1.1. Advanced Power Management (APM/ACPI)

Putting your GNU/Linux PC in suspend or hibernate mode.

VMAJOR=1
VMINOR=1
DRIVER="speedstep-centrino"
OPTS="-i 2
-t /proc/acpi/thermal_zone/THM/temperature 70
-a /proc/acpi/ac_adapter/AC/state
-p 10 25
-m 600000 -M 1600000"

1.2. Power Management Unit - PMU (Apple PowerBook)

PowerBooks don't support the APM specification, but they have a separate protocol for their PMU (Power Management Unit). There is a free (GPL) daemon called pmud that handles power management; it can monitor the battery level, put the machine to sleep, and set different levels of power consumption. It was written by Stephan Leemburg <stephan at jvc.nl>, and is available from PPC distribution FTP sites. There is also an older utility called snooze available from the same sites that just puts the PowerBook to sleep.

1.3. Turn Monitor off, use Keyboard LEDs

There are some tools which allow to get information from your computer without using the monitor:

• bl : Blink Keyboard LEDs

• blinkd : "Blinks keyboard LEDs for an answering machine or fax machine. Blinkd is a client/server pair, that lets the keyboard LEDs blink, indicating things like the number of incoming voice calls in the voice box or incoming faxes in the spool."

• mailleds : Shows new mails with the keyboard LEDs, mailleds is a quiet, unobtrusive way to signify that you have new mail: a user daemon to blink LEDs when there is new mail.

• tleds : Blinks keyboard LEDs indicating TX and RX network packets. They blink Scroll-Lock LED when a network packet leaves the machine, and Num-Lock LED when one is received.

• ledcontrol: is a program that allows you to show different information on the normally-unused LEDs on your keyboard. You can configure it to show virtually any true/false condition accessible or indicate an arbitrary number. The monitoring is by default done by shell scripts to allow for maximal configurability.

1.4. Screensavers

xset dpms force standby
xset dpms force suspend
xset dpms force off

1.5. Virtual Servers: Consolidation and Virtualization

On enterprise networks, or on the Internet, security constraints may require that different services are run on different, isolated servers. The problem with this one server per service approach is that most spend a lot of idle time waiting for some rare activity bursts.

Several technologies now make it possible to run several GNU/Linux servers inside a real, physical GNU/Linux server. As in physical servers, each virtual server is isolated from the others. So, this approach retains the benefits of separate servers, but makes it possible to share some hardware resources like the CPU and network bandwidth. On the other hand, each virtual server enjoys a reserved amount of RAM and disk space.

The benefits of virtual servers are obvious in terms of cost, power consumption, optimum use of hardware resources, and consumption of computer materials. There is another key advantage for hardware maintenance: virtuals servers can very easily and transparently be migrated from one physical server to another.

Virtualization solutions:

• User Mode Linux - The original solution. Allows to run one or several Linux kernel executables on a Linux machine (with a standard kernel) as regular programs.

• Xen - An increasingly popular alternative, with very little performance overhead. Also allows live server migration to other hardware. Requires a patched Linux kernel.

Virtuals servers all already very popular solutions for website hosting, but virtualization still has a very strong potential in corporate networks.

1.6. Energy Star Label

Robert Horn <rjh at world.std.com> wrote: "

I had a chance to discuss Energy Star with the designers of desktop printers. They confirmed that the allowable stand-by power targets depend on the device, and they only knew their targets. But they made some other interesting comments:

• Energy Star ratings lead to significant operational power savings. Timer based power savings are the exception. Most savings come from designing in power on demand with low leakage drivers. For example, using stepper motors with low leakage current instead of high leakage.

  This savings is both from individual designs and from the resulting demand for low leakage products causing better and cheaper low leakage product designs. The old-style (e.g. typewriter) design with one motor (always on) and various clutches is no longer the least cost.

