Compaq Presario 4112

Oodles of info about the Compaq Presario 4112, a rather obscure model of Internet PC from 1996. Most resources here concern operating such a computer in the current day and age, as I have a working specimen courtesy of my late grandfather. Whether compiling this information was worth it is up for debate.

Still an ongoing project!
Last updated 10 February 2022, 11:55 EST

Compaq Presario 4112 with Compaq Presario 1425 monitor

Pictured with the Compaq Presario 1425 monitor

Specifications

These are the current specifications, not the stock options.

Processor	Intel Pentium P54CQS i586 @ 133MHz, 16KB L1
Memory	8MB integrated EDO DRAM @ 100 MHz 64MB NANYA 60ns FPM DRAM @ 100 MHz
Motherboard & chipset	Proprietary Intel PCIset 82430VX + PIIX3
Graphics	S3 Trio 64V+ 86C765, 1MB EDO RAM Compaq 213857-001 MPEG controller board Compaq Presario 1425 14″ SVGA colour monitor
Storage	Maxtor 90840D6 DiamondMax 2880 8.4GB Ultra-ATA/33 hard-disk drive @ 5400 RPM
Media	Compaq 239612-401 3½″ Dual-density Floppy Disk Drive Compaq 157844-001 12× IDE DVD-ROM drive
Audio	ESS ES1888F AudioDrive [NO LONGER WORKS] Sound Blaster Pro 2 CT1600
Networking	Creative DE5660 Modem Blaster V.90 data/fax/voice modem, 56Kbps Realtek RTL8029AS 10/100 Ethernet adapter
Expansion slots/ports	3 ISA 2 32-bit 5V PCI
Expansion slots/ports	DE-9 serial port DB-25 parallel port DA15 joystick port
Input	Whatever random PS/2 keyboard I pull out of the closet Logitech M-S48 Compaq-branded PS/2 mouse
Other devices & components	Steady-state 145-watt power supply (unknown model) StarTech expansion slot exhaust fan
Operating sys.	Microsoft Windows 98 Second Edition MS-DOS 6.22

BIOS date is 1996-05-23, if that’s relevant.

IRQ tables

This is more for my own reference than anything else. Keep in mind some of these are not standard IRQs.

	IRQ	DMA	I/O addr.	32-bit I/O addr.
Audio	3	1/5	220–22F 388–38B 330–331	-
Serial port	4	-	3F8–3FF	-
Diskette controller	6	2	3F0–3F5	-
Parallel port	7	3	378–37F 778–77A	-
Modem Blaster	10	-	2E8–2EF 810–817	-
Ethernet controller	11	-	1400–14FF	44000000–440000FF
USB PCI card	11	-	-	44080000–44080FFF 44100000–44100FFF

A detailed journal of restoration efforts

Some background: my late grandfather used this computer in the late 1990s while teaching at Lincoln High School in Harrison County, West Virginia. Much of the software on it before I wiped the hard disk clean (done because it was unbearably slow for reasons beyond my understanding) was education-related, and I even plan to sift through the hard disk image and put it up on the Internet Archive.

System dialog showing Wayman Price as the owner of the Presario 4112

In either case, after sitting in my study closet for several years and after several failed attempts at getting it booting on anything but Safe Mode, I decided to go all-in and make the damn thing work. The details of said “restoration” can be found below in a semi-chronological order.

Previous attempts at running

I had originally shelved the restoration (literally) because I could barely get it to boot into Safe Mode. Outside Safe Mode, some sort of issue regarding Norton AntiVirus Corporate Edition made it crash and burn every time I tried to boot it to C: normally.

Norton AntiVirus warning dialog with corrupted colours

And, I’m not entirely sure how nor why this happened, but I got a metric boatload of memory parity issues when running in any mode whatsoever from the hard disk. The following steps somehow resolved that, I guess.

Backing up and wiping the hard disk

This part was pretty simple: I plugged the drive into an IDE-to-USB adapter and copied the entire C: drive onto my computer, then wiped the MBR clean off using Disk Manager (Windows).

