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OpenSuSE 11.1 Quick Start Guide
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9.1 Laptops

The hardware of laptops differs from that of a normal desktop system. This is because criteria like exchangeability, occupied space, and power consumption are relevant properties. The manufacturers of mobile hardware have developed standard interfaces like PCMCIA (Personal Computer Memory Card International Association), Mini PCI, and Mini PCIe that can be used to extend the hardware of laptops. The standards cover memory cards, network interface cards, ISDN and modem cards, and external hard disks.

HINT: openSUSE and Tablet PCs

openSUSE also supports Tablet PCs. Tablet PCs come with a touchpad/digitizer that allows you to use a digital pen or even fingertips to edit data right on the screen instead of using mouse and keyboard. They are installed and configured much like any other system. For a detailed introduction to the installation and configuration of Tablet PCs, refer to Section 31.0, Using Tablet PCs, (↑ Reference ).

9.1.1 Power Conservation

The inclusion of energy-optimized system components when manufacturing laptops contributes to their suitability for use without access to the electrical power grid. Their contribution towards conservation of power is at least as important as that of the operating system. openSUSE® supports various methods that influence the power consumption of a laptop and have varying effects on the operating time under battery power. The following list is in descending order of contribution towards power conservation:

  • Throttling the CPU speed.

  • Switching off the display illumination during pauses.

  • Manually adjusting the display illumination.

  • Disconnecting unused, hotplug-enabled accessories (USB CD-ROM, external mouse, unused PCMCIA cards, WLAN, etc.).

  • Spinning down the hard disk when idling.

For more information on how to use the KDE power management applet, refer to Section 8.0, Controlling Your Desktop's Power Management with KPowersave, (↑ KDE User Guide ).

9.1.2 Integration in Changing Operating Environments

Your system needs to adapt to changing operating environments when used for mobile computing. A lot of services depend on the environment and the underlying clients must be reconfigured. openSUSE handles this task for you.

Figure 9-1 Integrating a Mobile Computer in an Existing Environment

The services affected in the case of a laptop commuting back and forth between a small home network and an office network are:

Network

This includes IP address assignment, name resolution, Internet connectivity, and connectivity to other networks.

Printing

A current database of available printers and an available print server must be present, depending on the network.

E-Mail and Proxies

As with printing, the list of the corresponding servers must be current.

X (Graphical Environment)

If your laptop is temporarily connected to a beamer or an external monitor, the different display configurations must be available.

openSUSE offers several ways of integrating a laptop into existing operating environments:

NetworkManager

NetworkManager is especially tailored for mobile networking on laptops. It provides a means to easily and automatically switch between network environments or different types of networks, such as wireless LAN and ethernet. NetworkManager supports WEP and WPA-PSK encryption in wireless LANs. It also supports dial-up connections (with smpppd). Both desktop environments (GNOME and KDE) include a front-end to NetworkManager. For more information about the desktop applets, see Section 10.4, Using KDE NetworkManager Widget and Section 10.5, Using GNOME NetworkManager Applet.

Table 9-1 Use Cases for NetworkManager

My computer…

Use NetworkManager

is a laptop

Yes

is sometimes attached to different networks

Yes

provides network services (such as DNS or DHCP)

No

only uses a static IP address

No

Use the YaST tools to configure networking whenever NetworkManager should not handle network configuration.

SCPM

SCPM (system configuration profile management) allows storage of arbitrary configuration states of a system into a kind of snapshot called a profile. Profiles can be created for different situations. They are useful when a system is operated in changing environments (home network, office network). It is always possible to switch between profiles. To get SCPM up and running on your system, install the package kscpm, add the Profile Chooser KDE applet to your panel, enable SCPM using the YaST Profile Management module, and configure the users that should be allowed to switch profiles without the need of entering the root password. Determine whether profile changes should survive a system reboot or whether they should be discarded upon shutdown. Make sure all resource groups (i.e. services like network and printer, for example) are active. Proceed to creating actual profiles using the SUMF (SCPM Unified Management Front-End) tool which is started via Profile Chooser. Create profiles for all the different setups you want to use this system in. Switching between profiles can either be done in the running system via the Profile Chooser applet or at system boot time via the F3 key. When switching profiles, SCPM automatically adjusts your system configuration to the new environment laid out in the profile you have chosen.

SLP

The service location protocol (SLP) simplifies the connection of a laptop to an existing network. Without SLP, the administrator of a laptop usually requires detailed knowledge of the services available in a network. SLP broadcasts the availability of a certain type of service to all clients in a local network. Applications that support SLP can process the information dispatched by SLP and be configured automatically. SLP can even be used for the installation of a system, sparing the effort of searching for a suitable installation source. Find detailed information about SLP in Section 21.0, SLP Services in the Network, (↑ Reference ).

9.1.3 Software Options

There are various special task areas in mobile use that are covered by dedicated software: system monitoring (especially the battery charge), data synchronization, and wireless communication with peripherals and the Internet. The following sections cover the most important applications that openSUSE provides for each task.