• Energy Star was good organizational engineering. It never required designers to compromise quality or performance, which made it much harder to argue against design changes to reduce power consumption while idle. Since most of the savings begin the millisecond that parts stop moving, these savings are considerable.

• The power ratings on PC's are a safety rating, not a usage rating. So the 235W and 300W power supplies that commonly found in PCs are specifying their safety limits. Actual full power usage is much less, typically 20-30 percent of the safe limit. The designers also noted that it is actually difficult to measure the power consumption of a switching power supply. You need to use specially designed power meters. The regular AC meters are designed for motors, and are rather inaccurate for switching power supplies.

1.7. Using Spare CPU Cycles

Some Linux applications use idle time in computers to cure diseases, study global warming, or any other scientific research. They run as a low-priority process (nice 20), so you can work without noticing that it's doing its task. Another use is for people who use P2P software and leave the PC turned on for long hours unattended, all that time the PC can be using the electricity it is consuming for a practical purpose:

• BOINC

• Distributed.net

1.8. Miscellaneous Power Saving Techniques

Linux halts the CPU in the idle cycle to further reduce power consumption. Early reports of OS/2, Win3.1/95, NT, and Linux showed Linux to use far less power than DOS-based O/S's that spun in the idle loop and consumed power -- this may have changed hence it would need research to validate.

Most Linux-users tend to leave their computer on for years whenever possible. However, several modern BIOS's support an unattended powerup, and with cron you can even do an unattended shutdown. No need to leave the computer on night after night. Other techniques to powerup your computer at certain times are: ACPI-Wakeup, NVRAM-wakeup and the settime command. Computers can even be power up on request remotely by means of Wake-on-LAN using a network connection or Wake-on-Ring using an old fashioned serial interface and a modem.

Beware of animated web pages! Web pages containing Flash, Java, or just animated images can consume a lot of CPU. When you leave your computer and keep it on, make sure you close all browser pages with animations. Otherwise, your PC may be left running at full speed while you are not using it.

To disable animated images in Mozilla Firefox go to about:config, find image.animation_mode and change its value to none or once.

Do not forget to switch off your DSL modem / wireless router / ISP box / printers at night or during vacations if you don't use them. These devices consume quite a lot (typically 15W).

3.1. Fan

• libsensors0 is a library to read temperature/voltage/fan sensors

• lm-sensors: "Kernel drivers to read temperature/voltage/fan sensors. This is a module for reading the temperature/voltage/fan sensors in Linux via the LM78/79 chip and possibly sensors on the SMBus (System Management Bus, usually found in P6 and P-II systems). The LM80 and a LM78-clone called W83781D are also supported."

• ACPI, see APM chapter

• RTSensors can be configured by the user as an expert controller: The user can specify the max/min speed of the system fans, the maximum affordable temperature and so on. The controller tries to reduce fan speed to reduce noise while the temperature is in a safe range chosen by the user. So fan speed is modified automatically by the control algorithm, you don't have to use those mechanic or thermal regulators on your fans anymore.

3.2. Harddisk

To avoid unneccessary hard disk noise you may use the same techniques as described in the power saving chapter. Hard disks in most laptops are the primary source of noise. Modern laptop and notebook hard drives come with a so-called "Acoustic Management", just have a look into the manual to get an overview about the possible settings.

The noise of the hard disk can be very disturbing, see man hdparm to reduce the spin of the disk.

Some hard disk manufacturers offer dedicated tools, e.g. Hitachi's Feature Tool allows to change the drive Automatic Acoustic Management settings to the Lowest acoustic emanation setting (Quiet Seek Mode), or Maximum performance level (Normal Seek Mode).

3.3. Speakers

For the console setterm -blength 0 and for X xset b off turns the bell off. See also PCMCIA-HOWTO, and much more details in the Visible-Bell-mini-Howto by Alessandro Rubini.

