Resurrected Entertainment

Building a RetroBox

July 7, 2007

Playing games through emulators or virtualization software is one thing, playing them on a real box, powered by real hardware is quite another. The tactile sensation, the whir of the power supply, and the smell of electro-static dust crud slowly wafting through the ventilation is enough to send chills down my spine. Seriously, I can’t stand it.

Besides all of those tangible qualities, there is also the very real compatibility of the games to consider. They may not run perfectly in your emulated environment. On my primary machine, for example, DOSBox does not run any of my computationally expensive games very well such as Wolfenstein, DOOM, Hexen, etc – basically, any 3D FPS game. VMWare may also not produce the sound very accurately (assuming I can even find a way to get audio to work in FreeDOS on the machine I am using). I also found it enjoyable building the machine and locating the parts for it. My local used hardware store was a great help as well as raiding my own closets for any spare pieces lying around. This little venture also helped to ferret out any unneeded parts for charitable donations.

As a bench mark, I used Ultima VII: Black Gate and Serpent Isle, since those two games had very demanding audio and memory requirements. The games also required a decent processing speed, mouse support, and a modern video card supporting VGA graphics modes. When I say “very demanding,” I mean when compared to the technology of the day. If you were to use a machine made using today’s technology, it would simply be too fast. Many games wouldn’t operate correctly and it would be next to impossible to find MS-DOS compatible drivers.


The two most important pieces of hardware to consider would be your motherboard and your sound card. You may have noticed I neglected to mention processor and video card. If you pick a motherboard from the same era as Ultima VII, it most likely won’t have a CPU socket (although my RetroBox does and provides a Socket 7 interface) so you would typically be stuck with the on-board processor. The video card is less important, although I would make sure it has a reasonably high number of video modes, and optionally, high-quality video output that suites your taste and matches the capabilities of your monitor. You should also try and get a PCI video card since a 16-bit ISA bus can be a bottle neck for Pentium processors during the early to mid 1990s. The last video card I used in this machine was a Trident Super VGA card. I loved that card, but when I upgraded to a new card sporting a PCI interface the difference in speed was very obvious.

Should you choose to build a machine yourself, I have provided a list of components I used to build mine. You will probably want to alter the list to suit availability and personal preference, but if you choose to build it to my specifications, I can guarantee you the machine will run Ultima VII perfectly:

  • GMB-486SPS 80486 PCI Green Motherboard
  • Intel P133 Microprocessor
  • Sound Blaster 16 ISA Sound Card
  • Matrox G400 PCI Video Card
  • Yamaha 4x4x16 CD-ROM Drive
  • Generic PCI Network Interface Card
  • Microsoft Compatible Mouse
  • 40 GB Hard Drive
  • 3 1/2″ Floppy Drive
  • 250W Power Supply

The size of the hard drive is somewhat arbitrary. Forty GBs is a lot of space for a DOS installation. I could install every game in my collection including Windows 3.1, compilers, word processors, and anything else I could find around the house and it still wouldn’t fill half the hard drive, which is why I partitioned the drive and installed Windows 95 as well. I did this more for network connectivity, so that I could copy files back and forth easily (although I will probably forgo the Windows installation and use an Ethernet packet driver and SSH/SCP to move files around). Just remember that hard drives available today will probably not be compatible with older motherboards. The BIOS or your operating system may not recognize your disk or refuse to utilize most of the space.

Remember, you should probably work out an effective way for you to get files from your home network to your RetroBox. It could be more difficult to find a motherboard capable of interfacing with USB devices, and even if you did find one, you would need to install Windows with USB support.

TIP: Some earlier versions of Windows 95 did not support USB devices, so be careful if you’re purchasing a copy on eBay. Another alternative to Windows would be to install FreeDOS – it has USB support, although I am not sure if it would recognize the hardware on all motherboards. The OS is built for old and new machines, so I’m guessing luck is on your side.


I use a number of light weight drivers and utilities to make my RetroBox compatible with Ultima VII. The CD-ROM, mouse, and sound card all require drivers. I wanted a light weight driver and device extension software for my Yamaha drive so I chose to go with the generic CD-ROM driver provided by Mitsumi called MTMCDAI.SYS and extension software called SHSUCDX.EXE written by Jason Hood and John McCoy. For the sound card I use the standard Sound Blaster drivers and related software. For the mouse, I chose something a lot smaller than the typical Microsoft compatible mouse driver. The mouse driver is called CuteMouse; it’s open source and optimized for size. It’s only 6 KBs compared to the Microsoft driver which is 56 KBs – a huge savings!

However, the best piece of software I found was a program called UMBPCI. It only works for specific CPUs, but if you have an Intel P2, P3, Celeron, or Xeon, then they are all compatible since they are all L2 cacheable. Processors which do not work are 486/SX/DX/DX2/Dx4/SLC, 386/SX/DX, 286/SX, or 8086. If you own one of those processors then you may want to try HIRAM.EXE which works in a similar way to UMBPCI. So, what does UMBPCI actually do? Here’s a concise explanation taken from the documentation (it has been edited for clarity):

UMBPCI.SYS extends Microsoft’s HIMEM.SYS by supplying the ‘Request XMS-UMB’ function. Microsoft’s EMM386.EXE does the same thing, when loaded with the ‘NOEMS,’ ‘HIGHSCAN,’ or ‘RAM’ parameters in CONFIG.SYS.

UMBPCI.SYS creates UMBs (Upper Memory Blocks) using the existing system memory intended to be used as Shadow RAM, but disabled by default, only in the C800-EFFF range, not using the address range B000-B7FF. That particular memory area is normally used for monochrome video (used by older graphics adapters), not for BIOS (ROM) extensions, therefore X86 chipsets cannot enable shadow RAM within this region. UMBPCI.SYS enables this memory and disables its write protection.

UMBPCI.SYS takes only 240 Bs of conventional RAM (224 Bs code + 16 Bs environment), while providing up to 629 KBs of free conventional memory, provided you’re loading all the devices/drivers/TSRs to use high memory!

Microsoft EMM386.EXE creates UMBs from the computer’s physical XMS (eXtended Memory Specifications) by virtually remapping XMS to the upper memory area using the Memory Management Unit (MMU) of 386 and higher CPUs. It needs an additional 150 KBs of XMS, 4 KBs of low memory and 7 KBs of UMA (Upper Memory Area) when loaded. It also switches the CPU into protectedmode, which tends to be slower, because it’s necessary to use the MMU. UMBPCI.SYS leaves the CPU in real mode, for better compatibility and faster performance.

Basically what this boils down to is the ability to load all of your drivers and software to a region other than conventional memory. This makes games like Ultima VII, which is a complete memory hog, very happy indeed.

For some games, I also use a utility called PENTSLOW.COM which slows down a Pentium class CPU by disabling branch prediction, v-pipeline, and internal cache. This produces a more even gradient for speed changes, unlike some software driven tools (essentially TSR programs which simply loop) that produce choppy or ineffective speed reductions. I also down-clock my CPU in the BIOS from 133 MHz to 100 MHz which helps Ultima VII cope with the faster processor. You may also wish to use a disk management tool like SMARTDRV.EXE which can help improve the performance of disk intensive software.

For your benefit, I have made all of my batch files, configuration files, drivers and software available to you. Let me know how your RetroBox works out!

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