From: broeker AT acp3bf DOT knirsch DOT de (Hans-Bernhard Broeker) Newsgroups: comp.os.msdos.djgpp Subject: Re: DJGPP Support Dual Processor? Date: 27 Sep 1999 14:50:04 +0200 Organization: RWTH Aachen, III. physikalisches Institut B Lines: 27 Message-ID: <7snp5s$l6f@acp3bf.knirsch.de> References: <199908181620 DOT MAA28656 AT delorie DOT com> <7sbk10$6n5$3 AT lure DOT pipex DOT net> NNTP-Posting-Host: acp3bf.physik.rwth-aachen.de X-Trace: nets3.rz.RWTH-Aachen.DE 938436610 15687 137.226.32.75 (27 Sep 1999 12:50:10 GMT) X-Complaints-To: abuse AT rwth-aachen DOT de NNTP-Posting-Date: 27 Sep 1999 12:50:10 GMT X-Newsreader: TIN [version 1.2 PL2] To: djgpp AT delorie DOT com DJ-Gateway: from newsgroup comp.os.msdos.djgpp Reply-To: djgpp AT delorie DOT com Eli Zaretskii (eliz AT is DOT elta DOT co DOT il) wrote: > On Wed, 22 Sep 1999, Duncan Coutts wrote: > > DJGPP runs using DPMI which has many nice features such as memory > > protection, virtual memory, but it is still Dos single tasking. > There's nothing inherently single-tasking about DPMI. As a matter of > fact, Caldera's DR-DOS already supports multi-tasking with its DPMI > host. It's even stronger than that: if memory serves, DPMI was invented to allow multitasking, in the first place. DPMI was designed as the inner core of Windows 3.x: it provided the multitasking machinery needed for Windows to be able to support stuff like multiple simultaneous DOS boxes in virtual machines, and the task switching between Windows apps. In a nutshell, Windows 3.1 is a central DPMI server running multiple clients, one of them being the GUI itself. AFAIK, many of the limitations found in DPMI, as compared to its predecessor VCPI, are mandated by exactly this support for multi-tasking. It offers less control over the virtual memory hardware and over protection levels because in multi-tasking, allowing such control would be disastrous. -- Hans-Bernhard Broeker (broeker AT physik DOT rwth-aachen DOT de) Even if all the snow were burnt, ashes would remain.