Error Codes

    All the FCB functions report an error by returning 0FFh in the AL
    register.  Other functions report an error by setting the carry flag
    and placing an error code in the AX register.  DOS 2.x functions
    return the error codes 0 - 12h.  Under DOS 3.x, it is best to call
    function 59h to obtain more detailed error information.

Code  Meaning                           Code  Meaning
 00h  No error                           22h  Invalid disk change
 01h  Invalid function number            23h  FCB unavailable
 02h  File not found                     24h  Sharing buffer overflow
 03h  Path not found                     32h  Network request not supported
 04h  No handle available                33h  Remote computer not listening
 05h  Access denied                      34h  Duplicate name on network
 06h  Invalid handle                     35h  Network name not found
 07h  Memory control blocks destroyed    36h  Network busy
 08h  Insufficient memory                37h  Network device no longer exists
 09h  Invalid memory block address       38h  Net BIOS command limit exceeded
 0Ah  Invalid environment                39h  Network adapter hardware error
 0Bh  Invalid format                     3Ah  Incorrect response from network
 0Ch  Invalid access code                3Bh  Unexpected network error
 0Dh  Invalid data                       3Ch  Incompatible remote adapter
 0Eh  Reserved                           3Dh  Print queue full
 0Fh  Invalid drive specification        3Eh  Not enough space for print file
 10h  Attempt to remove the current      3Fh  Print file was deleted
      directory                          40h  Network name was deleted
 11h  Not same device                    41h  Access denied
 12h  No more files                      42h  Network device type incorrect
 13h  Disk write-protected               43h  Network name not found
 14h  Unknown unit                       44h  Network name limit exceeded
 15h  Drive not ready                    45h  Net BIOS session limit exceeded
 16h  Unknown command                    46h  Temporarily paused
 17h  Disk data error (CRC)              47h  Network request not accepted
 18h  Bad request structure length       48h  Print or disk redirection paused
 19h  Seek error                         50h  File exists
 1Ah  Unknown media type                 51h  Reserved
 1Bh  Sector not found                   52h  Cannot make directory entry
 1Ch  Printer out of paper               53h  Critical-error interrupt failure
 1Dh  Write fault                        54h  Too many redirections
 1Eh  Read fault                         55h  Duplicate redirection
 1Fh  General failure                    56h  Invalid password
 20h  File sharing violation             57h  Invalid parameter
 21h  File locking violation             58h  Network device fault

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  The following information is returned by the DOS function 59h:

  Error class:

    Code    Meaning
     01h    Out of resource
     02h    Temporary situation; try again later
     03h    Authorization
     04h    Internal error in system software
     05h    Hardware failure
     06h    System failure; serious failure of system software
     07h    Application software error
     08h    Item requested not found
     09h    Bad format (e.g., unrecognizable disk)
     0Ah    Item locked
     0Bh    Media error (e.g., CRC error)
     0Ch    Already exists
     0Dh    Unknown

  Suggested action:

    Code    Meaning
     01h    Try again now.
     02h    Try again (a few times) after a pause, then prompt user to
            continue or abort.
     03h    Ask user to correct input, then retry.
     04h    Orderly abort; close files, then shut down the application.
     05h    Immediate abort; don't even try to close files.
     06h    Ignore.
     07h    Ask user to do something (like insert appropriate disk), then
            retry.

  Locus of error:

    Code    Meaning
     01h    Unknown
     02h    Block device (e.g., disk drive)
     03h    Network
     04h    Serial device
     05h    Memory