Date: Around 1999
My computer has an American Megatrends Enterprise 4 eisa vl bus
motherboard. I have 4 scsi hard drives connected to a DPT eisa
controller card. After switching from Win.3.11 to Win 95 my hard
drives would only come up in dos compatablillity mode (16 bit). After
getting no-where with Microsoft I called DPT. They informed me that
Win.95 and the eisa bus do-not get along when scsi disks are involved.
They told me that the eisa.vxd driver is the problem. They told me
to use devise manager to remove the controller. They then said to re-
install the controller and then re-name eisa.vxd to eisa.old. They
said to reboot and the disks should come up in 32 bit mode. They did,
however the bus will not recognize any card I try to add unless I
enable eisa.vxd. If I do my disks are back in 16 bit mode. I have been
struggling with this for almost two years. Im told that if I go with
ide drives I will not have this problem but Im reluctant to give up
my scsi's. Can you help?
Yes, if you go with IDE's you will not have this problem, but that probably
won't work for you.
However, if you have been dealing with this problem for a couple of years
and upgraded from Win 3.11, I will assume that you probably have an older
computer, and you also do not have EIDE, or the current standard in IDE
technology either, so your IDE choices will be limited to drives that aren't
made anymore, or to finding old software work arounds. If you have an IDE
controller in your computer, it is probably not an EIDE controller, and
without EIDE, the new, larger IDE drives won't work.
If this isn't the case and you do have a relatively new motherboard with PCI
controllers, the easiest solution would be to replace your SCSI controller
with a PCI SCSI controller.
The problem of having relatively new hardware becoming quickly outdated will
continue to get worse with Win98, Win NT, and Windows 2000. Since Microsoft
is moving towards an OS like Win NT with each release, a lot of hardware is
going to get dropped from their support. The goal, for them, is to have a
single OS that will run on multiple platforms, and that means that they have
dropped support for a lot of hardware, and will probablly continue to drop
support for hardware that is old, obscure, or just isn't viable across
The upshot of all this is that you will most likely have to keep working
around the problem for a while. I would suggest enabling your eisa.vxd,
installing your new hardware, and then going through the process to
re-enable your drives in 32 bit mode like DPT suggested.
When you are ready to upgrade your system, you might consider going with an
IDE drive. It used be that if you wanted a fast, large drive you needed to
get a SCSI drive. That is no longer the case. With the EIDE standard, IDE
drives can be as very large, and improvements in technology have made them
faster. You can still find a larger, faster SCSI drive than you can get in
and IDE drive, but only by about 25% larger and just a little faster.
The largest SCSI drive I found was a whopping 50GB, and had a 7.4 ms access
time. The largest IDE drive I found, however, was also huge a huge 40GB,
and had a 9 ms access time. The SCSI was 25% larger and roughly 22% faster.
Since both drives are really fast for a person, but really slow for a
computer, the speed difference really isn't that critical for almost all
normal, professional, and technical people.
The capacity difference of these drive also will be irrelevant to most
people. SCSI can chain a lot of drives together, but if someone is
considering chaining 50GB drives together, they probably need to consider
RAID or some other fail-safe technology.
The thing that makes IDE so great is that the 50GB drive cost over $900, and
the IDE drives cost under $300. Laying out 3 times the money for a 25%
increase in capacity and speed is just a little hard to do.
With IDE becoming so popular the prices have fallen dramatically, and the
capacity and speed has increased dramatically. Now a comparable SCSI drive
will cost more than twice what a similar IDE drive will cost.
When you do get ready to upgrade your, if you want to keep you SCSI drives,
you should buy a 32 bit PCI controller. It will be faster than your EISA
controller, and it will be compatible.
Hope this helps you a little bit.
You have a computer support question, which ain't real appropriate
for a bulletin board existing for the purpose of helping K-12 students
grasp scientists. For what it's worth, my suggestions are:
(1) Pay for the expert knowledge you want. Hire a computer support
expert to solve the problem.
(2) Get on a newsgroup and ask fellow users.
(3) Dump Win95 and transfer to Linux.
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Update: June 2012