Z.1 NRAO workstations — general information

All NRAO workstations run some version of the Unix operating system, Linux on PCs and Mac OS/X on Apple products. Unix systems are intrinsically sensitive to the difference between upper and lower case. Be sure to use the case indicated in the comments and advice given in the following notes. AIPS itself is case-insensitive, however; conversion of lower-case characters to upper-case occurs automatically. (Unix systems have a variety of characters for the prompt at monitor (job-control) level, and allow users to set their own as well. We will use $ as the prompt in the text below.)

Z.1.1 The “midnight” jobs

The versions of AIPS on all NRAO PC systems are kept up to date continually with the master versions on the Socorro Linux PC called dave. This is achieved by automated jobs that start running at very antisocial hours of the early morning. Any changes formally made to the TST version of AIPS are copied to the relevant computers and recompiled/relinked. Midnight jobs run in Charlottesville, Socorro, Green Bank, and many other sites around the world.

Z.1.2 Generating color hard copy

Z.1.2.1 Color printers

Color printers are, these days, simply printers that understand the color extensions to the PostScript language used to describe plots. The NRAO owns several Tektronix color printers, two public ones in Charlottesville (ps1color in the AIPS Caige and ps3color in the Library) and two at the AOC in Socorro (ps213c on the ground floor and ps324c upstairs in the former library). You may display your PostScript file on the printer in Socorro simply by typing

$ lpr -Pps324c filename  C R

where filename is the name of your file.

The paper size is 8.5 × 11 inches, which is the default for AIPS tasks TVCPS and LWPLA. To have the file printed on transparency paper use queue ps1tektran rather than aoc324c/trans. Full control over this complex printer is available with the multiprint command; type multiprint --help  C R for information. If you do not wish to save the plot as a disk file, you may also print it directly from within AIPS. The color printer is one of the printer choices when you start up AIPS, but you probably want to select a regular PostScript printer as your default printer. You can change your printer selection with the verb PRINTER; use PRINTER 999  C R to see what your choices are and then PRINTER n  C R to choose the printer numbered n. AIPS print routines will re-direct PostScript files that actually contain color commands to the first PS-CMYK printer in the list, but will not re-direct ordinary print jobs to some printer other than a color printer.

Z.1.2.2 Software to copy your screen

To obtain a color hard-copy of what is on your screen, there are several software options you can choose. These include TVCPS, xv, and import. Having created a PostScript (or other format) file, you can print it on color printers at the NRAO or copy the file via e-mail, scp, or ftp to some other site.

The TVCPS task in AIPS will create a color Encapsulated PostScript file from whatever is displayed on the AIPS TV server (XAS). If you use the OUTFILE adverb, this file is saved with whatever name you specify (see §3.10.1). If you specify a black-and-white output to TVCPS, then the output can be sent to any PostScript printer. Color PostScript must be sent to a color printer. You can, of course, edit the saved file (if you are a PostScript wizard or use HELP POSTSCRIPT) and can insert the file (since it is encapsulated) in another document.

The xv program is a Unix utility program available on most systems at the NRAO. It is mainly intended for image display of GIF, JPG, TIFF, and other format files. When you start xv, click the right button mouse anywhere in the xv window to bring up the control window. One of its features is a screen grab which is controlled by the “Grab” button in the lower right corner of the control window. Before you press this, arrange your windows and icons so that you can see exactly what it is you want to grab (e.g., the XAS server). Now press the “grab” button. A window with instructions will appear. Move the cursor to the top left of the area you want to grab. Then press and hold down the center mouse button, and drag the mouse cursor until it is at the bottom right of the area you want to grab. As you do this, you will see a box pattern on the screen outlining the area selected. Once you are done selecting the area, release the mouse cursor. When xv has finished grabbing the screen, whatever you grabbed will appear in the main xv window. You can now use the “save” button of the control window to save this as any format you want. One nice feature of this is the “save as Postscript” option. It allows you to scale, rotate, and position the image in relation to the page. Its user interface is better than most image utilities.

