|lnx1.physics.ubc.ca||2 x 700 Mhz PIII||512 Mb||20 Gb||nVidia GEForce 2 MX (32Mb)|
|lnx2.physics.ubc.ca||2 x 700 Mhz PIII||512 Mb||20 Gb||nVidia GEForce 2 MX (32Mb)|
|lnx3.physics.ubc.ca||2 x 800 Mhz PIII||512 Mb||20 Gb||nVidia GEForce 2 MX (32Mb)|
In addition, there are nine older, and significantly less powerful PCs located on the same side of the lab, which are currently configured as "X-terminals", and which are served by the machine lts1.physics.ubc.ca. You can login to lts1 from any of these machines, and from there you can open one or more terminal applications and, from those, ssh to any of the lnx boxes. This configuration of the older PCs as X-terminals is new, so there may still be some glitches that need to be worked out. Again, contact me immediately should you encounter problems.
NOTE: During the term, Physics 410 students have priority use of the lnx consoles. However, the other PCs in the room may be reserved from time to time for use in other courses. Please refer to the Lab Schedule for times when the lab is booked for such purposes.
Please make careful note of the following:
Note that your home directory on these machines ("the lnx machines") will be distinct from your home directory on physics.ubc.ca, but that you will have a common home directory on physics.ubc.ca and lts1.physics.ubc.ca. Those of you who had physics accounts prior to approximately August 2003 may find that adjustments need to be made to your shell-start up files to take into account this commonality. Again, contact me if you have any questions in this regard.
At the current time, it is not possible to access your lnx files directly from physics (lts1) or vice versa.
Notes on Linux Desktop Environments: Over the past few years, great progress has been made in equipping Linux with powerful graphical user interfaces (GUIs, window managers) to the core operating system and major applications. When you login to the console of one of the lnx machines, you can select from no fewer than 11 such interfaces! I recommend that you use one of the following window managers
IMPORTANT!!: When first logging-in at a console of one of the lnx machines, do the following:
IMPORTANT!!: Note on X-terminal Desktop Environments: At the current time you can only use Gnome, NOT KDE, on the X-terminal PCs. With luck, this will get fixed shortly. (If you do choose KDE from the login window on one of the X-terms, the system will (probably) initiate your login, present you with a KDE start-up wizard, etc., but you will also encounter error-message pop-ups, and eventually will be returned to the login screen.)
Note on lnx home directories: The lnx machines have access to each others' disks via NFS (Network File System). The process of attaching a remote file system to a directory name within the local Unix system (i.e. to a directory name somewhere within the file hierarchy rooted in /) is known as mounting the file system. In a shell, you can generate a listing of all of the file systems currently mounted with the Unix df command. For example, you can see the output of df as executed on lnx1 HERE.
Again, each of you has a single home directory on the lnx machines, and that directory is physically located on one of the machines lnx1, lnx2 or lnx3. (I leave it as an exercise for you to determine on which specific machine yours is located.) Let's consider the case of the ``test'' user jdoe, whose home directory is physically located on lnx1, within the file system /home:
[jdoe@lnx1 ~]$ cd [jdoe@lnx1 ~]$ pwd /home/jdoejdoe now logs into lnx2 and executes the same command sequence:
[jdoe@lnx1 ~]$ ssh lnx2 Warning: Permanently added 'lnx2,188.8.131.52' (RSA) to the list of known hosts. jdoe@lnx2's password: No mail. [jdoe@lnx2 ~]$ cd [jdoe@lnx2 ~]$ pwd /d/lnx1/home/jdoeThis behaviour can be understood by looking at the specific part of the output from df which tells us about the file systems from lnx1 which have been mounted on lnx2:
[jdoe@lnx2 ~]$ df | grep lnx1 lnx1:/home 19449328 7048332 11413004 38% /d/lnx1/homeSince the remote, physical file system lnx1:/home has been mounted on the local file system /d/lnx1/home, when logged into lnx2, jdoe's working directory is indeed /d/lnx1/home/jdoe.
Moreover, things have been set up so that you can use the "long" form of your home directory on all of the machines, so that, for example, jdoe can execute the following:
[jdoe@lnx1 ~]$ cd /d/lnx1/home/jdoe [jdoe@lnx1 ~]$ pwd /home/jdoe
Note that the specific name of the local mount point, e.g. /d/lnx1/home, is a matter of convention ('d' for disk, then the hostname, then the remote file system name); other system administrators will use different conventions for NFS mounts.
Finally, as mentioned above, you can access your lnx home directories directly from physics since the /home filesystems on the lnx machines are NFS-mounted on physics as
/d/lnx1/home /d/lnx2/home /d/lnx3/homeThus, for example, on physics, any of
physics% cd /d/lnx1/home/userid physics% cd /d/lnx2/home/userid physics% cd /d/lnx3/home/useridshould take you to your lnx home directory.
As always, contact me immediately if you have any questions, or encounter any problems, regarding this issue.