From: mikey@cs.mcgill.ca (The Procrastinator P1000)
Subject: Re: WARNING !!!!! MS WINDOWS 3.1 SmartDrive Problem
Organization: Tessier-Ashpool monitor, Maas-Neotek Corp
Date: Fri, 14 Aug 1992 00:36:26 GMT


There's a fair amount of disinformation in both of these posts.. 
I don't speak for Microsoft, just for me.

>>>
* exuptr@exu.ericsson.se (Patrick Taylor) Has publicly proclaimed:
*
>In article <1992Aug13.040731.2286@cs.mcgill.ca> tennis@cs.mcgill.ca (Pascal PROULX) writes:
>
>>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 :
>
>>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.
>
>Ok.

Any and ALL caching programs do this. Any program that is going to do disk I/O
should be checking the multiplexer (int 2Fh and int 31h) and the VM state. 
Further, all files should be closed, and flushed. If the file is, however, in
the process of being written, all that can happen is the allocation entry for 
file is incomplete. Left unchecked this can cause corruption, in rare cases. 


>
>>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.
>
>This could happen without smartdrive.  Windows is unpredicatble about when
>it will decide to write something to disk.  Solution: don't turn your
>PC off without exiting Windows and parking your drive heads.

Exactly, well almost. Most modern (last 3-5 years) drives don't need to be 
parked. In fact, if you try and park a sector translation drive (IDE,ESDI,SCSI)
with an old MFM utility you can do nasty things to the drive.

Windows isn't that unpredictable when it will write things to disk. If you're 
not swapping you're usually ok. In all cases you should close any app before
exiting windows. If you don't it's not "Windows" that isn't writing things
out, it's each individual app, which has files open. The PageFile VxD can't 
be corrupted by a shutdown, if it's writing, only open files can.

None of the above are Smartdrv problems. Smartdrv provides a pool of memory to
windows to cache the disks with. It was decided, however, to leave default
caching of INI files out of win 3.1 for this (and a few other) reasons. 

>
>>3) If a power failure occurs during the gap before cached data is written to
>>   the hard disk, you could damage your FAT tables.
>
>This could happen without smartdrive, too.  Solution: buy a UPS.  Nothing
>else can give you nearly perfect protection.

This can ruin your day if you're running ANYTHING ON ANY computer. 


You're trying to blame a single item with generic dangers of Computing.
What do you do if you have a caching controller and the power dies.
I mean , write behind is not the best thing to use for data security if 
you want speed. But YOU the USER must be logical and responsible. Turning a 
machine off with files open is known to cause problems, regardless of the OS.

Just trying to clarify...
					-mikey
-- 
|mikey@cs.mcgill.ca-Mike Gallop- t-mikeg@microsoft.com        McGill Comp Sci |
|Programming n. 1. The art of debugging a blank sheet of paper.	              |
|	       	2. A pastime similar to banging one's head against a wall, but|
| but with fewer opportunities for reward.                                    |
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