What went wrong

Mid-1990s PCs’ BIOSes couldn’t keep up with the ever-increasing capacity of hard disk drives. One solution—Logical Block Addressing—generally worked as following:

Change options in your BIOS to make it believe your big hard disk was only 504 MiB, the maximum allowed under normal circumstances.
Make the BIOS only ever boot to the hard disk, which contains some special code within the readable 504 MiB (though usually right at the beginning).
At boot, load the aforementioned special code into a specific area of RAM, replacing the BIOS’ own routine for disk access, and allowing any program loaded thereafter to access any part of the disk.
Run a bootloader that allows you to use floppy disks, boot to OS, &c. just like a normal boot sequence would.

In particular, my Presario 4112 used EZ Drive to do the above. Well… wiping the hard disk wiped off EZ Drive. The computer was stuck permanently booting to the hard disk, which had absolutely nothing on it, churning out 1790 - Disk 0 Errors in the process. Blank screens abound. However, with the hard disk removed, it booted to floppy. Odd.

Getting the computer to boot right

After the above incident, I took to Reddit. After being informed of the existence of the aforementioned EZ Drive (though it took a bit more research to figure out that’s exactly what it was), I somehow reached the exact solution:

Disconnect the hard disk. Insert the QuickRestore diskette and CD (covered in the next section) and boot the computer.
Run D:\F10SETUP\SETUP.EXE (assuming D: is your CD-ROM drive) and make sure the computer can boot from floppy.
Zero out the beginning hundred or so sectors of the hard disk—including the MBR—using another computer, then reinsert it while the computer is powered off.
Boot the machine to the QuickRestore diskette, and restore the machine’s BOMID to the very beginning of the hard disk using UIABOMWR.EXE (hidden from DIR; it’s there!).

To this day, I’m not entirely sure why this worked.

Frustrations with QuickRestore

The Presario worked as-is—ignoring the OS issues—, but, given it had only 8MB of onboard RAM, it was excruciatingly slow running Windows 98. I decided that Windows 95 would be the best option, and I fortunately had access to an original copy of the Presario 4100/7100 Series QuickRestore disc and diskette. One problem: even after inputting the serial number on the chassis, it said I needed Compaq part number 183771-001 to restore my PC. That’s what I had in the drive. I eventually gave up and went with Windows 98 Second Edition as detailed later.

The old Compaq software isn’t entirely useless, however; this is explained later when extracting drivers.

Necessary hardware upgrades

I figured that if I had to do a clean install, I might as well go all-out and make it work right like my grandfather had it.

Memory

Thing is, I’m fairly sure he had some sticks of memory in there considering he’d have had to run the setup program with the /nm switch to check for memory, because, having known him, he’d have just gone for the upgrade or stayed with Win95. I just picked up a couple 72-pin EDO RAM SIMMs from eBay and slapped it in. Only after I put it in did I learn I needed to run EDO RAM in pairs. Do your research, kids. Anyway, I bought another stick and waited another week before proceeding.

Processor

Overclocking, meanwhile, is as simple as changing jumpers on the motherboard. You should buy a 200MHz Pentium MMX CPU if you want the speed of a 200MHz CPU, but you can just change the jumpers to overclock whatever you’ve got in there (stock is 120MHz). I went with 166MHz, which requires the P8 jumper to be across pins 3 and 4, and the P9 jumpers to be across pins A2–A3 and B2–B3.

		1–2	2–3	3–4
A1–A2	B1–B2	75 MHz	90 MHz	100 MHz
A1–A2	B2–B3	—	120 MHz	133 MHz
A2–A3	B2–B3	—	150 MHz	166 MHz
A2–A3	B1–B2	—	—	200 MHz

However, the entire airspace inside the chassis is now prone to getting uncomfortably hot, considering the lack of a CPU fan. Given it was about 80°F in my girlfriend’s dorm room at the time of this change thanks to the A/C malfunctioning building-wide, I improvised by sacrificing our one box fan to pull air up through the sides of the case and past the heatsinks. Shockingly (or thankfully not so), it worked pretty well. Looked absolutely goofy, though, as you can see here:

I now have an expansion slot exhaust fan placed near the CPU, so temperature isn’t as much an issue.

Expansion cards

Considering the lack of drivers and/or broken state of the presumably OEM hardware, I replaced the modem (Compaq part no. 221506-001) and Ethernet adapter (Compaq part no. 40125) with a Modem Blaster V.90 and Realtek adapter, respectively (see specs above). Every time I tried to play sound, MMTASK.EXE froze, which I somehow resolved by installing a Sound Blaster Pro 2 (very old card by Win98’s time) as a stopgap; I can only assume the on-board sound card is just fried somehow and/or hasn’t the right driver.

