bash$ lpr -#3 article.html
bash$ lpr -P laserjet -s mybook.pdf

Nowadays most distributions replaced LPD with a new spooler called CUPS, it's more easy to configure, supports more printers, and could work as a server or client for Internet Printing Protocol (IPP) beside ethernet socket printers, remote LPD Unix printing and Mirosoft/Samba shared printers. The good news that you don't have to learn much, CUPS supports both BSD styled commands (eg. 'lpr') and System V styled commands (eg. 'lp'), just activate this service on some runlevel using your distribution GUI or console tools (eg. 'chkconfig --level 2345 cups on' then 'service cups start')

You could configure your printers using your distribution tools, the CUPS command line tool 'lpadmin', CUPS web interface using your browser, or less likely by editing '/etc/cups/cupsd.conf' which has a format similar to Apache configuration file. To enable CUPS web administration tool (it's safely running behind 'xinetd') edit '/etc/xinetd.d/cups-lpd' to have the line 'disable = no' then open any web browser ('mozilla', 'epiphany', 'konquror' or even 'links') then goto the address 'http://localhost:631' then interact and follow the instructions, this page is only visible to local host (127.0.0.1) by default, see 5.3.8. subsection of Setting up servers section..

You could manage CUPS system from command line using 'lpadmin' for example to add a parallel printer and call it 'MyPrinter' and make it the default printer (-d option) use something like this:

bash# lpadmin -p MyPrinter -v parallel:/dev/lp0 -P /PATH/DRIVER.ppd
bash# /usr/bin/enable MyPrinter
bash# /usr/sbin/accept MyPrinter
bash# lpadmin -d MyPrinter

bash# lpaddin -p HisPrinter -v smb://myname:mypass@WINNT/INKJET -P /PATH/DRIVER.ppd
bash# /usr/bin/enable HisPrinter
bash# /usr/sbin/accept HisPrinter
bash# lpadmin -d HisPrinter

Free drivers shipped with CUPS are simple generic drivers and you need better drivers for professional printing. Thank God, professional optimized photo-quality drivers from www.LinuxPrinting.org are shipped as packages with most distributions, it's called 'foomatic' (see www.linuxprinting.org/foomatic.html), it also offers support for larger number of printers (visit 'www.LinuxPrinting.org' to check a list of supported printers) and PPD files are used to drive all priners (even non-Postscript printers), 'foomatic' comes with a smart filter called 'foomatic-rip' that works for all kinds of spoolers. There is a GUI tool in another package called 'foomatic-gui' a GNOME based application to setup your printers. More photo-quality PPD drivers could be found on Gimp Print packages.

Besides LinuxPrinting.org drivers and tools you could find some tools and drivers from your printer vendor, If you have a Postscript printer you could take the PPD file from the Windows driver (it could found on the CD that come with the printer) or from Adobe www.adobe.com/products/printerdrivers/winppd.html. Hewlett-Packard (HP) printers are very common and they offer good support, you may check related resources like 'http://hp.sf.net', 'http://hpinkjet.sf.net' (in Debian there is a package called 'hpijs'), and 'http://hpoj.sf.net' the last one provides support(tools and drivers) for most "all-in-one" peripherals like OfficeJet, LaserJet, Printer/Scanner/Copier ("PSC"), and PhotoSmart printer products (in Debian they put the GUI tool to display 'hpoj' LCD panel in another package called 'hpoj-xojpanel').

If you want to buy a new printer make sure to visit the Linux Printing site before you buy, no matter from which vendor, for example HP offers good help to open source developers, but there are some models of HP printers that does not work in Linux! check the database of supported printers and the state of the support at www.linuxprinting.org/database.html. Most home users buy an Inkjet printer then all what they print is less than a dozen of pages per year, because about 3 ink cartridge replacements costs the same as a new printer!! most Inkjets are cheap but the cost per paper is very high, this is not bad for home users who want to have a cheap high quality colored printer (although they could generate a PDF file, put it on a floppy or a flash memory then print it on any computer services store having a mono laser printer). For real work usually you don't need colors (bills, forms, reports,...etc), you need a long lasting heavy duty printer that produce more pages in a short time, and low cost per page, black and white laser printers are the first choice fort this task. Some companies still use dot matrix printers, this is the choice for poor line printing of text in a single fixed width font but they are cheap (both the printer and the cost per page) and could print on forms of continous paper, although some Laser printer could do that! If you want an advice visit www.linuxprinting.org/suggested.html, to support the future of printing in Linux, buy from vendors that contribute to Linux printing listed at www.linuxprinting.org/affiliate.html.

