User`s guide

Upon return, Function 102 returns a Directory Code in register A with the value
zero if the function is successful, or OFFH, 255 decimal, if the specified file is not
found. Register H is set to zero in both of these cases. If a physical or extended error
is encountered, Function 102 performs different actions depending on the BDOS
error mode (see Function 45). If the BDOS error mode is in the default mode, a
message identifying the error is displayed at the console and the calling program is
terminated. Otherwise, Function 102 returns to the calling program with register A
set to OFFH and register H set to one of the following physical or extended error
codes:
01 Disk I/O error
04 Invalid drive error
09 ? in filename or filetype field
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BDOS Function Calls CP/M 3 Programmers Guide