rommel@lan.informatik.tu-muenchen.dbp.de (Kai-Uwe Rommel) (09/08/89)
Some days ago I wrote, that I have written a dualboot program for DOS and OS/2 on the same partition. I got three requests for it. Please wait some more days for answer because I want to write some instructions for using the program before I post it. One of the people who asked for the program, asked if it won't be easier to create two independent partitions on the disk, one for DOS and one for OS/2. I think this question may be of more general interest, so I wrote this article. Generally, it is possible to create different partitions for the two operating systems - for disk wizards. But there is a problem to get it running and there are disadvantages of this method. Both DOS and OS/2 have exactly the same file system structure (at least since DOS 4.00 is available, if you think about >32M partitions). To install DOS or OS/2 on a harddisk, you create usually a bootable root partition and perhaps an extended partition (disk >=40MB and DOS 3.30). The FDISK programs coming with DOS or OS/2 don't allow to create more than one root partition on a single disk. To create more than one, you have to change the type of the partition created first manually, using Norton Utilities or an adequate software, to an unknown value for DOS. Then you can create a second one. To change the active partition, i.e. the one from which is booted, you have to change the active flag and the types of both partitions as well. That means, this doesn't save you from writing some kind of dual booting software. The disadvantages of this methods are clear. It makes data transfer between the two boot partitions not very easy. Another point is, that DOS and OS/2 share some software: - The C, PASCAL and FORTRAN compilers from Microsoft and their Macro Assembler run on both systems (same executables !). - Multiplan 4.0 and Word 5.0 run on both systems too. - The DOS and OS/2 versions of dBASE IV can share at least their data files. - Many PD and other utility programs are available as bound executables, that run on both systems. If you don't want to duplicate the programs on the disk and want some file transfer between DOS and OS/2, you have to create a third, shared extended partition. And I think three partitions make the disk organization somewhat unflexible. Kai Uwe Rommel, Munich