SMARTDRV

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Supported DOS versions:	MS-DOS 5+
How easy to use?	Moderate
How safe to use?	Fairly safe
How common?	Less well known
Internal or external command?	External

Description

Starts SMARTDrive, a disk caching program which speeds up access to frequently used files.

Command Syntax

Loading SMARTDrive:

SMARTDRV [[drive[+ | -]] ...] [/e:elementsize] [initcachesize] [wincachesize] [/b:buffersize] [/c] [/r] [/l] [/q] [/v] [/s] [/u]

Once SMARTDrive has started:

SMARTDRV [[drive[+ | -]] ...] [/c] [/r]

[[drive[+ | -]] ...] specifies the drive you wish to cache. A + caches both reads and writes and a - caches reads only. If neither + nor - are used, the caching in the table below is used:

Drive Type	Cache Type
Floppy drive	None
Floppy drive created with InterLink	Read only
Hard drive	Read and write
CD-ROM drive	Read only

/e:elementsize specifies how many bytes to move at a time. This can be 1024, 2048, 4096 or 8192 (the default)
initcachesize specifies the size of the cache SMARTDrive should use when Windows isn't running. If this is left out, SMARTDrive uses the amount described by the table below.
wincachesize specifies the size of the cache SMARTDrive should use when Windows is running. If this is left out, SMARTDrive uses the amount described by the table below. If initcachesize is smaller than wincachesize, SMARTDrive sets initcachesize to the samer size as wincachesize
/b:buffersize specifies the size of the read ahead buffer. This can be any multiple of elementsize.
/c writes all cached information to disk. See comments for more details.
/r clears the contents of the cache and restarts SMARTDrive
/l prevents SMARTDrive from loading into upper memory blocks (UMBs), even when these are available
/q instructs SMARTDrive not to display messages when it starts. This cannot be used with the /v switch.
/v instructs SMARTDrive to display messages when it starts. This cannot be used with the /q switch.
/s displays status information about SMARTDrive
/u disables caching of CD-ROM drives

Default values for initcachesize and wincachesize

Extended memory	Default initcachesize	Default wincachesize
Up to 1MB	All extended memory	Zero (no caching)
Up to 2 MB	1 MB	256 KB
Up to 4 MB	1 MB	512 KB
Up to 6 MB	2 MB	1 MB
Over 6 MB	2 MB	2 MB

Comments

One major flaw in older versions of SMARTDrive, particularly the one supplied with DOS 6.0, is that it does not always write cached data to disk before the DOS prompt reappears. This can cause serious damage and data loss. Before rebooting with the reset switch or switching off, ALWAYS run SMARTDRV /C to ensure this does not happen. Rebooting with CTRL+ALT+DEL is caught by SMARTDrive and this is not a problem.

If you wish to cache a CD-ROM drive. SMARTDrive must appear AFTER MSCDEX is loaded (otherwise it can't find the CD-ROM; pretty obvious really).

When using Windows 3.11 it is not necessary to use SMARTDrive for hard disk caching as it comes with its own disk cache, IFSHLP.SYS, which uses less memory. However if you wish to cache CD-ROM drives you will need to use SMARTDrive.

SMARTDrive should not be started while Windows is running.

Some hard disk controllers cannot work properly with the memory provided by EMM386 or Win3.1x's 386 enhanced mode. To enable it to work, add the following line to your CONFIG.SYS file:

DEVICE=SMARTDRV.EXE /DOUBLE_BUFFER

This must appear BEFORE EMM386 and it cannot be loaded into high memory.