Forcing Plug-and-Play for network interface card

While installing Windows 95 onto a machine with a freshly
formatted hard disk the network interface drivers were not
installed properly. My hypothesis is that if I could invoke
plug-and-play action for the NIC then all would start to
work fine.

My hypothesis is based on the fact that I went through all
this once before with the same brand of system (Dell
Optiplex GXi, 3C905 NIC for 10/100 Mbit/s). Only when the
plug-and-play sequence occurred the NIC driver installation

Currently my system is in a dead-end state with the
following properties: If I remove the non-functioning driver
(using the CP/System/DevMgr dialogue) and reboot, no PnP
action occurs. If I then try the CP/AddNewHardware procedure
no new HW is detected even though the poor thing searches
itself for a couple of minutes. If I then choose to specify
explicitly that I want to add a network adapter (also under
CP/AddNewHardware) it asks for software and loads it. This
procedure completes without complaints, but it ends up with
a non-functional driver (with a yellow blob in the
CP/System/DevMgr list). In other words, I am back in the
dead-end state.

Last time I went through this I eventually re-installed
Windows 95 by running its SETUP.EXE program and answering
all the questions along the way. Towards the end of this
lengthy exercise the plug-and-play behaviour was
displayed. I provided the driver SW asked for (same disk was
used), and the end result was a properly working NIC driver.

While I could try this disgraceful resort once again, I
really feel that there must be a better way--some trick that
one of you experts know about? I award 300 points for the
first effective solution to this problem.
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Unfortunately there is no switch to activate PNP support in windows.  This is done and handled stricktly by the OS itself.

I know it sound ridiculous but that's the way it is.
In Short there is NO solution for your answer.

What has happened here, is when you reinstalled windows, it has properly detected the card and therefore installed the needed drivers for it in conjunction with the CARD drivers.

I can even go further and tell you that some BIOS have an option to DISABLE PNP OS, but Windows will still detect the PNP cards if he sees them.

So your options were:

1) Some files were missing to detect that PNP card
2) Reinstall windows 95 which would run the detection engine that will eventually sees the new card.

To tell you the truth, we see weird things like this everyday in our business.  I just got off with a client machine that could FAX but not communicate with the modem, spent 3 hours trying to get it happening without any success.

Left the machine as is, just turned off for the night, came back next morning, set my mind clear to resolve the issue, and ALONE without any interference from my part, the MODEM works as if nothing has happened.

Now my techs could give me 100 of theories whay it did and it didn't but where is the truth?? Now figure!!

So to come back to the subject, if you ever encounter problems like this and you need to run another setup please do use the following method instead:


Reinstall win95 from the command prompt using (setup /p f ) command.
This setup switches will clean your system files and replace missing and damaged files, keeping all your apps and updated drivers.

The switch  f

Means a Clean Registry mode. It forces Detection to clean the root branch of the registry before starting. It will also remove commands that are pointing to the wrong locations including Win 95 files.

The switch  /p

The string can contain one or more detection switches separated by a semicolon (;). For example, if you want to use  /p f

The switch /d

This switch can be used if you do not want Setup to use your existing configuration (like Win.ini and System.ini files).

To restore or adjust your windows installation:
 From dos insert your CD type this command... at your CD-ROM drive letter
" setup /d /p f "  Without quotes

You would want at that stage to choose from  "Full or Custom Setup", choose Custom. This will give you more control through a step by step of the setup.

Hope that this has helped

Sorry I should have added also;
that it might have been a CORRUPTED file that got reinstalled during the setup.

eubrafoAuthor Commented:
Thanks magigraf for suggesting useful switches to the SETUP
program. In the end, this may be what I must do.

However, I still think that there should be a better way. I
remove the non-functioning drive (in CP/System/DevMgr). There
is no PnP action when I reboot. I expect that by doing some
further modification to the file system (like, removing some
files), or by twiddling something in the registry, I should
be able to reach the state where a reboot invokes PnP action. Question is, what modification should I do?
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Believe me there isn't and just to make you feel good I will ask the Registry expert to come join us here. (maybe I will lear something too)
Meanwhile keep the question locked, until he comes to reveal his tips.


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Sent him an e-mail, he will be shortly with us.
Hi eubrafo and magigraf,
I'm sorry It took me so long to get here.  Thanks for the invitation magigraf.

