On Mon, Mar 30, 2015 at 8:37 PM, Rugxulo <rugx...@gmail.com> wrote: > On Mon, Mar 30, 2015 at 6:59 PM, dmccunney <dennis.mccun...@gmail.com> wrote: >> >> Win98 is a protected mode OS, and DOS serves as a real mode >> loader. Once Win98 is up and running, DOS is out of the loop, and >> Win98 *is* the OS. > > If DOS is "out of the loop", then why are you still able to run DOS > files (.COM, .EXE, .BAT)?? Does Windows emulate it? Or is it really > just calling back to DOS itself? What is responding to the int 21h > kernel calls?
<sigh> This is OS development 101. Do you think a new OS intended as a followup to an existing product throws out the baby with the bathwater and does everything differently, so existing apps won't run? It includes it. Part of the problem for Windows 9X was maintaining backwards compatibility. It needed to be able to run old 16 bit DOS apps as well as apps written for Windows. Batch files were interpreted by COMMAND.COM, and COMMAND.COM was available. COM and EXE files were programs run under the OS, and Windows supported the system calls those programs used. There would be no need to call the underlying DOS, because the required stuff was part of Win98. I repeat, DOS was a real mode loader, whose function was to load Windows. Once it had, Windows took over. > For something like Windows XP, then definitely DOS isn't there, it's > emulated in NTVDM. But to pretend that Win98 runs all by itself > without DOS is a bit of a stretch. No, it isn't. Win98 needed DOS to load it. That's it. And that requirement is a consequence of X86 segmented architecture with real mode and protected mode. The machine started in real mode, and needed a real mode loader to load the protected mode OS. NT finally removed that requirement and could be booted without DOS, but the issues of maintaining backwards compatibility made getting there a one step at a time process. > Hasn't this already been discussed to death before? MS was later sued > (and lost) for illegally bundling their DOS with their Windows. I I don't recall that, and rather doubt there was anything illegal about it. MS owned MSDOS and Windows, and could use them and bundle them as they desired. > think Caldera (or Lineo or whatever they were eventually called) even > legitimately proved that they could boot Win95 atop DR-DOS. Win95 and > MS-DOS weren't bundled for technical reasons, only marketing reasons. > It was much closer (technically) to Windows 3.1 than most people > realize. You could indeed boot Windows atop DR-DOS, but why bother? You would only be likely to do so if you already ran DR-DOS and wanted to run Windows too. And remember, DR-DOS began because DR had customers wanted a ROMmable version of DOS for embedded applications. MSDOS at the time was not architected to provide the required separation between code and data, and could not be embedded in ROM. Offering DR-DOS as a consumer product was a later development. Most folks who got Windows got it as the next step beyond DOS, and wanted to simply install it and run it. They did not want to first install a flavor of DOS and then install Windows on top of it. And then, as now, people generally bought Windows PCs with the OS already installed by the vendor. I remember the early days when the PC was first out, and MSDOS/PCDOS, Digital Research CP/M 86, and the UCSD P-system were all fighting for a chunk of the PD market. MS won. The others lost. Deal with it. > I'm not sure why they bothered. Obviously NT had much higher > requirements back then (mid '90s), e.g. 16 MB minimum (and 80 MB disk > space?) while Win95 could (very slowly) run atop a 4 MB 386. They > wouldn't even fix NTVDM bugs for Quake (from id Software, compiled for > DOS via DJGPP) because "NT wasn't for games"! But that's all lost to > the sands of time now that XP fully replaced Win9x for "home" users. > (2000 first added Win9x-era LFNs and FAT32, but even that wasn't yet > targeted at home users, hence we were only offered Windows ME.) MS was focused on business users (and still is - Win10 is very much geared to the Enterprise market ). NT was aimed at the business desktop. Part of the problem from an OS perspective was that games for platforms like DOS assumed they were the only program running and owned the hardware, and would write directly to the hardware to get performance. That's a no-no in a multitasking OS. It took a while before MS realized that gaming was market and money could be made in it, and did things like implement Direct-X to provide OS modulated access to the hardware that games needed. ______ Dennis https://plus.google.com/u/0/105128793974319004519 ------------------------------------------------------------------------------ Dive into the World of Parallel Programming The Go Parallel Website, sponsored by Intel and developed in partnership with Slashdot Media, is your hub for all things parallel software development, from weekly thought leadership blogs to news, videos, case studies, tutorials and more. Take a look and join the conversation now. http://goparallel.sourceforge.net/ _______________________________________________ Freedos-user mailing list Freedos-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/freedos-user
