Date: Fri, 18 Apr 1997 20:27:50 +0200 (MET DST) From: Mark Habersack Reply-To: grendel AT hoth DOT amu DOT edu DOT pl To: Lorier cc: Matthias DOT Paul AT post DOT rwth-aachen DOT de, opendos-developer AT delorie DOT com Subject: Re: Usage of directory entries In-Reply-To: Message-ID: Organization: PPP (Pesticide Powered Pumpkins) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Precedence: bulk On Fri, 18 Apr 1997, Lorier wrote: > >and Linux - a not so trivial task (probably much harder than just emulating > >DOS). This approach has several advantages, one of them being 100% > >compatibility with DOS software. > > Yeah, Linux 3.0.0 is supposedly going to do Dos apps natively isn't it? :) Yeah ;-)) > Yeah, a proxy would be nice and probably be done... It'd just be subtly more > difficult than anyone expects :) True... sand but true... > >> How does the DRIVER.SYS support work? I've heard lots of references but > >> phyiscal information has come forward :) > > >There are several in 0x2F calls that allow you to insert your driver into > >chain of block device drivers. Every call to such a device is redirected to > >your driver which handles just the standard set of IOCTL calls. The info > >should be in INTRLIST, but should it not be there, I can write a short > >resume. > > Hmm, I'll have to get a uptodate version of that. :) You should! > >> Hmm, a CD-ROM is readonly (like a network drive), is Changable (like a > >> network drive being mapped in vs a HDD which never changes).... The other > >> way of handling a CDROM would be like a big floppy... > > >And that would be much more natural, wouldn't it? > > It would be, but the "natural" way is almost never the way its done, You > should know that by now! :) Yeah ;-))) > >> DRVSPACE/DBLSPACE are a bit of a hack, but I assume they hook in, they >> > appear to do it before CONFIG.SYS is loaded. > >There is a code inside the M$ dos kernel which looks for these files and > >loads them as a part of the system kernel standard device drivers set. It's > >being done by IO.SYS. At least I think so. > > Hmm... when's this source available? :) Of M$-DOS??!?!? Are you kidding?!?!? It's TOP SECRET!!! ;-))) > >You don't need it at all! Linux doesn't need to! The only think to know is > >A location of the superblock (or in DOS nomenclature, bootblock) which > >contains the necessary information to load OS kernel and find the boot-up > >of drivers. > > Yeah, the BootSector looks for the root directory (it could look anywhere) > for information to load the OS Kernal(io.sys), but loading the drivers out > of Config.Sys requires *reading* config.sys :) And what stops us from allocating some space before the root dir (which is *always* at the partition start) and put all the configs there - in linear way, sector by sector - config.sys first, others following (autoexec.bat may be stored the usual way. The config.sys in superblock would just install a driver for the root FS. The config would store entire allocation map of the device driver in logical HDD coords (as related to the partition in question) - clean and easy, isn't it? All the other drivers would be loaded from the "normal" config.sys > >chose the better product. Here it's only a matter of marketing, > >unfortunately... > > Linux marketing has become a success and a 1/2, Word of mouth appears to be > working wonders... And some good press... Yes, that will be a success!