Well, the registry has little to do with PnP. yes there's a lot of references there but if you look at:
HKEY_LOCAL_MACHINE\Enum  then probably
You'll see that it's all bios related. Meaning "This is what I picked up when I ran thru my Startup Proceedure". That was the computer talking.
On many PnP's, particularly network and Bus-mastering issues we have to turn the Bios's PnP enable off. And Then jump a whole lot of hoops to get what we want.
The only trick I know, non-registry, is doing just that. Disable PnP in Bios, run the Wizzard, add the drivers, power-off, boot and enable the PnP again, and make whayever tweaks "Might* be necessary.
============Here's a little about PnP
Plug and Play (PnP) is a system for configuring devices, usually in the
form of add-in cards, that enables them to work together without
conflicting with each other. PnP consists of:

* PnP and non PnP cards (devices)
* PnP initialisation and run-time routines within the Operating System
(OS) and utility software
* PnP BIOS routines

There are three types of PnP cards that can be auto-configured:

* PC Cards (PCMCIA).

All other devices are non PnP, have a static configuration and classified
as ISA Legacy Devices. PnP devices are configured around Legacy devices.
Windows95 configures Legacy devices with the 'Add New Hardware' wizard.

Resource Usage (IRQs, I/O ports, DMA channels and memory windows):
PnP can use one of two methods of determining resource usage.

1. Determine the resources that are not generically detectable and
establish the areas unavailable for configurable devices.

2. Extended System Configuration Data (ESCD) method. ESCD stores Legacy
information and the Last Working Configuration (LWC) of configurable
devices. This allows the system to ensure that resource assignment and
device placements are the same each time the computer is powered on.
This is important when using device drivers that get their resource
allocation information from a static source, such as the command line
parameters in config.sys file.

A fully PnP compliant system requires a PnP BIOS. ESCD configures PnP boot
devices as part of the Power On Self Test (POST) before booting the
operating system. ESCD also allows run-time software (Windows95 Device
Manager) to request specific resource assignments for PnP devices. This
allows difficult to place configurations to be manually setup or disabled.

PnP elements:
There are four elements to a PnP system.

1. The PnP BIOS starts the auto-configuration of the PnP cards during the
POST. This in turn isolates any Legacy devices and ascertains the
resource needs of PnP devices.

2. The ESCD functions are used to determine resources already in use by
Legacy devices, and which are available for PnP devices. A PnP BIOS
must be able to configure the card or cards that are required to boot
the operating system (video and disk controllers), and may also
configure all the cards in the computer, which is necessary for
operating systems that don't feature native support for PnP cards.
After identifying the PnP cards, the PnP BIOS compares these cards
with those in the ESCD. If found, they are configured as stored in the
corresponding ESCD entry. This ensures that when no new hardware has
been installed, the PnP devices are configured identically for each
session. If the PnP BIOS cannot find an entry in the ESCD, it consults
the ESCD to determine what resources are free and assigns these to the
new card. In addition, the ESCD allows system software and utilities
to communicate with the BIOS, by placing their desired resource
allocations in the ESCD.

3. The Configuration Manager (CM), configures the PnP cards not
configured by the PnP BIOS, by using the ESCD in a similar manner as
the BIOS does.

4. The ISA Configuration Utility (ICU) is designed to assist in
determining a conflict-free configuration for standard (Legacy) ISA
cards, as well as providing advanced configuration support for PnP
cards. The ICU will allow certain functions in multi-function cards to
be disabled and the configuration of particular cards to be locked:
primarily for use with non PnP supporting operating systems.

The PnP BIOS performs the following steps to configure the PnP devices
before starting the machine:

* Builds a structure called the Resource Map, to determine the available
system resources - IRQ, I/O ports, DMA channels and memory windows.

* The Resource Map is then initialised to indicate the resources

* The BIOS determines the resources used by the system board devices,
either by looking up the information in the ESCD, or by enquiring from
the BIOS the resources used by system board devices.

* The PnP BIOS then interrogates the ESCD in order to determine
resources that are allocated to Legacy cards, and updates the Resource
Map. At this stage, the Resource Map contains all the necessary
information on all Legacy devices.

* PnP ISA cards are examined to establishes its resource needs.

* After identification, the boards are configured, starting with the
last known working configuration for each card in the ESCD. For new
cards, the system will use the first alternative configuration that
matches the card's resource requirements. However, if none are found,
then the next set of available resources is tried. If the system runs
out of resources, it will go back to the previously configured cards
and attempt to re-configure them to make room for the new card.

