Int 2F/AX=4A10h/BX=0000h

SMARTDRV v4.00+ - INSTALLATION CHECK AND HIT RATIOS

AX = 4A10h
BX = 0000h
CX = EBABh (v4.1+; see Note), and CX <> 0EDCh

Return:
AX = BABEh if installed
DX:BX = cache hits
DI:SI = cache misses
CX = number of dirty cache elements
BP = version in BCD (4.10 = 0410h)
4.0  = 0400h (Windows 3.1)
4.01 = 0401h (MS-DOS 6.0, 1992/07/30)
4.10 = 0410h (1992/11/11)
4.20 = 0420h
5.0  = 0500h (MS-DOS 6.2)

Notes: Most of the SMARTDRV API, including this call, is supported by PC-Cache v8.0 and recent versions of the Norton Caches. The internal name for SMARTDRV is "BAMBI", hence the magic "BABE".. If DBLSPACE.BIN is installed but SMARTDRV has not yet been installed, then calls of this function with CX<>EBABh on entry cause DBLSPACE.BIN to display the error message "Cannot run SMARTDrive 4.0 with DoubleSpace" and abort the caller with INT 21/AX=4C00h. Since the Novell DOS 7 - DR-DOS 7.03 NWCACHE supports a similar install check at this function, but the returned registers contain different data, the caller must take the returned AX value into account to ensure proper interpretation of the returned info. The caller should ensure CX <> 0EDCh to avoid any interaction with the NWCACHE and COMMAND.COM special case of CX=0EDCh. Although this is an install check, NWCACHE always flushes delayed writes to disk, when calling this function with CX<>0EDCh or while /FLUSH:ON is active, but this is nothing to rely upon. The reason for this could be to get more accurate statistics, while SMARTDRV just takes a on-the-fly snapshot of the statistic vars.. The private NWCACHE/NLCACHE install check INT2Fh/D8C0h does not flush to disk, and therefore can be used by callers that must ensure the buffers aren't flushed on this function (e.g. alternative command shells may need this to make their "flush before prompt" feature configurable).. The NWCACHE 0EDCh special case will most probably vanish with future issues of NWCACHE (2.0+).. SMARTDRV v3.x had a completely different API using IOCTL calls, which was also supported by the Norton Caches

BUG: Although DS and ES registers are listed as unmodified, some releases of SMARTDRV seem to trash the DS register, at least the MS-DOS 6.2+ KEYB takes care to preserve the DS register when calling this function.

Category: Caches/Spoolers - Int 2Fh - S

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