The power and capabilities of laptops are sometimes limited as described above. But in turn, they have a feature which desktops don't have, their mobility. I try to give a survey about applications which make sense in connection with laptops. Since I couldn't try all of them, there is currently little documentation. If you can provide further material, please contact me.
I'm not an expert in this field, so I just mention the tools I know. Please check also for other applications. Besides the usual tools tcpdump, netcat, there are two applications I prefer, which may be used to analyze network traffic:
The Multi Router Traffic Grapher (MRTG) is a tool to monitor the traffic load on network-links. MRTG generates HTML pages containing GIF images which provide a LIVE visual representation of this traffic. Check http://www.ee.ethz.ch/stats/mrtg/ for an example. MRTG is based on Perl and C and works under UNIX and Windows NT.
Network Top - ntop
http://www-serra.unipi.it/~ntop/ is a Unix tool that shows the network usage, similar to what the popular top Unix command does. ntop is based on libpcap and it has been written in a portable way in order to virtually run on every Unix platform and on Win32 as well. ntop can be used in both interactive or web mode. In the first case, ntop displays the network status on the user's terminal. In web mode a web browser (e.g. netscape) can attach to ntop (that acts as a web server) and get a dump of the network status. In the latter case, ntop can be seen as a simple RMON-like agent with an embedded web interface.
Though designed to work from a single floppy, the Linux Router Project (LRP) , seems useful in combination with a laptop, too.
When thinking about the powers of laptops, hacking and cracking networks may come into mind. Though I don't want to handle this topic here, but instead recommend the Security-HOWTO.
If you are giving lectures, readings or presentations in different places, a laptop might suit your needs. You can combine it with an overhead display, a beamer or a second monitor. For a second monitor or a beamer make sure it is supported by your laptop.
Though Microsoft's PowerPoint is often used for such things, there are also Linux solutions:
KPresenter and others. And GNOME
http://www.gnome.org/ .
mgp, is an X11-based presentation tool. The home page is
http://www.Mew.org/mgp or
ftp://ftp.Mew.org/pub/MagicPoint/ or
http://jiji.mew.org/mgp/ .
A Linux laptop can be used to collect data outside an office, e.g. geodesy data, sales data, network checks, patient data in a hospital and others. There is support for wireless data connections via cellular phone modems and amateur radio. I am not sure whether PCMCIA radio cards are supported, see Aironet Wireless Communications http://www.aironet.com/.
There are laptops available with cases build for a rugged environment (even waterproof laptops). In some environments, for instance in hospitals, take care of the Electro-Magnetic-Compatibility of the laptop. This is influenced by many factors, for instance by the material used to build the case. Usually magnesium cases shield better than the ones made of plastics.
With KDE http://www.kde.org (K-Office), GNOME, http://www.gnome.org/ and the commercial products WordPerfect, Staroffice and Applixware http://www.applix.com/ Linux has more and more business software applications. With the corresponding hardware, e.g. a portable printer and a cellular phone which connects to your laptop, you will have a very nice mobile office.
AFAIK there are currently three methods to connect a digital camera to a laptop: the infrared port (IrDA), serial port and maybe USB. There are also some auxiliary programs for conversion of pictures, etc.
Eric <dago@tkg.att.ne.jp> wrote: "I finally succeeded in downloading pictures from my digital camera, but not exactly the way I expected, i.e. not through USB port but using pcmcia card port and memory stick device, part of digital camera hardware. Anyway, some interesting things to mention:
Sony (pretending using a standard) uses the msdos format to store images as JPEG files ; so the best way to have your OS recognizing them is to mount the raw device like a msdos filesystem; using mount directly doesn't work (don't know why) but an entry in the /etc/fstab file allows you to mount the device correctly. i.e.:
/dev/hde1 /mnt/camera msdos user,noauto,ro 0 0
newfs before mount works too, but there is nothing to see at all ;-) I think both noauto and ro are important flags; I tried without it and it didn't work. Somehow the mount I got seems buggy . And if ro is missing, the camera doesn't recognize back the memory stick and it needs to be msdos-formatted.
According to the camera documentation , both pcmcia and USB port behave the same (for Mac and Windoze - i.e. you see a file system auto mounted) - I deduce for Linux it should be the same thing too, as long as the USB driver is installed. I think now that mounting USB raw device the way I did with pcmcia should work, but I still couldn't find which device to use."