* The BIOS then scans the standard expansion BIOS memory area looking
for the expansion BIOS signatures for Legacy ISA and PnP ISA cards.
These are initialised on detection.

* The PCI Configuration Space is examined and PCI devices initialised.
As PCI devices are fully configurable by definition, these devices are
configured on a first come/first served basis. Again, the last working
configuration stored in the ESCD is tried before any attempt to
dynamically configure resources.

* If one or more PCI cards can't be configured, an error is generated
and the task of configuration is passed to the Configuration Manager.

* The expansion BIOSs are initialised and the ESCD structure updated
with the new PCI device configurations - ESCD data for PnP ISA card
configurations is carried out by the Configuration Manager.

                             Plug and Play Problems

Most PnP problems seem to be caused by the BIOS claiming the board before
Windows95 has a chance to detect and allocate its resources. To see what
interrupts and ports have been allocated, select:

* control panel
* system applet
* device manager tab
* double click on 'computer'

All Interrupts Used Up:
PCs are limited to 15 interrupts (IRQs) most of which are allocated to
hardware other than add-in cards. Problems arise when all 15 IRQs have been
used, manual selection will then have to be used to set the IRQ and/or Port
Address to a shared value

BIOS taking control of settings:
The PnP BIOS may be detecting the card and setting it up before Windows 95
starts. If this happens and you don't want it to, then see if the pnp
option can be turned off by jumpers on the card or through a software
driver for the card

If the CMOS BIOS is preventing an IRQ from being selected, check the BIOS
settings and alter to allow specific IRQs to be used

Computer reports hardware present, when it is not:
Occationally Windows 95's will report incorrectly that it has found
hardware that is not present (due to the motherboard's chipset reserving
resources for hardware). These reserved resources cannot easily be
overriden, but the computer can generally be coaxed into sharing its
resources once the BIOS settings have been suitably altered.

I hope this helps.

Thanks Bud, for stoping by.
Here's some easy things to try first. There's no magic in the registry to cure this.

1. Make sure that the Bios is set for Plug and Play and not set to non-PnP.

2. Pull the NIC itself and make sure that if it has a PnP Bios that no pins are configured on the card except for those to enable PnP.

3. Load the INF file (drivers) that came with the card, unless it's an OEM version, in which case you'll have to download them from 3com. If you have OSR2, current drivers are on the cd rom disk.

4. Go into device manager, scroll down to network adapters and make sure there are no entries there for any type of NIC. If there are, highlight them and remove them.

5. Shut down windows and then your system. Insert the NIC and connect it to the rest of the network and make sure the cables are connected properly.

6. Now restart your system. If everything has been done correctly, Windows will find the NIC and install the driver. Windows will probably also ask for the Win95 cd rom disk as well.
eubrafoAuthor Commented:
Thanks magigraf, smeebud, and dew_associates, for providing
definitely non-trivial explanations and hints. I am going for a
short business trip so it will be a few days before I can try
them out. Do stay tuned!
Eubrafo, unless you reject the proposed answer, it the site will automatically accept it for you after 3 days

First of all the answer would be autograded after 2 weeks of inactivity.

Second why would you want him to reject my answer??
Did you bring anything new here??
All what you proposed is a trial in installing his card, but he asked for a swicth to make Win95 PNP or not, and I don't see that anywhere in your answer.

Regards to all
I don't know where you got these 3 days autograded, but if this is a new technique you're using to make them reject the answer fast, humm.. Well It does not work that way. (Sorry)
No heart feelings
Mag, you always seem to have a comment when none is warranted. There ?'s were autograded from Thursday last that did not have any response since the day before! Now, do you have a comment to that! By the way, no hard feelings!
Well I do have a comment for that.
E-mail Linda and report the problem.  They are having some problems these days.  Just reported to her about an answered question that showed up for 2 days as waiting for answer.  So mistakes do happen on EE.

The way it has been programmed is 15 days of no activity it will be autograded, and these info are from EE staff not me.

And I guess you know me by now, I will always stand for what I have been informed as correct by the owners of EE.
eubrafoAuthor Commented:
Back now from trip and short vacation too; I finally had the time to try out the
procedure proposed by dew_associates. Unfortunately it did not work. I then
decided to try my own awkward trick (re-installing Win95 a second time, see
initial problem description). Again, this caused PnP to happen and the NIC
became usable.

Oh well, if I ever have to put Win95 onto a Dell Optiplex computer again (I wish I
won't), I am prepared to do it the stupid way, that is to install Windows 95 twice
in succession :-(
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