References:

• Debian and Windows Shared Printing mini-HOWTO
• The Linux Printing HOWTO
• The Linux Printing Usage HOWTO
• The Linux Print2Win mini-HOWTO

4.1.6. Scanner.

All you have to do is to tell programs that use the scanner (eg. 'xsane' and 'gimp') which device to use (eg. /dev/usb/scanner0), you could link /dev/scanner to point to the real scanner device.

4.1.7. Digital cameras and video capturing.

Digital still cameras could be treated using usual media mounting using 'mount' command (as a SCSI disk, see devices list below), or through specific programs like 'gtkam' or 'kamera'.

TV tuners, web cameras or any type of motion-picture-capturing (video capturing) can be accessed through a unified interface called Video4Linux (V4L) provided by Linux kernel (as modules), there are many applications that use Video4Linux mainly 'xawtv' or 'tvtime' (tvtime.net) all you have to do is to configure them to use the right device (see devices list below) throught the GUI or through 'v4l-conf' package (and may be through your distribution specific tools, as in Mandrake). There are some applications designed specially for web cameras the best example is 'gnomemeeting', a network video conference application see 2.6.4. Interactive Internet. subsection. Many years ago people started to watch TVs in color! have you ever thought to watch your TV in ASCII Art text!! a package called 'ttv' uses 'aalib' to show the motion picture on your 'tty' console. If you don't have X and you still want to watch it in real colors, you could use 'fbtv' that uses Linux Frame Buffer instead of X11. There are many more packages related to Video4Linux found on my Debian:

• 'came' a rewrite of the 'xawtv' webcam app using 'imlib2'.
• 'scantv' scan TV channels for all stations at once and write them into 'xawtv' configuration file (and others)
• 'libdscaler' a Video deinterlacer plugins for 'tvtime' using DScaler DLLs loaded by Wine
• 'kvdr' DVB (digital TV) Video Disk Recorder for KDE
• 'wmtv' Dockable Video4Linux TV player for WindowMaker and alike.
• 'camorama' a small GNOME2 utility to view, alter and save images from a Video4Linux device (including webcams).
• 'vgrabbj' a command line tool to grab a image from a Video4Linux device and save it in JPEG/PNG format.
• 'camstream' a nice QT GUI for Video4Linux that support Webcamming, Video conferencing, Recording movie clips (AVI, Quicktime) and Using a webcam as a security camera, it could be found on 'www.smcc.demon.nl/camstream'.
• 'motion' V4L Capture Program supporting Movement Detection, MPEG output and webcams (may be used for secrity).
• 'webcam' capture images from a Video4Linux device and upload them to web server using FTP or SSH.
• 'camserv' takes a video-for-linux video stream, generally from a camera, and streams it out live to requesting clients (web browsers)

4.1.8. Network adapter and Modems.

If your computers is connected to a LAN it's usually uses Ethernet cards, the device for the first Ethernet cards is '/dev/eth0' to tell more use something like:

bash# dmesg | grep eth
bash# lspci -v | grep eth

Back to modems, if you are using a real serial modem (an external serial modem) then you need no driver just point to the modem driver for example:

bash# ln -sf /dev/ttyS0 /dev/modem

Lucent Venus chipset:
   Multitech MT5634ZPX-PCI,
   Zoom 2920 (Digitan DS550-558),
   Actiontec PCI56012 (IBM 33L4618 or GVC MD0223)
USR/TI Kermit chipset:
   the 3Com/USR 3CP5610 family, which includes models 5613, 5609, and OEM models 2976, 2977, and 3258
TOPIC TP560i chipset:
   Well Communications FM-56PCI-TP (GVC MD0321), and
   Archtek Smartlink 5634PCV.
Conexant RC56D-PCI chipset:
   none observed yet ???!

bash$ lspci -vv | grep -i 'modem'

Warning

If you are buying a new modem make it an external serial (not USB) modem, most internal modems are fake, even if there are a full-featured open source driver that make it work, it still a fake modem, it's driver (on any OS) uses your CPU and RAM to do what the modem missing controller chip should do, also you can't be sure that the driver will be updated with all kernels in future. If you can't afford an external serial modem at least buy a real internal modem (with real controller chip) and in worst cases a fake modem but with open source free driver like IBM ACP-mwave (the driver is called 'mwavem' in Debian) You should avoid fake modems that have closed source drivers or half-open source drivers, any fake modem makes you computer 25% slower and it's not always cheaper.