4.1. Printing of Drafts / Multiple Pages on One Sheet of Paper

Use psutils package to put more than one page on one sheet of paper. This collection of utilities is for manipulating PostScript documents. Page selection and rearrangement are supported, including arrangement into signatures for booklet printing, and page merging for n-up printing.

For example, to create a PostScript document with 4 pages per sheet:

psnup -nup 4 doc.ps > doc4p.ps

Often HTML pages are not optimised for printing. You may use html2ps, a HTML to PostScript converter, to print HTML pages. "This program converts HTML directly to PostScript. The HTML code can be retrieved from one or more URLs or local files, specified as parameters on the command line. A comprehensive level of HTML is supported, including inline images, CSS1, and some features of HTML 4.0."

Or you may use mpage to print 2 up or 4 up (PS documents or ASCII text). This may be used to save up to 50 percent or more of your paper.

4.2. Double Sided Printing

One important way to save paper is to print on both sides of the paper. Depending on the printer capabilities, this can either be done manually (printing odd and even pages in 2 passes), or by instructing the printer to use both sides.

4.3. Reading From the Monitor Instead From Paper

Or use less/xless/gless as a viewer instead of printing. You can view PostScript documents with gs and view PDF documents with either xpdf or acroread (from Adobe). Ask yourself, do you --really-- need a hardcopy each time you decide to print something out.

For your own documents, a good idea is to create them in landscape mode, making them easier to read without having to scroll up and down. Otherwise, readers may find reading from the screen inconvenient and may then prefer printing. See PDF editions of the free Tux Magazine for a nice examples.

What are the reasons why people don't read from the monitor:

• Reading is slower up to 30 percent, see Jakob Nielsen: In Defense of Print. The speed can be improved by better hardware (e.g. TFT display, greater screen, though this is against the other below to take smaller CRTs) and better display software and fonts (type-1, t1lib, truetype, freetype).

• Paper seems better organizable and more secure to some people. I suppose this can be treated by better software (e.g. Linux) and hardware, too.

Some people use handheld PC (e.g. PalmIII, Newton Message Pad, Psion 5) to carry around documents to read rather than printing them out. At TuxMobil you may get information about Linux compatibility for handheld PCs and PDAs. Or they take eBook readers to read "Electronic Paper". At TuxMobil there is a section about Linux compatibility for eBook readers, too.

4.4. Other Techniques

Another means of saving paper is through the use of comments and redline/strikeout markings when exchanging a document with a co-worker/colaborator. For example, a draft could be written using WordPerfect, then E-MAILed to a co-worker. They could update the draft and send it back to you. You can use WordPerfect's redline/strikeout features to see the changes. The document need not be printed until it is "final" or in "final draft" status.

Question: Can you use the back side of paper in a laser printer? I have not had much luck. You can use the paper that has been in a laser printer in an inkjet printer by using the other side.

You should purchase smaller computers and monitors when possible. This will save packaging material translating into less solid waste. For example the box for a 15" CRT monitor is 2-3 times the size of the box for a 15" LCD monitor. Linux works well with 15" LCD monitors on smaller computers like the Netwinder or E3000 .

Tough smaller monitors may have another ecological caveat: because it's inconvenient to browse to longer documents, people may tend to print the documents instead of reading them from the screen.

Some have expressed the concern that LCD displays may use more toxic materials and manufacturing processes than CRT displays, hence their usage actually may be worse on the environment. The original information above concerned the solid waste issue, which is fairly tangible and hence more controllable.

Does anyone know of studies or additional research to help clarify and resolve this issue?

Recycle your used paper, ink, and packing materials.

You may use refillable printer cartridges. In Germany the are marked with the Blauer Engel label.

Laser printer cartridges can often be used much more longer if you shake them when the message toner low appears at the message panel.

• LaTeX documents: Using \usepackage{ccfonts} replaces the usual fonts by ones with wider lines and bolder serifes, improving readability at low resolutions. They are darker (i.e. use more ink) than the CM fonts and not as beautiful, so I would not recommend them for normal-size printings.

