Portable computers may be divided into different categories. This is a subjective decision, but I try to do so. My groupings roughly follow the generally accepted marketing categories. The criteria could be:
Most peripheral cables are appallingly heavy. If you get a subnotebook and carry it around with a bunch of external drives, cables, and port expander dongles and power converter, you may be lugging a heavier bag than if it were all in one box. Subnotebooks are useful mainly if you can afford to leave all the other junk behind.
Weight greater than 4.0 kg (9 lbs). Features like a PC, but in a smaller box and with LCD display. Examples: lunchbox or ruggedized laptops (e.g., http://www.bsicomputer.com/)
Weight between 1.7 and 4.0 kg (4 to 9 lbs). Features custom hardware and usually a special CPU. Examples: HP OmniBook 3100, COMPAQ Armada 1592DT. The terms laptop and notebook seem equivalent to me.
Weight between 1.3 and 1.7 kg (3 to 4 lbs). Features: external floppy drive, external CD drive. Examples: HP OmniBook 800CT, Toshiba Libretto 100, COMPAQ Aero, SONY VAIO 505.
Weight between 0.7 and 1.3 kg (1.5 to 3 lbs). Features: proprietary commercial operating systems. Examples: HP200LX.
Weight below 0.7 kg (1.5 lbs). Features: proprietary commercial operating systems and often non-Intel CPU with commercial operating systems like PalmOS, EPOC32, GEOS, Windows CE. Examples: Newton Message Pad, Palm III (former Pilot), Psion Series 3 and 5, CASIO Z-7000.
Watches, digital pens, calculators, digital cameras, cellular phones and other wearables.
Due to a lack of support by some hardware manufacturers, not every feature of a laptop is always supported or fully operational. The main devices which may cause trouble are: graphic chip, IrDA port, sound card, PCMCIA controller , PnP devices and internal modem. Please try to get as much information about these topics before buying a laptop. But often it isn't quite easy to get the necessary information. Sometimes even the specifications or the hotline of the manufacturer aren't able to provide the information. Therefore I have included a Linux Compatibility Check chapter in the Hardware In Detail sections below.
Depending on your needs, you might investigate one of the vendors that provide laptops pre-loaded with Linux. By purchasing a pre-loaded Linux laptop, much of the guesswork and time spent downloading additional packages could be avoided. See Kenneth E. Harker's page for a list of vendors http://www.cs.utexas.edu/users/kharker/linux-laptop/.
Besides its Linux features, there often are some main features which have to be considered when buying a laptop. For Linux features please see the Hardware In Detail section below.
Don't underestimate the weight of a laptop. This weight is mainly influenced by:
Laptops come with one of two types of displays: active matrix (TFT) and passive matrix (DSTN). Active matrix displays have better color and contrast, but usually cost more and use more power. Also consider the screen size. Laptops may be purchased with screens up to 15". A bigger screen weighs more, costs more, and is harder to carry, but is good for a portable desktop replacement.
The available battery types are Lithium Ion (LiIon), Nickel Metal Hydride ( NiMH) and Nickel Cadmium (NiCd).
LiIon batteries are the most expensive ones but a lot lighter than NiCd for the same energy content, and have minimal -- but present -- memory effects. NiMH is better than NiCd, but still rather heavy and does suffer some (although less than NiCd) memory effects.
Unfortenately most laptops come with a proprietary battery size. So they are not interchangeable between different models.
For details about systems which are supported by the Linux Kernel, see the Linux FAQ . See also Current ports of Linux OS
There was a long series of Apple PowerBooks and other laptops based on the m68k chip. Macintosh Portable (an ugly 16-pound first attempt); PowerBook 100, 140, 170, 145, 160, 180c, 165c, 520c, 540c, 550c, 190; Duo 210, 230, 250, 270c, 280. The PowerBook Duos were available at the same time as the PowerBooks, they were a sort of subnotebook, but were designed so that you could plug them into a base station (a DuoDock) with more RAM, peripherals, etcetera, so that they could also act as a desktop computer. The first PowerPC PowerBooks were the ill-starred PowerBook 5300 (after the 190) and the Duo 2300c.
For a complete list of all Macintosh computers ever made, with specifications, see Apple-History.
