From: mccall@mksol.dseg.ti.com (fred j mccall 575-3539)
Newsgroups: comp.os.msdos.misc
Subject: Re: WARNING !!!!! MS WINDOWS 3.1 SmartDrive Problem
Date: 18 Aug 92 15:54:05 GMT
Organization: Texas Instruments Inc

In <1992Aug17.202907.12273@schbbs.mot.com> P70008@waccvm.corp.mot.com (Bill Nelson) writes:

We've seen this bit of FUD cropping up all over.  There are a few
misstatements in it, from my reading.

>The following article was taken from the PC WORLD ONLINE via the America
>Online BBS and is an important warning for all MS WINDOWS 3.1 users.

>The following information was passed on to PC WORLD ONLINE by PCW George,
>(George Campbell, a PC WORLD Editor).

>"After considerable testing, I have discovered a major problem with the
>version of SmartDrive included with Windows 3.1. The default installation
>of SMARTDRV.EXE enables write caching on your hard disks. Most often this
>is not a problem but, under certain circumstances, it could crash your hard
>disk. A typical situation is described below :

This is NOT a "major problem".  It is supposed to work this way and is
documented to work this way.  It is not the only write-behind cache
for MS-DOS, and practically every 'real' computer system in the world
works this way. 

>1) If you use a program wich handles multiple boot-up configurations by using
>   alternative Autoexec.bat and Config.sys files then automatically
>   re-booting, SmartDrive won't write the new files to the hard disk before
>   the computer reboots. This could cause damage to you FAT table if the disk
>   write is only partiallt completed. In most cases, however, the copying job
>   will not be done, and the computer will reboot safely.

As noted by the original poster, the way to deal with this is to place
the command SMARTDRV /C in the batch file immediately preceding the
reboot command.  This will flush all buffers and everything will work
fine. 

>2) In some Windows programs, not enough time is allowed for SmartDRive to
>   write files to disk. In this case, if you shut off your computer for some
>   reason, your files will not be saved. In the worst scenario, your FAT tables
>   may be damaged.

If this is happening and you're pulling the plug immediately after
writing and before exiting Windows, yes, you could have this problem.
Exiting Windows will cause the cache to be flushed.  You can get the
same damage WITHOUT SmartDrive loaded, if you are in the habit of
pulling the plug on your computer while it is still in Windows and
right after you issue a command to write from a program.

>3) If a power failure occurs during the gap before cached data is written to
>   the hard disk, you could damage your FAT tables.

There is no additional risk, since you could also have a power failure
during a 'normal' write which would do the same thing.


>******************
>SOLUTION :
>******************

>Disable write-caching in SmartDrive. This is not a documented in the Windows
>Manual, but is ducomented in SmartDrive's help screen. To disable
>write-caching, modify the line in your AUTOEXEC.BAT file as shown below :

This *IS* documented in the Windows manual (or in one of the files
they tell you to read after you install -- I forget exactly which, but
I know I've seen the whole thing with SMARTDRV clearly explained
without invoking 'help' on it.

Do NOT disable write-caching.  It is totally unnecessary and it will
indeed slow things down.  Instead, simply fix any BAT files that
reboot the machine, as noted above.  Other than that, exit to a DOS
prompt and wait 5 seconds (the default pause time -- buffers will be
flushed after 5 seconds or when the processor is idle, whichever
occurs first) before powering down your machine.

This is all clearly documented in the book that no one reads and the
files that never get looked at.


-- 
"Insisting on perfect safety is for people who don't have the balls to live
 in the real world."   -- Mary Shafer, NASA Ames Dryden
------------------------------------------------------------------------------
Fred.McCall@dseg.ti.com - I don't speak for others and they don't speak for me.
Newsgroups: comp.os.msdos.misc