• Size-Reduction: Instead of psnup or other parts of the pstools check for enhanced Perl rewritings of psnup.

  It has a lot of options, which allow to set all 4 margins and the inner gutter separately. Since reduced documents are not very pretty anyway, this can be used to reduce the margin, leaving more place for the text. This probably requires some experimenting (trying new values over and over, checking the result with ghostview).

  The normally used options are:

  • -p2 (or -p4 etc., like -2 in the old psnup)

  • -NIH (don't decorate)

  • -l10 -r20 -b30 -t40 (add to margins)

  • -g50 (add to gutter)

  (these values vary depending on the papersize and the margins of the original, negative values are allowed).

• PDFjam is a small collection of shell scripts that provide a simple interface to some of the functionality of the pdfpages package for pdfLaTeX. At present, the utilities available are pdfnup, pdfjoin, and pdf90. PDFjam depends on a working installation of (pdf)LaTeX. pdfnup puts multiple document pages together on one physical page at a reduced size. pdfjoin concatenates multiple PDF documents. pdf90 rotates the pages of PDF documents. For Mac OS X, some example applications (droplets) are provided for drag-and-drop access to the scripts.

• Different ink printers are more or less capable to print on the backside of already used paper sheets. That's particularly useful to reuse all single sided paper sheets you receive for free every week! Try different manufacturers. Older Canon ink printers offer 360 dpi, older HP ink printers 300 dpi. The readability of 4 pages/sheet using LaTex 10pt lies in between this features.

• Non-Linux: If you have to work with MS-Windows you should get the original Adobe-PostScript-Driver, instead of using the ones from MS-Windows. These drivers offer more than one page per paper sheet. AFAIK both psnup programs don't work with Adobe-PS, MS-Windows-PS and the PostScript extracted from MS-Windows-PDF files. The Computer-Modern-Fonts (without German diacritical characters) are available as TTF fonts on the CTAN servers. With these fonts you may enhance the aesthetical value of documents and save some paper space, too.

• Ghostscript has a new output format pswrite, which creates output in correct PostScript. This feature can be used to repair broken PostScript e.g. from Microsoft drivers, allowing their postprocessing with psnup etc.

• impose+ is a set of PostScript utilities. The main program is impose, which is used for two-up printing of DSC-compliant PostScript (including that from Netscape, dvips, and FrameMaker). It makes an effort to remove white space from the printout by probing the original PostScript for the bounding box of the printed area. This makes the output much more esthetic than does a simplistic layout of non-cropped original pages.

• hpgs is a printer driver that lets you to print on a HP 6xx Series printer using economic mode. It relies on the printer driver included in GhostScript to do everything but put the printer into economic mode.

• Besides command line tools for sophisticated printing there are also usefull GUI applications available. KPrinter opens automatically when you click on the "Print" icon of any KDE application. Choose your print job settings by going through the dialog and the click on the "Print" button. kprinter is a very versatile tool. Depending on the actual features and power of the print subsystem of your com- puter, kprinter translates the former's abilities into a nice and easy-to-understand GUI e.g. if your print subsystem does not support duplexing, kprinter will not show the option.

• gnome-manual-duplex is a utility that adds manual duplex to the "Print" menu.

• ecofont is an open source sans serif font with holes added to save printer ink.

• If you need to print a lot of Web pages from inside your FireFox webbrowser, the Nuke Anything Enhanced extension will help you to save some ink and paper. Once installed, it adds a "Remove this object" option to the right-click context menu. Place your mouse over information you don't need printed (menu bars, big graphical logos and so on) and use "Remove this object" to zap them temporarily. Clean up the page, then print just what you need.

Wade Hampton provided the biggest part of this chapter. Some suggestions are from Ralf Muschall.