Finally, the import program provides similar functionality to the “grab” feature of xv, with many options about output formats and much more. Enter import -help  C R for a summary of the options. For example, enter import  -quality 100  outfile.jpg  C R. The cursor will change to a plus sign. Position it at the top left corner of the area you wish to grab, hold down a mouse button, and drag the cursor to the bottom right of the area you wish to capture. When you let up on the button, the file outfile.jpg will be written in jpg format. The file extension determines the format, so .eps will produce encapsulated PostScript.

Z.1.3 Using the tape drives

For a general discussion of magnetic tapes, including the required software mount, see §3.9. The following describes how to deal with the individual tape drives at the AOC.

Z.1.3.1 Mounting tapes on Exabyte and DAT drives

There are still tape devices in each of the AIPS Caiges: rooms 209, 211, and 257. Be aware that they are not much used and are not maintained on a regular basis. You may have to try more than one to find a device that works for your tape. There are “toaster” disk devices on every public workstation. These are more reliable and have much more storage capacity, so tape should never be a medium of choice now. The devices are kept to allow old data tapes to be read.

Exabyte (8mm) and DAT (4mm) drives have a window or opening through which a mounted tape may be seen. Before touching anything, look in the window or opening to see if there is already a tape in the drive. If there is, ask around to make sure that the tape is no longer in use. Remember that the user of the drive may be in an office as much as two floors away and that Unix does not provide much protection. If you dismount a remote user’s tape and mount your own, that user may well write on it, thinking that he is writing on his own tape, without knowing that he is destroying all your data.

On most drives, there will be a single button on the front panel of the device somewhere. When the device becomes available, press this button to open the door. If there was already a tape in the drive, it will be ejected after some whirring and clanking and a few seconds. If a tape is ejected, remove it. Now put your tape in the drive, label facing upwards. On Exabytes, push the door closed gently. For DAT drives, lightly push the tape into the drive until the device “grabs” the tape and pulls it in the rest of the way. Exabyte and DAT tapes have a small slide in the edge of the tape which faces out which takes the place of the write ring of 9-track tapes. For 8mm (Exabyte) tapes push the slide to the right (color black shows) for writing and to the left (red or white shows) for reading. With 4mm DAT tapes, the slide also goes to the right for writing (but white or red shows) and to the left for reading (black shows).

It is necessary to wait until the mechanism in the drive has “settled down”, i.e., when the noises and flashing lights have stopped, before you can access the drive. The first access is, of course, the software MOUNT command from inside AIPS.

Z.1.4 Gripe, gripe, gripe,

The so-called “designated AIP” is now Eric Greisen at all times (except when he is on vacation). He assists local and remote users with their AIPS problems, providing quick advice or simple fixes to bugs, More complex problems may require some time and may even require receipt of the user’s data in order to debug the problem. Contact the designated AIP (and all members of the group) at the e-mail address daip@nrao.edu. The “my.nrao” web portal lets you into the “helpdesk” which has an AIPS department. Management prefers if you use this approach to request assistance.

Suggestions and complaints entered on all computers with the GRIPE verb (see §11.1) are sent immediately by e-mail to daip and thereby to all members of the group. All traffic via daip from 2000 to the present is archived at listmgr/cv.nrao.edu/pipermail/daip and is well-known to Google. You might try Googling your AIPS error message to see if you get something useful. We stand willing, and are now able, to respond to user problems and requests on a timely basis.

The Gripes database described in AIPS Memo No. 88 used to be maintained, but appears to have disappeared.

Z.1.5 Solving problems at the NRAO

Below are details specific to NRAO systems for handling some of the problems which may arise in AIPS.

Z.1.5.1 Booting the workstations

Modern workstations, especially the powerful PCs and Macs, are complex Unix systems which may have remote users within the NRAO and guests from elsewhere on the Internet. Users should never attempt to boot the system on their own. If the machine appears to be dead, find or call one of the people listed on the bulletin boards in the AIPS Caige for this purpose.

