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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.
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
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is a laptop
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Yes
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is sometimes attached to different networks
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Yes
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provides network services (such as DNS or DHCP)
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No
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only uses a static IP address
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No
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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 ).
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