7 ms·
Decades ago, I wrote a very simple operating system. It was an MSDOS EXE that when run, took over all available memory and rewrote all the interrupt vectors. Yo
by billpg 9y ago
Decades ago, I wrote a very simple operating system. It was an MSDOS EXE that when run, took over all available memory and rewrote all the interrupt vectors. You couldn't "exit" back to DOS because by then it had gone - you could only power-cycle the machine and let MSDOS boot up normally.
Because it launched from DOS, many insisted to me it wasn't really an operating system. What was it if it wasn't an operating system?
- jacquesm 9y agoAn operating system exports abstract facilities such as hardware, storage and other useful bits to other software we call applications. How you get there doesn't matter, what you do once you are there makes the difference. So I guess both you and your friends were wrong.
- gpderetta 9y agoYou could think of MSDOS as a glorified bootloader...
- laumars 9y agoTo be fair, Windows used MS DOS as a bootloader for decades.
- a-priori 9y agoOnly the consumer line that ended at Windows ME. The Windows NT line, which subsumed the consumer line starting at Windows 2000, always used its own bootloader. So has Windows CE.
- laumars 9y agoWell yes, clearly. That's why I used past tense rather than saying "still uses" and why I didn't mention NT nor CE (I also didn't mention Microsoft BASIC nor Xenix - just so you know they didn't use DOS as a bootloader either :P). I figured the context was obvious given the audience of HN, but clearly not. Anyhow, my point was just to reinforce the GP's point that it's ok to think about DOS as a bootloader because Microsoft have done exactly this themselves.
- bogomipz 9y agoSure that's what the splash screen was actually hiding right?
- laumars 9y agoThe splash screen would start when win.exe (or was it win.com? I forget now) started. So you'd catch a glimpse of DOS before the splash. This was back in the 9x era though. Back in the days of 3.x I think it was still pretty common to boot to DOS and then start Windows manually.
- isostatic 9y agoYes in dos/win3.1 you might have win.exe at the end of autoexec.bat, you might have dosshell in there. You might have some Novell "login.exe" instead. Or maybe it was good old command.com. Win95 had a full screen splash which was an RLE file called logo.sys, loaded by the win95 boot process. I don't think autoexec even ran under 95/98/me. I'm sure that Wikipedia will have the full history though.
- laumars 9y agoAutoexec did run on Win95. I remember spending hours tweaking it back in those days. Though I think it was mainly used for DOS programs and maybe some environmental variables (eg for JAVA). I remember writing my own logo.sys boot splashes. If I recall correctly they were just bitmaps with a couple of values altered in a hex editor to define which sequence of colours (in the colour palette) to animate.
- gmueckl 9y agoNovell Netware actually used DOS as a glorified boot loader. Also, there was at a point a small DOS program that acted as a Linux boot loader. It brought you from a DOS prompt straight to a Linux virtual terminal without reset. I think SuSE shipped it for a while as an alternative means to launch their setup, but memory fades.
- bri3d 9y agoloadlin.exe! It ran under memory-unsafe Windows (95/98/Me) as well.
- mmphosis 9y agoAccording to the File Manager the linux kernel is a DOS/Windows program: Name: vmlinuz-* Kind: DOS/Windows executable