System Monitoring

Two KDE system monitoring tools are provided by openSUSE:

KPowersave

KPowersave is an applet that displays the state of the rechargeable battery in the control panel. The icon adjusts to represent the type of power supply. When working on AC power, a small plug icon is displayed. When working on batteries, the icon changes to a battery. The corresponding menu opens the YaST module for power management after requesting the root password. This allows setting the behavior of the system for different power sources.

KSysguard

KSysguard is an independent application that gathers all measurable parameters of the system into one monitoring environment. KSysguard has monitors for ACPI (battery status), CPU load, network, partitioning, and memory usage. It can also watch and display all system processes. The presentation and filtering of the collected data can be customized. It is possible to monitor different system parameters in various data pages or collect the data of various machines in parallel over the network. KSysguard can also run as a daemon on machines without a KDE environment. Find more information about this program in its integrated help function or in the SUSE help pages.

In the GNOME desktop, use GNOME Power Manager and System Monitor.

Synchronizing Data

When switching between working on a mobile machine disconnected from the network and working at a networked workstation in an office, it is necessary to keep processed data synchronized across all instances. This could include e-mail folders, directories, and individual files that need to be present for work on the road as well as at the office. The solution in both cases is as follows:

Synchronizing E-Mail

Use an IMAP account for storing your e-mails in the office network. Then access the e-mails from the workstation using any disconnected IMAP–enabled e-mail client, like Mozilla Thunderbird Mail, Evolution, or KMail as described in GNOME User Guide, (↑ GNOME User Guide ) and KDE User Guide, (↑ KDE User Guide ). The e-mail client must be configured so that the same folder is always accessed for Sent messages. This ensures that all messages are available along with their status information after the synchronization process has completed. Use an SMTP server implemented in the mail client for sending messages instead of the systemwide MTA postfix or sendmail to receive reliable feedback about unsent mail.

Synchronizing Files and Directories

There are several utilities suitable for synchronizing data between a laptop and a workstation. For detailed information, refer to Section 11.0, Copying and Sharing Files.

Wireless Communication

As well as connecting to a home or office network with a cable, a laptop can also wirelessly connect to other computers, peripherals, cellular phones, or PDAs. Linux supports three types of wireless communication:

WLAN

With the largest range of these wireless technologies, WLAN is the only one suitable for the operation of large and sometimes even spatially disjointed networks. Single machines can connect with each other to form an independent wireless network or access the Internet. Devices called access points act as base stations for WLAN-enabled devices and act as intermediaries for access to the Internet. A mobile user can switch among access points depending on location and which access point is offering the best connection. Like in cellular telephony, a large network is available to WLAN users without binding them to a specific location for accessing it. Find details about WLAN in Section 30.1, Wireless LAN, (↑ Reference ).

Bluetooth

Bluetooth has the broadest application spectrum of all wireless technologies. It can be used for communication between computers (laptops) and PDAs or cellular phones, as can IrDA. It can also be used to connect various computers within visible range. Bluetooth is also used to connect wireless system components, like a keyboard or mouse. The range of this technology is, however, not sufficient to connect remote systems to a network. WLAN is the technology of choice for communicating through physical obstacles like walls.

IrDA

IrDA is the wireless technology with the shortest range. Both communication parties must be within viewing distance of each other. Obstacles like walls cannot be overcome. One possible application of IrDA is the transmission of a file from a laptop to a cellular phone. The short path from the laptop to the cellular phone is then covered using IrDA. The long range transport of the file to the recipient of the file is handled by the mobile network. Another application of IrDA is the wireless transmission of printing jobs in the office.

9.1.4 Data Security

Ideally, you protect data on your laptop against unauthorized access in multiple ways. Possible security measures can be taken in the following areas:

Protection against Theft

Always physically secure your system against theft whenever possible. Various securing tools, like chains, are available in retail stores.

Strong Authentication

Use biometric authentication in addition to standard authentication via login and password. openSUSE supports fingerprint authentication. For more details, see Section 32.0, Using the Fingerprint Reader, (↑ Reference ).

Securing Data on the System

Important data should not only be encrypted during transmission, but also on the hard disk. This ensures its safety in case of theft. The creation of an encrypted partition with openSUSE is described in Section 36.0, Encrypting Partitions and Files, (↑ Reference ). Another possibility is to create encrypted home directories when adding the user with YaST.

IMPORTANT: Data Security and Suspend to Disk

Encrypted partitions are not unmounted during a suspend to disk event. Thus, all data on these partitions is available to any party who manages to steal the hardware and issue a resume of the hard disk.

Network Security

Any transfer of data should be secured, no matter how it takes place. Find general security issues regarding Linux and networks in Section 38.0, Security and Confidentiality, (↑ Reference ). Security measures related to wireless networking are provided in Section 30.0, Wireless Communication, (↑ Reference ).

OpenSuSE 11.1 Quick Start Guide
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  Published under the terms fo the GNU General Public License Design by Interspire