NEW "fake drives"!

Posted on 1998-01-16
Medium Priority
Last Modified: 2013-12-16
I have just re-installed my win95 on my notebook, but two extra drives have now appeared!
My computer is a Pentium 150 MHz, 32 MB RAM, 2 GB HD, external SCSI CD-R and HP 4p (also SCSI).

They cannot be accessed and are called "non-permanent drive" (translated from danish).
I now have drive "a,c,d,e,f,g" where "d" and "e" are the ones. My "a" is discdrive, "c" is main drive, "f" is CD-ROM and "g" is SCSI CD-R.

I have seen that other people have the same problem but doesn´t get an answer.

Before i re-installed win95 i used the command "format c:" to format my HD. Can it have anything to do with the formatting?

The drives is not listed in Control Panel/System/Device Manager/Disk Drives. The only place i can see them is in explorer and My Computer and in DOS.

FDISK only shows my "C:" drive.

What about PCMCIA-cards, can they cause the trouble? I have got a Psion Dacom PCMCIA-modem.

If you enter Control Panel/System, and select the last tab which sayssomething about the computers ressources, there are two notes in the white area. They say that drive d: and e: "uses MS-DOS comperative-mode" (not sure if right translation)

The reason that i re-installed win95 is because of the eternal bugs in win95 that causes it to hang or crash, which it allmost did every 20 minute!

I hope you are able to help:)

                                             Jakob Adeltoft

Question by:Jakob Adeltoft
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Accepted Solution

smeebud earned 800 total points
ID: 1753421
Phantom Drives. Please read carefully.
Article ID: Q138899 The information in this article applies to:

The Ios.log file is created by the I/O Supervisor (IOS) as it attempts to determine whether or not it can safely install 32-bit drivers. Windows 95 creates an IOS.LOG file in the Windows directory if any drives are using MS-DOS Compatibility mode.

MORE INFORMATION ================

The Ios.log file has several sections, each of which is described below.


INT 13 - Interrupt 13 is the hard disk drive interrupt. When the operating system needs to access the hard disk, it issues an INT 13 call. This typically is serviced by the BIOS, but device drivers and TSRs may intercept the request.

INT 4B - Interrupt 4B is the interrupt used by Common Access Method (CAM) versions 1.9 and earlier.

INT 4F - Interrupt 4F is the interrupt used by Common Access Method (CAM) versions 2.0 and later.

Hook - Hook is a synonym for "intercept." For example, an "INT 13 hooker" is a device driver or program that intercepts all INT 13 calls. The reasons for doing so may be innocuous (a screen saver), beneficial (a device driver that enables you to access a device that otherwise would be inaccessible), or harmful (a virus).

TSR - (Terminate and Stay Resident) - A program, typically loaded in the Autoexec.bat file, that loads itself permanently into memory.

Unit number - A unit number is a drive letter converted to a number. Drive A is unit number zero, drive B is unit number one, and so on. These are sometimes referred to as "logical units," which should not be confused with SCSI logical unit numbers (LUNs).


The first section of the Ios.log file summarizes IOS takeover. This section may contain none, one, or more of the lines listed below in the order in which they normally appear.

Incompatible driver xxxxxxxx. Load FastDisk for driver if possible

The indicated device driver hooks INT 13 in a manner that Windows 95 has considered unsafe, but which would become safe if a Windows 3.1 FastDisk driver were installed.


This usually means that the Dosdrv.sys or Pcidrv.sys driver is in the Config.sys file, probably as a driver for a Promise Technologies caching controller, but the corresponding 32-bit FastDisk driver is not loaded.


To resolve this message, obtain the appropriate 32-bit FastDisk driver, copy it to the Windows\System folder, and then add the following statement to the [386Enh] section of the System.ini file:


Error issuing int 25h: unit nn, error nn

IOS performed an INT 25h (disk read) request to determine which physical device is associated with unit number nn, but the device driver returned an error code. Furthermore, the specified driver does not have the "non_disk" attribute in the Ios.ini file.

Possible error codes include:

80 device failed to respond (timeout) 40 seek operation failed 20 controller failed 10 data error (bad CRC) 08 DMA failure 04 sector not found 02 bad address mark 01 bad command


This message is often caused by device drivers and TSRs that create disk drives that do not correspond to physical devices. The Microsoft Interlnk program is one example.


Remove any device drivers and TSRs that provide "phantom" disk drives, or add them to the Ios.ini file as "non_disk" drivers.

Unsafe driver xxxxxxxx controlling unit nn

IOS has determined that the indicated device driver is unsafe due to the way it manages unit nn.


Remove the indicated device driver from the Config.sys and Autoexec.bat files.

Monolithic driver xxxxxxxx controlling unit nn

IOS is unable to communicate with the indicated device driver in order to take over its functionality because the device driver does not support ASPI or CAM or INT 13. Furthermore, the specified driver does not have the "monolithic" attribute in the Ios.ini file.


Remove the indicated device driver from the Config.sys and Autoexec.bat files.

Unsafe CD-ROM driver, xxxxxxxx, disabling protect mode CDROM

The specified CD-ROM driver was found in the [CDUnsafe] section of the Ios.ini file.


Remove the indicated device driver from the Config.sys and Autoexec.bat files.

Too many TSRs are hooking INT 13 & h/w interrupts.

There are too many device drivers and TSRs in the Config.sys and Autoexec.bat files that hook INT 13. The maximum number of TSRs and device drivers that can hook INT 13 without forcing MS-DOS Compatibility mode is 20.


Reduce the number of device drivers and TSRs in the Config.sys and Autoexec.bat files.

UnKnown int 13 hooker xxxxxxxx

NOTE: This section does not apply if the name of the INT 13 hooker is "MBRINT13." See the "Unknown INT 13 hooker MBRINT13" section.

IOS cannot use 32-bit disk access due to the presence of the indicated device driver or TSR.


The specified device driver or TSR hooks INT 13 and is not on the Ios.ini list of safe TSRs and drivers.



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