Note also that readers should *not* go to www.linuxppc.org for hardware compatibility with 68k laptops--as the name implies, LinuxPPC is only for PowerPC machines. The proper place to go for information on running Linux on m68k Macintoshes is: linux-m68k.
In particular, their hardware compatibility list is at: linux-m68k-status and it states in regards to laptops:
"Much like laptops of the Intel/Linux world, Mac laptops have generally different setups that can be very hard to figure out. Also, because of a general lack of machines to test, we are only aware of boots on the Powerbook 145, Powerbook 150, Powerbook 170, Powerbook 180, and Powerbook 190. Even if it boots, we currently have no support for Powerbook-style ADB, the APM support, or just about anything else on them. This means the only way to log in is with a terminal hooked up to the serial interface, this has been tested on the 170."
"Several Powerbooks have internal IDE which is supported. PCMCIA drivers will be forthcoming if someone can supply the necessary hardware information to write a driver. As always, an FPU is needed also. Many of the later models have the 68LC040 processor without FPU, and many of these processors are broken with respect to the FPU trap mechanism so they can't run regular Linux binaries even with FPU emulation. Current status on Powerbooks 140, 160, 165, 165c, 180c, 190, 520 and Duos 210, 230, 250, 270c, 280, and 280c is unknown."
Also there are two Atari laptops, for which I don't have enough information. The following quotations are from the Atari Gallery.
"The STacy was released shortly after the Mega ST to provide a portable means of Atari computing. STacy computers were shipped with TOS v1.04.
Designed to replace the STacy as the defacto portable ST computer, the ST Book brought the basic computing power of an ST to a lightweight notebook computer. This machine was only released in Europe and Atari only shipped a very small quantity. The ST Book was shipped with TOS v2.06."
Is there an Amiga notebook?
BTW: The team at iMac Linux has managed to get the iMac DV to boot Linux to a usable point. You may get information about the iBook there as well.
For PDAs with ARM/StrongARM CPU see the PDA chapter below.
More about Linux on Wince boxes may be found at LinuxCE-FAQ.
At higher speed, a CPU consumes more power and generates more heat. Therefore, in many laptops a special low-power CMOS CPU is used. Usually, this special CPU doesn't use as much power as a similar processor used in a desktop. These special CPUs are also more expensive. As a side effect you may find that laptops with a desktop CPU often have a fan which seems quite loud.
An enormously important issue. Anything based on PPC or Pentium will generate enormous amounts of heat which must be dissipated.Generally, this means either a fan, or a heat sink the size of the case.If it's a fan, the air path had better not ever get blocked, or it will overhead and burn out.This means machines with a fan mounted in the bottom are a big, big mistake: you can't use them on a soft surface.
Though you might use your desktop computer to do longer writings, a good keyboard can save you some headaches and finger-aches. Look especially for the location of special keys like: <ESC>, <TAB>, <Pos1>, <End>, <PageDown>, <PageUp> and the cursor keys.
Laptops are quite expensive if you compare them with desktops. So you may decide between a brand or no-name product. Though I would like to encourage you to take a no-name product, there are some caveats. I have experienced that laptops break often, so you are better off, when you have an after sales warranty, which is usually only offered with brand products. Or you may decide to take a second hand machine. When I tried this, I discovered that the laptop market is changing quite often. A new generation is released approximately every three months (compared by CPU speed, harddisk capacity, screen size etc.). So laptops become old very quick. But this scheme often isn't followed by the prices for second hand laptops. They seem too expensive to me. Anyway if you plan on purchasing a second hand machine, review my recommendations on checking the machine. For German readers there is an online market place at http://www.hardware.de, which offers a good survey about current prices for second hand machines.
If you travel abroad pay attention to the voltage levels which are supported by the power supply. Also the power supply is often one of the heavier parts of a laptop.
Specifications, manuals and manufacturer support often are not helpful. Therefore you should retrieve information from other sources too:
If you can't find the necessary information through the above mentioned sources, you are on your own. Luckily, Linux provides many means to help. For details see the Hardware on Detail section below. In general you may use:
dmesg or by looking into /var/log/messages.
cat /proc/pci Please read the kernel documentation pci.txt. You may get further information about unknown PCI devices at the database from Craig Hart at
http://members.hyperlink.net.au/~chart. From 2.1.82 kernels on you may use the lspci command from the pci-utils package.
isapnp-tools .
scsi_info by David Hinds for SCSI devices or scsiinfo.
