DOS SmartDrive

SmartDrive is disk cache software included with DOS and Windows starting with DOS 4.01 and Windows 3.0. SmartDrive speeds up hard disk performance by reserving a block of memory and reading and writing larger chunks from the disk (see cache). There are two versions of SmartDrive depending on DOS and Windows version.

       File name        DOS     Windows
     SMARTDRV.SYS    4.01, 5      3.0
     SMARTDRV.EXE        6        3.1

DOS 4.01 & 5 and Windows 3.0
The SMARTDRV.SYS driver is loaded from CONFIG.SYS, and its default setting uses 256K of extended memory, for example:

     device=c:\dos\smartdrv.sys

You can reserve more memory by adding the number of K's to the line; for example, to reserve two megabytes, type:

 device=smartdrv.sys 2048     extended memory
 device=smartdrv.sys 2048 /a  expAnded memory

Note!
In order to use extended or expanded (EMS) memory for your disk cache, you must load the extended memory or EMS driver from CONFIG.SYS before loading SMARTDRV.SYS. See DOS HIMEM.SYS, DOS EMM386.EXE and cache.

DOS 6 and Windows 3.1
The SMARTDRV.EXE program is loaded from the AUTOEXEC.BAT file. If a SCSI drive was detected on installation, SMARTDRV.EXE is also loaded from CONFIG.SYS as in the following example:

             No SCSI drive detected
    c:\dos\smartdrv        in AUTOEXEC.BAT

              SCSI drive detected
    c:\dos\smartdrv        in AUTOEXEC.BAT
    CONFIG.SYS:
    device=c:\dos\smartdrv.exe /double_buffer

To determine if the device= line can be removed from CONFIG.SYS, type smartdrv (after SMARTDRV has been loaded in AUTOEXEC.BAT). If every line under the column "buffering" reads NO, you can remove the line.

SmartDrive's default setting uses 1 to 2MB of extended memory depending on the amount of RAM installed. You can reserve more memory by adding the number of K's to the line. The following AUTOEXEC.BAT example reserves 4MB (4096KB) of extended memory for DOS applications. The second number (2048KB) limits Windows to reducing the cache size to 2MB. After Windows is exited, the cache is restored to 4096K.

        c:\dos\smartdrv 4096 2048

Note!
In order to use extended memory for your disk cache, you must load the extended memory driver from CONFIG.SYS before loading SMARTDRV.SYS. See DOS HIMEM.SYS.

In Windows 95, the Smartdrive cache was replaced with the 32-bit Protected Mode Vcache driver.