n̲ ̲S̲y̲s̲t̲e̲m̲
The interfaces to the external communication lines
from C/AFTN, telex accesses, to packet switched CIDIN
lines are all through the standard CHRISTIAN ROVSING
A/S Line Termination Units (LTUs) as described in 3.2.2.
3.5.2.1 C̲/̲A̲F̲T̲N̲ ̲L̲i̲n̲e̲s̲ ̲a̲n̲d̲ ̲T̲e̲l̲e̲x̲ ̲A̲c̲c̲e̲s̲s̲e̲s̲
Both the conventional leased AFTN lines and the dial-up
telex accesses are connected to the programmable LTUs
through Line Interface Adapter (LIA) modules and a
telex multiplexer for the full capacity of 92 channels.
A patch panel with monitor access is installed between
the LIA module and the HCAA communication lines to
allow for patching of individual lines and for the
monitoring of the lines (initial only).
3.5.2.2 C̲B̲I̲ ̲a̲n̲d̲ ̲C̲I̲D̲I̲N̲ ̲L̲i̲n̲e̲s̲
The CBI and CIDIN lines are interfaced to the LTUs
of the ASC through four channel modems with an external
interface of V27. The line dependent features are implemented
in the LTUs.
3.6 T̲E̲R̲M̲I̲N̲A̲L̲ ̲E̲Q̲U̲I̲P̲M̲E̲N̲T̲
3.6.1 V̲i̲s̲u̲a̲l̲ ̲D̲i̲s̲p̲l̲a̲y̲ ̲U̲n̲i̲t̲s̲
The terminal equipment consists of CHRISTIAN ROVSING
VDUs in modern ergonomic styling and with user friendly
keyboards.
The operational ASC system is equipped with 2 of the
VDUs for operational and technical control of the system.
Should the load require more positions, those can be
added by connecting more VDUs on the additional lines.
The watchdog of the ASC should be equipped with a third
VDU for the reconfiguration of the system. This need
no manning, but serves as a system supervisor console.
The terminals are designed with fixed and variable
function keys and menu driven control. The operational
and technical control position can be accomplished
from one and the same terminal; should the message
load require it, both VDUs can become operational positions.
The possible ASC HW/SW maintenance system is equipped
with 1 CHRISTIAN ROVSING VDU.
3.6.2 H̲i̲g̲h̲ ̲S̲p̲e̲e̲d̲ ̲P̲r̲i̲n̲t̲e̲r̲s̲ ̲B̲P̲ ̲9̲0̲0̲
The BP-900 line printer is a high speed band printer
for the ASC. It is designed and built to provide excellent
print quality and reliability at heavy duty cycles
using a horizontally moving interchangeable steel band.
Print speed is 900 lines per minute using a 64 character
set.
The BP-900 is built for handling high volume using
the Dataproducts's Mark V hammerbank, the BP-900 will
print millions of pages each year with minimum service.
The modular design allows for quick and easy repair.
3.6.3 M̲a̲t̲r̲i̲x̲ ̲P̲r̲i̲n̲t̲e̲r̲
The matrix printer for the SW/HW maintenance system
provides for a hardcopy facility for software listings
and hardware diagnostic routines.
The matrix printer is employing a serial interface
and has a printing speed of 120 cps.
3.6.4 P̲a̲p̲e̲r̲t̲a̲p̲e̲ ̲R̲e̲a̲d̲e̲r̲ ̲a̲n̲d̲ ̲P̲u̲n̲c̲h̲
The ASC system is equipped with a papertape reader
for reading externally generated telex tapes. The system
is also equipped with a papertape punch for the possible
punching of telex tapes.
3.7 P̲O̲W̲E̲R̲ ̲S̲Y̲S̲T̲E̲M̲
The total ASC must function with high availability,
and the system is depending on continuous power supply.
The external power is of limited quality in terms of
voltage and frequency tolerances.
The optional no-break power system for the ASC is a
complete, modern solid state uninterruptable power
system with built-in voltage and frequency stabilization,
see figure 3.7-1 for schematic functioning.
The no-break power system is permanently coupled to
the ASC, inclusive the battery element; which eliminates
any switching in case of mains failures and results
in an un-interrupted message switching function. The
uninterruptable power system is dimensioned for a freestanding
power supply from the batteries of 1/2 hour with a
12 hour recharging period.
In order to provide for the 6 hour main power failure,
a diesel generator is a part of the option. In case
of main failure of more than a short time the generator
is switched in. The battery itself is providing the
direct short time power supply.
The generator can, however, be replaced by an existing
generator or another alternative power source, which
will reduce the price considerably.
For maintenance purpose, or in the event of a failure,
the charger and inverter can be bypassed, utilizing
a Constant Voltage Transformer (CVT) which will be
able to supply the ASC from either the generator or
the main supply.
Figure 3.7-1
No-break Power Supply
Basic Configuration
