1. How do I change my password in the lab?
2. How do I log in to the lab remotely?
3. How do I record a cd?
4. How do I record a dvd?
5. How do I use the scanner?

TeX questions

1. TeX is telling me I have an `overfull hbox'.

How do I change my password in the lab?

Use "kpasswd" in a command window.

How do I log in to the lab remotely?

We have turned off telnet and ftp access to the lab to increase security. You need to use ssh and scp or sftp instead, which protects your password. The easiest way to log in is to use a java-capable browser to go to http://math.whitman.edu, and then click on the "Secure login" link.

There are also free and commercial versions of ssh, scp and sftp for windows, os x and linux. If you have a standalone ssh program, you can connect to any of the lab machines from campus, not just the one named "math" (which is where you'll end up if you use a browser). The command "finger showall@math.whitman.edu" will show you the names of the lab machines and who is logged in on each. If you are on campus, you should ssh to a machine that is not being used, if possible, or to "math". If you are off-campus you can only ssh to math.whitman.edu.

A good ssh program for windows is PuTTY, and a good sftp program is WinSCP. For OS X try Fugu.

How do I record a cd?

1. Before you burn a CD, I strongly suggest you read the man pages for mkisofs and wodim.

2. To burn a data CD, you must first have an "image" of the CD contents in a file. You may have downloaded such an image, or you may need to create one from a collection of files.

3. If you need to create an image, you use the "mkisofs" command. In the simplest case, you will be transferring an entire directory structure to the cd. Suppose you have a directory called "mycd" in your home directory for this purpose. NOTE: Typically the file cdimage can be quite large; the capacity of a CD is 650-700 megabytes. Please construct it in /tmp as follows:

    
   mkisofs -r -U -o /tmp/cdimage ~/mycd
   

   You can use any name you want for "cdimage". To learn more about the various option flags for mkisofs read the man page for mkisofs. In particular, if you want this cd to be as portable as possible, you may not want the -U flag.

4. Once you have the CD image, put your recordable CD in the cd burner--this is the bottom of the two drives on the lab machines. Then give this command:

   wodim -v speed=s dev=ATA:0,1,0 /tmp/cdimage
   

   replacing "s" by the speed you wish to use. Make sure to use a speed that is supported by the blank cd you have. You can get the default speed by leaving the "speed=s" option out.

   Once you start burning, you must let the whole process finish; if you interrupt it, the cd will be unusable.

5. When you are finished, delete /tmp/cdimage.

   Before you try to burn a cd, make sure that the information will fit on your cd. For example, if you are making a backup of your home directory, then in your home directory give the command "du -sm". This should display the number of megabytes in your entire account. CDs have a capacity of either 650 or 700 MB--make sure that the number displayed is no greater than the capacity of your cd. If it is, you can backup to multiple cds by selecting only some of your subdirectories when using mkisofs. You might also be able to delete unneeded files. For example, the .dvi and .log files produced when you run TeX can be recreated, so there is no need to back them up. If you have C or C++ programs, you can delete any .o files and even the executable programs, since these can be recreated by compiling the program again. If there are core files (sometimes created when a program crashes) you can delete them; they are named either "core" or "core.xxxx" where the x's are digits. You may have a large netscape or mozilla cache if you browse the web in the lab; from inside the browser you can empty the cache and free up some space. If there are files you don't want to lose, but don't often need, you can delete them after you back them up, so your next backup of new files will be smaller. Be aware, however, that cds can go bad, so it is unwise to maintain your only copy of important information on a cd.

How do I record a dvd?

The dvd burner on fortitude will record dvd-r, dvd+r, dvd-rw and dvd+rw disks; we have had some trouble with dvd-r disks, so we suggest you use dvd+r and dvd+rw disks. These instructions are for burning data dvds using growisofs, which in turn uses mkisofs, so you should read the man pages for these programs to learn more. Basic usage is quite simple. Suppose you want to backup your entire home directory. Put the blank dvd in the dvd writer (the top drive). From your main directory (you can get there by typing "cd" in a terminal window) give this command:

growisofs -speed=1 -dvd-compat -Z /dev/dvd -U -r -v .

The period at the end, after a space, is important--it means the current directory. Using speed=1 actually seems to burn at about speed 4, so make sure your dvds are rated at least that high (almost certainly they will be). If you want to burn at a faster rate you can give a different speed or leave the speed out entirely to get the default speed.

Before you give the growisofs command, make sure that your directory will fit on your dvd. In your home directory, give the command "du -sm". This should display the number of megabytes in your entire account. A dvd will hold 4700000000 bytes or about 4482 megabytes or about 4.4 gigabytes. (Some manufacturers call one billion bytes a gigabyte, so your dvd may claim that it holds 4.7 gigabytes. In the technical world, one gigabyte is 2^30 bytes.) There is a single command to backup your home directory on dvd: backup-dvd.sh. It works just like the backup commands for cds, except the one command will work with any kind of dvd: -r, +r, -rw, +rw.

How do I use the scanner?

Once you've logged on to pride, give the command "xsane &" in a command window to open the scanning software. Basic use of the program is straightforward, and help is available.

TeX answers

TeX is telling me I have an `overfull hbox'.

Faced with the prospect of either putting too little on a line or too much, TeX puts too much and warns you about it. If you view the output, you should see a line that runs into the right hand margin; it will also be marked with a thick black bar in the right margin (you may have to scroll the view window to the right to see it). Sometimes the problem is that you have done something genuinely wrong; for example, if you accidentally put too much stuff in math mode (between dollar signs), TeX may not find a good place to break the line, because TeX tries to avoid breaking a line in the middle of a formula. At other times, it may be that a long word or mathematical formula happens to occur right at a desirable place for a line break. In this case you can usually rewrite the sentence slightly so the line can be accomodated. It may also be that the long word can be hyphenated, but that TeX doesn't know how to do it. In this case you can insert information telling TeX where it is acceptable to hyphenate the word. Put `\-' at every place in the word that a hyphen is acceptable, like this: ab\-at\-toir. DON'T put hyphens without the `\' in the word, as they will be inserted no matter what.