ACC: Memory or Disk Space Problems Using MS-DOS 6.0

• Microsoft Access versions 1.0, 1.1, 2.0

SYMPTOMS

Advanced: Requires expert coding, interoperability, and multiuser skills.

When you are working in Microsoft Access, you receive an error message stating that you are out of memory. The message may be accompanied by other messages stating that you have insufficient space in your TEMP directory, or that you have insufficient disk space.

CAUSE

If you are running MS-DOS 6.0, these error messages may be due to the way the memory on your computer is configured, or to the use of file compression on your hard disk.

RESOLUTION

Check each of the items described below and make any necessary changes.

MORE INFORMATION

DoubleSpace

MS-DOS 6.0 includes its own disk compression program called DoubleSpace. This program makes your hard disk seem larger than it actually is by compressing the files on the disk. The DoubleSpace program has an option to let you specify the compression ratio that will be used. You can increase the default compression ratio that DoubleSpace sets up, but increasing this ratio usually does not result in additional usable space on your hard disk.

The average file compression ratio is about 1.5 to 1. With this ratio, a 20 MB disk could actually yield about 30 MB of usable space. If you set the DoubleSpace compression ratio to 16 to 1, the disk will show about 320 MB of usable space, but will still only actually provide about 30 MB of space.

If you have set up a high compression ratio, the hard disk may show far more free space than can actually be used. If you attempt to install Microsoft Access to such a disk, you can run out of disk space during the installation process.

If you are using DoubleSpace, you can check your compression ratio by typing "dblspace" (without the quotation marks) at the MS-DOS prompt. From the Drive menu, choose Info. If the compression ratio is set larger than the estimated compression ratio, choose Ratio and set the new estimated compression ratio to match the estimated compression ratio. This will give you the most accurate information about the amount of actual usable free disk space.

MemMaker

MS-DOS 6.0 includes a memory-management utility called MemMaker that helps optimize the configuration of your computer's memory. This utility may alter two commands that can affect Microsoft Access.

The first item is the FILES=<xx> line in your CONFIG.SYS file. Microsoft Access requires that <xx> be 50 or greater, but the MemMaker utility sometimes sets this line to less than 50. Check your CONFIG.SYS file with any text editor and make sure that the line reads FILES=50.

The second item is the DEVICE=EMM386.EXE line in your CONFIG.SYS file. The MemMaker utility sometimes adds the HIGHSCAN parameter to this line, but this parameter can cause conflicts on some computers. You may want to remove this parameter and any i=<xxxx>-<xxxx> parameters, and make sure that the NOEMS switch is present. For example, the line might read DEVICE=EMM386.EXE NOEMS.

Undelete

If you are running the Delete Sentry option of the Microsoft Undelete program, your hard disk may show an incorrect amount of disk space. This is because Delete Sentry makes a hidden copy of all deleted files. These hidden files are stored for seven days, and are not counted when you use the DIR command to show available disk space.

If you run out of disk space when you are installing Microsoft Access, use the DIR /A command to show all files. This command will show you any hidden files, including hidden files stored by the Delete Sentry. You can delete the hidden files to free up disk space, but these files will no longer be guaranteed to be recoverable. \* \* If you run into unusual problems, one means of troubleshooting may \* be to switch the SET TEMP= statement to point to the uncompressed \* drive.

REFERENCES