Index for interrupt INT 2A

Table of Contents by Order
2A00 - INT 2A - NETWORK - INSTALLATION CHECK
2A0000 - INT 2A - AT&T Starlan Extended NetBIOS (var length names) - INSTALLATION CHECK
2A01 - INT 2A - NETWORK (Microsoft,LANtastic) - EXECUTE NETBIOS REQUEST,NO ERROR RETRY
2A02 - INT 2A - NETWORK (Microsoft) - SET NET PRINTER MODE
2A0300 - INT 2A - NETWORK - CHECK DIRECT I/O
2A04 - INT 2A - NETWORK - EXECUTE NetBIOS REQUEST
2A0500 - INT 2A - NETWORK - GET NETWORK RESOURCE AVAILABILITY
2A06 - INT 2A - NETBIOS, LANtastic - NETWORK PRINT-STREAM CONTROL
2A07 - INT 2A U - PC Network v1.00 - RECEIVER.COM - ???
2A2001 - INT 2A - MS Networks or NETBIOS - ???
2A2002 - INT 2A - NETWORK - ???
2A2003 - INT 2A - NETWORK - ???
2A4147DX0000 - INT 2A U - NetSoft DOS-NET v1.20+ - INSTALLATION CHECK
2A7802 - INT 2A - NETWORK - PC LAN PROG v1.31+ - GET LOGGED ON USER NAME
2A80 - INT 2A CU - NETWORK - BEGIN DOS CRITICAL SECTION
2A81 - INT 2A CU - NETWORK - END DOS CRITICAL SECTION
2A82 - INT 2A CU - NETWORK - END DOS CRITICAL SECTIONS 0 THROUGH 7
2A84 - INT 2A CU - NETWORK - KEYBOARD BUSY LOOP
2A86 - INT 2A U - PC Network v1.00 - RECEIVER.COM - ???
2A8700 - INT 2A CU - PRINT - BEGIN BACKGROUND PRINTING
2A8701 - INT 2A CU - PRINT - END BACKGROUND PRINTING
2A89 - INT 2A U - PC Network v1.00 - RECEIVER.COM - ???
2A90 - INT 2A U - IBM PC 3270 EMULATION PROGRAM - ???
2AC2 - INT 2A U - Network - ???
2AC4 - INT 2A U - PC Network v1.00 - RECEIVER.COM - ???
2AD800 - INT 2A U - Novell NetWare Lite - SERVER - DOS CRITICAL SECTION DISABLE
2AD801 - INT 2A U - Novell NetWare Lite - SERVER - DOS CRITICAL SECTION ENABLE
2AD850 - INT 2A U - Novell NetWare Lite - CLIENT - START SERVER CRITICAL SECTION
2AD851 - INT 2A U - Novell NetWare Lite - CLIENT - END SERVER CRITICAL SECTION
2AD852 - INT 2A U - Novell NetWare - DOS Requester v1.03 - SERVER LOADED
2AD853 - INT 2A U - Novell NetWare - DOS Requester v1.03 - SERVER UNLOADED
2AE0 - INT 2A U - PC Network 1.00 - ???
2AFF90 - INT 2A - PC/TCP PREDIR.EXE - ???
2AFF91 - INT 2A - PC/TCP PREDIR.EXE - ???
2AFF92 - INT 2A - PC/TCP PREDIR.EXE - INSTALLATION CHECK
2AFF93 - INT 2A - PC/TCP PREDIR.EXE - ???
2AFF94 - INT 2A - PC/TCP PREDIR.EXE - ???
2AFF95 - INT 2A - PC/TCP PREDIR.EXE - GET CONFIGURATION STRINGS
2AFF96 - INT 2A - PC/TCP PREDIR.EXE - SET PRINT JOB TERMINATION CONFIGURATION
2AFF97 - INT 2A - PC/TCP PREDIR.EXE - GET PRINT JOB TERMINATION CONFIGURATION

INT 2A - NETWORK - INSTALLATION CHECK
	AH = 00h
Return: AH <> 00h if installed
	CF set if NetWare v2.15 NetBIOS emulator installed
Note:	supported by PC LAN Program, LAN Manager, LANtastic, NetWare, 10NET,
	  etc.
SeeAlso: INT 5C"NetBIOS"

INT 2A - AT&T Starlan Extended NetBIOS (var length names) - INSTALLATION CHECK
	AX = 0000h
Return: AH = DDh
SeeAlso: INT 5B"Extended NetBIOS"

INT 2A - NETWORK (Microsoft,LANtastic) - EXECUTE NETBIOS REQUEST,NO ERROR RETRY
	AH = 01h
	ES:BX -> NCB (see #03249 at INT 5C"NetBIOS")
Return: AL = NetBIOS error code
	AH = status
	    00h no error
	    01h error occurred
SeeAlso: AH=04h,AX=0500h,INT 5B"Extended NetBIOS",INT 5C"NetBIOS"

INT 2A - NETWORK (Microsoft) - SET NET PRINTER MODE
	AH = 02h
	???
Return: ???

