I didn't actually fail dos, but I failed the a+os with a 603. But it feels
like I failed a dos test. As I started digging through
what I could remember on the test, I got hung up on a couple of issues and
mainly io.sys and msdos.sys and what was
actually going on in the boot process. Jon Krabbenschmidt has given me a
ton of information concerning the boot
process and went out of his way to help me....Thanks Jon...!
And Dom.Stocqueler, I appologize for being a little
testy....,dkjhelklsjflkjal;skj...it happens to me on occasion and
usually when I am deeply concentrating on an issue. My sense of humor goes
byby....
===============
And since I don't care if I get flamed anymore for being non cisco or having
a non cisco comment and already having
the answer to my question, I will post my original mail that Jon helped me
with plus the answer he gave me and a couple
of others also....It might refresh everyone's memory on something noone
really thinks about much anymore, but I just
find it so interesting.....Maybe it will help someone else. Thank you to
the smart people on this site. There were a
couple of other very good answers also, but these two cover the gist of what
I wanted to know.
Jenn
===================================
My question:
-----------------------
I just recently failed my a+ os test and so I am digging again through my
book. Now just so you will know the book I am
using is "course technology" and is entitled "Enhanced a+guide to Managing
and Maintaing Your PC". I also have the a+ book by Michael Myers, but it is
not the book I am referring to in this
particular scenerio/question. What I am doing is looking up a few specific
questions I was unsure of
on my test and sometimes I get a little carried away and get too deep which
is probable the case here, but here goes.....
One of the questions was a t/f question and it read: The IO.sys file
executes the config.sys. That seems very simple and so I put true for my
answer and
believed it to be true, but i was not absolutely sure of this, so I started
reading. The other day after the
test, in reading about the boot process, it says that when the 'dos
operating system' is loaded, when the io.sys is
finished it turns control over to the msdos.sys and that there is a program
'within the
msdos.sys' that executes the config.sys file. The key words I am seeing here
is the words"within the msdos.sys".
Then a couple of pages on further in the book, it is discussing the
95 operating sys and the boot process. It said that io.sys executes the
config.sys when
booting. Does this mean that the initial boot process is different
depending on
whether you are booting up dos or a gui/windows type environment?
If that is so, when loading dos os, what is the name of the program within
msdos.sys that executes the config.sys file? It didn't say.
In case you have this book, the first portion is on page 73 in the
second paragraph under step 3. This is where it discusses the program with
the msdos.sys that exe's the config.sys file. On os-95, this is on page 77,
step 5.
And if you don't have the book, this is specifically what it says:
On page 73 and is referring to dos here:
"The IO.sys file contains more bios sw. MSDOS.sys contains sw to
manage files, run applications sw, and interface with hw. Once these two
files are loaded into memory, the boot record program is no longer needed,
and control turns to a 'program' stored in msdos.sys. This program looks on
the
hard drive for a file named CONFIG.sys. CONFIG.sys is the first os file that
you, as a user, can change. After config.sys is exectuted, MSDOS.sys looks
for
another dos file named command.com. This file has three parts: more code to
manage i/o, programs for internal dos commands, such as copy and dir, and a
short program that looks for another file name AUTOEXEC.bat."
Now, is very close to specifically says that when loading dos os that the
i/o.sys does not execute the config.sys. It says that a program within
msdos.sys does that.
Then on page 77 in referring to 95, it says:
step 5: Again, just as with dos, io.sys loads. In fact io.sys is
areally a small core dos module. io.sys looks for a config.sys file, and if
found, the config.sys file executes.
step 6: after config.sys is complete, io.sys looks for msdos.sys.
The role of msdos.sys in 95 is much different from its role
in dos.
=============
My comments on this.
If for dos, the msdos.sys has an internal program that
executes config.sys and in windows, the io.sys executes the config.sys, how
can you answer a question with a true or
false answer if the real answer is.....it depends on the operating sys being
loaded.?????
correct or not?
So now, my question is what is the name of the program in
msdos.sys that actually does the executing of the config.sys?
Opinions..comments...
Sorry this is so long and I also realize this is probably not pertinent to
the test in a real sense but this is driving me nuts as
I can't find the answer anywhere and believe me I have looked.