bash$ su -
bash# cd ~ali # goto the home folder of the user having the drivers
bash# pwd
 /home/ali
bash# tar -xvzf hsfmodem-X.XX.XXlnxtXXXXXXXXfree.tar.gz # use TAB to type the filename
bash# make install 
bash# hsfconfig --help
bash# hsfconfig
bash# hsfconfig --region # select your counrty code.
bash# cd /dev
bash# ln -sf ttySHSF0 modem
bash# ls -l ttySHSF0  # see permissions
bash# chmod 777 ttySHSF0  # insecure! allow everybody to use it
bash# exit
bash$ hsfconfig
bash$ hsfconfig --region

this example is for HSF Conexant modems replace 'hsfconfig' with 'hcfpciconfig' or 'hcfusbconfig' and replace the device '/dev/ttySHSF0' with '/dev/ttySHCF0' or '/dev/ttySHCFUSB0'.

You could get generic RPM package (it's a source package that build itself) named 'hsfmodem-VER.rpm.zip' or 'hcfmodem-VER.rpm.zip' they are installed easily, put them at your home folder and do:

bash$ su -
bash# cd ~ali # goto where you put the driver
bash# pwd
 /home/ali
bash# unzip hsf*.zip # also you could press TAB
bash# rpm -Uvh hsf*.rpm # also you could press TAB
bash# cd /dev 
bash# ln -sf ttySHSF0 modem
bash# ls -l ttySHSF0  # look at the permissions
bash# chmod 777 ttySHSF0  # allow every body to use it.
bash# hsfconfig --region # select your country code
bash# exit 
bash$ hsfconfig
bash$ hsfconfig --region

Another fake modem that had been used widely is Motorola SM56, Motorola had stoped producing it,selling it and supporting it but it did not release the source code of it's old Linux driver so that Linux community do it's job, the latest and last driver from it was for RedHat Linux 7.1 (in other words Linux kernel 2.4.5, I'm not sure), the first method to use this modem is to install that old kernel (from source or from package repositories) then install that driver, a better solution is to download a new driver found at 'www.sm56.tk' this site lists files for different GCC versions (rrecent distibutions uses GCC version 3.x) after you extract it issue 'make install' then set the proper permissions for the device file '/dev/sm56'.

Please note that you should give the specific modem device proper permissions and owned by proper user and group, issue 'ls -l /dev/ttyS0' to see what your distribution did with the first serial port so you could do something like it, you could create a group called 'modem' and let it the group of the device file then allow reading and writing for members, then when you want any user to be allowed to dialup the modem add him to this group.

There are some fake modems having open source drivers like 'IBM ACP-mwave', but most fame modems have a closed binary only driver of half-open drivers (they say that drivers contain top-secret confidential hardware specification! or it need extra cost) this is very annoying but it's changing, people now know that they are fake.

If you are using Mandrake, after you install the drivers (if needed, ie. having a fake modem) goto Mandrake Control Center and select Networks then Connection then select auto detect then select normal modem and enter the device to be '/dev/modem' (the is better than something like '/dev/ttyS2'), follow the wizard then try to connect.

When every thing is Okay use 'kppp' or 'gnome-ppp' to dialup your ISP, set them to use the device '/dev/modem'. If it fails, try running them as root if it succeed then it must be permission problem, use 'chmod' and 'chown' to fix it. The following links could be useful regarding softmodems.

www.linmodems.org Linmodems Support for Soft-Modems
http://flash.to/modem http://start.at/modem - Uptodate Modems Table by chipset