INT 2A - NETWORK - CHECK DIRECT I/O
	AX = 0300h
	DS:SI -> ASCIZ device name (may be full path or only drive specifier--
		  must include the colon)
Return: CF clear if direct physical addressing (INT 13,INT 25) permissible
	CF set if access via files only
Notes:	do not use direct disk accesses if this function returns CF set or the
	  device is redirected (INT 21/AX=5F02h)
	use AH=00h to determine whether the network is installed; if not,
	  direct physical access is allowed
	may take some time to execute, so programs which need to check
	  frequently should save the result of the first call
	this function is called by the DOS kernel on INT 25 and INT 26
	supported by PC LAN Program, LAN Manage, LANtastic, NetWare, 10NET,
	  etc.
SeeAlso: INT 13/AH=02h,INT 13/AH=03h,INT 25,INT 26,INT 21/AX=5F02h

INT 2A - NETWORK - EXECUTE NetBIOS REQUEST
	AH = 04h
	AL = error retry
	    00h automatically retry request on errors 09h, 12h, and 21h
		  (see #03248 at INT 5C"NetBIOS")
	    01h no retry
	    02h ???
	ES:BX -> Network Control Block (see #03249 at INT 5C"NetBIOS")
Return: AX = 0000h if successful
	AH = 01h on error
	    AL = error code
Notes:	invokes either INT 5B or INT 5C as appropriate
	supported by PC LAN Program, LANtastic, LAN Manager, NetWare, 10NET,
	  etc.
	NetWare 2.15 NetBIOS emulator returns CF clear if successful, CF set
	  on error
	PC LAN Program defines any non-zero return value in AH as an error
	  indicator for subfunction 00h, and any non-zero return value in AX
	  as an error indicator for subfunction 01h
SeeAlso: AH=00h,AH=01h,AX=0500h,INT 5B"Extended NetBIOS",INT 5C"NetBIOS"

INT 2A - NETWORK - GET NETWORK RESOURCE AVAILABILITY
	AX = 0500h
Return: AX reserved
	BX = number of network names available
	CX = number of network control blocks available
	DX = number of network sessions available
Notes:	supported by PC LAN Program, LAN Manager, LANtastic, NetWare, 10NET,
	  etc.
	the application should call this function before using any network
	  resources, and maintain its own count to avoid exceeding the
	  network's resource limits
SeeAlso: AH=00h,AH=01h,AH=04h,INT 5C"NetBIOS"

INT 2A - NETBIOS, LANtastic - NETWORK PRINT-STREAM CONTROL
	AH = 06h
	AL = function
	    01h set concatenation mode
		all printer output put in one job until return to DOS prompt
	    02h set truncation mode (default)
		printer open/close or BIOS/DOS output switch starts new job
	    03h flush printer output and start new print job
Return: CF set on error
	    AX = error code
	CF clear if successful
Notes:	subfunction 03h is equivalent to Ctrl/Alt/keypad-*
	supported by PC LAN Program, LANtastic, NetWare, 10NET, etc.
	LANtastic v4.x no longer supports this call
	this function sets the printer mode for all redirected printers
SeeAlso: INT 21/AX=5D08h,INT 21/AX=5D09h,INT 2F/AX=1125h

INT 2A U - PC Network v1.00 - RECEIVER.COM - ???
	AH = 07h
	???
Return: ???
Program: PC Network is an early networking package which was renamed the
	  IBM PC Local Area Network Program (PC LAN Program) as of v1.10
SeeAlso: AH=86h

INT 2A - MS Networks or NETBIOS - ???
	AX = 2001h
	???
Return: ???
Note:	intercepted by DESQview 2.x

INT 2A - NETWORK - ???
	AX = 2002h
	???
Return: ???
Note:	called by MS-DOS 3.30-6.00 APPEND

INT 2A - NETWORK - ???
	AX = 2003h
	???
Return: ???
Note:	called by MS-DOS 3.30-6.00 APPEND

