Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84; site phri.UUCP Path: utzoo!utcs!mnetor!lsuc!pesnta!phri!roy From: roy@phri.UUCP (Roy Smith) Newsgroups: net.unix Subject: Re: UNIX coresident with VMS Message-ID: <522@phri.UUCP> Date: Fri, 11-Oct-85 21:30:07 EDT Article-I.D.: phri.522 Posted: Fri Oct 11 21:30:07 1985 Date-Received: Sat, 12-Oct-85 14:19:27 EDT References: <5732@tekecs.UUCP> <10605@ucbvax.ARPA> Organization: Public Health Research Inst. (NY, NY) Lines: 28 Keywords: dual-purpose file system > >Is it possible to have UNIX and VMS coresident on the same physical disks? > > It should be possible to do this, provided [...] UNIX does not tamper with > the VMS partitions of the disk, and that VMS does not tamper with the UNIX > partitions of the disk. I remember an example of a program which was both legal Pascal and legal C (in SIGPLAN notices, I think). The trick, of course, was to hide the C code inside of Pascal comments, and the Pascal code inside of C comments, sharing code whenever compatible syntax made that possible. Any dual Unix/VMS wizard (do such creatures exist?) want to try building a disk which has both a valid Unix and a valid VMS file system *on the same partition*? To be fair, both file systems can be read only. Presumably you would hide the Unix inodes and directories in the VMS data files and vice versa (I know VMS doesn't have inodes, but it must have something like them). Competition for the lowest numbered physical blocks (boot block, Unix super block, free list, etc) would be the real tough part. Brownie points if the two file systems contain the same text file using the same physical data blocks. Talk about portability; imagine using the same file system image to distribute software to both Unix and VMS sites! -- Roy Smith System Administrator, Public Health Research Institute 455 First Avenue, New York, NY 10016