Software sanity monitor

A system for collaborative bar code error detection and correction comprises a network of individual scanning entities for scanning bar-coded labels. Each individual scanning entity includes a scanning system having a decoder for decoding scanned bar code information and a printhead defect identifier for identifying printhead defects from scanned bar code information that cannot be decoded and for constructing printhead defect models for use in correcting future bar code scans. A log is provided at each individual scanning entity for storing locally constructed printhead defect models and printhead defect models that have been constructed at other scanning entities in the network. Each individual scanning entity has an error corrector for correcting erroneous scanned bar code information using the locally stored printhead defect models.; Further, each scanning entity includes a network connection for broadcasting locally constructed printhead defect models to the network and for receiving broadcasts of printhead defect models constructed at other scanning entities in the network.