VariableTypeRangeIntroducedNotes
_LINFOstring-pre R12Hardware lock serial number; responds to (getvar "_LINFO") only.
_PKSERstring-R9[2]The AutoCAD serial number (read-only).
Note that in versions of AutoCAD prior to R11(?), the serial number was a string in the executable which could be hacked to read 00-000000. In R11(?) a hook into the ZOOM command was enabled to immediately crash AutoCAD if the serial number string was tampered with.[2]
_SERVERboolean0/1R11[2]Network license server status (read-only).
_VERNUMstring-R13AutoCAD build number.
AUXSTATinteger-32768 - 32767R13auxiliary input device status[3]
AXISMODEboolean0/1pre R12Holdover from old AXIS command; no longer used.
AXISUNIT'(x y)-pre R12Holdover from old AXIS command; no longer used.
BS_BITS[2]integer-32768 - 32767R11 only
DBGLISTALL**R10[2]Unknown function.
*Note that this was an integer with range -32768 - 32767 from R10 - R11, then it became a boolean (0/1).[2]
ENTEXTSinteger[0, 1, 2]R12Controls drawing extents calculation.
0 : extents are calculated each time they're needed (slower, but uses less memory).
1 : cache extents of each entity in short (2-byte) values if possible (compromise between speed and memory efficiency).
2 : cache extents of each entity as long (4-byte) values (fastest extents calculations, but uses more storage memory).
ENTMODSinteger0 - ~4GigR12Increments every time a database object is modified (read-only).
FORCE_PAGINGinteger0 - ~4GigR13
GLOBCHECKinteger[0, 1, 2, 3]R133 : show DCL dialog size when displaying dialog.
>0 : disallow local-language commands (very useful for developers!).
JWDEBUG[2]??R9 - R10Probably a "debug" flag used by a programmer with initials J.W. (John Walker?)
KESDEBUG[2]??R9 onlyProbably a "debug" flag used by a programmer with initials K.E.S.
LAZYLOADboolean0/1R13
NODENAMEstring-R13AutoCAD node name.
NOMUTTboolean0/1R14.011 (True) : No input prompts are displayed.
PHANDLEinteger0 - ~4GigR12
PRODUCTstring-R14Product name (e.g. "AutoCAD") (read-only).
PROGRAMstring-R14Executable name (e.g. "acad") (read-only).
QAFLAGSbitcode0 - 32767*R11bit 0 (1) : ^C in menu macro cancels grips (acts like keyboard <Esc>).
bit 1 (2) : no pause during text screen listings.
bit 2 (4) : no "alert" dialogs (text display instead).
bit 7 (128) : accepts "screen picks" (point lists) via (command) function.
*Note that this was an integer with range -32768 - 32767 in R11, then it changed to 0 - 32767 in R12.[2]

Additional Information:

  1. Undocumented system variables are sometimes named internally with an asterisk preceding their name. The asterisk may be included when retrieving such system variables via AutoLISP. For example, (getvar "_PKSER") and (getvar "*_PKSER") both return the serial number.[2]
  2. Prior to R12, AUPREC and LUPREC accepted integers in the range 0 - 18. Beginning with R12, these two system variables no longer accept values larger than 8. If you save an R11 drawing with LUPREC or AUPREC values higher than 8, they are honored in R12 and later -- however, once you change them they cannot be changed back (except via UNDO).[2]