INT 2A U - NetSoft DOS-NET v1.20+ - INSTALLATION CHECK
	AX = 4147h ('AG')
	DX = 0000h
Return: DX = 4147h if installed
	    DS:SI -> configuration data (see #02554)
Program: DOS-NET is a shareware networking package by Albert Graham
Note:	this call is supported by CLIENT.COM, SERVER.COM, ROUTER.COM, and
	  NETDOS.COM
SeeAlso: INT 65/DX=4147h,INT 65/DX=4741h

Format of DOS-NET v1.20 configuration data area:
Offset	Size	Description	(Table 02554)
 00h	BYTE	???
 01h	BYTE	interrupt number used by DOS-NET APIs
 02h	WORD	function number to place in AX for above interrupt
 04h	BYTE	minor version as two BCD digits (e.g. 20h for v1.20)
 05h	BYTE	major version number (01h for v1.20)
 06h  2 BYTEs	???
 08h	WORD	??? (used by ARCNET.COM)
		bit 15: ??? (set by MACTEST.COM)
 0Ah	WORD	??? (used by NDIS.COM and ODI.COM)
 0Ch 22 BYTEs	???
 24h	DWORD	-> ??? function (set by PROTECT.COM)
 28h 12 BYTEs	???
 34h	DWORD	-> ??? function (set by FASTVIEW.COM)
 38h	DWORD	-> ??? function (set by FASTVIEW.COM)
 58h	DWORD	-> ??? (offsets 04h and 1Ah from value are used by NETFILES)
	???
 7Ch	WORD	???
 7Eh	WORD	??? (may be high half of a DWORD at 7Ch)
	???
 A8h	DWORD	-> ??? (used by SM.COM)
	???
114h	WORD	???
116h	WORD	??? (may be high half of a DWORD at 114h)
	???
1BDh	BYTE	??? flags
		bit 0: ???
		bit 6: ???
	???
1E1h	BYTE	???
	???
208h	WORD	??? (used by SM.COM, MACTEST)
282h	WORD	???
284h  2 BYTEs	???
286h	WORD	??? flags
		bit 0: ???
	???
31Eh	WORD	???
320h	WORD	??? (used by NDIS.COM and ODI.COM)
322h  8 BYTEs	???
32Ah	WORD	??? (used by NDIS.COM and ODI.COM)
	???
33Eh  4 BYTEs	??? (used by ODI.COM)
342h  N BYTEs	??? (used by NDIS.COM)
	???
3CFh	BYTE	??? flags
		bit 2: ???
3D2h	BYTE	installed-component flags
		bit 0: PROTECT installed
		bit 1: NETCACHE installed
		bit 3: SM.COM installed
		bit 7: NETDEBUG installed
3D3h	BYTE	installed-component flags
		bit 0: NETFILES installed
		bit 6: FASTVIEW installed
	???
3FFh	BYTE	??? (used by NDIS.COM)
400h	BYTE	???
401h	BYTE	??? (used by SM.COM)
402h	BYTE	??? (used by SM.COM)
	???
448h	BYTE	???
449h	BYTE	??? (used by MACTEST)
44Ah	BYTE	??? (used by PROTECT)
44Bh	BYTE	???
44Ch	BYTE	???
44Dh	BYTE	??? (used by SM.COM)
44Eh	BYTE	??? (used by SM.COM, MACTEST)
	???

INT 2A - NETWORK - PC LAN PROG v1.31+ - GET LOGGED ON USER NAME
	AX = 7802h
	ES:DI -> 8-byte buffer to be filled
Return: AL = 00h if no user logged on to Extended Services
	AL <> 00h if user logged on to Extended Services
	    buffer at ES:DI filled with name, padded to 8 chars with blanks.

INT 2A CU - NETWORK - BEGIN DOS CRITICAL SECTION
	AH = 80h
	AL = critical section number (00h-0Fh) (see #02555)
Notes:	normally hooked to avoid interrupting a critical section, rather than
	  called
	the handler should ensure that none of the critical sections are
	  reentered, usually by suspending a task which attempts to reenter
	  an active critical section
	the DOS kernel does not invoke critical sections 01h and 02h unless it
	  is patched.  DOS 3.1+ contains a zero-terminated list of words
	  beginning at offset -11 from the Swappable Data Area
	  (see #01687 at INT 21/AX=5D06h); each word contains the offset within
	  the DOS data segment of a byte which must be changed from C3h (RET)
	  to 50h (PUSH AX) under DOS 3.x or from 00h to a nonzero value under
	  DOS 4.0+ to enable use of critical sections.	For DOS 4.0+, all
	  words in this list point at the byte at offset 0D0Ch.
	MS Windows patches the DOS kernel's calls to INT 2A/AH=80h-81h into
	  far calls to its own handler, and does not reflect the calls back
	  to INT 2A unless SYSTEM.INI contains ReflectDOSInt2A=1 or
	  ModifyDOSInt2A=0 in the [386Enh] section
	Novell NETX does not issue INT 2A/AH=80h and INT 2A/AH=81h calls when
	  it intercepts INT 21 calls and processes them itself
SeeAlso: AH=81h,AH=82h,AX=8700h,INT 21/AX=5D06h,INT 21/AX=5D0Bh

