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The kernel is the code in memory that other programs call for "help" with things it can't or don't want to do itself. Thats independant of protection etc.. Of course DOS has a kernel, you can't call all non-protected or non-32bit OS:es for non-kernel... Right?

EDIT:

That would fit in nicely with the "DOS has no kernel" observation above - DOS doesn't do any multiplexing, the running program controlls all of the system until it exits and reloads command.com.

I understand the point, but without DOS, the program is left only with BIOS functions, so at the very least int 0x21 could be called DOS kernel?

bubach wrote: Of course DOS has a kernel, you can't call all non-protected or non-32bit OS:es for non-kernel... Right?

The thing is that command.com is completely replaced in memory when another exe is started, and reloaded when the exe exits. I am not a DOS wizz, but I'd say that smells like "no kernel present, please leave this system as you would like to find it".

I understand the point, but without DOS, the program is left only with BIOS functions, so at the very least int 0x21 could be called DOS kernel?

The BIOS isn't "kernel", it's "Basic Input / Output System".

Afaik, noone ever talked about a "kernel" in DOS back in DOS days. There were drivers, command line interpreter, system tools and TSRs, yes. But no kernel wherever.

Imvho, if you have not at least multiple address space or protection rings, the notion of a "kernel" becomes very hard to apply... if dos 'INT 21' is a kernel, then why BIOS isn't ? see my point ?

yeah, yeah.. whatever.. >:(
then my os doesn't have a kernel, and will never have. :'(

DOS is an operating system but not a kernel

yes, because it offer tools to manage tou system, do some editing or programming and lauches other programes

we can say the it is a standalone shell that offer some services (int 21 stuff)

why we can't say that it is a kernel : coz it doesn't manage memory/cpu/process/... resources, everything is done by the chipsets or by the BIOS.

ehh, it _does_ "manage" memory, it has functions to allocate/deallocate mem. as for cpu/process resources, why should it have that when it's desinged to be single tasking?

bubach wrote: ehh, it _does_ "manage" memory, it has functions to allocate/deallocate mem. as for cpu/process resources, why should it have that when it's desinged to be single tasking?

erm ... i thought it was using BIOS stuff to do that (I mean, there is no sp?cific structures to manages processes or resources .... I think) ::)

DOS had its own (undocumented) Memory Control Block and Program Segment Prefix (or whatever) to keep track of what's available and what's running.