Author: Robert Hyatt
Date: 18:31:08 02/03/99
Go up one level in this thread
On February 03, 1999 at 20:15:16, Christophe Theron wrote:
>On February 03, 1999 at 18:03:46, Robert Hyatt wrote:
>
>>On February 03, 1999 at 12:54:24, Ed Schröder wrote:
>>
>>>>Posted by Robert Hyatt on February 03, 1999 at 09:55:20:
>>>
>>>>unless something has changed drastically, it doesn't do that. It _allows_ a
>>>>program to access memory beyond 640K, but it doesn't 'protect' it. Otherwise
>>>>you couldn't run something like this and hang the system:
>>>>
>>>> main() {
>>>> int a[1000];
>>>> int i;
>>>> for (i=i;i<10000000;i++) a[i]=0;
>>>> }
>>>
>>>>Dos has never had the concept of 'a task' which is why "TSR (terminate and
>>>>stay resident)" programs were developed. They sit in memory, can write >_anywhere_ and you don't ever know unless they blow you up...
>>>
>>>IMO a TSR program isn't able to write (or read) above 1 Mb. Is this
>>>a correct view?
>>
>>no. Any 'program' running under dos can access any byte of memory in the
>>machine. which can be a problem. Normally TSR programs don't bother extended
>>memory because they have no idea what is used and what is free, but they _can_
>>poke around up there if they want... and some do...
>
>
>Any TSR program could do that, but only if it is willing to access extended
>memory, as it requires some specific calls to the HIMEM driver or to the BIOS
>routines.
>
>In case of the Auto232 driver, I would bet that a bug in this piece of software
>will never touch any byte in extended memory. It can screw itself by misusing a
>segment register for example, but this way it will only overwrite something in
>the first megabyte (known as "DOS memory").
first, extended memory is a 'side issue' here... the chess engine executable
is almost guaranteed to be loaded into low memory, and the auto232 driver
certainly is, because it catches interrupts from the serial port that connects
the two machines. And it can do most anything it wants. I'd suspect that _if_
it does a "wild store" it will zap something in the first 10 segments, but that
is enough to make a chess engine behave strangely, of course...
>
>I would say that a program loaded into extended memory (after the first
>megabyte) will almost never suffer of a memory overwrite by Auto232. The problem
>is that DOS can be touched by a bug in Auto232, which is of course another
>story...
>
>
>
>>>>>Rebel10.0c (with auto232) is currently running on 2 autoplayer pairs
>>>>>under Win98 and a third autoplayer pair is running under Win95. No
>>>>>incompatible problems noticed sofar.
>>>
>>>
>>>>I assume your autoplayer 'bug' was not under windows? Because if it was,
>>>>then this changes things. The only thing that can access your memory is part
>>>>of _your_ program (including the auto232 driver code you include, of course,
>>>>but 'other programs/processes' can't touch you in win98. Only things that are
>>>>part of your code..
>>>
>>>No. I always have tested outside Windows using a clean boot without
>>>any memory managers. Now I have started auto232 from the DOS-box
>>>within Win98. I wonder if this is good enough to be safe as I know
>>>HIMEM.SYS behaves different in the DOS-box than if you launch a
>>>program from the desktop.
>>>
>>>Ed
>>
>>
>>That I don't know. The only windows 'box' I use is the box it came in where
>>it stays and never makes it onto my hard drive. :)
>
>
>And I confirm that this way you save yourself a lot of trouble.
>
>I hope someday users will be wise enough to understand that Windows is a counter
>productive OS and eventually demand some reliability.
>
>Current users only demand to be able to change the screen colors. Looks like
>they don't mind loosing a day of two of hard work because of a bug in their
>favorite software. But if they cannot change the colors or the background image,
>they ask for a refund.
>
>We will provide Windows software, but I still hope that one day users open their
>eyes and ask for a real, robust, reliable operating system. Not a toy.
>
>
> Christophe
NT isn't bad at all, but windows 95/98 is basically trash. And even NT
has serious problems when put in a networking environment... our secretaries
are happy if their machines stay up for a whole work-day without needing a
reboot.
My unix/linux/solaris boxes stay up until hardware breaks or I upgrade the
software. And _never_ crash...
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