The new software runs of FreeBSD-stable (currently 4.10). Currently
it is loaded onto the hard drive and run from there, or it may be run
from a bootable CD-ROM, which is should be configured to run the softare
on most PCs, even if they normally run Windows.
Each exhibit has an optional configuration file which lets you change
the defaults for things like hue, saturation, brightness, microphone and
speaker volume. Also, nearly all the text may be changed to any UTF8
Unicode string, which should make it easy to use other languages. I leave
it to others to see if right-to-left text like Hebrew or Arabic will work.
The source code is available for all this software. It is available for any
use as long as the author is given credit. Software improvements, exhibit suggestions,
and new exhibits are welcome. If there is enough interest, I will set up
CVS access or put the whole thing on sourceforge.
The software comes from many sources. All software is believed to be open source
and freely-usable, or at least under GPL. If you believe that copyright violations
exist, please let me know.
In general, the software should run on any PC that FreeBSD runs on. I make
no promises here. I have been focusing on bare-bones PCs that fit in my
luggage as a luggable solution. Laptops work fine, except I know
of no supported, high-speed video source for laptops.
From Logisys Corp. (URL gone)
I have used the NetPC SLIM PC, with video/audio/LAN/ATA100/IEEE1394,
including a 20GB drive (the smallest available, and used only for development
and debugging) and Mitsumi 54x CD-ROM. The Intel Pentium 4 at 2.4GHz is
plenty fast enough for all the video transforms, and the 256MB of RAM is
way more than we need. The cost, including shipping to New Jersey, was
just under $600. I installed the Hauppaugh WIN/TV card in one of the
two PCI slots. It cost about $50 additional.
The Ethernet port is currently only used for development. We could do a lot
of cool things with a network connection. Perhaps a shutdown service for
the museum closing time.
Unlike the previous exhibits, we only use the computer's VGA screen for output.
The original exhibits had separate video and screen outputs. Normally, we
drive a VESA VGA screen for the exhibit, but an X version is available that
is useful for debugging. It is a bit slower for some of the functions.
At present, we obtain 320x240x32 images. We used to get smaller pixels,
but it complicated processing at only modest performance improvements, which
today's CPUs no longer need.
We use the standard microphone input and speaker or line out output for sound.
The embedded microphone in a laptop works, but picks up noises from the disk,
the fan, etc.
I have attempted to write this software clearly and simply, using the simplest
auxiliary software possible. The need for Unicode characters complicated things.
The program is written entirely in ANSI C. Hardware-specific code is isolated
in particular libraries and files.
Software from the ports collection
From the FreeBSD ports collection we need:
The X version requires the GLX and DRI extensions.
I hated to do this: I'd like to run standard software where ever reasonable,
but I couldn't.
I didn't want museums to have to configure the X window system, so I
use raw VESA VGA access. This has necessitated a couple of small, simple, slightly
vexing kernel patches to FreeBSD. One patch allows the kernel to report VESA
modes that are reported disabled by the VGA BIOS, something ATI boards do. Apparently
they only claim to support VESA modes when Windows drivers are installed. It
turns out that the hardware supports them well enough for our uses anyway.
We use 32-bit pixels in the VGA memory, which is not available in FreeBSD's
rudimentary VESA support. (They go up to 24-bit pixels, which some graphics
cards don't support. And 24-bit pixels ran slower than 32-bit pixels in my
tests.) Therefore, the second mod lets a user program running as root to select
any VGA mode he wants that is in the BIOS table. This would actually be a reasonable
permanent change to the kernel.
The kernel must be built to support the BT484 card. To the kernel
configuration file add:
# Brooktree driver has been ported to the new I2C framework. Thus,
# you'll need to have the following 3 lines in the kernel config.
# The iic and smb devices are only needed if you want to control other
# I2C slaves connected to the external connector of some cards.
and you will need:
sh MAKEDEV bktr0
The program will need read/write access to /dev/bktr (for /Brooktree
input) or /dev/ugen* for the dlink camera.
Finally, both bare-bones MiniITX PCs failed to boot an unmodified FreeBSD.
Something in the disk DMA stuff is incompatible, causing timeouts. If
ATA DMA is turned off, it works fine, and still darned fast. The boot
I added a patch to the kernel to make that the default, and the machine works
fine. In fact, it builds new systems and kernels with blazing speed, so I guess
the DMA isn't that vital.
Though careful coding practices have been used in most areas, I do not expect
the general public to have access to the keyboard, or to a network port. Coding
efforts have focused on making the publicly-accessible portions of the interfaces
bulletproof and reliable.
At present, the exhibits need to run as user root to access the
VGA displays. This ought to be changed, but shouldn't be a big deal on
these single-user, isolated hosts, or when run from a CD-ROM.
The X version can be run without root as long as the various input devices
are accessible to the program.