1 Copper

I/O subsystem error

After trying to load some Antivirus or other software I am having the following problem. The software installs normally as far as the reboot, then the problems start!

The system gets as far as the windows splash screen then the next message I get is;

While initializing device IOS:
Error: An I/O subsystem driver failed to load. Either a file in the .\iosubsys subdirectory is corrupt, or the system is low on memory.

I can restart the system in safe mode but the only way to get the system to boot normally is to start in Safe Mode Command Prompt Only, run Scanreg/restore and away we go.
This obviously means that the software will not run. Even uninstalling the software in Safemode requires me to restore the registry to get it to reboot normally.

I am running W98SE on a Dimension XPS B800r PIII 800 with 128MB ram.
Please help as this is driving me nuts.

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1 Reply
4 Ruthenium

RE: I/O subsystem error


Thank you for using the DellTalk forum.

Here is further information.
The following MS-KB article was created for Windows95,
but since Windows98 uses most of the same files, it should
work to get your problem fixed as well.
PRB: Windows 95 May Fail to Boot Due to I/O Subsystem Failure
The information in this article applies to:

Microsoft Windows 95
Under some circumstances Windows 95 may fail to boot, and will display the following error message:

Error: An I/O subsystem driver failed to load Either a file in the .\iosubsys subdirectory is corrupt or the system is low on memory.

This problem may occur when all memory below 1MB is allocated prior to initialization of Ios.vxd. Ios.vxd must allocate memory below 1MB for use as real-mode buffers. If Ios.vxd can't allocate this memory, it fails to load, which in turn causes Windows 95 to fail to boot.

Memory below 1MB is typically reserved for components that specifically request it. However, it is possible that Windows 95 will allocate all memory between 1MB and 16MB during initialization, forcing system DMA buffers (which must lie below 16MB) below 1MB, and therefore preventing Ios.vxd from being able to allocate memory below 1MB.

This problem can be worked around by adjusting the maximum cache size allocated by Vcache.vxd. Vcache.vxd allocates an initial cache size that is no larger than 9MB. Setting the maximum cache size to less than 9MB also reduces the initial cache size, freeing up memory below 16MB and allowing Windows 95 to boot properly.

The maximum cache size is set by adding a "maxfilecache" line to the vcache section of System.ini. The following example shows what an entry in System.ini would look like to set the maximum cache size to 6MB:


Click on Start, Shutdown, Restart in MS-Dos mode
The system should restart to a Dos prompt.
Change to the C:\Windows\ directory.
To do so type in: CD Windows , and then press Enter
When you are at a C:\Windows prompt, type in, Edit System.ini , and press Enter
Now you should get a Blue screen with the words System.ini at the top.In this screen you have several entries and categories.Using the Up and Down arrow keys, find the category for [vcache]
Move your cursor to the line under the [vcache] category, and press Enter.This should put a blank line under [vcache], now type in: maxfilecache=6144
Then simply go to File at the top of the screen, then choose Exit.When you are asked if you want to save the changes, say Yes. Now you are done.

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