DOS Fn 22H: Write Random File Record

                                                         Compatibility: 1.0+ 
 Expects: AH    22H
          DS:DX address of an opened FCB
 Returns: AL    0 if write was successful
                1 if disk full error
                2 if DTA + FCB recSize would overrun a segment (no write)
    Info: Sets FCB curBlk and curRec to the agree with randomRec then
          writes recSize bytes from the DTA to disk at the specified file

   Notes: ■ Be sure to set recSize to the record length and randomRec in
            the FCB to the desired record number.

See Also: Fn 40H (write file via handle)
          FCB File I/O
          Handle-Oriented File I/O
          DOS Functions