hi, I am using the external data memory (xdata) to store some variables,since my internal data memory(256 bytes)overflows. The test case executes without error for small memory model(If i remove some variables),but it fails for large memory model. For example if char dest[30]="mark"(declaration) makes the data memory to overflow, i replaced the declaration as xdata char dest[30]="mark".Now it creates hex file without any error.But the test case fails.can any one tell me what may be the reason for the failure?. Note:The test case works properly for small model Thanks in advance chris