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AmigaDOS Packet Interface Specification
by John Toebes
AmigaDOS communicates with file systems and other DOS handlers by
sending and receiving packets. Opening and closing file handles
(including console file handles), creating directories, and renaming
disks all require DOS to tell a handler to perform these actions
through sending a packet. The particular action a handler performs
depends on the type of packet it receives.
This article documents the standard AmigaDOS packet types. For
information on how to use packets to communicate with handlers see
the AmigaDOS Manual.
Packets sent to a file system or handler can be divided into several
basic categories:
o Basic Input/Output
These actions deal with tranferring data to and from objects
controlled by the handler.
o File/Directory Manipulation/Information
These actions are used to gain access to and manipulate the high
level structures of the file system.
o Volume Manipulation/Information
These actions allow access to the specific volume controlled by the
file system.
o Handler Maintenance and Control
These allow control over the handler/file system itself, independent
of the actual volume or structure underneath.
o Handler Internal
These actions are never sent to the handler directly. Instead they
are generally responses to IO requests made by the handler. The
handler makes these responses look like packets in order to simplify
processing.
o Obsolete Packets
These packets are no longer valid for use by handlers and file
systems.
o Console Only Packets
These packets are specific to console handlers. File Systems can
ignore these packets.
Much of this information can be extracted from Developer Conference
notes, The AmigaDOS Manual, and various Fred Fish disks. However,
because there is no single complete reference to these packet types,
a consolidated view of all the packets is presented here. Several
structures are referenced here which can be found by looking at the
include files <dos/dos.h> and <dos/dosextens.h>. (If you are using
the 1.3 version of the include files, these are in the libraries
directory instead of the dos directory). Before attempting to work
with a file handler you should first become familiar with these files.
Each packet type documented in this article is listed with its action
name, its corresponding number, any AmigaDOS routines which uses this
packet, and the list of parameters that the packets uses. The C
variable types for the packet parameters are one of the following
types:
BPTR This is BCPL pointer (the address of the given object shifted
right by 2). Note: this means that the object must be
aligned on a longword boundary.
LOCK This is a BPTR to a FileLock structure returned by a previous
ACTION_LOCATE_OBJECT. A lock of 0 is legal, indicating the
root of the volume for the handler.
BSTR This is a BPTR to a string where the first byte indicates the
number of characters in the string. This length byte is
unsigned but because it is stored in a byte, the strings are
limited to 255 characters in length.
BOOL A 32-bit boolean value either containing DOSTRUE (-1) or
DOSFALSE (0). Note: equality comparisons with DOSTRUE should
be avoided.
CODE A 32 bit error code as defined in the dos/dos.h include file.
Handlers should not return error codes besides those defined
in dos/dos.h.
ARG1 The FileHandle->fh_Arg1 field.
LONG A 32 bit integer value.
Summary of Defined Packet Numbers
This is a listing of all the DOS packets defined by Commodore.
Packets 0-1999 are reserved for use by Commodore. Unless otherwise
noted, packets 2050-2999 are reserved for use by third party
developers (see chart below). The remaining packets are reserved for
future expansion (Note: packets 2008, 2009, 4097, and 4098 are in use
by Commodore).
Decimal Hex Action #define
0 0x0000 ACTION_NIL
1 <Reserved by Commodore>
2 0x0002 ACTION_GET_BLOCK
3 <Reserved by Commodore>
4 0x0004 ACTION_SET_MAP
5 0x0005 ACTION_DIE
6 0x0006 ACTION_EVENT
7 0x0007 ACTION_CURRENT_VOLUME
8 0x0008 ACTION_LOCATE_OBJECT
9 0x0009 ACTION_RENAME_DISK
10-14 <Reserved by Commodore>
15 0x000F ACTION_FREE_LOCK
16 0x0010 ACTION_DELETE_OBJECT
17 0x0011 ACTION_RENAME_OBJECT
18 0x0012 ACTION_MORE_CACHE
19 0x0013 ACTION_COPY_DIR
20 0x0014 ACTION_WAIT_CHAR
21 0x0015 ACTION_SET_PROTECT
22 0x0016 ACTION_CREATE_DIR
23 0x0017 ACTION_EXAMINE_OBJECT
24 0x0018 ACTION_EXAMINE_NEXT
25 0x0019 ACTION_DISK_INFO
26 0x001A ACTION_INFO
27 0x001B ACTION_FLUSH
28 0x001C ACTION_SET_COMMENT
29 0x001D ACTION_PARENT
30 0x001E ACTION_TIMER
31 0x001F ACTION_INHIBIT
32 0x0020 ACTION_DISK_TYPE
33 0x0021 ACTION_DISK_CHANGE
34 0x0022 ACTION_SET_DATE
35-39 <Reserved by Commodore>
40 0x0028 ACTION_SAME_LOCK
41-81 <Reserved by Commodore>
82 0x0052 ACTION_READ
83-86 <Reserved by Commodore>
87 0x0057 ACTION_WRITE
88-993 <Reserved by Commodore>
994 0x03E2 ACTION_SCREEN_MODE
995 0x03E3 ACTION_CHANGE_SIGNAL
996-1000 <Reserved by Commodore>
1001 0x03E9 ACTION_READ_RETURN
1002 0x03EA ACTION_WRITE_RETURN
1003 <Reserved by Commodore>
1004 0x03EC ACTION_FINDUPDATE
1005 0x03ED ACTION_FINDINPUT
1006 0x03EE ACTION_FINDOUTPUT
1007 0x03EF ACTION_END
1008 0x03F0 ACTION_SEEK
1009-1019 <Reserved by Commodore>
1020 0x03FC ACTION_FORMAT
1021 0x03FD ACTION_MAKE_LINK
1022 0x03FE ACTION_SET_FILE_SIZE
1023 0x03FF ACTION_WRITE_PROTECT
1024 0x0400 ACTION_READ_LINK
1025 <Reserved by Commodore>
1026 0x0402 ACTION_FH_FROM_LOCK
1027 0x0403 ACTION_IS_FILESYSTEM
1028 0x0404 ACTION_CHANGE_MODE
1029 <Reserved by Commodore>
1030 0x0406 ACTION_COPY_DIR_FH
1031 0x0407 ACTION_PARENT_FH
1032 <Reserved by Commodore>
1033 0x0409 ACTION_EXAMINE_ALL
1034 0x040A ACTION_EXAMINE_FH
1035-2007 <Reserved by Commodore>
2008 0x07D8 ACTION_LOCK_RECORD
2009 0x07D9 ACTION_FREE_RECORD
2010-2049 <Reserved by Commodore>
2050-2999 <Reserved for 3rd Party Handlers>
4097 0x1001 ACTION_ADD_NOTIFY
4098 0x1002 ACTION_REMOVE_NOTIFY
4099- <Reserved by Commodore for Future Expansion>