Microsoft KB Archive/37245

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Strange Behavior Using the SELECT Utility on 3.5-Inch Drives PSS ID Number: Q37245 Article last modified on 02-23-1993 PSS database name: O_MSDOS



The information in this article applies to:
- Microsoft MS-DOS operating system version 4.00


This article describes problems you may experience with the MS-DOS Version 4.00 SELECT utility. These problems are caused by systems that have 3.5-inch drives that are not properly recognized by their ROM BIOS. This article also shows a method to work around this problem.

More Information:

The SELECT utility of MS-DOS Version 4.00 behaves slightly differently, based on the media of the distribution disks. If you use the 5.25-inch 360K disks, there is an INSTALL disk and a SELECT disk, among others. On the 3.5-inch 720K distribution disks, both of these disks are combined into a single disk. When the SELECT utility is looking for the files on these disks, it checks the media. If the drive being used for the installation is a 360K disk, the SELECT utility prompts you to insert the SELECT disk. However, if the drive being used for the installation is a 720K 3.5-inch drive, SELECT realizes that both of these files have been consolidated onto the current disk.

The SELECT utility works correctly in normal situations; however, you may experience some problems with systems that do not fully support 3.5-inch drives.

Systems that don’t fully support 720K 3.5-inch drives are usually due to an improper mixing of hardware and ROM BIOS, such that the ROM BIOS does not fully support the abilities of the hardware (the 3.5-inch drive). The results of such improper ROM BIOS and hardware vary, but the ROM BIOS usually assumes that the 3.5-inch drive is actually some form of 5.25-inch drive, usually 360K.

When the SELECT utility is run on such systems, it wrongly determines (through no fault of its own) that the drive being used for the installation is a form of 5.25-inch media, and thus prompts you to insert the SELECT disk. This is where the problem occurs, because the contents of the 5.25-inch media’s SELECT disk are contained on the 3.5-inch media’s INSTALL disk, and no disk switch needs to occur.

To work around this problem, you need to get the system to properly determine what form of media the installation disk is. (The PROPER solution is to upgrade the ROM BIOS to properly recognize this 3.5-inch drive.) If you are using MS-DOS, you can use the DRIVPARM command. Refer to the “Microsoft MS-DOS User’s Reference” for more information on the DRIVPARM command. The following is an example of how to use the DRIVPARM command in the file CONFIG.SYS to set up Drive A (physical drive 0) to properly behave as a 3.5-inch drive:


The /I option is new to MS-DOS Version 4.00, and improves the power of the DRIVPARM command, making 3.5-inch drives work better than they did in previous releases of MS-DOS.

Because this takes place only at boot time, it is necessary to edit the CONFIG.SYS of the boot disk. You should make a backup copy of the INSTALL distribution disk, then update the CONFIG.SYS of this disk with a DRIVPARM line for each 3.5-inch physical drive on the system that is not fully recognized by the ROM BIOS. Repeat the procedure for any installed versions of MS-DOS.

Additional reference words: 4.00 noupd

Copyright Microsoft Corporation 1993.