(Table 02555)
Values for DOS critical section number:
 01h	DOS kernel, SHARE.EXE, DOSMGR
	apparently for maintaining the integrity of DOS/SHARE/NET
	  data structures
 02h	DOS kernel, DOSMGR
	ensures that no multitasking occurs while DOS is calling an
	  installable device driver
 05h	network redirector
 06h	DOS 4.x only IFSFUNC
 08h	ASSIGN.COM
 0Ah	MSCDEX, CORELCDX
 0Fh	IBM PC LAN server (while intercepting INT 10/AH=06h,07h,0Eh)

INT 2A CU - NETWORK - END DOS CRITICAL SECTION
	AH = 81h
	AL = critical section number (00h-0Fh) (see #02555)
Notes:	normally hooked rather than called
	the handler should reawaken any tasks which were suspended due to an
	  attempt to enter the specified critical section
	MS Windows patches the DOS kernel's calls to INT 2A/AH=80h-81h into
	  far calls to its own handler, and does not reflect the calls back
	  to INT 2A unless SYSTEM.INI contains ReflectDOSInt2A=1 or
	  ModifyDOSInt2A=0 in the [386Enh] section
SeeAlso: AH=80h,AH=82h,AX=8700h

INT 2A CU - NETWORK - END DOS CRITICAL SECTIONS 0 THROUGH 7
	AH = 82h
Notes:	called by the INT 21h function dispatcher for function 0 and functions
	  greater than 0Ch except 59h, and on process termination
	the handler should reawaken any tasks which were suspended due to an
	  attempt to enter one of the critical sections 0 through 7
SeeAlso: AH=81h

INT 2A CU - NETWORK - KEYBOARD BUSY LOOP
	AH = 84h
Notes:	similar to DOS's INT 28h, called from inside the DOS keyboard input
	  loop (i.e. INT 21/AH=07h or INT 21/AH=08h) to allow the network
	  software to process requests
	Novell DOS 7+ calls this function with AX=8400h from inside of
	  the keyboard input loop.
SeeAlso: INT 28

INT 2A U - PC Network v1.00 - RECEIVER.COM - ???
	AH = 86h
	???
Return: ???
SeeAlso: AH=07h,AH=C4h

INT 2A CU - PRINT - BEGIN BACKGROUND PRINTING
	AX = 8700h
	CF clear
Return: CF clear if OK to print in background now
	CF set if background printing not allowed at this time
Desc:	used to inform interested programs that PRINT is about to start its
	  background processing, and allow those programs to postpone the
	  processing if necessary
Notes:	when PRINT gains control and wants to begin printing, it calls this
	  function.  If CF is clear on return, PRINT begins its background
	  processing, and calls AX=8701h when it is done.  If CF is set on
	  return, PRINT will relinquish control immediately, and will not
	  call AX=8701h
	PCVENUS (an early network shell by IBM and CMU) hooks this call to
	  prevent background printing while its own code is active
SeeAlso: AH=80h,AH=81h,AX=8701h

INT 2A CU - PRINT - END BACKGROUND PRINTING
	AX = 8701h
Desc:	used to inform interested programs that PRINT has completed its
	  background processing
Note:	called by PRINT after it has performed some background printing; not
	  called if AX=8700h returned with CF set.
SeeAlso: AX=8700h

INT 2A U - PC Network v1.00 - RECEIVER.COM - ???
	AH = 89h
	AL = ???  (ASSIGN uses 08h)
	???
Return: ???

INT 2A U - IBM PC 3270 EMULATION PROGRAM - ???
	AH = 90h
	???
Return: ???
Note:	the LANtastic redirector and SERVER.EXE use this function with AL=01h,
	  03h-07h,0Ch-11h

INT 2A U - Network - ???
	AH = C2h
	AL = subfunction
	    07h ???
	    08h ???
	BX = 0001h
	???
Return: ???
Note:	this function is called by the DOS 3.30-6.00 APPEND

INT 2A U - PC Network v1.00 - RECEIVER.COM - ???
	AH = C4h
	AL = subfunction
	    07h ???
	    08h ???
	BX = ???
	???
Return: ???
SeeAlso: AH=86h

