CP/M 3, MP/M II and CP/Net hardware error codes

 0 - Software error (eg file not found)
 1 - Select error (cannot access drive)
 2 - Disc is read-only
 3 - File is read-only
 4 - Invalid drive
 5 - File already open
 6 - FCB checksum error (MP/M II) - the calling program has tampered with the FCB.
 7 - Password error
 8 - File already exists
 9 - Filename contains ?
10 - Wheel protection error (ZPM3) / Too many files open (MP/M II)
11 - No room in system lock list (MP/M II)
12 - Not logged on to server (CP/Net)

CP/M 3 error codes

1. Return an Error Code in register A:
   • 20: Read Sequential
   • 21: Write Sequential
   • 33: Read Random
   • 34: Write Random
   • 40: Write Random w/zero Fill

   Register A BDOS Error Codes

   Code Meaning 00 Function successful 255 Physical error : refer to register H 01 Reading unwritten data or no available directory space (Write Sequential) 02 No available data block 03 Cannot close current exte 04 Seek to unwritten extent 05 No available directory space 06 Random record number out of range 09 Invalid FeB (previous BDOS close call returned an error code and invalidated the FCB 10 Media Changed (A media change was detected on the FCB's drive after the FCB was opened)

2. The following BDOS functions return a Directory Code in register A:
   • 15: Open File
   • 16: Close File
   • 17: Search For First
   • 18: Search For Next
   • 19: Delete File
   • 22: Make File
   • 23: Rename File
   • 30: Set File Attributes
   • 35: Compute File Size
   • 99: Truncate File
   • 100: Set Directory Label
   • 102: Read File Date Stamps and Password Mode
   • 103: Write File XFCB

   BDOS Directory Codes
   Code Meaning 00-03 successful function 255 unsuccessful function

3. If the Set BDOS Error Mode function is used to place the BDOS in return error mode, the following functions return an Error Flag on physical errors:
   • 14: Select Disk
   • 46: Get Disk Free Space
   • 48: Flush Buffers
   • 98: Free Blocks
   • 101: Return Directory Label Data

   BOOS Error Flags
   Code Meaning 00 successful function 255 physical error : refer to register H