4.1.9. Storage media.

Storage media are two types fixed and removable, we handle it with 'mount' that will map (mount or load) the content of the media (ie. a file system) to a folder in the Linux root file system, in specific to an empty folder (if it's not empty it's content will be hidden until it's umounted), but in fact the content of the folder is not change and there is no copying it's just a virtual process, this folder usually is a sub folder of '/mnt', in other words we create an empty folder there then tell Linux kernel to let me access to some device file system there using 'mount', each and every change to any file there will be writtten to the device. Mount syntax is like

mount [-t FS_TYPE] [-o OPTIONS] DEVICE MOUNT_POINT

When you are done with the device (in specific removable media) you could unmount it, the kernel will finish all writing process and flush all related buffers (modern operating systems like Linux schedule some slow tasks to be done later so that the system runs smoothly, if you remove the media before it realy write them physically data will be lost, it's important to tell the OS before you remove the media) to unmount it use 'umount' like this:

umount DEVICE
umount MOUNT_POINT

bash# mount -t auto /dev/fd0 /mnt/floppy

bash# umount /mnt/floppy

Warning

While some device is mounted to a folder, DO NOT rename the folder, move it or do any other change on it, you should work with the mapped folder contents not the folder itself, if you want to rename it you should unmount it first. The same way you can't format a device while it's mounted and you may check it if it's mount it for read only or not mounted.

Mounted devices will disappear in next boot so you have to issue 'mount' command again, if you want a device to be mounted by default on each startup (useful for fixed drives), you have to edit the file systems table '/etc/fstab' in which each line has the following syntax: device then (after white spaces), then the mount point folder, then the file system type (you could use 'auto'), then it's options (that used to be after '-o' with 'mount' tool) if there is no options use 'defaults'(you can't leave it empty), then the order of dump backup tool (not widely used) put '0' if you don't want this device to be included with this backup and at last the order of file system consistency checking (if check is needed) if you don't want any checking (even if the file system is inconsistence) put '0'. The following is a sample 'fstab' file:

# This is /etc/fstab those two lines are just comments they start with #
# Device	Mount_Point	FS_TYPE		Options		dump seq
/dev/hda7	/		ext3		defaults	0 1
# special virtual file systems 'proc' and 'swap'
none		/proc		proc		defaults	0 0
none		/dev/pts	devpts		mode=0620	0 0
/dev/hda9	swap		swap		defaults	0 0
# some non Linux partitions
/dev/hda1	/mnt/win_c	vfat		umask=0		0 0
# removable media
/dev/fd0	/mnt/floppy	auto		noauto,users	0 0
/dev/cdrom	/mnt/cdrom	auto		noauto,users,nohide 0 0

for devices on this table you could specify only the mount point(or the device) like :

bash# mount /mnt/floppy
bash# mount -o remount,ro /mnt/win_c

wait a minute! what does the floppy and CDROM doing in this table ? we have said that this table is useful for fixed drives to mount it automatically when the system starts, but does this mean that the floppy and the CDROM is mounted on each startp even though there is no media ? notice the 'noauto' option which mean don't mount it when system starts, this is useful to let you mount them by passing mount point only and optionally omitting the rest arguments, the option 'users' allow regular users to mount or unmount this device.

GUI provide simple way to mount devices (useful for removable media), in GNOME right click the desktop and select disks (or double click 'computer' icon on GNOME 2.6), in KDE you could right click the floppy/CDROM icon then select 'mount'. Some distributions automatically mount and display devices like CDROM or USB flash memory, but 'mount' tool is still there, if the device is not listed on 'fstab' then you have to specify both the device and the mount point folder, for example try this for CDROM

bash# dmesg | grep Floppy
Floppy drive(s): fd0 is 1.44M
bash# dmesg | grep -i CD
 hdb: CDROM ATAPI blah blah ...
bash# mount /dev/hdb /mnt/cdrom

There are many SCSI fixed and removable disks, it's a standard bus for very larg disks with high availability, many removable disks could be handled as SCSI disks although they are not, like CD-RW, USB flash disks, and digital cameras, this first SCSI disks is '/dev/sda' and the first partition of it is '/dev/sda1'. There are some tools specific to SCSI device found on 'scsitools' package, like

• scsiinfo: displays SCSI drive low-level information and modifies SCSI drive settings.
• scsifmt: low-level SCSI formatter.
• sraw: benchmarks raw SCSI I/O rates bypassing the buffer cache.
• scsistop: low-level SCSI drive start/stop program.
• scsi-spin: program to manually spin up and down a SCSI device.

Tip

To have faster disk reading you could disable updating 'access time', access time is the time of last reading or writing operation, you could use this time to find what files are no longer used in any way for the last some days to delete them for example but if you are not interested in it disable it to save time (usually for floppes and non Linux partitions), add the option 'noatime' to 'fstab' file, like this: '/dev/hda1 /mnt/win_c vfat umask=0,noatime 0 0' or as a mount option, like this: 'mount -o noatime /mnt/win_c '.

