Upgrading to Microsoft’s MS-DOS 5.0

Upgrading your old DOS operating system to Microsoft Corp.’s new MS-DOS 5.0 can be a quick and easy task--unless you have a hard disk larger than 32 megabytes.

One of the many advantages of DOS 5.0 over its most popular predecessor, DOS 3.3, is the ability to have hard disk partitions larger than 32 megabytes of storage space. With the old DOS, you had to divide larger hard disks into multiple partitions, no larger than 32 megabytes, and named Drives C, D, E and so on.

With 40-megabyte drives the norm these days and 100- to 200-megabyte drives commonplace, it is a lot nicer to have a single Drive C that incorporates all of the space on the hard disk of an IBM or compatible computer.

With MS-DOS 5.0, hard disks as large as 2 gigabytes (2,000 megabytes) can be given a single partition.

You have to perform the DOS 5.0 upgrade in several stages, however, to take advantage of larger partitions. (That’s true for any change you make in disk partitions, even if the changes create multiple drives of fewer than 32 megabytes each on the hard disk.)

Microsoft sells two versions of DOS 5.0--a standard version for new computers and a substantially cheaper upgrade version for existing computers. The difference is that the upgrade version can be run the first time only on a computer that is already running. The standard version is self-booting (starting), so it can be used out-of-the-box to start a computer that has no DOS on it.

I emphasize first time because you can use the DOS 5.0 upgrade version to create a standard, self-booting set of DOS floppy disks by typing the SETUP /F command. (See the Getting Started manual for detailed instructions.) Once you’ve done that, you have the same capability as the more expensive standard version.

If you’re going to replace an old hard disk with a new one, leave the old one running long enough to start the upgrade version, make a self-booting floppy DOS 5.0 disk set and test it by rebooting the computer from the floppy. Then you can turn off the computer and install the new drive.

By the way, the DOS 5.0 upgrade doesn’t care what kind of DOS you already have, as long as it is version 2.11 or later. It will upgrade Digital Research Corp.’s DR DOS or any other DOS, including another copy of DOS 5.0.

Even if you are just going to replace the DOS on your current hard drive, you should first make backup copies of the upgrade distribution disks, using the DISKCOPY or COPY *.* commands and then run the backup copy to make the self-booting DOS floppy set of disks.

Before installing it on your hard disk, be sure that you have backed up all of your files onto floppy disks. You can use your old DOS BACKUP command. The RESTORE command in DOS 5.0 will work with all previous versions of BACKUP.

But be careful. If you are going to eliminate partitions on a large hard disk, make sure that none of your directory names are duplicated on the various drives such as C, D, E, etc. The RESTORE command insists on putting files back into the same directories from which they were backed up, but not the same drives.

For instance, if you’ve got an old version of Windows software in a Windows directory on Drive D and the new version in a Windows directory on Drive C, you’ll end up with a big mess when both sets of files are restored to the same Windows directory on an enlarged Drive C. A disk management program like Xtree Gold is a big help in renaming directories.

Once all of your files are backed up, you install DOS 5.0 on your existing hard disk, leaving the existing disk partitions in place for the moment.

Next you need to verify that your system is working properly with the new DOS. Then back up the new DOS files by backing up the root directory and the DOS directory of Drive C. Otherwise the old DOS, not the new, will be restored onto the hard disk after you change its partitions.

Now for the scary part. When you repartition the hard disk, all of its files are destroyed. Anything that isn’t backed up will be lost forever.

Worse yet, if you haven’t made self-booting floppy disks of DOS 5.0 before you repartition, you won’t be able to start the computer again. And if your old DOS doesn’t recognize the new partition size, your whole day has been ruined.

OK, with backups complete and a DOS 5.0 self-booting floppy disk made and tested, you are ready to repartition the hard disk.

The program that does partitioning is called FDISK. Make sure that a copy of FDISK.COM and FORMAT.COM are on that new floppy boot disk you just made.

The first step in FDISK is to delete all of the logical drives in your Extended DOS partitions. Then delete the partitions. If you have several partitions, you have to do these steps for each. Finally, delete the Primary DOS partition.

Then you create a new Primary DOS partition. The program will ask if you want to use the entire disk for the partition.

Be sure to make the new partition “Active” as well, which is one of the options that FDISK provides. (If you don’t, you’ll get a mysterious message “No ROM Basic” later on when you try to boot the computer from the hard disk.)

With the new larger partition created, you’ll have to reboot with the DOS 5.0 floppy disk and format the new partition, using the FORMAT C: /S command.

If you have worked carefully, you’ll be rewarded with a better operating system and simplified hard disk file management. And if you are dismayed at how complicated this is, you are not alone. It is a real-life example of the old joke that you can’t get there from here. In its next upgrade of DOS, Microsoft should include a way to change partitions without destroying existing files.

Computer File welcomes reader comments but regrets that the author cannot respond individually to letters. Write to Richard O’Reilly, Computer File, Los Angeles Times, Times Mirror Square, Los Angeles, Calif. 90053.