TRAVELING LINUX. AN IMPLEMENTATION EXPERIENCE FOR UNATTENDED MANAGEMENT APPLICATIONS. by Maurizio Cachia SAD Trasporto locale S.p.A. - Bolzano S.IN.CO S.r.l. - Milano ABSTRACT SAD operates in the local public transport field in an alpine area to the North-East part of Italy. During several years, we were constructing an integrated payment system for all public transport operators (buses and trains) in our region. To manage this payment system we use at present about 90 PCs running under 1.2.13 Linux. Within a new automatic vehicle location project, we will further set up on board of every bus special industrial PC systems with GPS and radio (for data transfer). We operate on this system procedures (always on Linux) for traffic and tariff control. AN INTEGRATED PAYMENT SYSTEM About two years ago in the "Provincia Autonoma di Bolzano" started to operate a standardized payment system which allows the patronage to utilize with only one ticket all passenger public transport means, either on road or rail. On this way, has been promoted the setting up of an integrated information system with the aim of a standardized management of the several informations which could be obtained from the statistical data about passenger, and in general patronage, trips. The system is based on the use of on board electronic devices, with magnetic technology, which have been yield by a Belgian company with an international experience in this special field and have required more than four years for their final and whole setting up. The most important system features are as follows: - the service network is managed by 25 different companies with very different features and organizational models as well; - the need for a standardized system management forced us to develop a single software model that could self-define its own operational features, following the different conditions and the whole integration in the management proceedings for the book-keeping and operational control of the principal companies. Already from the first implementation steps, had been taken for granted the limits resulting from the hardware features and from the operational and development system. These limits were impossible to exceed when was necessary to integrate the lines managed by the "Ferrovie dello Stato" (National Railroad Company) It was required to set up in 37 rail stations devices like that on board, but running unattended. It was therefore necessary to get the disposal of tele-diagnostic functions, remote updating and automatic data collection. LINUX ON RAIL About the middle of 1993, we received from our consultants the first information about the existence of a Unix like operating system whose sources were available on Internet, with a license policy similar to that of the Free Software Foundation. The first approach to Linux, at that time on the 0.98 release, excited us at once, either because of the great stability already gained or because of the possibility that we had to develop our projects on the base of the available sources. Thus, we could implement an agreement with the system house which already cooperated with us, to obtain the supply of updated and tested Linux distributions and the development of the device drivers which were needed to drive our devices (not exactly standard). We modified the running of the magnetic records dealing unities and we brought them back to their natural terminal function, linkable to a personal computer through a strong and reliable transmission file. To the first months of 1993, we started the devices setting up inside the stations. After a testing period and following the availability of the first 1.0 Linux release versions, the whole system was put in action. Today, 90 systems are running overall: - 40 wholly unattended inside the rail stations; - 40 by the ticket-windows placed in the most important places of the country - 10 inside the bus-depots, aimed to read and collect data coming from buses through infrared transmissions. Every unattended system is made by a black box set in a burglar-proof case which contains a 486 33 MHz PC with a 16 Mbytes Ram and a 150 Mbyte hard-disk, a minimum of four serial ports (UART 16550A), a V32bis or V34 modem and a battery backup. To the black box are connected (in RS 485) from two to 6 ticket obliteration units like those set on the buses. The now used Linux release is the 2.0.2X (Elf version). The average system uptime lasts now more than 100 days; some system crash chances take still place, probably deriving from particular environmental conditions. To obviate this, we are testing to some places an hardware watchdog. The ticketing systems are of course different in presence of a monitor, a key board and terminal connections needed for Credit Cards treatment. Every night the central system is connected with all terminals, using Taylor UUCP for data collection and to start out some functions. Every week, we do a PPP connection to carry out with "ntpdate" the systems clocks adjustment LINUX ON THE BUS. The precise knowledge of the patronage mobility features is not enough to solve every management problem of a bus company. In this industry employees are spread on the land and can be reached for the service instructions only some time and at precise network points. This means the need for programming the employees and buses use ahead of time, also relevant, and does not allow to adequate in time the work organization in case of disturbs on the network, accidents, organization problems or unexpected demand changes. It was therefore put forward a survey on the check methods and technologies used in other country areas or abroad. In general, these systems were applied to the urban services of middling size metropolitan areas. The check service ends at the borders of the suburbs, above all because of the high investment costs needed for the radio transmission equipments. Architectures are normally based on these general features: a) assembling of almost all check intelligence to a central point that is able to process a great data quantity (in general, computers with for real time special operation systems); b) availability of a radio network with a great number of transmission channels and widespread cover, polling