Message-ID: From: Jonathan Tarbox - SSG To: "'Opendos AT mail DOT tacoma DOT net'" Subject: RE: [opendos] OpenDOS + Win95 w/FAT32? Date: Tue, 4 Feb 1997 15:57:54 -0500 MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: owner-opendos AT mail DOT tacoma DOT net Precedence: bulk Actually, you are still wrong but looking in the right direction, the superblock of the partition (say it was Ext2) would have the code to supply read-only support for it's FS, and the IFS line enabled the full read-write support for that and other IFS drives Example, (given that say HPFS and EXT2 IFS's were available) say I have a 1.6 gig boot drive and a 540 meg secondary drive.. I would want the 1.6 gig to have ANY filesystem but FAT, thus I would make the first disk with a 600 meg HPFS drive and a 1 gig EXT2 drive.. and possible FAT on the 540. Now using Linux's LILO I can boot from partition 1 or partition 2, the root blocks of each partition tell it how to at least read that file system used. Now in the OpenDOS CONFIG.SYS I would put two IFS lines, one for HPFS read/write support, and one for EXT2 read/write support... Without either the system could only read the HPFS, and could read/write the FAT on the second disk, but not be able to see the EXT2 since it doesn't know how to. But in that same exampe if I set it to load only the HPFS IFS it would be able to read/write to the HPFS and FAT partitions, but still not see/access the EXT2 partition. This may all sound reasonable, but I'm clueless on the actually programming of it.. But it should be able to work, since MS-DOS uses the same concept to the computer can see the system files on a FAT partition and Linux does the same with it's EXT2 partitions.. Jonathan Tarbox >---------- >From: Brian Dukes[SMTP:bdukes AT crox DOT demon DOT co DOT uk] >Sent: Tuesday, February 04, 1997 2:11 PM >To: opendos AT mail DOT tacoma DOT net >Subject: Re: [opendos] OpenDOS + Win95 w/FAT32? > >On Tue, 4 Feb 1997 16:34:24 +0000, you wrote: > >>Brian Dukes writes: >> >>> >Hmm, there is an interesting question. If filesystem support is loaded >>> >from CONFIG.SYS, and you want to have a 100% VFAT or even ext2fs >>> >filesystem, how will DOS be able to read the filesystem to find >>> >CONFIG.SYS so that it can load the file system driver that is required >>> >to read things from the filesystem that CONFIG.SYS is held on.... >>> >>> [SNIP] >>> >>> To be honest, I can't see that its going to be practical to move from >>> one IFS to another nilly-willy just by changing an instruction in the >>> CONFIG.SYS, >> >>Neither can I, that's not what I'm suggesting or indeed asking. >>However, there is a very good reason why you'd want to not build all >>filesystems into the DOS kernel. >> >>> for one the data stored under one IFS would be fairly incompatible >>> with the data stored under another .. and therefore, in order to >>> switch between filing systems you would probably ZAP the partition >>> first! >> >>You have totally missed by point. I was wondering out loud about the >>idea of not building the filesystem into the kernel of DOS but having >>the filesystem loaded from (for example) CONFIG.SYS. No-one shifts >>filesystem lightly and the fact that you will loose the data should be >>pretty self evident to anyone. >> >>Besides, I can't see your point. Even if they *do* ZAP the partiton >>(after taking a backup I'd hope), my question still stands. > > >Hmmm, I seem to have either gotten out of the wrong side of the bed >today or put my teeth in upside down. > >The original question/idea was to have an IFS= type command in >CONFIG.SYS ... all I was saying is that its not practical because its >too damn easy to change and to mess things up for one. > >I haven't missed your point Dave, I just didn't dwell on it. Your >point if I may paraphrase was that in order to read the IFS= >instruction from CONFIG.SYS, the boot process would need to know >something about the IFS in place in order to locate the config.sys and >start processing it! And what tells the boot process which IFS is >installed? > >The fact that these instructions were in the CONFIG.SYS would mean >that ANYONE would have the ability to alter the current IFS= without >any pre-thought! How many times have you had to go in and tidy up >someones CONFIG.SYS after they messed! What if someone took out the >IFS= line by accident then rebooted? > >I think we should look at operating systems like OS/2 or Linux to see >how they achieve the same goal ... personally I think the way Linux >works would be far better. > >Bri, hoping i've made myself a little clearer now > >