There are many useful options, for exmpale 'nodev' means to disable device special files on that file system, in other words files having device flag (on that file system) (like '/dev/fd0') becomes usual files not devices this option is used with removable media and non Linux partitions, another option is 'noexec' which mean no file on that file system is allowed to be executed, 'nosuid' option disables 'set user ID' flag on executable files which (the flag) enable a user to run a program as the owner of the file (the could be root).

The best option to use with removable media is 'sync' which means to wait until all writing is finished before return, unlike the default 'async' option which smoothely background writing process until you use 'sync' or 'unmount' commands to physically write data.

Recent kernels have the so called 'supermount' file system which enable you to mount removable media devices (eg. CDROM and floppy) automatically when you access to related folers (exactly what Windows users expect) and unmount them after a while of not using this device, if your kernel does not support it compile one from source and make sure that 'CONFIG_SUPERMOUNT' option is not disabled. Mandrake uses Supermount by default, one thing that makes it as easy as Windows! to do that yourself let's first try it temporary by typing as root:

bash# mount -t supermont -o dev=/dev/cdrom,--,ro,users none /mnt/cdrom

#/dev/cdrom	/mnt/cdrom auto		ro,users			0 0
none		/mnt/cdrom supermont	dev=/dev/cdrom,--,ro,users	0 0

Warning

With larg files and scratched poor disks, it could exceed the supermount timeout limit so it get umounted, which makes it very annoying to copy a file or just select them on the GUI, somewhere on the Internet I read about people complaining about using OpenOffice and supermount, you had better using usual mount/unmount. If you are using Mandrake goto Mandrake control center then mount points then click on the CDROM or floppy and unckeck 'supermount' checkbox, you could edit your 'fstab' by hand. You could make using removable media easy using 'autofs' which does not change your 'fstab' or disable the usual mount/umount method.

Another tool is called 'autofs' that automatically mount/unmount devices just like 'supermount' but unlike 'supermount' you could specify timeout and you don't have to touch your 'fstab' file, so you could use mount/unmount tools. After you install 'autofs' edit '/etc/auto.master' to specify the super folder which contain mount points subfolders, a nice trick if to make it a dot hidden folder like '/.auto', this is the first column, the next one is the configuration filename then some options like the timeout in seconds which could be only one second (like what I do) but documentations suggests much more (this depends on your usage and the quality of disks you have), a line in '/etc/auto.master' could be like:

/.auto	/etc/auto.map	--timeout=1

the configuration file specified in the second column '/etc/auto.map' look like this:

cdrom	-fstype=auto,ro,nosuid,nodev	:/dev/cdrom
floppy	-fstype=auto	:/dev/fd0

bash$ su
bash# mkdir /.auto /auto
bash# cd /auto
bash# ln -s ../.auto/floppy floppy
bash# ln -s ../.auto/cdrom cdrom
bash# chkconfig --level 12345 autofs on
bash# service autofs start

4.1.10. CDROM and recoding.

We have talked about how to mount and read CDROM, we will talk about some useful CDROM related tricks and work arounds, one of the most common problems related to CDROM reading is poor recording qulity or poor medium qulity, another less common problem is the annoying noise coming from fast rotating CDROMs, a solution for those problems is any of the following equivalent commands:

bash# hdparm -E 4 /dev/cdrom

bash# setcd -x 4 /dev/cdrom

bash# echo 'current_speed:4' > /proc/ide/hdb/settings

bash# echo 'file_readahead:1048576' > /proc/ide/hdb/settings
bash# echo 'unmaskirq:1' > /proc/ide/hdb/settings
bash# echo 'using_dma:1' > /proc/ide/hdb/settings

bash# hdparm -d1 -a8 -u1 /dev/cdrom

Recording CDs (called burning) using GUI or 'cdrecord' command line tool needs to specify the recoding device (CDRW device), if you have a usual IDE CD writer, first you have to pass 'hdX=ide-scsi' to the kernel using bootloader where hdX is the device name of it (eg. 'hdb' for primary slave), so we could use SCSI protocol on those IDE disks. 'cdrecord' needs the device to be passwd with 'dev=DEVICE' option, with new 2.6 kernels, DEVICE could be usual IDE device like '/dev/hdb' or '/dev/cdwriter' but in general with older kernels this is NOT safe, you should specify 3 numbers splited by comma ',' those numbers are the SCSI (or emulated) bus numbers, type the next command to list them:

bash# cdrecord -scanbus

bash# mkisofs -J -r mydir/ | cdrecord -v speed=12 dev=0,1,0 -data -

bash# mkisofs -J -r -o foo.iso mydir/
bash# cdrecord -v speed=12 dev=0,1,0 -data foo.iso