transmission method with every vehicle questioning to determine its position on land and very short time cadences (in general, less than a minute); c) when needed, in case of limited radio cover, integration with infrared active captors systems or with passive markers to reach vehicles or to allow them to correct their position; d) the intelligence on board is almost only made by devices with industrial electronics features and always proprietary technology based on moderate capacity CPU. In the last years, the above described check systems are characterized by a favorable evolution following the availability on the civil market of the location system, based on the GPS technology. This system, even if characterized by some limits in the very crowded areas, allows to simplify the vehicle location electronic systems and sometimes also a relevant accuracy increasing. Allowing for the experiences on the described solutions, were defined the system project features for the intercity and urban services in the "Provincia di Bolzano" which has to operate following these conditions: - the under control network lasts 2300 km of which more than three quarters laying in an alpine area; - the regulation and structural situation existing in the national spread of radio frequencies, does not allow the availability of a sufficient number of channels to construct a polling system on the land in question; - the existing of several different companies, with different organizational structures, requires to foresee the possibility to put into action control models with very light features too, but always consistent with a comprehensive system management; therefore, we exclude that the overall system functionality can be linked to a single control center which should define all interested vehicles and send out the operation instructions; - the existence of the magnetic payment system and its reached development level, requires its integration inside a single on board system which allows more developments and implementations. In this case, it seems needed to set up on every vehicle board a knot of the operation system that can develop, in strict autonomy, the production unity management functions, allowing the overall integration and the least resources spending. Functions have to be modular, that is put in action following the company needs which owns the vehicle and yields the service. It is needed that every vehicle can determine by itself its own position, time and its consistency with programs, without the need of a constant vehicle linkage with an operation center. Each working program change that can be foreseen for a vehicle and its operator, has to be put forward with a minimum of verbal communications and with an overall consistency with the instructions of the company central information system. The needs listed above, can find a solution only in a multitasking operational environment which allows the overall integration to the company information system (based on DG/UX 5.4.3 the implementation of Data General CO of Sys V rel.4 ). The availability of such a system on Intel base for more than 400 vehicles, could require license investments for more than some hundred million lira. Moreover, having the availability need of not exactly standard features in the trade systems (particular terminal use, watchdog management and advanced power managements) could be necessary to intervene at a system level with all the ipotetical troubles between the software distributor (italian) and the owner (american). In this framework does not therefore exist any alternative to confirm the Linux use for our project. The features in favor are as follows: System steadiness. With the 1.2.13 (and better in the stable 2.0) the machine average uptime is much more than that released time ago through the most widely circulating Unix trade systems for Intel platform. (We tried almost all of them !!!). Sources availability and quality. Many of the to us necessary special needs are already contained in the development version (power management, watchdog, networking on radio net, etc.). The others will be faced either intervening on sources or through cooperation with the developers. Our management applications were born in a Unix environment. From 1980 till today, we had to face different porting either on architectures or on different systems (Ultrix, BSD, SCO, Interactive, DG/UX). The porting on Linux was among all the most easy and linear. It does not cost anything !!! This was finally the basic reason that helped us to persuade our management. The automatic vehicle location system has reached today the setting up phase. Following an european call for bids, Data General CO. (Westboro-MA) was selected as on board PCs supplier. During July 1996, will start the systems setting up on the vehicles. The technical specification for the data transmission system is still on the way and anyhow it shall be integrated in a radio network already existing. Every vehicle equipment is composed by a 486/100MHz PC, a 16 Mb RAM, a 540 Mb hard disk, 10 RS232/422 serial ports, a SCSI controller, a type III PCMCIIA. In the same PC case (140 mm x 140 mm x 158 mm) are integrated a GPS Trimble differential system and an alimentation intelligent management unit which allows the programmed system ignition, the environmental functional parameters control and the battery back up functions. The systems are tested for very hard environmental conditions (functioning temperature between - 20 to + 50 Celsius degrees, shock and quivering resistance following MIL-SPEC specifications). To the PCs will be linked the already present on board terminals used for the payment system management (obliterators and issue console), the radio equipment and special public information panels. Linux is in the 2.0.20 version. ------------------- Maurizio live in a little village in the Dolomiti Alpes with his wife and a funny golden retriever named Lu. Work from the 1980 as system analyst in the Unix environment for the market of the public transport companies. From 1984 is technical manager of the Integrated Information System of SAD in Bolzano. It can be reached by e-mail at mau@sad.it --_=XFMail.1.1.p0.Linux:971119095350:20517=_-- End of MIME message