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Aptiva - The Double-Buffering Feature of SMARTDrive in Windows 3.1
Applicable to: United States
With Microsoft Windows 3.1, a version of the SMARTDrive disk-caching program was also introduced. The file name of the SMARTDrive disk-cache program is SMARTDRV.EXE. With this version of SMARTDRV comes a feature called double-buffering. This feature provides compatibility for hard-disk controllers that do not know how to address virtual memory. For example, a SCSI (Small Computer System Interface) hard-disk controller would use the double-buffering feature of SMARTDRV because this type of controller doesn't know how to address virtual memory.
SMARTDrive in Windows 3.1 is invoked via a command in the AUTOEXEC.BAT file. The CONFIG.SYS file, however, is used if your hard-disk controller requires the double-buffering feature. To invoke double-buffering for SMARTDrive, a DEVICE line is added to the CONFIG.SYS to specify SMARTDRV.EXE to use double-buffering. When the SETUP program of Windows 3.1 is used, it places a line to start SMARTDRV.EXE in the AUTOEXEC.BAT file. SETUP for 3.1 also checks the hard-disk controller to see if double-buffering is needed or not. If Windows can tell that double-buffering is not required it will leave the SMARTDRV.EXE line in the AUTOEXEC.BAT and do nothing else. If SETUP cannot tell whether double-buffering is required or if SETUP realizes that double-buffering is required by the hard-disk controller, it will add the following to the CONFIG.SYS:
DEVICE=C:\WINDOWS\SMARTDRV.EXE /DOUBLE_BUFFER
Thus, if you have the SMARTDRV.EXE line only in the AUTOEXEC.BAT file, you are using SMARTDrive (without double-buffering). If you have a line for SMARTDrive in AUTOEXEC.BAT and in CONFIG.SYS, you are using SMARTDRV.EXE with the double-buffering feature turned on. This doesn't necessarily mean that double-buffering is working on your system. It will only work if your hard-disk controller needs to use double-buffering.
If you find a line for SMARTDrive in both AUTOEXEC.BAT and CONFIG.SYS, you should check to see if the CONFIG.SYS line was added due to confusion on the part of the SETUP program. If this is the case, you can remove the line.
You can determine whether your computer needs to use double-buffering by going through the following steps:
1) Go into Windows.
2) Select the DOS prompt from the Main group.
3) At the prompt type SMARTDRV and press Enter.
4) You will see three columns of information about SMARTDRV. Look at the column labeled "Buffering." If every line in this column reads "NO," it means your hard drive controller does not need double-buffering. If you see a "-" in this column, the SETUP program was confused as to whether or not your hard-disk controller required double-buffering or not. A "NO" or "-" in this column means that double-buffering is not in use and the line in CONFIG.SYS can be removed. To get rid of double-buffering, edit CONFIG.SYS to remove the DEVICE line for SMARTDRV.EXE.
For more information on SMARTDrive and double-buffering, see chapter 14 "Optimizing Windows" in the Windows 3.1 manual.
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Hint Category |
DOS/Windows 3.x | |
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Date Created |
17-04-97 | |
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Last Updated |
22-01-99 | |
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Revision Date |
20-05-99 | |
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Brand |
IBM Aptiva | |
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Product Family |
PS/1 | |
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Machine Type |
2011, 2121, 2123, 2133, 2155, 2168 | |
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Model |
ALL | |
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