-----------------------
Jon's answer
----------------------
boot order/loading OS process
The system loads IO.SYS which contains the BIOS extensions that load the low
level drivers for the KB, block devices etc. It also loads some code that is
only used once at load/boot time. This stuff is placed at the top of your
conventional memory. (important to know for boot problem trouble shooting).
Than the MSDOS.SYS is loaded. It over laps the initialization code that was
used just to boot/load. Once the code is loaded it is initialized, the
MS-DOS kernel is loaded, which initializes device drivers like serial,
printer, (important for boot serial problems, devices etc. trouble
shooting), checks on the system status, resets the disk systems, and sets up
system default parameters. Once it's job is compete it returns control to
the IO.SYS initialization code in memory. Now.... if a config.sys is
present, it is opened and read 4 times. first to read and execute all
statements except DEVICE, INSTALL, and SHELL. The second pass reads and
executes each DEVICE (including DEVICEHIGH) statement in the order which
they appeared. This is very important to know for boot trouble shooting. The
third pass reads and executes any SHELL statements, if no SHELL statement
exists the COMMAND.COM is loaded. When COMMAND.COM is loaded it over writes
the initialization code left over from the IO.SYS which is no longer needed.
If an AUTOEXEC.BAT exists, COMMAND.COM, (which is now in control of the
system), will load and execute the batch file. If there is no AUTOEXEC.BAT
in the root than COMMAND.COM will request the current date and time, than
show the prompt. As you can see there is a lot to work with here for basic
trouble shooting. Knowing this well will still help you in today's
environment since the process is still basically the same.
Riddle...
Because the earlier "DOS" versions had adopted the slash as command switches
ie: format c: /s Microsoft could not use the standard slash to identify
the hierarchical subdirectory levels. So... MS substituted the backslash to
identify subdirectories beginning in ver 2.0 of MS-DOS when it moved it's OS
from the "partitioned" structure of CP/M to the "hierarchical" structure of
the Unix systems. This of course was necessary due to the "NEW" fixed disks!
and their growing size. This slash backslash substitution created huge
amounts of confusion and upset with the users of that time who were used to
Unix. In addition at that time most keyboards outside of the US did not even
have a backslash key!
--------------------------
Charles answer
----------------------------
>The boot process is different between DOS and Windows. Both require IO.SYS,
>in addition DOS requires MsDOS.SYS, but Windows does not need it. The reason
>is that IO.SYS is hardware-dependent, and directly interfaces with the
>hardware. The upper layers - DOS and Windows require the services provided
>by IO.SYS to access any part of the hardware. Rather than calling IO.SYS
>directly, DOS-based machines use another layer - MsDOS.SYS to interact with
>IO.SYS (note that some DOS games bypass MsDOS altogether, and call IO.SYS
>directly). Windows uses its own kernel to talk to IO.SYS, hence does not
>need MsDOS.SYS.
>
>Config.SYS is executed by MsDOS.SYS. MsDOS.SYS does not call any other
>program to execute Config.SYS. It merely jumps to a program segment that
>contains the initialization code, which executes Config.SYS. You can confirm
>this by Hex-editing MsDOS.SYS, and search for Config.SYS. You can even
>rename it, but the length has to be the same. As part of executing
>Config.sys, MsDOS.SYS looks for the line that contains the shell to load.
>After executing Config.sys, MsDOS loads the shell specified in Config.sys.
>If none was specified, then it looks for Command.com at the root directory,
>and loads it. Command.com then executes Autoexec.bat (if available).
>
>Windows does not need Config.sys and Autoexec.bat, but will happily read and
>execute them if they are in the root directory.
>
>This may be a bit more than you asked for...but there you have it.
>
>CM
And that is the end...
Jennifer Cribbs
7/4/2001 8:43:18 AM, "Circusnuts" wrote:
>You failed a DOS test ????
>
>----- Original Message -----
>From: "Jennifer Cribbs"
>To:
>Sent: Wednesday, July 04, 2001 7:46 AM
>Subject: thanks people [7:10974]
>
>
>> Thanks to everyone to helped me on dos. It is much appreciated. I plan on
>> testing again in a week or so hopefully.
>>
>>
>> Failing a test is just not fun...
>>
>> Jenn
>> Have a great day!!
>> Jennifer
Have a great day!!
Jennifer
Message Posted at:
http://www.groupstudy.com/form/read.php?f=7&i=11015&t=10974
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