Hello and welcome. I have a 7400 which fortunately still has a working hard drive. To my understanding most Compaq computers form this area store the bios configuration software on the hard disk. The bios itself is still in rom but you need the utility to access it and make changes. This usually comes in the form of a spxxxxx.exe where xxxxx is a five digit number. The utility will create a small non Dos partition which holds the setup software. I don't have this executable but you should be able to find it online.

As for hard drive alternatives/ adapters I have had mixed results on Compaq systems. I belive you can pre partition to a smaller size but then I don't know how that would work with the setup utility since I believe it expects to be the first partition. Others here were more experienced and can probably provide more information.

68k wrote on 2025-04-27, 22:39:

Hello! First post here!

I've recently been more interested in computers in general, and thought a good project would be to get my Compaq Armada 7800 running again. It worked before- ran NT 4.0 on its original HDD, until one fateful day it got unplugged while running, and the HDD no longer works properly. However, I wanted an opportunity to start from scratch anyway; the machine had a lot of things locked down by the previous company it came from, and many drivers seemed to not work properly.

So far it's been a good learning experience, but I'm not sure what to do about a replacement for the HDD. I naively assumed any reasonable 2.5" IDE drive would work, but apparently these machines require drives below a certain size, due to issues in how they handle partitioning for the operating system and BIOS programs (apparently the BIOS is stored on the HDD, not sure if this is an unusual practice?). Unfortunately, HDDs this small seem hard to find, and I don't want to trust another 30-year-old drive.

It should be fine with drives around 10GB to 32GB, make sure you have a floppy drive ready to install the diagnostics & setup partition before installing the os, I don't think it goes well if you try to do it after the disk is partitioned by the OS.

I've seen many converter boards for 2.5" IDE from formats such as compact flash, mSATA, microSD, etc. Are these safe bets, or would I encounter compatibility issues? Additionally, I bought a generic Multibay optical drive for it, since the original was missing. Are there notable differences across the standard?

Not electrically, I do the same with my Armada 7800. The connector fits but the MultiBay format shrunk down after the 7800 so it'll flop around in the bay but otherwise works well.
Same thing for the floppy drive as well 😀

Thanks for all the input! IDE-adapters might be the way forward.

Thermalwrong wrote on 2025-04-28, 02:54:

It should be fine with drives around 10GB to 32GB, make sure you have a floppy drive ready to install the diagnostics & setup partition before installing the os, I don't think it goes well if you try to do it after the disk is partitioned by the OS.

The floppy drive works (I replaced a belt in it awhile ago, apparently these are notorious for failure). I read that these programs need a particular formatting to work (FAT12, I think?) that isn’t available on all operating systems.

I do have an XP-era tower which I’m also in the process of bringing up, with the intent of putting Linux on it. Hopefully its FD is good!

Try doing a bad sector scan on the original HDD, using a 2.5" pata to usb adapter on another PC. So you can at least see if you can get some files off it.

2.5" no-name brand SSDs don't last more than one year unpowered (data is wiped). Samsung SSDs can last at least 2-3 years unpowered.

The Samsung 2.5" HDD in a mid 2000's laptop I have still works no problems. So I recommend those or Seagate/Western Digital if you want to "set it and forget it" for many years.