engine decoding functions and operator interface functions operating software may be utilized to operate the processor s for such functions seemingly simultaneously or in a multitasking role an exemplary image reader operating software architecture may be organized into processes or threads of execution processor s memory and associated circuitry which perform or control the exemplary scan and decoding functions may be provided in the scan engine or on associated circuit boards which are located within the housing of the reader decoding is a term used to describe the interpretation of a machine readable code contained in the photodetector output signal an exemplary function of the processor s may be to decode machine readable symbology provided within the target or captured image one dimensional symbologies may include very large to ultra small code 128 interleaved 2 of 5 codabar code 93 code 11 code 39 upc ean msi or other 1d symbologies stacked 1d symbologies may include pdf code 16k code 49 or other stacked 1d symbologies 2d symbologies may include aztec datamatrix maxicode qr code or other 2d symbologies operation of the decoding which may be executed in a user or factory selectable relationship to a scanning routine may be governed by parameters or configuration settings combinations of scanning and decoding parameters together.