4.1.11. Power managment and Laptops.

Linux supports many utilities to protect out environment see Linux Ecology-HOWTO by Werner Heuser. Linux could save power, generate less noise by slowing downing CD spinning and much more. X server could use "Energy Star" monitor power saving using 'xset', not only saves power but it may protect your monitor from burns (more effective than screen savers see section '2.2. After Installation.'). To use 'xset', first type xset +dpms then specify times of each stage (in seconds) with 'xset dpms standby_time suspend_time off_time', you could manually jump from mode to mode by 'xset dpms force standby|suspend|off|on'.

Linux supports Advanced Power Managment (APM), if your BIOS supports it, to know that type 'dmesg | grep apm', in order to be able to manage power a daemon called 'apmd' should be running check it with your service manager or type /etc/init.d/apmd restart at command line, this service is just a script that in do many things but mainly it will call 'modprobe apm' then run '/usr/sbin/apmd', if you fail, recheck your BIOS setup and try again.

A new standard for power managing is called Advanced Configeration & Power Interface(ACPI) that is supported by Linux kernels from 2.4 as patch (I found it on 2.4.19) and for sure in 2.6 kernels, most new Intel mother boards support the new ACPI technology. This technology offers many new features like measuring temperature or fan speed. Most hardware supports only one APM or ACPI, and even if both is supported you have to select one of them (or none) in BIOS setup, options could be like this 'ACPI aware OS' for ACPI. If 'apmd' faild try 'acpid' by activating the service or by typing '/etc/init.d/acpid restart', this script inserts related modules using 'modprobe', those are 'button', 'battary', 'ac', 'fan', 'thermal' and 'processor' like 'modprobe ac' then run 'acpid' daemon. A user space tool 'acpi' that controls this daemon, for example acpi -V to display ACPI information, also you could 'proc' file system like this:

bash# cat /proc/acpi/battery/BAT0/state
bash# cat /proc/acpi/battery/BAT0/info

Those two services could be used to tell laptop battary status, then all you have to do is to add the GUI applet at your desktop, right click the panel then select add then laptop battary. Besides applets there are many nice applications to indicate power status like many 'gdesklets' displays and themes of 'karmba' and 'superkarmba'.

There are many other applications related to Laptops or make life much easer for Laptop users, some tools are general (work for all Laptops) like:

• 'i8kutils' - Dell Inspiron and Latitude laptop utilities.
• 'toshset' - Access much of the Toshiba laptop hardware interface.
• 'toshutils' - Toshiba laptop utilities.
• 'tpctl' - IBM ThinkPad hardware configuration tools.
• 'tpb'- IBM ThinkPad special keys.
• 'sjog' - A program to use the "Jog Dial" on Sony Vaio Laptops.
• 'spicctrl' - Sony Vaio controller program to set LCD backlight brightness.

• 'tpconfig' - A Debian program to configure touchpad devices.
• 'sleepd' - puts a laptop to sleep during inactivity
• 'cpudyn' - CPU dynamic frequency control for processors with scaling
• 'laptop-net' - package takes a different approach to automagic network reconfiguration.
• 'gpsdrive' - GpsDrive displays your position provided from your NMEA capable GPS receiver on a zoomable map.

4.1.12. Memory dark corners.

We have mentioned before at subsection 8 of '1.5 How to install Linux ?' section, some information about BIOS settings related to shadow RAM (a copy of subroutines on slow ROM to faster RAM) we have said that you should disable this feature to save RAM. BIOS setup offer an option to do parity check using an extra smaller odd chip on the RAM slot, if the RAM slot have a no parity chip then this check is useless, when you buy a new RAM search for this chip.

Some old BIOSs can't handle more than 64MB of memory, if you put more than 64MB of RAM, it will tell Linux wrong size, to see how much of RAM Linux sees type 'free' (and other information like free memory,swap,...), also we could use 'dmesg | less LOWMEM', if the size is not reported correctly, but we could still use all of the RAM, just tell Linux to ignore BIOS RAM size report and pass it yourself like 'mem=128m' using your bootloader, remeber we use 'append' with LILO or add them after kernel command with GRUP.

