From: "smile773" Newsgroups: comp.os.msdos.djgpp References: <394d3bd4$1_1 AT news DOT siscom DOT net> Subject: Re: DPMI (How it works in simple terms, where to find) Lines: 22 X-Priority: 3 X-MSMail-Priority: Normal X-Newsreader: Microsoft Outlook Express 5.00.2615.200 X-MimeOLE: Produced By Microsoft MimeOLE V5.00.2615.200 Message-ID: Date: Tue, 20 Jun 2000 07:32:07 GMT NNTP-Posting-Host: 12.72.5.209 X-Complaints-To: abuse AT worldnet DOT att DOT net X-Trace: bgtnsc06-news.ops.worldnet.att.net 961486327 12.72.5.209 (Tue, 20 Jun 2000 07:32:07 GMT) NNTP-Posting-Date: Tue, 20 Jun 2000 07:32:07 GMT Organization: AT&T Worldnet To: djgpp AT delorie DOT com DJ-Gateway: from newsgroup comp.os.msdos.djgpp Reply-To: djgpp AT delorie DOT com Chris DPMI (DOS Protected Mode Interface) is a program interface that allows an application program running under the Disk Operating System (DOS) to take advantage of a DOS extender, which lets the program address a larger range of random access memory (RAM) than the 640 kilobytes to which PC programs are basically constrained. To use the extender, the program must be in "protected mode," a mode that ensures that program requests are not allowed to access certain portions of "protected" memory. (Programs running in the alternative "real mode" have access to all portions of memory, including system data.) Some programs are real mode (usually the older ones but not less important) and they don't behave themselves in a protected mode setting and are quickly terminated for taking matters into thier own hands. They are the progeny of the old 8086 architecture. We see many linux utilities ported to dos despite the frustration of working without documentation. I wonder if backward compatability of issues like pmode development is less advantageous than Dosemu development with the documentation.