The MS-DOS 6.0 DoubleSpace disk-compression utility executes some
floating point (non-integer math) calculations and therefore may
attempt to use a math coprocessor (80x87 or equivalent) if one is
present. If a machine's numeric processing system is substandard or
compromised due to the presence of device drivers, TSRs, or faulty
hardware, DoubleSpace may either report inaccurate time estimates for
completion or fail and generate the following errors:
- Run-time error
R6002 - floating-point support not loaded
- Run-time error
R6002 - floating-point error
- Error: R6101 - Floating Point Divide by Zero
MS-DOS 6.2 DoubleSpace does some floating point arithmetic, but it
does not attempt to use a math coprocessor even if one is present. This issue can occur in other programs that do not use the math coprocessor.
: In some cases, no runtime error(s) are displayed, and
DoubleSpace stops responding (hangs) early in the compression process.
: Since DoubleSpace has detected a potential problem with
your system, perform a full system backup or make sure you can fully
restore the machine from removable media before you proceed with these
Use the following steps to troubleshoot DoubleSpace R6002 errors:
- Turn the machine off, then turn it on again. Press the F5 key when
the "Starting MS-DOS" message appears to perform a "clean start." If
your machine requires that a device driver is loaded in the CONFIG.SYS
file to boot properly, press the F8 key to perform an "interactive
start" and load ONLY the device driver(s) required. If the machine is
rebooted at any point in the DoubleSpace process, be sure to use the
EXACT same clean or interactive start each time. If DoubleSpace
completes successfully, one or more of the device drivers or
terminate-and-stay-resident (TSR) programs that were bypassed are
probably causing the problem.
- If DoubleSpace still fails with the R6002 error, try adding the
following line to the CONFIG.SYS file using MS-DOS Editor or another
ASCII text editor:
Restart your computer to make this change take effect.
The SET NO87 environment variable instructs DBLSPACE.EXE not to use
the math coprocessor for floating-point calculations. The SET
statement should be placed in the CONFIG.SYS file, not the
AUTOEXEC.BAT file. (If DBLSPACE.EXE is restarted, it may not process
the AUTOEXEC.BAT file completely.)
It doesn't matter what you set NO87 to as long as the NO87 variable
is in the MS-DOS environment. For example, you could set NO87=NO or
NO87=MICROSOFT, and DoubleSpace would not use the math coprocessor.
To remove the NO87 environment variable, type "set no87=" (without
the quotation marks) at the MS-DOS command prompt and then press
- If DoubleSpace continues to fail, the coprocessor itself, the
coprocessor subsystem, or some other hardware component may be causing
In the case of 286, 386, and 486 SX machines, try removing the
coprocessor for testing purposes. If the machine is a 486 DX, verify
that the system's ROM BIOS is current and specifically designed for
use with a 486 DX, not a 386 or 486 SX.
In rare cases, incorrect CMOS or system board DIP switch settings,
faulty system RAM, or other hardware problems may cause R6002 errors.
Contact your system vendor or manufacturer to verify the CMOS and DIP
settings are correct. If the error persists, remove all system
components not absolutely required to operate the machine (optional
I/O adapters and so forth), use replacement parts (in the case of
system RAM), or have the machine inspected by a hardware repair
Article ID: 98345 - Last Review: December 23, 1999 - Revision: 1.0
- Microsoft MS-DOS 6.0 Standard Edition
Retired KB Content Disclaimer
This article was written about products for which Microsoft no longer offers support. Therefore, this article is offered "as is" and will no longer be updated.