4.1.13. Choosing best hardware to buy.

If you want to buy a new computer or any piece of hardware you should read Linux Hardware Compatibility HOWTO by Steven Pritchard , The Unix Hardware Buyer HOWTO by Eric Raymond or other documents found at 'www.tldp.org', search Linux forums,LUGs and newsgroups, because it's useless to ask the salesman if it's compitable with Linux unless he is a Linux fan or works for Linux related shops as 'www.LinuxMall.com'. Some Linux distribution companies sells computers (Desktops and Laptops) preinstalled with Linux like www.mandriva.com and www.linspire.com, also some computer vendors for example see 'www.hp.com/go/linux' and 'www.hp.com/desktops/linux'. For general (not Linux specific) hardware guidelines see 'www.faqs.org/faqs/pc-hardware-faq'.

The first advice is not to buy a piece with proprietary closed hardware design having no open source driver (even if they provide a good support with binary only drivers) because such vendors assume that their team is smarter than the rest of the world, they could provide support better than the community and they are their interests are more important than you. Richard B. Johnson comments (rejecting "confidential hardware interface specifications" excuse of binary only drivers): "I didn't know you guys were so advanced that you didn't use an electronic hardware interface! Your 'hardware interface specifications' use magnetohydrodynamics, and they are top-secret, right?"

Consider the case that you use two closed source drivers then you face a problem, how could you trace it and to whom you report the problem, quoted from Alan Cox on LKML: "nVidia driver loaded - bugs to nVidia. vmware loaded bugs to vmware, both loaded, God help you, nobody else will" the community can't help you, they don't have any thing but reverse engineering which takes alot of time and it's not fun (the main motive behind community-based programming), Alan Cox comments: "If nVidia would like to pay me as much as Microsoft is paid for driver certification then I might be able to find the time". You should learn from what heppened to Motorola SM56 modems (a binary only driver that was available once upon time) they are no more producing it, developing it or supporting it, it's not a magnetohydrodynamics-based device, it's just a simple old softmodem even though they still consider it a confidential property and refuse to release the source so that the community do the support for them!

The other advise is to ignore irrelevant benchmarks the look like this "This is 20% better than that" because it should specify in which field or for what for type of usage, taking them out of context may lead you to wrong decisions, below we discuss the case of CPU benchmarking as an example.

What is written on CPU in units of Hz (GHz or MHz) is called clock speed, some times more clock speed gives faster performance for example rough benchmarks by Ram Samudrala (concering their researhes on protein folding simulation program, www.ram.org) showed that Athlon 1.5 GHz is 38% faster than a PIII 1.0 GHz which you may expect but the very Athlon 1.5 GHz was 8.66% faster than Xeon 1.7 GHz on the same benchmarks even though the later has faster CPU clock, the key to understand this is to know that different CPUs have different Instructions Per Clock ratio (IPC) for example that Xeon do 6 IPC whereas that Athlon do 9 IPC, it's like a man walking and couting 1, 2, 3,...etc. his counting speed need not be synchronized with his steps, his speed at counting is worthless, and even his number of steps per second if his steps are short while other man's steps are long, maybe the first is faster for short-distance race while the other is faster for long-distance stamina-challenging race, some CPUs are faster for integer operations others are faster for float point operations, if you overpay for a CPU designed for optimized float point operations, while you work in system software development and most of the work time is in compiling kernels and tools, then it's likely that you never use any float point operation at all!! you waste your money and get nothing done. On the other hand, if you running a research on empirical float point data simulating an earthquake using deeply customized FORTRAN, your CPU had better support something like 3DNow from AMD. back to the walking man analogy, what if this man is slow but he knows shortcuts or able to do a few things in the same time, MMX found on many recent CPUs (including Pentium II or more from Intel and K7 or more AMD) could do four 8-bit operations as one operation (by aligning them to a 32-bit integer), but this mean that you will notice enhanced performance only if you use software calling the new instructions. CPU performance is not every thing, that one man is slow but he has a car! if you are running games all the time and you could notice that it's more about if you have OpenGL hardware acceleration on your video card (and it's driver) a slow PIII with such card is for sure better than a PIV with a video card having no hardware acceleration, those accelerated cards has what we call attached processors they do some specific jobs even faster than the CPU, besides that the main CPU could do other things while attached processors works on others.

