DOCUMENT:Q101884 19-NOV-1999 [msdos] TITLE :How to Detect a DoubleSpace Drive from a Batch File PRODUCT :Microsoft Disk Operating System PROD/VER:MS-DOS:6.0,6.2,6.22 OPER/SYS: KEYWORDS: ====================================================================== ------------------------------------------------------------------------------- The information in this article applies to: - Microsoft MS-DOS operating system versions 6.0, 6.2, 6.22 ------------------------------------------------------------------------------- This information applies to both Microsoft DoubleSpace and Microsoft DriveSpace. For MS-DOS 6.22, use DRVSPACE in place of DBLSPACE for commands and filenames. SUMMARY ======= MS-DOS batch files cannot distinguish between compressed drives and uncompressed drives. However, you can use the MS-DOS Debug utility to create a program that sets an errorlevel depending on whether a drive is compressed with DoubleSpace. An MS-DOS batch file can then test this errorlevel to determine whether the drive is a DoubleSpace- compressed drive. NOTE: Microsoft Product Support Services does not provide support for writing the Debug script or batch file discussed in this article, or troubleshoot problems related to compiling, running or using this program or batch file. MORE INFORMATION ================ This following is an example of how to use the MS-DOS Debug utility to create a program file called ISDBL.COM. ISDBL.COM determines the following: - Whether DoubleSpace is loaded in memory -and- - Whether a specified drive is a DoubleSpace-compressed drive ISDBL.COM returns the following errorlevels: Results Errorlevel ------------------------------------------ DoubleSpace compressed drive 1 DBLSPACE.BIN is not loaded 0 Invalid drive 0 Other errors 0 NOTE: ISDBL.COM tests the current drive if no drive is specified on the command line. Creating ISDBL.COM ------------------ ISDBL.COM is created using a Debug script file, which contains all the commands you would enter from within DEBUG to create ISDBL.COM. To create ISDBL.COM, follow these steps exactly: 1. Create a text file called C:\ISDBL.SRC using a text editor (such as Windows Notepad or MS-DOS Editor). This is the Debug script file. C:\ISDBL.SRC should contain the following lines exactly as they appear. NOTE: Press the ENTER key at the end of each line below. A 100 MOV AX,2901 MOV SI,81 MOV DI,012D INT 21 MOV DL,[012D] DEC DL JGE 0119 MOV AH,19 INT 21 MOV DL,AL MOV AX,4A11 MOV BX,1 INT 2F MOV AX,4C00 AND BL,80 JZ 012B INC AL INT 21 RCX AE N ISDBL.COM W Q NOTE: You MUST press the ENTER key twice after the last "INT 21" line and once after the "Q" at the end of the Debug script. 2. From the MS-DOS command prompt on drive C, enter the following command to create the ISDBL.COM program: DEBUG < ISDBL.SRC Debug reads and follows the instructions in the ISDBL.SRC file. It is recommended that you do not use this command from within Windows or when other programs are running. If ISDBL.SRC contains an error, Debug probably is not told when to quit; therefore, you will have to restart your system. Debug may even be instructed to cause your system to stop responding (hang). If this happens, restart your system and examine ISDBL.SRC for accuracy. If there are no errors in ISDBL.SCR, a few screens of information are displayed, ending with :012B INT 21 :012D -RCX CX 0000 :AE -N ISDBL.COM -W Writing 000AE bytes -Q where is a combination of letters and numbers, the exact combination of which varies. The remaining information should be exactly as above if ISDBL.COM was compiled correctly. Debug places the ISDBL.COM file in the current directory, which in the example above is C:\. It should be 174 bytes in size. Using ISDBL.COM --------------- You can now run the ISDBL.COM program from within a batch file to get information about a specific drive. Below is an example batch file: DBLTEST.BAT ----------- @ECHO OFF REM This batch file uses ISDB.COM to test a drive to see if it REM was compressed with DoubleSpace. REM REM DBLTEST.BAT assumes that ISDBL.COM in in the current REM directory or a directory on the MS-DOS Path. REM REM The syntax for running this batch file is: REM DBLTEST : REM REM where : is the name of the drive to test, for example C: REM If no drive is specified, the current drive is tested. REM ISDBL %1 IF NOT ERRORLEVEL 1 GOTO FAILURE ECHO The drive %1 is a DoubleSpace compressed drive. GOTO END :FAILURE ECHO The drive %1 is not a DoubleSpace compressed drive. :END How ISDBL Works --------------- In determining whether the drive is compressed, ISDBL assumes that DoubleSpace is running. ISDBL checks the specified drive by using Interrupt 2F, function 4A11. This function is the DSGetDriveMapping application programming interface (API) call for DoubleSpace. If the drive is compressed, then Bit 7 of BL will be set. Otherwise, it is zero. This result is simply returned at the end of ISDBL. REFERENCES ========== Additional query words: 6.00 6.20 ====================================================================== Keywords : Technology : kbMSDOSSearch kbMSDOS622 kbMSDOS620 kbMSDOS600 Version : MS-DOS:6.0,6.2,6.22 ============================================================================= THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY. Copyright Microsoft Corporation 1999.