[techtalk] request for ideas

[Karl-Heinz Zimmer]

On 10/11/99, 11:37:42 PM, R Pickett wrote erroneously:

> On Mon, 11 Oct 1999, Karl-Heinz Zimmer wrote:

> > So smart DOS does some very nice thing: *without* asking
> > the user it overwrites the contents of the disk.  The
> > cached directory contents are written just over the *real*
> > directory structure because DOS tries to 'repair' the
> > supposedly damaged directory.

> Dir might (or might not) incorrectly DISPLAY the contents
> of the disk from the cache, but even brain-dead DOS does
> not automatically dwiddle the FAT table or directory tree
> of a piece of media while _reading_ it.

Ok, dear R.,

what are you trying to tell us?

I am not telling the truth?

I did explicitly write that DOS *does* these things and you
tell us 'even ... does not automatically dwiddle the ... directory
tree ... while reading.'

I don not know about your reasons to behave that way but i know
what i have seen: that time i was at university and i was able
to demonstrate that 'gag' as often as someone like you wouldn't
believe me.
This doesn't have anything to do with the 'PS/3 model 30' floppy
drives or something like that but happened with nearly all high
density drives for 3.5''.

> > This is not a fantasy story of mine but did really happen and
> > things like this were the reason why i erased *all* MS software
> > on my home PC two years ago.

> I can see a scenario where 'dir a:' coughed up the incorrect
> information from the cache, and therefore lead to user error
> that caused the loss of data.

Would you mind just believing that i am telling the truth?
Will you?

It's of little use to 'see a scenario' - i have seen plenty of
test disks that were perfectly damaged by having the root directory
overwritten with the preceding disk's directory contents.

> But think it through -- how is it going to compare the cached
> data to what's on the disk, unless it reads the disk first?

Why should i 'think it through'?
I am working as software developer since over ten years now and
you really *can* believe me that this idiotic directory overwriting
game of DOS is one of the astounding things i have ever seen.

> nd why would it read the disk if it's in that error condition
> of not having the media changed flag set?

Why?  Because it's written by duds?  Because someone wanted to
ensure that the cache is up-to-date but then confused everything
and ended up believing his silly cache more than believing the
contents on the disk?
Because DOS tries to be more smart than the user?
Because on-the-fly correction of erroneous contents was the idea
of an extremely smart boy at the MS software labs?
I don't know and i don't mind: the result is the same - loss of
data without any reason!

> It thinks it's the same disk, so why would it even read, much
> less write, the floppy?

Why?  I don't know.

> That's just counter to the point of caching information.

Just believe me that it happened.

> In either case, if a floppy drive doesn't set the media changed
> flag, that's a broken piece of hardware, not an OS issue.

I think i *now* understand what you are trying to tell me:

the fault is in the hardware!

Forget it: the fault is in the OS because the duds who implemen-
ted this 'error correction' feature thought they are the smar-
test guys ever but instaed of that implemented *nonsense* by
supposing that the 'media changed flag' would allways be set
correctly.

The better way would be to ask the user if he changed the medium
and tell him that the contents of the cache are other than the
contents of the disk AND tell him that this 'media change auto
detection feature' of his drive seems do be aout of order - NOT
to erase date be trying to correct things.

When such things occur in Linux this is because someone is
breaking a rule: ''Never change media without first unmounting!''

For DOS there was no such rule: instead of that there were plenty
of examples in the user's manual showing the idiotic 'DIR A:'
command and giving you a good chance of data loss.  THAT's the
reason why i got so angry about the guys that implemented features
like this one.

Forget about DOS and about Windows 9x!

( Unfortunately since Windows 2000 seems to be a merge of Win 9x
  and Win NT i expect it to combine the errors of both 'worlds'. )

Best greetings,

Karl-Heinz
-- 
K.-H. Zimmer     *     Hamburg     *     Germany




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