UNIX/PC Computing Frequently Asked Questions
1) Accessing Linux files from a PC: I have a new PC (or I reinstalled Windows)
and I can't access my Linux files via Network Neighborhood.
2) Backup: Do you back up my files?
3) Copy/paste in Linux: How do I copy and paste text in Linux?
4) Disk space: How much disk space can I use?
5) Files in temp or ftp: My files from temp or ftp disappeared overnight.
6) Login: I cannot log in to Unix
7) MEDx: How do I run MEDx remotely?
8) Printing (Unix): How do I print a file in Unix?
9) Printing (Windows): How do I add a printer in Windows?
10) Printing problems: What do I do when I can't print?
11) Unix/Linux: I'm new to Unix/Linux. How do I get started?
12) Web page: I want to setup a personal web page on Claymore.
13) Web page password protection: I want to password protect a web page on claymore
14) Web search: Claymore web search did not find my stuff.
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1) Accessing Linux files from a PC: I have a new PC (or I reinstalled Windows)
and I can't access my Linux files via Network Neighborhood.
The Linux workstations run samba, which lets them appear
in the Network Neighborhood in Windows as if they
were Windows PCs. By default, Windows sends passwords
in a different format than in Linux. If you try to
connect to Linux you will get an error "The account
is not authorized to log in from this station"
(or something similar). In order to access the
Linux computers, you need to run a file which will
update the registry to tell Windows to use the same
format as Linux. The next time you reboot your computer
you will be able to access Linux.
1. First, exit from all programs because you will need to reboot
after updating the registry.
2. Click on the link corresponding to your version of Windows:
Windows 95
Windows 98
Windows NT
Windows 2000
(or get the appropriate file from the Samba website)
-- Windows XP Professional uses a different method; if you use
XP please contact the CABI Computer Administrator
3. Login as "member" if prompted for a username and password.
4. Choose "Open this file from its current location" and click OK.
5. Choose "Yes" to update the registry, then click OK.
6. Reboot your computer.
You should also consider using the Windows AFS client,
which will allow you to access your AFS files directly from the
fileservers, rather than going through one of the Linux workstations.
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2) Backup: Do you back up my files?
It depends where you put them. UNIX home
directories are backed up to tape regularly.
The data volumes dv01, dv02, etc., which may
be mounted in your home directory, are not
backed up due to limited resources; users are
responsible for storing their data to CD, DVD,
or other media. Also, we do not back up /afs/cabi/temp
or the data on the FTP site on claymore.
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3) Copy/paste in Linux: How do I copy and paste text in Linux?
In Linux, to copy text select it with the left mouse
button. The text is automatically copied to the clipboard
(you don't need to do cntrl-c like you do in Windows).
To paste the text, click once with the middle mouse button.
In some programs, you should use the Edit menu to copy
and to paste. If the previous method (selecting text to
copy and then clicking the middle mouse button to paste)
does not work, use the Edit menu.
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4) Disk space: How much disk space can I use?
User home directories are 1-2 GB. Additionally, you
may have 5 GB data volumes dv01, dv02, etc. mounted in
your home directory, especially if you or the PI that
you work with has bought some disks for the CABI.
The disk space in your home directory and the dv*
volumes are not pooled; each volume has its own
quota.
In order to find out how much space is available in
a directory (or more precisely, how much space is
available in the volume in which the directory resides),
use the AFS command 'fs listquota' (abbreviated 'fs lq'):
fs lq [<directory>]
If you omit the directory name, fs lq reports the
free disk space for the current directory.
Another useful command is du, which can tell you how
much disk space files and directories use. If you use
the du command in your home directory, be sure to
exclude the Backup subdirectory with the option
"--exclude=Backup".
Note that you can also store data temporarily in the temp
directory /afs/cabi/temp (make a subdirectory there for
your data). You can also store data in the /temp directory
of most Linux workstations (again, make a subdirectory),
although it is not shared across the network as is the
AFS temp directory. These directories are not backed up,
and don't expect data to stay there for long.
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5) Files in temp or ftp: My files from temp or ftp disappeared overnight.
Yes, that is not a bug, it is a feature. The temp
directory (/afs/cabi/temp) and the ftp data transfer
directory (visitor ftp) are both automatically cleaned
every night to maintain roughly a third of the capacity
available. These places were never intended for permanent
storage. The cleanup process starts by deleting the oldest
and biggest files first. How long your files stay there is
therefore dependent on what other files are there and thus
is hard to predict. If you want to store something permanently,
place it in your home directory.
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6) Login: I cannot log in to Unix
There are a few possibilities:
1. You don't have an account set up yet.
2. The password is wrong. Note that the password
is case sensitive. Normally you have nine tries
to get the password right.
3. You have been locked out of the filesystem.
If you try to log in with the wrong password
nine times, you will be locked out for up to
34 minutes. If you let the system manager know
he can unlock your account.