If you don't want to install a complete Linux you may retrieve this information by using a micro Linux ( see appendix A). The package muLinux provides even a small systest program and TomsRtBt comes with memtest. To use memtest you have to copy it on a floppy dd if=/usr/lib/memtest of=/dev/fd0 and to reboot from this floppy.
If your laptop came with Windows, you may determine a lot of hardware settings from the installation. Boot into DOS or Windows to get the information you need.
Using Windows9x/NT to get hardware settings, basically boot Windows, then Start -> Settings -> Control Panel -> System -> Device Manager and write down everything, or make a hardcopy from the display using the <PRINT> key, plus keep a log of settings, hardware, memory, etc.
Using MS-DOS and Windows3.1x you can use the command msd, which is an akronym for MicroSoft Diagnostics. Or you might try one of the numerous DOS shareware utilities: CHECK-IT, DR.HARD and others.
Sometimes it's difficult to know what manufacturer has built the machine or parts of it actually. The FCC "Federal Communications Commission On-line Equipment Authorization Database may be used, if you are having problems identifying the manufacturer of a laptop or notebook computer (or other electronic device,) this site lets you search the FCC database based on the FCC ID number you can usually find on the equipment if it was marketed in the United States of America."
The Lothar Project is a Mandrake-related project to provide a GUIed interface to get at hardware configuration information on Linux-based systems. It provides a library for different system informations, too.
Many laptops are no more compatible with Windows than Linux. David Hinds, author of the PCMCIA drivers, points out that Toshiba notebooks use a proprietary Toshiba PCMCIA bridge chip that exhibits the same bugs under Windows as under Linux. IBM Thinkpads have serious BIOS problems that affect delivery of events to the power management daemon apmd. These bugs also affect MS-Windows, and are listed in IBM's documentation as considerations.
Some incompatibilities are temporary, for instance laptops that have Intel's USB chip will probably get full USB support, eventually.
If you encounter a device which is not yet supported by Linux, don't forget it's also possible to write a driver by yourself. You may look at the book from Alessandro Rubini, Andy Oram: Linux Device Drivers.
Some recommendations to check an used laptop, before buying it:
bonnie.memtest and crashme to achieve a memory test.
Byte or by compiling a kernel.e2fsck. There is also a Linux tool dosfsck or the other fsck tools.time dd if=/dev/hda of=/dev/null bs=1024k .
AFAIK there is no Linux tool like the DOS tools CHECK-IT, DR. HARD, SYSDIAG and others. These tools include many of the tests in one integrated suite. One of the best IMHO is the tool PC Diagnostics 95 made by Craig Hart
http://members.hyperlink.net.au/~chart . Despite the 95 in its name it's plain DOS, tiny (76KB programm and 199KB data) reliable and free. Unfortenately it contains no check for the IrDA port.
Please note this quotation from the disclaimer: "This program is written with the target audience being a trained, experienced technician. It is NOT designed to be used by those ignorant of computer servicing. Displays are not pretty but functional. Information is not explained since we are not trying to educate. This software should be considered to be just like any other tool in a tech's toolbox. It is to be applied with care, in the right situation, in order to find answers to specific problems. If you are an end user who is less than confident of dealing with computer hardware, this is probably not a program for you."
Laptop computers, unlike desktop machines, really do get used up. Lithium batteries are good for no more than 400 recharge cycles, sometimes much fewer. Keyboards wear out. LCD screen backlighting grows dim. Mouse buttons fail. Worst of all, connectors get loose as a result of vibration, causing intermittent failures (e.g. only when you hit the <Enter> key). We have heard of a machine used on the table in a train being shaken to unusability in one trip.
It's difficult to give any recommendations for a certain laptop model in general. Your personal needs have to be taken into account. Also the market is changing very quickly. I guess every three months a new generation of laptops (according to harddisk space, CPU speed, display size, etc.) comes into the market. So I don't give any model or brand specific recommendations.