8.1. Recycling of Hardware

The commercial computer market is largely driven by vendors seeking to sell new hardware and software. There is no commercial marketing benefit in promoting reuse.

Hence Linux doesn't require big hardware, it's very useful if you like or need to use old and small hardware.

8.2. Other Techniques

NiCad batteries need to be discharged periodically to prevent the memory effect and prolong their lifespan.

Batteries such as NiCad, Lead Acid, and NiMH contain TOXIC chemicals. Techniques should be taken to prolong their lifespan, and when you do discard them, they should be recycled, not thrown in the trash.

One technology to watch is the Iron battery. Such a battery could reduce some of the toxic waste problems associated with used batteries, however such a battery is probably a few years away.

Some remarks about backlights in laptops, monitors (screensavers), harddisks (hdparm), etc. have to be written.

8.3. Linux BadRAM Patch

The objective of the BadRAM Patch is to run the Linux kernel in such a way that it can handle defective RAM modules. With defective RAM, I mean RAM which has some bits wrong at some (known) addresses. Normally, such RAM is considered useless and thrown away; the larger RAMs get, the higher the chances of failing addresses. With ever growing RAM sizes, it would therefore be pleasant to have an alternative to discarding of defective RAM chips.

8.4. Installing Linux on Older Hardware

Lightweight Linux, Part 1: Hardware is only as old as the software it runs: a modern operating system and up-to-date applications return an older system to productivity. This article provides best practices and step-by-step guidance on how to build a working Linux system on older hardware or on modern hardware with limited memory and storage.

Purging of uneeded Locales: localepurge for Debian/GNU Linux is just a simple script to recover disk space wasted for unneeded locale files and localized man pages. Depending on your installation, it is possible to save some 20, 30, or even more megabytes of disk space usually dedicated for locales you'll probably never have any usage for.

8.5. Upgrading and Repairing Computer Hardware and Communication Devices

Usually manufacturers declare the warranty to be void if the case was opened by people other than their own staff. If you want to try it anyway you may find some interesting links about how to repair, disassemble, upgrade or mod laptops or notebooks, repair broken PDAs and HandHelds, as well as repair mobile (cellular) phones, repair portable audio and video players, repair, clean and mod a computer mouse, repair printers, ink and toner cartridges, repair hard disk drives, repair and clean computer keyboards and repair and mod GPS navigation devices and repair personal computers - PCs.

BTW: here are some non-computer related links to guides explaining, how to repair (digital) cameras, repair cars.

8.6. Other Operating Systems

Courtesy of George White <gwhite at bodnext.bio.dfo.ca>: Or you can buy an older computer (SGI, Sun, NeXT) that comes with unix and is capable of running a wide range of open source software. In some cases (SGI Indigo2) you can still run current OS versions, in others you may do better with an open source OS such as Linux, but in either case you have access to lots of good software and tools to write your own. The lower power consumption of older computers means you get more reserve time from an UPS or can use a small alternative power source if you don't have access to "mains" power.

9.1. Using Consumer Electronics Devices

Linux is increasingly used in Consumer Electronics (CE) devices, in particular in network appliances such as Wifi routers, DSL modems, Network Attached Storage (NAS) servers, IP cameras and other small devices.

Thanks to the GNU GPL license, kernel and application source code for these devices are freely available. More and more device owners are taking advantage of this to develop other uses for these devices. Thanks to the progress of Linux in embedded systems, making its own embedded system is increasingly easy.

Using such devices instead of regular PCs yields many advantages: much lower power consumption, no noise (no fans), built with much fewer materials (small size), and much lower cost (for your purse and for the environment).

• NSLU2-Linux - A community of people running Linux on the Linksys NSLU2 device. This device is originally a Network Attached Storage server, featuring a 266 MHz ARM CPU, 8MB of flash, 32MB of SDRAM and a rich connectivity: Connectivity: USB (for attached storage), Ethernet and a serial port. That's all you need in a versatile Linux computer. Many different cool applications are listed by the project.

