fig1 a vehicle tracking system comprises on board units 1 in vehicles which communicate wirelessly via mobile networks 2 to gateways 3 in this diagram two wireless protocols are indicated namely gprs and sms however there are typically a variety of additional protocols the gateways 3 communicate using protocols such as udp and tcp via the internet 4 with a host system having receivers 5 which are operating system services and a data storage system 6 the incoming data is written from the receivers 5 to the data storage system 6 referring to fig2 there are n receivers 5 each comprising a port porti a process proci a data log logi and a decoder deci the decoders deci decode data from all logs and write the decoded data to memory caches 35 which are transferred to a hub 36 of the data storage system 6 the hub 36 routes the data to an analysis engine 37 which in turn processes the data and maintains a number of database tables 38 39 and 40 in more detail fig3 illustrates a method 50 which is carried out for each thread from a receiver port porti to the hub 36 of the steps in the method 50 steps 51 55 are performed by the relevant receiver process proci to result in raw data being stored in a log logi in step 51 packets.