Assembly Language Help (alang.hlp) (Table of Contents; Topic list)
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Int 21h Function 21h
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  Interrupt:   21h     Function:   21h
 
  Title:       Random Read
 
  See also:    Read File or Device
 
  Description:
 
     Reads a selected record from a file into memory.
 
     Input                     Output
 
     AH = 21h                  AL = 00h (if read successful)
     DS:DX = segment:offset       = 01h (if end-of-file)
             of previously        = 02h (if segment wrap, read canceled)
             opened file          = 03h (if partial record read at
             control block               end-of-file)
                                    -♦-