OpenDiS (Open Digita Support) is a library and utility program for cameras such as the Kodak DC-220, DC-260, DC-265, and DC-280, that run Flashpoint's Digita operating system. The library is a unix implementation of the Digita Host Interface Specification, intended for embedding Digita support in other products such as gPhoto. The utility is a simple command-line program for standalone downloading of photos from the cameras.
gPhoto enables you to take a photo from any digital camera, load it onto your PC running a free operating system like GNU/Linux, print it, email it, put it on your web site, save it on your storage media in popular graphics formats or just view it on your monitor. gPhoto sports a new HTML engine that allows the creation of gallery themes (HTML templates with special tags) making publishing images to the world wide web a snap. A directory browse mode is implemented making it easy to create an HTML gallery from images already on your computer. Support for the Canon PowerShot A50, Kodak DC-240/280 USB, and Mustek MDC-800 digital cameras.
photopc is is a library and a command-line frontend to manipulate digital still cameras based on Fujitsu chipset and Siarra Imaging firmware. The program is known to work with Agfa, Epson and Olympus cameras. Should also work with Sanyo, but this is untested. The cameras typically come with software for Windows and for Mac, and no description of the protocol. With this tool, they are manageable from a UNIX box. Bruce D. Lightner <lightner@metaflow.com> has added support for Win32 and DOS platforms. Note that the program does not have any GUI, it is plain command-line even on Windows. For a GUI, check out the phototk program.
AFAIK there are currently two methods to connect a video camera to a laptop: a ZV port and maybe USB, but I don't know how this works with Linux. I have heard rumors about using a sound card for video data transfer to a Linux box, see
http://worldvisions.ca/~apenwarr/ . I have heard rumors about a Linux-QuickCam-mini-HOWTO, but couldn't find a reliable URL yet. Check the sane package which is build for scanner support, this should contain support for still-grabbers as well.
kmc_remote provides a graphical interface for controlling Kodak Motion Corder fast digital cameras over a serial connection. kmc_remote is built on the kmc_serial library, part of the kmc_utils package. kmc_remote provides a virtual button panel and simple one-touch commands for changing system variables which would involve multiple button operations on the real camera button console. Buttons, record settings (image size, record rate, shutter speed, trigger mode, burst mode), and playback rate control should be fully functional. All camera models are supported, as well as both PAL and NTSC video.
Intel PC Camera Pro Pack is one of the first webcams with USB ports. Also SONY has announced a webcam with USB port. See a survey at Steve's Digicams.
If you have a ZV port in the laptop, it should be easy to connect it to a TV set, using either NSCA or PAL, but I don't know whether either works with Linux.
AFAIK there are two methods to connect a cellular phone to a laptop: via the infrared port (IrDA) or via the serial port. See the Linux/IrDA project for the current status of IrDA connections. AFAIK only the Ericsson SH888, the Nokia 8110 and the Siemens S25 provide infrared support.
From the Hardware-HOWTO I know there is Trimble Mobile GPS available. You may also connect a GPS via a serial port. Most GPS receivers have a data port and can connect to a PC with a special serial cable.
dgpsip provides correct GPS location with DGPS signal from internet.
AFAIK laptops are used in HAM contests. Please see HAM-HOWTO by Terry Dawson, VK2KTJ, <terry@perf.no.itg.telstra.com.au> .
Together with an antenna and software like seesat or sattrack you can use a laptop to locate a satellite for visual observation. You could also use xephem on a laptop when stargazing.
Many people are using laptops for aviation related topics. The Aviation HOWTO is an FAQ, HOWTO like document that provides pointers to software packages that run under the Linux operating system and are useful to private, commercial, or military pilots. The ultimate goal is to enable pilots to use the Linux operating system for all their aviation related computing needs.
There are some groups of which could gain a specific profit by using laptops. For instance blind or visually impaired people (I explicitly avoid to say handicapped people). See ACCESS-HOWTO and
Blinux - Linux for blind people for more information. BRLTTY is a program which supports different braille terminals. Festival is a speech synthesis system. Screen and cursor magnifiers are available.