  The NSLU2 device is still available in the shops on all continents, for a very cheap price: approximately 90 € or 90 US Dollars. This makes this device extremely popular!

• OpenWRT - A project to run Linux on WiFi routers based on the Linksys WRT chipset. A typical configuration includes a 125 to 200 MHz ARM CPU, 4 MB of flash, 16 MB of RAM, and Ethernet, WiFi, serial port (often) and a USB host port (often).

  Devices based on the Linksys WRT chipset are available for sale on all continents, costing between 50 and 100 € / US Dollars. They are very popular too!

In a nutshell, do not buy a new PC for small applications. Reuse your old computers or buy a consumer device on which you can run Linux!

9.2. Using Embedded Linux Boards

Instead of using a PC, or even instead reusing a consumer device, you may also create your own system using dedicated embedded system boards. Because of lower volumes, such boards may be a bit more expensive, but they can achieve much reduced size and power consumption. Both low and higher volumes are available too.

Here are a few noteworthy examples:

• Picotux - The smallest Linux computer in the world, only slighly larger than a RJ45 connector. Pretty cheap too.

• Gumstix - Small, affordable embedded boards with the size of a gumstick. Backed by an active community too.

See this independent list of interesting board suppliers for more details.

13.1. Ecolab

Ecolab is both the name of a software package and a research project that is looking at the dynamics of evolution. EcoLab is a system that implements an abstract ecology model. It is written as a set of Tcl/Tk commands so that the model parameters can easily be changed on the fly by means of editing a script. The model itself is written in C++.

13.2. Tierra

Tierra by Tom Ray is a tool for studying digital evolution and ecology that runs on Linux and other OSes.

13.3. Linux in Environmental Research

Courtesy of Wade Hampton: Linux is ideally suited for use as a research tool for environmental experiments. There are small embedded Linux solutions that can be used for remote monitoring or telemetry. There are VERY small Linux implementations from PC-104 systems to embedded systems like the uCsimm. Linux even flew on the shuttle controlling biological experiments.... Linux has been used for weather research on NOAA's Hurricane Hunter aircraft.

Linux is also an ideal platform for researching ecological and environmental information via the Internet using standard WWW-based tools like Netscape.

Linux may even be used to model complex biological and environmental processes. beowulf clusters have been used to run complex simulations of environmental processes, for example Earthdome, listed in the Beowulf projects page.

13.4. SWARM

SWARM is a software package for multi-agent simulation of complex systems that is being developed by the Swarm Development Group (SDG).

Swarm is intended to be a useful tool for researchers in a variety of disciplines, especially artificial life. The basic architecture of Swarm is the simulation of collections of concurrently interacting agents: with this architecture, we can implement a large variety of agent based models. The source code is freely available under GNU Licensing terms.

13.5. Climate-Dynamics

Linux clusters are used in climate modeling, for example in the University of Bern in Switzerland.

13.6. UNCERT

UNCERT is a geostatistical uncertainty analysis package applied to groundwater flow and contaminant transport modeling. This package was developed for evaluating the inherent uncertainty in describing subsurface geology, hydraulic properties, and the migration of hazardous contaminants in groundwater flow systems. It is well suited for the aforementioned purposes, but is also sufficiently general to be usable by researchers in a wide range of disciples.

13.7. EcoTopia

The EcoTopia web site uses computer simulation to model Santa Cruz, California as an ideal environmental community. For Ecotourists and Green Consumers, EcoTopia strives to offer the nation a model of integration of technology and environmental remediation using computer modeling and image forecasting.

13.8. Digiqual

Digiqual is a package to manage a quality and environmental control system for a factory. The package consists of six modules, but only the first module has been released. The modules are Supplier Evaluation, Non Conformity, Documentation, Maintenance, and Internal Audit, and Training. All data are stored in a PostgreSQL database by the psycopg connector.