Making the best of DOS. (using DOS 6.0's DoubleSpace and MemMaker programs)
by Clifton Karnes

DOS 6 has caused quite a stir recently. Judging from the sales figures, it's clearly an upgrade that a vast number of DOS users want, but some people have reported problems, especially with two modules: DoubleSpace and MemMaker.

At COMPUTE, six editors have installed DOS 6. All have used MemMaker, three have installed DoubleSpace, and none have had any problems. But since problems have been reported, we advise caution. Here's some advice on how to save your system if you have problems with DOS 6's DoubleSpace or MemMaker.

First, MemMaker and DoubleSpace are complex applications. If you're not familiar with drive letters, paths, and memory addresses, don't install these programs yourself. Get a knowledgeable friend or co-worker to help you.

The best defense is a recent backup. So before you do anything else, make a backup of your hard disk.

After you make the backup, restore a few files to make sure the backup is reliable. This is extremely important. If you need to restore later, you want to know how to do it, and you want to be sure your backup is OK. Now, make a copy on floppies of the software you used to make the backup, put the backup and the software aside, and relax.

Let's tackle DoubleSpace first. This utility compresses and decompresses data on the fly and, for all practical purposes, nearly doubles the size of most hard disks. It will also slow down some 386 machines. We recommend at least a 25-MHz 386SX with a minimum of 2MB RAM (so you can run SMARTDrive or another disk cache) for installing DoubleSpace.

The first step is to install DOS 6, if you haven't already done so. Do this, and use your system for a day or two before you try installing DoubleSpace or MemMaker. After you and your system have adjusted to DOS 6, defragment your hard disk.

Next, before you run DoubleSpace, make sure you're also running any software that normally creates virtual drives on your system (CD-ROM or network drives). This will help DoubleSpace choose a drive letter for its physical drive that won't conflict with your usual environment. At COMPUTE, we've had no problems running SMARTDrive when installing DoubleSpace, but it seems wise to disable SMARTDrive for the installation. Creating your DoubleSpace volume may take several hours, so be prepared.

Hopefully, everything will go smoothly. After the installation, you should be able to run SMARTDrive again without problems. If you do have problems, refer to the paragraph after the next.

Consider the next month a DoubleSpace-testing period. Back up your important files every day and look for any signs of trouble on your compressed volume. At least twice a day, run DBLSPACE / CHKDSK on the compressed volume to test it for integrity. If you notice lost clusters, don't panic, Try disabling SMARTDrive's write-caching feature with the line smartdrv i, where i is the letter of your physical drive. (You can easily reenable write caching with the line smartdrv i+.)

If you do have severe problems with your DoubleSpace volume, you can recover by following these steps: Install DOS 6 on a freshly formatted floppy, boot from the floppy, reformat your hard disk using the /s switch, reinstall DOS 6 on your hard disk, and restore your backup. If you want to go back to a previous version of DOS, install that version on the formatted floppy and then on your hard drive.

Now to MemMaker. First determine whether you need to run MemMaker at all. Do you have DOS programs that run out of memory? If you don't or if you're using Windows almost exclusively, you probably don't need to load device drivers and TSRs high.

If you do need to load some programs into upper memory, do it manually first. Load the largest drivers first and use the keywords DEVICEHIGH in CONFIG.SYS and LOADHIGH in AUTOEXEC.BAT. To see how much memory you've freed, use the command MEM/C I MORE.

Experiment with the order of the programs, too. This can make a big difference. If you can free enough memory this way, don't bother running MemMaker. If you can't free enough conventional memory, you'll want to run MemMaker, but first, do this: Create a subdirectory off your root directory called BACKUP and copy your CONFIG.SYS and AUTOEXEC.BAT files into it. (If you're running Windows, it's a good idea to copy your WIN.INI and SYSTEM.INI files here, too.) If there's trouble with MemMaker, you'll still have your original copies.

Now, run MemMaker and follow the onscreen instructions. After MemMaker is finished, check your memory situation again. If MemMaker garnered more conventional memory for you, fine. If it didn't, go back to your backups. If MemMaker locks up when it's running, reboot your computer and bypass your CONFIG.SYS file by pressing F5 when you see Now starting MS-DOS . . . . Next, copy your backups and reboot your computer.