Date: Tue, 11 Mar 1997 09:58:50 -0700 (MST) From: Terry Lambert <terry@lambert.org> To: chuckr@glue.umd.edu (Chuck Robey) Cc: terry@lambert.org, joerg_wunsch@uriah.heep.sax.de, FreeBSD-hackers@freebsd.org Subject: Re: pcvt/132 columns Message-ID: <199703111658.JAA25415@phaeton.artisoft.com> In-Reply-To: <Pine.OSF.3.95q.970310201236.6130B-100000@thurston.eng.umd.edu> from "Chuck Robey" at Mar 10, 97 08:14:20 pm
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> > As to your question, it's a non-sequitur... DOS supports .EXE files, > > but BIOS POST does not. You also presume (incorrectly) that DOS is > > an OS. > > Terry, I may not think very highly of DOS, even given the context in > which it was written, but it is an OS, at least I maintain it is. Could > you defend that remark? It is a disk loader and a non-reentrant real mode interrupt handler; I know this is already common knowledge... It does not have these OS features: o Multitasking (an OS which can not multitask is a loader, not an OS) o Resource tracking o Memory (the big one) o Open file handles o Anything not hung off the PSP o Memory protection o System reentrancy (there is a single BIOS call stack for most BIOS calls, which is why they are not available to TSR's that don't supply their own system stack) o Fault recovery (pretty obvious it can't be done without resource tracking and memory protection, etc.) In addition, an OS enables software engineering. I could go on for days about how DOS fails in this regard. Regards, Terry Lambert terry@lambert.org --- Any opinions in this posting are my own and not those of my present or previous employers.
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