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Police command and control system
Police command and control system To meet the communications requirements of large police forces, computerized command and control systems are necessary. Steve Marsh describes the UK West Midlands police system.
Following the experimental computerized command and control system used in Birmingham, UK, the West Midlands police are introducing an operational system to cover the whole of the West Midlands. This paper describes the applications available on the system, and stresses the reliability and recovery aspects in particular.
netted to the computer system via rented BP0 lines, and there are 17 VDUs at the central control room connected via internal lines. In addition, there is a traffic control centre that acts as an extension of the central control room with 4 VDUs connected via BP0 lines (Figure 1).
Investigation into the potential of a dedicated computer for real-time applications in the field of command and control in the police service in Britain began, under the direction of the Police Scientific Development Branch (PSDB) of the UK Home Office, with the installation of a Ferranti Argus 500 computer in Birmingham in 1971. The system has been operational since 1972, and has formed the basis for command and control systems in other UK police forces, notably Glasgow, Staffordshire, Suffolk and Dorset. Local government changes in April 1974 led to the formation of the West Midlands Police (WMP). To meet the control and communications requirements for this large new force, it was decided to install a computerized command and control system as part of a new communications network. The experience gained with the Birmingham and Glasgow systems showed the need for enhanced facilities and the importance of reliability and response times.
Incident logging and distribution
OPERATIONAL
FACILITIES
The organization of resources (patrol cars, foot patrol and beat officers) in the WMP is decentralized and based on subdivisions, and hence the majority of incidents (alarms, fires, road traffic accidents etc.) are dealt with by a local sub control. In general, these are received at a central force control room, typically via a 999 call. Hence the heart of the command and control system is its ability to: l l l
When a call for police service is received at either the force control or at one of the subdivisional controls, the details of the incident are entered, via a VDU, into a fixed-format pro forma (incident log), together with any action taken. The incident log is then sent to whichever other user(s) of the system need to know about, or act upon, it, a new incident log being created every time an incident is reported to the police. The receiving user is informed of the arrival of an incident log at his VDU by audible and visual warnings, the incident log meanwhile being added to a queue of such messages for his terminal. It may then be obtained by pressing a ‘display unsolicited message’ key on the VDU. The system incorporates a series of reminders which the computer sends automatically at predetermined intervals to the users to ensure that incident logs are not left incomplete and that the need for action is not overlooked. Once the initial logging of an incident has been completed, it may be recalled for
record details of incidents at source, distribute incidents to the appropriate subdivision for action, provide accurate and up-to-date information on the location and availability of all resources.
To achieve this, each of the 32 subdivisions
Subdivision
nationol computer
Force control
has a VDU conTraffic control
Leasco Software Ltd., Reliance House, 150-l Maidenhead, Berks. SL6 4LD, UK
vol 1 no 4 august 7978
52 Bath Road,
0140-3664/78/0104-0183
Figure 1. WMP communications
$ 02.00 0 1978 IPC Business Press
783
updating or inspection. A complete record, or log, of each incident is therefore built up, describing when it occurred, what action was taken, and with what results.
format. This enables users to record in detail and in chronological order everything that is relevent on a series of free format pages. Any number of users may add to the log simultaneously, and a complete printout of the entire log can be produced when required.
Street index There is an inbuilt street index of the West Midlands containing information on every street and landmark, so that a control room operator receiving a call for assistance does not have to look at astreet guide or map to decide to which subdivision to route it. The location information entered into the incident log is used to search the street index for an exact match on the name provided and hence determine the subdivision and other relevent information. If an exact match cannot be found because of a spelling mistake, a list of near misses is supplied. When an exact match is found, the incident log is routed automatically to its correct destination. The street index overcomes the difficulty of lack of local knowledge, an important consideration when dealing with an area encompassing Birmingham, Coventry and Wolverhampton.
Incident recall Incident logs when created are initially stored on magnetic disc for up to 21 days, and are then archived to magnetic tape for long-term storage. They may be recalled by a variety of methods. For recent incidents, the unique serial number allocated to a log on its creation may be used for immediate recall. Alternatively, the call sign of a resource sent to the incident may be used, e.g. when an officer leaving the incident reports results to his controller. For older incidents, a combination of location and type between given dates and times will produce a list of summaries of incidents fitting the description from which the appropriate one can be selected, or details printed on the line printer as required. It is also possible to scan backwards and forwards through incidents dealt with by a specific VDU, or those that have been tagged as being of special interest.
