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FAQ for NCRA Systems

NCRA Computer Systems – Frequently Asked Questions


Last Update: 11.8.2005

This is tentative FAQ only. If some of the listed service/facility failed, pls address your mail to with error message(s). We will be updating this FAQ periodically. Pls visit this page frequently.


For Fedora Core 3 specific issues /home/vvs/system/fc3-faq.html

  1. What are printers configured?

    npcr : Network Printer in Computer Room (HP2300 DTN) configured in dhruva. This printer is connected MSEB mains raw power and not to UPS power. This printer is installed in Computer room No. 237. This printer will print on both sides of paper. All are requested to print from dhruva who are logging into our systems from computer room PCs. The command is

    ssh dhruva

    lpr -Pnpcr filename

  2. What are Tape drives available?

    Exabyte Eliant 720 drive in genpro configured as /dev/nst1

    HP DAT72 drive in genpro configured as /dev/nst0

    HP DAT72 drive in yamuna configured as /dev/nst0

    (HP DAT72 will read/write DDS3 data cartridges)

    HP DDS3 drive in mutha configured as /dev/nst0

    Exabyte EXB-8505 drive configured in bheema as /dev/nst0

    HP DDS3 drive in bheema configured as /dev/nst1

    Tandberg SDLT 160/320 external drive configured in bheema as /dev/nst2

    Tandberg SDLT 110/220 internal drive configured in mula as /dev/nst0

    HP DDS3 drive configured in pavana as /dev/nst0

  3. How to write to CD-R media?

    There are 3 CD writers available in Computer room. One Samsung combo drive in dhruva, another HP CD writer in pavana. One HP DVD writer (CD-R can be written using this drive) installed in kaveri. Suppose, user directory is /temp1/data1, use the following command

    cdrecord -scanbus [to know device number, normally 0,0,0 to be given for cdrecord command]

    cd /temp1

    mkisofs -R data1 | cdrecord -v dev=ATA:1,0,0 -data -

    One CD-R can take unto 700 MB of data. Pls verify before writing to CD-R.

  4. How to write to DVD+R media?

    One HP DVD writer installed in kaveri machine. Suppose, user directory is /temp1/data1, use the following command

    cd /temp1

    growisofs -Z /dev/dvd -R -J data1

    One DVD+R media can hold up to 4.1 GB of data only. Pls verify your data size before writing.

    If input file is ISO image file, then

    growisofs -dvd-compat -Z /dev/dvd=FC3-test3-i386-DVD.iso

    For appending to existing data to DVD+R media

    growisofs -M /dev/dvd -R -J data1

    For some reason if above command failed, then try

    Instead, the following two commands seem to work:

    mkisofs -o <filename> -R -J <directory>

    <directory> is the directory where files are present to be written to DVD, <filename> is the image created by above command (mkisofs)

    dd if=<filename> of=/dev/dvd seek=0 obs=32k

  5. How to print in color printer?

    We have one HP-4600 DN Color Laser Duplex printer. This printer is connected to MSEB mains raw power and not to UPS power. This printer is intalled in Computer room No.235. This printer will print on both sides of paper. This is reachable from dhruva and use the following command.

    lpr -Pnp4 filename

  6. How to get access to large disk space, which is greater than home quota size?

    We have one disk partition called /temp1. Which is available in all the PCs in computer room. All the files in this area will be cleared after 24 hours from time of creation. It has lot of disk (34 GB). Pls create your sub-directory in /temp1 and then use the disk space for your temporary storage.

  7. How to solve startx problem?

    Generally, there will be some problem, if you have .gnome area created under different versions of Linux OS. This happens in computer room. You just use as follows.


    \rm -rf .gnome* .gconf* [if gnome is your default desktop] or

    \rm -rf .kde* [if kde is your default desktop]

  8. How to print on single side of paper using Duplex printers?

    From dhruva, use the following command to print on single side of paper.

    lpr -Pnpcrs filename [For npcr mono (black) printer ]

    lpr -Pnp4s filename [For np4 color printer]

  9. How to print transparency in color printer?

    Just use the following command from dhruva;

    lpr -Pnp4t filename

  10. How to use IDL, Mathematica and Matlab software?

    Just login to yamuna computer using ssh and start executing the software. This software has single user network floating license.

  11. If PDF files are not readable / printable using ggv/gv/xpdf, what to do?

    Use acroread reader for linux (Fedora Core 3) as follows;

    In linux, as root

    mount genpro:/disk/linux/ /a

    cd /a/contrib/acroread

    rpm -Fvh acroread-5.0.10-1.1.fc3.rf.i386.rpm or

    rpm -ivh acroread-5.0.10-1.1.fc3.rf.i386.rpm

    If your OS is Fedora Core 2, then use acroread-5.0.10-1.1.fc2.rf.i386.rpm

    If your OS is RedHat 9, acroread-5.0.10-1.0.rh9.rf.i386.rpm

    There are other set of plugins for mozilla browser in the same area. That is you can read pdf files from mozilla browser.

  12. SSH Login failed with “Remote Host identification changed”. What to do?

    The error may look like this:



        Someone could be eavesdropping on you right now (man-in-the-middle attack)!


        Please contact your system administrator.

        Add correct host key in /home/<username>/.ssh/known_hosts to get rid of this message.

        Offending key in /home/<username>/.ssh/known_hosts:3

        Host key verification failed.

    There are two ways to get over this error. Simply edit the file ~/.ssh/know_hosts or ~/.ssh/know_hosts2 and delete the corresponding remote host entry. Then try ssh.

    OR simply delete the file ~/.ssh/know_hosts or ~/.ssh/know_hosts2. This file will be re-created during subsequent ssh session beginning.

    This remote host identification change happens every time hardware or software changed.

  13. ggv (Gnome Ghost View) not working in PCQLinux 2005. What to do?

    In PCQLinux 2005,

    ggv will not display content of any ps file. Download the file

    dhruva:/disk/PCQLinux2005/VFlib2-2.25.6-25.i386.rpm and install as follows;

    # rpm -ivh Vflib2-2.25.6-25.i386.rpm

    That is it.

  14. How to auto mount USB memory stick in newer Linux?

    Check whether haldaemon is running? If not start using system-config-packages or ntsysv as root and preferrably reboot. Then who ever logs in console will get permission for USB memory stick.

  15. How to take backup using tar and remote tape drive?

    tar cvf - * | ssh user@host "dd of=/dev/nst0" -------- where host is name of machine where tape drive installed.

    for retrieving using similar setup --------

    ssh user@host "dd if=/dev/nst0" | tar xvf -

  16. PGPLOT C program compilation error?

Command: gcc -g -o test -I/some_directory/pg520lnx test.c -L/usr/X11R6/lib -lX11 -lm

-L/some_directory/pg520lnx -lcpgplot -lpgplot

Giving following errors:

.../libpgplot.a(pgenv.o)(.text+0xbc): In function `pgenv_': : undefined reference to `s_copy'

.../libpgplot.a(pgenv.o)(.text+0x2fe): In function `pgenv_': : undefined reference to `s_cat'

.../libpgplot.a(pgmtxt.o)(.text+0xab): In function `pgmtxt_': : undefined reference to `i_indx'

Solution: change gcc to g77


use gcc to compile and f77 to link...

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