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msdos.sys in 9x

JSW77

studynotes.net states that "Windows 9x uses a new, IO.SYS, which replaces the DOS system files IO.SYS and MSDOS.SYS." My A+ book (Jean Andrews, thomson course technology) doesnt mention this at all and in fact states that Msdos.sys is required to be present. However, the chapter is using the MS-Dos mode as its example of an OS booting up. Does 9x load differently depending on if it is loading into MS-dos mode or the "protected" windows mode (are different system files used)? And if so, is it true that Msdos.sys is needed for the MS-dos mode startup but not for the windows mode startup? Hope im making sense, and thanks.

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Comments

RussS

Read here my friend
http://support.microsoft.com/default.aspx?scid=kb;EN-US;118579 That should put you in good stead

JSW77

I appriciate it RusS!

bwolfe

Actually, I used the same book and it does comment on the Win9x version of Msdos.sys.

It says:

"Windows 9x includes a file named Msdos.sys but it is only a text file that contains some parameters and switches that can be set to affect the way the OS boots."

- pg 609 last paragraph, marked as important info for the OS Exam

Then on page 622 it goes on to explain exactly how Win9x Msdos.sys is different from the original version and how you can use it to affect your configuration of Win9x. The book also gives you a picture of the Msdos.sys file contents on page 625 and a list of all the possible parameters and their options on page 624.

In Win9x more of the workload is given to IO.SYS and the other files, Msdod.sys, config.sys, and autoexec.bat are used for making confguration changes and loading drivers and TSRs. But Msdos.sys is still present in Win9x, is still checked by IO.SYS, and must be 1024 bytes in size... which is why if you open it you will see its just a few commands followed by lots of 'X's used as filler.

Also.. you stated...

"However, the chapter is using the MS-Dos mode as its example of an OS booting up. Does 9x load differently depending on if it is loading into MS-dos mode or the "protected" windows mode (are different system files used)?"

In fact the book makes it quite clear that Win9x loads into 'real mode' first then switches into 'protected mode'. It even steps through the process. I suggest you go over chapter 12 of that book again.

BTW... which edition of the book do you have? Besides the different editions there are also different versions of that book. Mine for instance is the 'Comprehensive' version of the Enhanced Third Edition.