Resource handling Details of the operational status, availability and location of each resource are maintained in a file. This is updated . manually by the resource’s controller from information that he has obtained by voice message over the radio network, or automatically from information obtained direct from those resources fitted with dashboard mounted digital encoders. These transmit the (coded) data in digital form via VHF radio direct to a decoder and thence to the computer system. Current resource availability for the relevant subdivision is displayed with the details of an incident log at the action stage. Any resources sent to that incident will have their current status and availability entered automatically into the current resource file, together with the incident location. Displays of individual, subdivisional, divisional or force-wide resources can be obtained as required.
Major incident A major incident facility is available for use when an incident takes place that has too much data for the normal incident
184
Teleprinter messageswitching Integrated with the command and control system is the force teleprinter network, in which the computer acts as a messageswitching centre providing an automatic store-and-forward capability for formatted messages. The latter are stored on magnetic disc for a minimum of 24 hours, and may be rerun on request. In addition, hard-copy printouts of incident logs or of a particular screen of information can be obtained on teleprinters from any VDU.
Police national computer interface In addition to these major tasks of command and control, the system will be linked to the police national computer (PNC) at Hendon via a computer - computer interface that will enable all the VDUs and teleprinters to use the full PNC facilities currently available to dedicated terminals.
Management information Management information can be derived from the data held in the system in a variety of forms. It is produced automatically at predetermined intervals, i.e. daily, weekly or monthly or on demand. The simpler time-critical reports are produced by the command and control system. The more complex and time-consuming reports are produced on the West Midlands County Council 1904s computer, information being transferred between the machines on magnetic tape.
COMPUTER SYSTEM Great emphasis has been placed on reliability and response time. The system is designed to give a mean response time of 2 s (90% within 4 s) for the priority transactions at projected 1983 levels of workload (Table 1 ), and to have a mean time between total system failure of about 3 years.
Table 1. Projected
1983 workload Number of incidents
Average day Peak day Peak hour
2 800 3 600 590 Number of resources on duty
Beat patrol cars force mobiles Foot patrols
up to 250 up to 150 up to 550
computer communications
Figure 2. Normal operation
The system is based on dual Ferranti sors, each machine having: l l l l
Argus 700s proces-
192 kwords of main store, 2 Mbyte fixed head system disc, 2 64 Mbyte moving head discs, communications multiplexer (CMX).
The machines are linked together by a processor interconnection channel (PIC). The following equipment is switchable between the two machines: l
2 magnetic tapedecks, 1 line printer, cassette tape, line equipment.
Table 2 Normal-operation
machine workload
distribution
machine A
machine B
Incident logging Resource handling Teleprinter message switching PNC interface Major incident
Street index Incident recall Management information
The 64 Mbyte discs that hold the main data (incident log files, resource files etc.) in duplicate are also switchable between machines.
A transaction usually enters the system from a VDU, a record is read from disc and various operations are performed. As a result, one or more updates to the incident log and resource files will be made. The appropriate records are updated both in files on A and via the PIC in the files on B. When the updates are finished on both machines, an output message is sent to the VDU and the transaction completed.
NORMAL
SECURITY
0 l l
OPERATION
Normally, the system is set up (Figure 2) with machine A having control of the online equipment, and B the magnetic tapes and line printer. Duplicate files are maintained, each machine having its own copy which is kept in step with the other by updates across the PK. In this mode the workload is shared between the two machines, A performing the high priority online transactions and B the lengthy searches and offline work (Table 2).
vol I no 4 august 1978
AND RECOVERY
Database security is achieved primarily by having two copies that are kept in step at all times and secondarily by taking archive copies to magnetic tape every 24 h. All inputs from VDUs are secured on machine B before an acknowledgement is sent to the VDU. Thus, if a failure should occur on machine A, it is not necessary to reinput the message; processing can be continued on B.
185
Teleprinter 192 k store I
A
I,, ,,orel Argu7s00S~
Argus 7 0 0 S
2 Mbyte disc
disc
4i yte I ISC
)
IS4 ibytel IS4ibyte OlSC
OlSC
LP
Figure 3. Fallback operation Security is further increased by a watchdog timer unit that must be addressed by each processor at a predetermined frequency; if it is not, the machine failing to do so is assumed to be malfunctioning, and is automatically isolated, the equipment described above being switched to the other machine. The isolation unit can also be addressed by program and operated manually if necessary. When a failure occurs on one machine, processing is brought to a consistent state, where possible. The machine is isolated by program, and processing is continued on the other machine, all available units having been switched. A processor failure, however, would cause the watchdog to isolate the machine. In this case, the other machine would take action based on its security copies of messages, disc transfers in progress etc. to recover the system state prior to the failure. Processing would then continue. In either case, the user should not be aware of a machine failure having occurred.