INT 2A U - Novell NetWare Lite - SERVER - DOS CRITICAL SECTION DISABLE
	AX = D800h
Return: nothing
Desc:	sets ??? flag, and sets ??? to initial value
Note:	called by CLIENT for communication between client and server
SeeAlso: AX=D801h,AX=D850h

INT 2A U - Novell NetWare Lite - SERVER - DOS CRITICAL SECTION ENABLE
	AX = D801h
Return: nothing
Desc:	clears the ??? flag set by AX=D800h
Note:	called by CLIENT for communication between client and server
SeeAlso: AX=D800h,AX=D850h

INT 2A U - Novell NetWare Lite - CLIENT - START SERVER CRITICAL SECTION
	AX = D850h
Return: nothing
Desc:	increments an internal byte-sized counter
Note:	this function is intercepted by DV/X 1.10 PEERSERV.DVR and the
	  Advanced NetWare 4.0 DOS Requester
SeeAlso: AX=D851h

INT 2A U - Novell NetWare Lite - CLIENT - END SERVER CRITICAL SECTION
	AX = D851h
Return: nothing
Desc:	resets an internal byte-sized counter to zero
Note:	this function is intercepted by DV/X 1.10 PEERSERV.DVR and the
	  Advanced NetWare 4.0 DOS Requester
SeeAlso: AX=D850h

INT 2A U - Novell NetWare - DOS Requester v1.03 - SERVER LOADED
	AX = D852h
Return: ???
Note:	calls the NetWare Lite SERVER installation check, and sets ??? pointer
SeeAlso: AX=D853h,INT 2F/AX=D880h

INT 2A U - Novell NetWare - DOS Requester v1.03 - SERVER UNLOADED
	AX = D853h
Return: ???
Note:	clears the pointer set by AX=D852h
SeeAlso: AX=D852h

INT 2A U - PC Network 1.00 - ???
	AH = E0h
	AL = subfunction??? (01h,02h, maybe others)
	???
Return: ???
Note:	called by PCNet 1.00 NET.COM, a shell program from which others are run

INT 2A - PC/TCP PREDIR.EXE - ???
	AX = FF90h
Return: AX = ???
Note:	PREDIR.EXE is the network printer redirector included as part of the
	  PC/TCP system by FTP Software, Inc.

INT 2A - PC/TCP PREDIR.EXE - ???
	AX = FF91h
	BX = ???
Return: AX = status???

INT 2A - PC/TCP PREDIR.EXE - INSTALLATION CHECK
	AX = FF92h
Return: AX = 0000h if installed
	   BX = redirected printer port (FFFFh if no printers redirected)
	   CX = version (CH = major, CL = minor)
Note:	PREDIR.EXE is the network printer redirector included as part of the
	  PC/TCP system by FTP Software, Inc.

INT 2A - PC/TCP PREDIR.EXE - ???
	AX = FF93h
Return: AX = ???

INT 2A - PC/TCP PREDIR.EXE - ???
	AX = FF94h
	BX = ???
	CX = ???
	DX = ???
Return: AX = ???
Note:	PREDIR.EXE is the network printer redirector included as part of the
	  PC/TCP system by FTP Software, Inc.

INT 2A - PC/TCP PREDIR.EXE - GET CONFIGURATION STRINGS
	AX = FF95h
	CX = what to get
	    0000h ??? (returned pointer to "C:\COMMAND.COM")
	    0001h spooling program
	    0002h ???
	    0003h spool file name
	    0004h swap file name
Return: AX = status
	    0000h successful
	BX:DX -> ASCIZ configuration string

INT 2A - PC/TCP PREDIR.EXE - SET PRINT JOB TERMINATION CONFIGURATION
	AX = FF96h
	CX = what to set
	    0000h ???
	    0001h print-on-hotkey state
	    0002h print-on-exit state
	    0003h print job timeout in clock ticks
	    0004h print-on-EOF state
	BX = new value (0000h disabled, 0001h enabled except for timeout)
Return: AX = ???
SeeAlso: AX=FF97h
Note:	PREDIR.EXE is the network printer redirector included as part of the
	  PC/TCP system by FTP Software, Inc.

INT 2A - PC/TCP PREDIR.EXE - GET PRINT JOB TERMINATION CONFIGURATION
	AX = FF97h
	CX = what to get
	    0000h ???
	    0001h print-on-hotkey state
	    0002h print-on-exit state
	    0003h print job timeout in clock ticks
	    0004h print-on-EOF state
Return: AX = status
	    0000h successful
	BX = old value (0000h disabled, 0001 enabled except for timeout)
SeeAlso: AX=FF96h