The only word of advice I have on installing hardware is such: remove all expansion cards before assuming something’s wrong with the actual computer itself. A Win98-compatible WiFi PCI card I put in prior to trying to install said OS caused seemingly random yet consistent garbage output (as shown below) on boot roughly 75% of the time, and it took me about two days of on-and-off looking at literally everything else before I thought to remove the cards.

Seemingly random characters on a monitor

Otherwise, just follow normal guidelines, such as managing your IRQs well.

Installing Windows 98 Second Edition

To access any more than 503 MiB of the hard disk, you’ll need to install EZ-Drive. Since we’re no longer on MS-DOS, we can delete the automatically created 4+ partitons using FDISK, presumably from some sort of MS-DOS floppy—but make sure to boot to said floppy using EZ-Drive! You can leave the drive partitionless; Windows setup will take care of formatting it with proper FAT32.

Other than that, you need to prepare a Windows 98 SE boot floppy as the Presario 4112 cannot boot from CD-ROM. As long as the Win98 SE CD-ROM is inserted before the computer boots from floppy, everything should go smoothly from here.

Installing OEM software/drivers from the QuickRestore CD

As I hadn’t the patience to hack QuickRestore to function properly, I decided to just extract the .ZIP files from the CD and pick out what I thought was necessary.

Before anything else, you’ll want to extract all the .ZIP files in D:\NA02, assuming D: is your CD-ROM drive. The password for these zip files is PREDATOR001, case-sensitive. From here on, C:\INST will represent the directory to which you extracted the archives (because that’s just what I named mine).

Drivers

Windows should have installed drivers for vital system components, and nothing in Device Manager should be drastically incorrect. As for OEM hardware, take note of this table:

Manufacturer	Device name	Notes
Compaq	Compaq Floppy Disk Controller	Replaces Standard Floppy Disk Controller.
Compaq	Compaq IDE Controller	Replaces Standard IDE Controller.
Compaq	Compaq Presario 1425	Replaces Plug and Play Monitor. Ignore this if you don’t have the original monitor.
ESS Technology, Inc.	ES1888 Plug and Play AudioDrive	For some reason, Microsoft’s 1998 driver for this led to my computer crashing, so I had to roll back.

For each device above, check whether either it or an entry which you suspect is the generic driver for said device is present in Device Manager. If so:

Open the device’s properties window, and navigate to the Driver tab. Click Update Driver.
Select Specify the location of the driver (Advanced), and click Next.
Select Display a list of all the drivers in a specific location, so you can select the driver you want. Click Next.

Meanwhile, if not present:

Open the Add New Hardware wizard. Click Next until you’re presented with the option No, the device isn't in the list. Select the type of hardware, then click Next.

Now, in both cases:

Select Have Disk. In the textbox with the label Copy manufacturer's files from, type C:\INST\WINDOWS\INF. Click OK.
Select the device manufacturer and device name as indicated. Click Next.
Click through everything till it installs.

There’s likely an easier way to go about installing the OEM drivers, but so be it.

To-do list

Get the Easy Access bezel to work
Properly install Compaq Phone Center
Restore some superficial Compaq branding for the hell of it
Fix APM driver

Software downloads

I’ve got a good bit of nonstandard hardware in mine, so I’m only listing drivers and software appropriate for the original configuration. Do note that some drivers can’t just be downloaded from here and have to be extracted from the QuickRestore disk.

Restoration/install disks

File	Description	Download
Compaq QuickRestore for Presario 4100/7100 Series	Restores Win95 and setup tools to a hard disk along with all the OEM bloatware.	[1] {2}
Compaq QuickRestore Diagnostics diskette	Required to boot the above QuickRestore CD. Also includes a couple useful tools.	{1}
Compaq Personal Computer Setup	Utility to create a diskette that allows restoration of the setup partition.	{1}

Drivers

File	Description	Download
Easy Access Keyboard	Enables the Easy Access buttons on a Compaq OEM keyboard.	{1}
ESS Audio	Necessary on the 4112; Microsoft’s drivers don’t work for some reason.	{1}
Presario 336-VSC Modem	Necessary driver for the Compaq 33.6Kbps voice modem as Microsoft provides no compatible driver.	{1}

Generally useful files can be found on my Windows 98 resource page.