FALLBACK OPERATION When failure renders one machine inoperable, for example machine A as described above, the system will run on the other (Figure 3), handling all the online workload and still maintaining dual files of the database. The management information system would not normally be run under these conditions, although it would be possible with some degradation in response time. When the fault has been repaired, the system will be reconfigured back to normal operation in a controlled manner under system/operator dialogue.
186
Machine B will now be in control of the online equipment, i.e. there is a reversal of the original roles, no special significance being attached to the designations A and B in terms of functional ability. In the event of a total system failure, the teleprinter network can continue to operate by manual use of a patching jackfield.
TRAINING Apart from the initial requirement of several hundred officers, there is an ongoing requirement to train men while the system is in use because of promotions, resignations etc. The system incorporates a training mode that enables any VDU to be logged on as a training subdivisional or control VDU. All the facilities of the live system are available to update a special set of resources, send to incidents etc. Training mode VDUs are able to access all real resources and incident logs, but are not allowed to update them.
SO FTWAR E The system uses the Ferranti Argus 700 standard operating system OSC45, with enhancements written by Leasco. The latter performs the necessary recovery and dual aspects, and control the transaction processing. All the applications and system software have been written in CORAL 66.
computer communications
CONCLUSION The WMP command and control system represents a significant improvement on the old experimental Birmingham system, especially with regard to reliability and response time. It has been designed to accommodate the projected load in 1983, and still have an expansion capability. The system is currently being phased in to the West Midlands, and will be fully operational in November 1978.
ACKNOWLEDG EMENTS The author wishes to thank the West Midlands Police for permission to publish this paper, and in particular all those
vol 1 no 4 august 1978
members of the force who have devoted much of their own time to the project.
REFERENCES Jones B 'Command and control of the emergency services' Comput. Comm. Vol 1 No 1 (February 1978) pp 19-24 Fraser G 'Wanted-a national computer plan' Comput. Comm. Vol 1 No 3 (August 1978)
187
Following the experimental computerized command and control system used in Birmingham, UK, the West Midlands police are introducing an operational system to cover the whole of the West Midlands. This paper describes the applications available on the system, and stresses the reliability and recovery aspects in particular.
netted to the computer system via rented BP0 lines, and there are 17 VDUs at the central control room connected via internal lines. In addition, there is a traffic control centre that acts as an extension of the central control room with 4 VDUs connected via BP0 lines (Figure 1).
Investigation into the potential of a dedicated computer for real-time applications in the field of command and control in the police service in Britain began, under the direction of the Police Scientific Development Branch (PSDB) of the UK Home Office, with the installation of a Ferranti Argus 500 computer in Birmingham in 1971. The system has been operational since 1972, and has formed the basis for command and control systems in other UK police forces, notably Glasgow, Staffordshire, Suffolk and Dorset. Local government changes in April 1974 led to the formation of the West Midlands Police (WMP). To meet the control and communications requirements for this large new force, it was decided to install a computerized command and control system as part of a new communications network. The experience gained with the Birmingham and Glasgow systems showed the need for enhanced facilities and the importance of reliability and response times.
Incident logging and distribution
OPERATIONAL
FACILITIES
The organization of resources (patrol cars, foot patrol and beat officers) in the WMP is decentralized and based on subdivisions, and hence the majority of incidents (alarms, fires, road traffic accidents etc.) are dealt with by a local sub control. In general, these are received at a central force control room, typically via a 999 call. Hence the heart of the command and control system is its ability to: l l l
When a call for police service is received at either the force control or at one of the subdivisional controls, the details of the incident are entered, via a VDU, into a fixed-format pro forma (incident log), together with any action taken. The incident log is then sent to whichever other user(s) of the system need to know about, or act upon, it, a new incident log being created every time an incident is reported to the police. The receiving user is informed of the arrival of an incident log at his VDU by audible and visual warnings, the incident log meanwhile being added to a queue of such messages for his terminal. It may then be obtained by pressing a ‘display unsolicited message’ key on the VDU. The system incorporates a series of reminders which the computer sends automatically at predetermined intervals to the users to ensure that incident logs are not left incomplete and that the need for action is not overlooked. Once the initial logging of an incident has been completed, it may be recalled for
record details of incidents at source, distribute incidents to the appropriate subdivision for action, provide accurate and up-to-date information on the location and availability of all resources.