We have found that with Windows 95/98 Network
Neighborhood connections to Unix and with the
screen lock on the Suns you get 3 attempts.
4. Your home directory is full, ie you have reached
your quota. This prevents you from logging into
a Unix machine with a desktop (eg, KDE or CDE).
However, you can still connect from your PC via
the AFS client or Network Neighborhood, or you can
log in via telnet or ssh, or you can log into a
virtual console. You can then delete data that you
no longer need.
5. If you are ssh-ing from kryten to another
Linux computer, you need to specify ssh protocol 2
with the -2 option. For example to ssh from kryten
to zarquon, type
ssh -2 zarquon
(kryten runs an older version of Linux (so that
MEDx will run on it). The defaults with ssh protocol
1 will not work. However, if you ssh to kryten from
another Linux computer the defaults will work.)
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7) MEDx: How do I run MEDx remotely?
Currently MEDx is installed on kryten, so if kryten is
occupied by someone else you need to run MEDx remotely.
Log onto another Linux computer and type
xhost kryten
This will give the kryten permission to display X Windows
graphics on the computer that you are logged into.
("xhost +" will allow any machine to display on
the computer that you are logged into.)
Next telnet or ssh to kryten and then
type
export DISPLAY=<your_machine>:0.0
where <your_machine> is the name of the computer
that you are logged into. You can now run MEDx.
(Note: for most X Windows programs, ssh will
take care of the permissions and the DISPLAY
variable; however, MEDx has a bug.)
Example: you are logged into trillian and want to
run MEDx on kryten. Type
xhost kryten
ssh kryten
(input your password)
export DISPLAY=trillian:0.0
medx &
Note: It has recently been brought to my attention that with
telnet you no longer need to export the DISPLAY variable.
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8) Printing (Unix): How do I print a file in Unix?
On a Linux machine,
lpr [-P <printer>] <file>
and on a Sun,
lp [-d <printer>] <file>
where
<file> is the name of the file
-- can be text or postscript
<printer> is the name of the printer and is optional.
CABI printer choices:
-- hp4m (default printer for Image Analysis Lab)
-- hp4050 (default printer for CABI West)
-- dellcolor (in Raj's office)
For more information and options, see the man pages for
lp or lpr ("man lp" or "man lpr").
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9) Printing (Windows): How do I add a CABI printer in Windows?
Golem is the print server for CABI printers. You need to
run the Add Printer Wizard, choose the appropriate printer
from the list of printers on golem, and install the appropriate
print driver on your PC (if not already installed).
(The Add Printer Wizard is slightly different in different
versions of Windows, so the description below may be a bit
different from what you'll see.)
Note: I recommend the postscript drivers over the PCL drivers. If you
need to print to a postscript file you can use the postscript driver;
also, sometimes files do not print correctly with a PCL driver (although
that is very rare). Usually either driver is fine, though.
Windows 2000
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1. Click Start --> Settings --> Printers
2. Double-click Add Printer, click Next
3. Choose Network printer, Next
4. Click Next to Browse for a printer
5. Scroll down to Golem, double-click Golem, select the printer name, Next
-- You may get a message saying that the server does not have
the correct printer driver installed. Click OK.
6. Install the printer driver:
-- from Manufacturers list, choose HP
-- from Printers list, choose the appropriate printer:
HP C LaserJet 4500-PS (or HP Color LaserJet 4500)
HP LaserJet 4/4M PS (or HP LaserJet 4M)
HP LaserJet 4050 Series PS (or PCL)
7. Choose whether to use the printer as your default printer
8. Click Next, OK, or whatever... then Finish
Windows 95/98/NT and HP LaserJet 4m
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1. Click Start --> Settings --> Printers
2. Double-click Add Printer, click Next
3. Choose Network printer, Next
4. Choose Browse, choose Golem, the printer name, Next
-- You may get a message saying that you do not have
a suitable printer driver installed. Click OK.
5. Install the printer driver:
-- from Manufacturers list, choose HP
-- from Printers list, choose HP LaserJet 4M
6. Click Next, OK, or whatever... then Finish
Windows 95/98/NT and HP Color LaserJet 4500N or HP LaserJet 4050N
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Windows 95/98/NT don't have drivers for these printers,
so you should use the print drivers in the download
directory on golem. Here is how to get them:
Connect to golem through the Network Neighborhood.
Then navigate to the appropriate folder corresponding
to the version of Windows and the type of printer.
For example, for Windows 95, go to
\\Golem\download\Windows95\drivers\printers.
Then copy the subfolder (hplj_color or hplj_4050n)
to your hard drive (it doesn't matter where --
you'll delete it later).
Run the Add Printer wizard:
1. Click Start --> Settings --> Printers
2. Double-click Add Printer, click Next
3. Choose Network printer, Next
4. Choose Browse, choose Golem, the printer name, Next
-- You may get a message saying that you do not have
a suitable printer driver installed. Click OK.
