PIGLET

PIGLET
Personal Interface to Access Grid,
Linux Exclusively Thanks

Overview

Hardware

Software

Audio

PIGLET is a single machine configured to deliver exactly the functionality of a traditional 3 machine access grid node, as specified by ANL (Argonne National Laboratory). Recently, specifications for a Windows based single machine node (the PIG) were released. While this acronym is now being used as the basis of PIGLET's name, the system itself has actually been in use at Vislab since early 2002.

In supporting the full functionality of a traditional access grid node, PIGLET easily surpasses the features of a Windows based PIG, even with the lower powered CPU shown in the following table.

	PIG	PIGLET
Required CPU	Dual Xeon P4, 1.5GHz or better	Single P4, 2.26GHz
Viewable screens	3	4
Camera count	2	3
Capture card type	Osprey 200	Any?

Based on published PIG hardware specification (July 2002) and PIGLET built at Vislab.

In August 2002, Vislab's PIGLET was rebuilt to incorporate more powerful graphics cards and motherboard, with the result that PIGLET is now capable of running OpenGL based graphics programs, in particular Performer, OpenInventor and OpenDX. The sections below describe this current incarnation of Sydney Vislab's PIGLET.

One of the tested capture cards is capable of hardware MJPEG compression enabling sending or receiving video at full PAL D1 resolution of 720x576 at 25fps (NTSC is also possible).

Shortcomings?

Being Linux based, PIGLET is not capable of participating by itself in sessions where Windows programs are required e.g. PowerPoint slide shows via DPPT. Although PowerPoint files are easily played locally using CrossOver Office, and DPPT itself is a Java application, we haven't had time to put the two together yet. If anyone figures it out, please let us know! In the meantime, we have a Windows machine nearby on which we run DPPT. We use VNC to incorporate the Windows machine's desktop into PIGLET's projected display.

Hardware

The computer components used are:

Soltek SL-85 ERV 533MHz FSB motherboard (includes on-board sound)
1x 2.26GHz P4 cpu
500MB DDR PC-2700 SDRAM
1x PNY Quadro4 550-XGL dual output AGP vga card
2x PNY Verto GeForce4 MX420 PCI vga cards
40GB IDE hard drive
3Com 3C996-T gigabit NIC
floppy drive, CDROM, case

3x Hauppauge TV-GO-FM Model 709 video capture cards

Some alternate pieces of hardware which were tried and also found to be acceptable:

PNY Quadro4 750-XGL dual ouput AGP vga card (better than 500-XGL but twice the price)
Intel PWLA8390MT E1000 gigabit NIC
HIS Riva TNT PCI vga cards (easier to find, but less performance than GeForce4 MX 420)
Linux Media Labs LML33 MJPEG card (full PAL/NTSC hardware MJPEG capture/play)

The gigabit NICs are really only useful when connected to a gigabit network. Prior to gigabit installation, 100BaseT performance was generally found to be OK as long as no network transfer of full PAL/NTSC (from LML33 card) was attempted.

Due to the number of available PCI slots, one of the Hauppauge video pacture cards is removed when we want to use the LML33 card.

A Logitech Quickcam Pro 4000 USB camera has also been added to our PIGLET. See the Pro 4000 usb installation tips.

PIGLET is housed in a rack-mount case, but any type of case should be OK.

Software

Our PIGLET was built with Slackware Linux (version 8.1), however any modern distribution should work. The machine should be set up to run in X windows mode and have a web browser installed (we use Mozilla 1.0).

The applications required to run the machine as an access grid node are listed below. Installation instructions are available for some of these applications. Some of the software is available as source code and/or Slackware package format.

The greatest departure from the ANL's Windows based PIG (and recipe system) is the use of the Virtual Venues Daemon (VVD). This daemon tracks the user's browser based movement through a virtual venue, restarting the video, audio and mud applications appropriately.

ALSA full-duplex audio drivers	Installation	Original site
rat audio application	Installation	Original site
tkMOO-lite mud application	Installation	Original site
vic video application	Installation	Original site
vnc remote desktop application	Installation	Original site
vvd venue tracker & application execution daemon	Installation	Original site

PIGLET uses Matt Delco's RTPtv to multicast full PAL/NTSC MJPEG video streams from the LML33 card. RTPtv's vserver and vclient programs must be run manually, since they are not yet under the control of VVD.

Audio

A full-duplex audio driver is required for correct operation. The default OSS drivers supplied in the current stable Linux kernel release (v2.4.x) are generally considered to be unsuitable. Suitable OSS drivers are apparently available from 4Front Technologies but we have not tried them and they are not free (although inexpensive). We use the open source drivers from ALSA which require building from source code.