To achieve this, each of the 32 subdivisions
Subdivision
nationol computer
Force control
has a VDU conTraffic control
Leasco Software Ltd., Reliance House, 150-l Maidenhead, Berks. SL6 4LD, UK
vol 1 no 4 august 7978
52 Bath Road,
0140-3664/78/0104-0183
Figure 1. WMP communications
$ 02.00 0 1978 IPC Business Press
783
updating or inspection. A complete record, or log, of each incident is therefore built up, describing when it occurred, what action was taken, and with what results.
format. This enables users to record in detail and in chronological order everything that is relevent on a series of free format pages. Any number of users may add to the log simultaneously, and a complete printout of the entire log can be produced when required.
Street index There is an inbuilt street index of the West Midlands containing information on every street and landmark, so that a control room operator receiving a call for assistance does not have to look at astreet guide or map to decide to which subdivision to route it. The location information entered into the incident log is used to search the street index for an exact match on the name provided and hence determine the subdivision and other relevent information. If an exact match cannot be found because of a spelling mistake, a list of near misses is supplied. When an exact match is found, the incident log is routed automatically to its correct destination. The street index overcomes the difficulty of lack of local knowledge, an important consideration when dealing with an area encompassing Birmingham, Coventry and Wolverhampton.
Incident recall Incident logs when created are initially stored on magnetic disc for up to 21 days, and are then archived to magnetic tape for long-term storage. They may be recalled by a variety of methods. For recent incidents, the unique serial number allocated to a log on its creation may be used for immediate recall. Alternatively, the call sign of a resource sent to the incident may be used, e.g. when an officer leaving the incident reports results to his controller. For older incidents, a combination of location and type between given dates and times will produce a list of summaries of incidents fitting the description from which the appropriate one can be selected, or details printed on the line printer as required. It is also possible to scan backwards and forwards through incidents dealt with by a specific VDU, or those that have been tagged as being of special interest.
Resource handling Details of the operational status, availability and location of each resource are maintained in a file. This is updated . manually by the resource’s controller from information that he has obtained by voice message over the radio network, or automatically from information obtained direct from those resources fitted with dashboard mounted digital encoders. These transmit the (coded) data in digital form via VHF radio direct to a decoder and thence to the computer system. Current resource availability for the relevant subdivision is displayed with the details of an incident log at the action stage. Any resources sent to that incident will have their current status and availability entered automatically into the current resource file, together with the incident location. Displays of individual, subdivisional, divisional or force-wide resources can be obtained as required.
Major incident A major incident facility is available for use when an incident takes place that has too much data for the normal incident
184
Teleprinter messageswitching Integrated with the command and control system is the force teleprinter network, in which the computer acts as a messageswitching centre providing an automatic store-and-forward capability for formatted messages. The latter are stored on magnetic disc for a minimum of 24 hours, and may be rerun on request. In addition, hard-copy printouts of incident logs or of a particular screen of information can be obtained on teleprinters from any VDU.
Police national computer interface In addition to these major tasks of command and control, the system will be linked to the police national computer (PNC) at Hendon via a computer - computer interface that will enable all the VDUs and teleprinters to use the full PNC facilities currently available to dedicated terminals.
Management information Management information can be derived from the data held in the system in a variety of forms. It is produced automatically at predetermined intervals, i.e. daily, weekly or monthly or on demand. The simpler time-critical reports are produced by the command and control system. The more complex and time-consuming reports are produced on the West Midlands County Council 1904s computer, information being transferred between the machines on magnetic tape.
COMPUTER SYSTEM Great emphasis has been placed on reliability and response time. The system is designed to give a mean response time of 2 s (90% within 4 s) for the priority transactions at projected 1983 levels of workload (Table 1 ), and to have a mean time between total system failure of about 3 years.
Table 1. Projected
1983 workload Number of incidents
Average day Peak day Peak hour
2 800 3 600 590 Number of resources on duty
Beat patrol cars force mobiles Foot patrols
up to 250 up to 150 up to 550
computer communications
Figure 2. Normal operation
The system is based on dual Ferranti sors, each machine having: l l l l
Argus 700s proces-
192 kwords of main store, 2 Mbyte fixed head system disc, 2 64 Mbyte moving head discs, communications multiplexer (CMX).