5. Install the printer driver:
-- click Have Disk... then Browse...
-- navigate to the folder you copied from the
download directory, choose the .inf file, OK
6. Click Next, OK, or whatever... then Finish
7. Now you can delete the folder that you copied from
the download directory.
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10) Printing problems: What do I do when I can't print?
If you have a problem printing to the HP4si (in the DMP main office)
please contact the Helpdesk (x6521). If you can't print from your
Windows PC to any of the printers, the problem is probably with your
PC (or the NKI network) and you should contact the Helpdesk (x6521)
if you can't fix it.
If you have a problem printing to one of the CABI printers, excluding
the HP4si (ie the hpcolor, hp4050, or hp4m), please contact the CABI
system administrator. Sometimes the problem is that the print queue
on the server is down (which can happen when someone turns off and on
the printer). When the print queue is down no one can print to that
printer until the system administrator logs onto the server and restarts
the print queue.
You can also try printing to a different printer or transferring your
files to another platform and printing there (we have separate print
queues for Linux and Windows). Alternatively, if you can't print from
your Windows PC to one of those 3 printers, you can try using balrog
as the print server. You can go through the "Add printer wizard" (see
above) and choose balrog rather than golem. (However, normally please
use golem.) Be sure to let the CABI system administrator know that there
is a problem.
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11) Unix/Linux: I'm new to Unix/Linux. How do I get started?
Linux is a variant of Unix which is free and under active development.
In CABI we do not have the resources to teach people how to use Unix
or Linux, so we recommend that if you want to learn it there are several
tutorials on the web. On www.google.com you can search for "Unix tutorial"
or "Linux tutorial". Alternatively, you can buy a book such as
Learning the Unix Operating System by Peek, et al.
Also, note that our systems are slightly different than conventional
Unix systems in that we run the Andrew File System (AFS). Most noticeably
for the user, AFS handles file permissions in a different way than other
Unix filesystems do. You can find a description of AFS here.
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12) Web page: I want to setup a personal web page on Claymore.
Your public_html subdirectory in your Unix
home directory (e.g., /afs/cabi/doe/public_html)
will be the root directory of your web site.
Place an HTML file called index.html in it. Then
create other HTML files and subdirectories in it.
The index.html file can now be accessed using hyperlink
http://claymore.rfmh.org/~doe/ (if your username
happens to be "doe"). To avoid difficulties in the
future, we recommend using relative links within
your site whenever possible (e.g., from index.html,
use link "images/image.jpg" to reach file image.jpg
in the images subdirectory of public_html).
You also need to set permissions so that others can access your
web page. You need to give list permission to everyone for your
home directory:
fs setacl ~ system:anyuser l
Everyone also needs to have read permission for your
public_html subdirectory. This is set by default, so you will
not need to do anything unless you have previously changed it.
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13) Web page password protection: I want to password protect a web page on claymore
You can password protect your public_html directory or any
subdirectory of it. This will password protect the associated web
pages. To do this you need a file called .htaccess in the directory
that you want to protect. This file will have (among other things)
the path of a password file that you will need to create.
Here are the steps:
1. Create the password file with the htpasswd command:
htpasswd [-c] <pswd_filename> <username>
and enter the password that you want when prompted
-c means create the password file; otherwise htpasswd will append to the file
<pswd_filename> is the name of the password file
<username> is a username that you want to use for the authentication
For example,
htpasswd -c ~smith/pwd/.htpasswd fred
will create the file and put it in my 'pwd' subdirectory
2. Create a .htaccess file and put it in the directory that you
want to protect. A typical .htaccess file would have
AuthType Basic
AuthName <text>
AuthUserFile <pswd_filename>
require user <username>
AuthType should be Basic (the type of authorization that we're using)
<text> should be text to appear in the authentication dialog box
<pswd_filename> is the path to your password file (should be full path, /afs...)
<username> is the same as in #1
For example
AuthType Basic
AuthName "For my eyes only"
AuthUserFile "/afs/cabi.rfmh.org/usr/smith/pwd/.htpasswd"
require user fred
Note:
You can put the password file anywhere in your home directory;
it is suggested that you put it outside of your public_html
directory so no one can get access to it through the web.
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14) Web search: Claymore web search did not find my stuff.
Providing you searched for keywords that actually
are present in your materials, the search may not
discover the right page for one of several reasons:
- It is too fresh. The engine rebuilds all indexes
overnight, so try again tomorrow.
- It is not in a supported format. The engine knows
how to deal with HTML, MS-Word (mostly), PDF, and
Postscript. Other files are ignored.
- It is not in a public place. Only publicly accessible
directories are searched (those without any password).
Search includes your homepage, though.
If none of the above applies, let us know and we'll look
into it.
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This page was last updated on 12/5/2006. |