Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!wuarchive!texbell!rutgers!aramis.rutgers.edu!athos.rutgers.edu!rbthomas From: rbthomas@athos.rutgers.edu (Rick Thomas) Newsgroups: comp.os.minix Subject: Re: switching file systems Message-ID: Date: 7 Oct 89 06:47:31 GMT References: <24987@louie.udel.EDU> <2453@ucsfcca.ucsf.edu> <1989Oct5.181148.8229@utzoo.uucp> <3544@ast.cs.vu.nl> Organization: Rutgers Univ., New Brunswick, N.J. Lines: 40 > From: ast@cs.vu.nl (Andy Tanenbaum) > The real reason for decoupling, however, is to make the IBM and Atari > disks exactly the same (little endian). On an Atari, one would read in > an inode, fumble with it a little, and get a proper in-core inode structure > with the same 32-bit addresses as on the PC. I think that only 6 routines > would be needed: > read and convert an inode > deconvert and write an inode > read and convert a bit map > deconvert and write a bit map > read and convert a superblock > deconvert and write a superblock > > I don't think these routines will be more than a page or two. Also, those routines could be used -- line for line, probably -- in the applications programs (like fsck and mkfs) that need to know about physical file system formats. Thus finessing (most of) the problem of having lots of commands that have to be rewritten to accommodate file-system-switch. Adding new file-system types then becomes a trivial task of relinking with an updated library. (-; Well, actually it depends a lot on how bizarre the new files system type is, but you get the idea... Some of Henry's suggestions sounded pretty bizarre, even to me. Can you imagine what would happen if you did "fsck /dev/proc" ? ;-) (It would be nifty to be able to access a DOS disk from Minix via regular Minix commands, as Henry suggested. No need for dosread/write/dir ever again!) (Of course, if this discussion is starting to sound familiar to you, all of it has been said before with regards to BTL Research's V8 UNIX.) Rick -- Rick Thomas uucp: {ames, att, harvard}!rutgers!jove.rutgers.edu!rbthomas internet: rbthomas@JOVE.RUTGERS.EDU bitnet: rbthomas@zodiac.bitnet Phone: (201) 932-4301