The machines are linked together by a processor interconnection channel (PIC). The following equipment is switchable between the two machines: l
2 magnetic tapedecks, 1 line printer, cassette tape, line equipment.
Table 2 Normal-operation
machine workload
distribution
machine A
machine B
Incident logging Resource handling Teleprinter message switching PNC interface Major incident
Street index Incident recall Management information
The 64 Mbyte discs that hold the main data (incident log files, resource files etc.) in duplicate are also switchable between machines.
A transaction usually enters the system from a VDU, a record is read from disc and various operations are performed. As a result, one or more updates to the incident log and resource files will be made. The appropriate records are updated both in files on A and via the PIC in the files on B. When the updates are finished on both machines, an output message is sent to the VDU and the transaction completed.
NORMAL
SECURITY
0 l l
OPERATION
Normally, the system is set up (Figure 2) with machine A having control of the online equipment, and B the magnetic tapes and line printer. Duplicate files are maintained, each machine having its own copy which is kept in step with the other by updates across the PK. In this mode the workload is shared between the two machines, A performing the high priority online transactions and B the lengthy searches and offline work (Table 2).
vol I no 4 august 1978
AND RECOVERY
Database security is achieved primarily by having two copies that are kept in step at all times and secondarily by taking archive copies to magnetic tape every 24 h. All inputs from VDUs are secured on machine B before an acknowledgement is sent to the VDU. Thus, if a failure should occur on machine A, it is not necessary to reinput the message; processing can be continued on B.
185
Teleprinter 192 k store I
A
I,, ,,orel Argu7s00S~
Argus 7 0 0 S
2 Mbyte disc
disc
4i yte I ISC
)
IS4 ibytel IS4ibyte OlSC
OlSC
LP
Figure 3. Fallback operation Security is further increased by a watchdog timer unit that must be addressed by each processor at a predetermined frequency; if it is not, the machine failing to do so is assumed to be malfunctioning, and is automatically isolated, the equipment described above being switched to the other machine. The isolation unit can also be addressed by program and operated manually if necessary. When a failure occurs on one machine, processing is brought to a consistent state, where possible. The machine is isolated by program, and processing is continued on the other machine, all available units having been switched. A processor failure, however, would cause the watchdog to isolate the machine. In this case, the other machine would take action based on its security copies of messages, disc transfers in progress etc. to recover the system state prior to the failure. Processing would then continue. In either case, the user should not be aware of a machine failure having occurred.
FALLBACK OPERATION When failure renders one machine inoperable, for example machine A as described above, the system will run on the other (Figure 3), handling all the online workload and still maintaining dual files of the database. The management information system would not normally be run under these conditions, although it would be possible with some degradation in response time. When the fault has been repaired, the system will be reconfigured back to normal operation in a controlled manner under system/operator dialogue.
186
Machine B will now be in control of the online equipment, i.e. there is a reversal of the original roles, no special significance being attached to the designations A and B in terms of functional ability. In the event of a total system failure, the teleprinter network can continue to operate by manual use of a patching jackfield.
TRAINING Apart from the initial requirement of several hundred officers, there is an ongoing requirement to train men while the system is in use because of promotions, resignations etc. The system incorporates a training mode that enables any VDU to be logged on as a training subdivisional or control VDU. All the facilities of the live system are available to update a special set of resources, send to incidents etc. Training mode VDUs are able to access all real resources and incident logs, but are not allowed to update them.
SO FTWAR E The system uses the Ferranti Argus 700 standard operating system OSC45, with enhancements written by Leasco. The latter performs the necessary recovery and dual aspects, and control the transaction processing. All the applications and system software have been written in CORAL 66.
computer communications
CONCLUSION The WMP command and control system represents a significant improvement on the old experimental Birmingham system, especially with regard to reliability and response time. It has been designed to accommodate the projected load in 1983, and still have an expansion capability. The system is currently being phased in to the West Midlands, and will be fully operational in November 1978.
ACKNOWLEDG EMENTS The author wishes to thank the West Midlands Police for permission to publish this paper, and in particular all those
vol 1 no 4 august 1978
members of the force who have devoted much of their own time to the project.
REFERENCES Jones B 'Command and control of the emergency services' Comput. Comm. Vol 1 No 1 (February 1978) pp 19-24 Fraser G 'Wanted-a national computer plan' Comput. Comm. Vol 1 No 3 (August 1978)
187