The last advice is to buy the best no matter from which vendor, what name is written on it, don't hesitate to buy a clone, if it's better. Don't buy an overpriced brand name computer, if you live in a country outside the supporting plan (eg. many third world countries) of the manufacturer, because most of the extra money goes for support you never get. A friend of mine buy a well-known overpriced brand computer when he call for support, it goes like this:

• "A: yes, we have the latest products, we cover all the country ..."
• "B: I know, I have one and I'm calling for support -"
• "A: no, sorry! we are just authorized dealers! call the regional office on that-far-country."

1. Reputation of manufacturer (unmeasurable and meaningless).
2. Market share of manufacturer (meaningless and irrelevant).
3. Amount of marketing hype.
4. Irrational parameters (for example, superstition or prejudice: "would you buy a processor labeled 131313ZAP and painted pink ?")
5. Perceived value (meaningless, unmeasurable and irrational).
6. "You get what you pay for."

4.1.14. Devices appendix.

This is a segment of the devices list found on 'www.lanana.org/docs/device-list',

		[can be mounted]
/dev/hda	First whole IDE hard disk or CD
	/dev/hda1 First partition on it
/dev/ram0
/dev/fd0
	/dev/fd0u1440
	/dev/fd0u1722
	/dev/fd0u2880
/dev/loop0
/dev/sda	First SCSI disk whole (as ide)
        /dev/sda1 ... First partition in the 1st scsi (as ide)
/dev/st0	First SCSI tape, mode 0
/dev/st0l	First SCSI tape, mode 1
/dev/nst0	First SCSI tape, mode 0, no rewind
/dev/md0	First metadisk(RAID) group
/dev/nwflash	Netwinder flash memory
/dev/scd0	First SCSI CD-ROM (or SCSI emulated)
/dev/sr0	First SCSI CD-ROM  (old)
/dev/rom0	First ROM card (rw)
/dev/rrom0	First ROM card (ro)
/dev/flash0	First flash memory card (rw)
/dev/fflash0	First flash memory card (ro)
		[printers]
/dev/lp0	Parallel printer on parport0
/dev/usb/lp0	First USB printer

		[mice]
/dev/usb/mouse0		First USB mouse
/dev/logibm		Logitech bus mouse
/dev/psaux		PS/2-style mouse port
/dev/inportbm		Microsoft Inport bus mouse
/dev/atibm		ATI XL bus mouse
/dev/jbm		J-mouse
/dev/amigamouse		Amiga mouse (68k/Amiga)
/dev/atarimouse		Atari mouse
/dev/sunmouse		Sun mouse
/dev/amigamouse1	Second Amiga mouse
/dev/smouse		Simple serial mouse driver
/dev/pc110pad		IBM PC-110 digitizer pad
/dev/adbmouse		Apple Desktop Bus mouse
/dev/vrtpanel		Vr41xx embedded touch panel
/dev/vpcmouse		Connectix Virtual PC Mouse
		[other input]
/dev/input/js0			First joystick
/dev/touchscreen/ucb1x00	UCB 1x00 touchscreen
/dev/touchscreen/mk712		MK712 touchscreen
/dev/usb/scanner0		USB scanner
/dev/sg0			First generic SCSI device may be scanner
/dev/scanners/cuecat		CueCat barcode scanner
/dev/gs4500			Genius 4500 handheld scanner
/dev/wvisfgrab			Quanta WinVision frame grabber
/dev/video0			Video capture/overlay device
/dev/radio0			Radio device
/dev/vtx0			Teletext device
/dev/vttuner			TV tuner on teletext interface
/dev/dcxx0			miroVIDEO DC10/30 capture/playback card
/dev/av0			Philips SAA7146-based audio/video card
		[other]
/dev/usb/cpad0	Synaptics cPad (mouse/LCD)
/dev/phone0	First telephony device
/dev/ttyTB0	First USB BlueTooth device
		[symbolic links]
/dev/mouse	mouse port	Current mouse device
/dev/tape	tape device	Current tape device
/dev/cdrom	CD-ROM device	Current CD-ROM device
/dev/cdwriter	CD-writer	Current CD-writer device
/dev/scanner	scanner		Current scanner device
/dev/modem	modem port	Current dialout device
/dev/root	root device	Current root filesystem
/dev/swap	swap device	Current swap device