Z.1.5.2 Printout fails to appear

Check the AIPS output messages that appeared shortly after you submitted your print job, whether it be from PRTMSG or LWPLA, or some other task. You should see the output of the Unix command to show the printer queue status. If anything went wrong with the print submission, an error message should be obvious. If not, check the output of the lpq command, see what print queue was involved, and check it again from the Unix command level (not from inside AIPS).

AIPS will delete spooled files about 5 minutes after they are submitted. If the print queue is stalled (due, say, to a jammed printer) or backed up with a lot of jobs, it is possible that the file was deleted before it was gobbled up by the print spooler. This time delay has been made a locally-controlled parameter, so it is possible to set it to values higher than 5 minutes.

Finally, check to see if the printout was (a) diverted to the “big” printer (psnet in room 213 at the AOC or ps3dup in the Charlottesville library) because it was too long for the smaller printers, (b) you forgot which printer you had selected on aips startup, or, at the AOC, (c) someone has taken the output and filed it in the “today” file bin (at the AOC this is on the left side of the post directly behind the psnet printer).

Z.1.5.3 Stopping excess printout

To find out what jobs are in the spooling queue for the relevant printer, type, at the monitor level:

$  lpq  C R

to list default print queue

$  lpstat  C R

to list default print queue under Solaris

or to display a specific queue

$  lpq -Pppp  C R

to show printer ppp

$  lpstat ppp  C R

to show printer ppp under Solaris

where ppp might be psnet at the AOC or ps3dup in Charlottesville. If the file is still in the queue as job number nn, you can type simply

$  lprm -Pppp nn  C R

to remove the job

$  cancel nn  C R

to remove the job under Solaris

lprm and cancel will announce the names of any files that they remove and are silent if there are no jobs in the queue which match the request.

Unfortunately, it is now very difficult to stop long print jobs. The large memories of modern printers mean that more than one print job can already be resident in the printer while your long unwanted job is being printed. Therefore, turning off the printer is not an option. Try to be more careful and not generate excess printout in the first place (save a tree).

A nice option available for most AIPS print tasks or verbs is adverb OUTPRINT which allows you to divert the output to a text file. Then you can use an editor like emacs to examine the file in detail before printing. The Unix command wc -l file will count the number of lines in a text file called file for you; note that -l is the letter ell, not the number one. AIPS provides a “filter” program to convert plain (or Fortran) text files to PostScript for printing on PostScript printers. The command

$  F2PS -nn < file | lpr -Pppp

will print text file file on PostScript printer ppp. The parameter nn is the number of lines per page used inside AIPS; it is likely to be 97 if direct printing comes out in “portrait” form or 61 if the direct print outs come out in “landscape” form.

Z.1.5.4 CTRL Z problems

The last process placed in the background via CTRL Z can be brought back to the foreground by typing fg  C R in response to the monitor level % or $ (or whatever) prompt Alternatively, the user can type  jobs  C R, which displays all background processes associated with the current login and can bring a specific process to the foreground by typing fg % m  C R, where m is the job number as displayed by the jobs command as [m]. For example, if a user initiated his AIPSn by typing aips new pr=4 C R and:

^  Z

CTRL Z typed by accident (or intentionally).

Stopped

aips new is put in the background as “stopped” and user is returned to the Unix level.

$  jobs  C R

to display status of background jobs.

[1] + Stopped aips new

info from Unix, where [1] means job 1, “Stopped” is job 1’s state and “aips new” is the command used to start up job 1.

$  fg m  C R

to return job m to the foreground.

aips new

appears on the screen just to tell the user to which job he is talking (i.e., it does not re-execute aips new). You should now be talking to your AIPSn again.

 C R

to get AIPSn > prompt.

Z.1.5.5 “File system is full” message

The message write failed, file system is full will appear when the search for scratch space encounters a disk or disks without enough space. This is only a problem when none of the disks available for scratch files has enough space, at which point the task will shut down. Use the BADDISK adverb to avoid disks with little available space.

Z.1.5.6 Tapes won’t mount

Occasionally, both local and remote tape mounts may not work successfully. The source of the problem is often your failure to load the tape physically into the device or to wait until the device is ready to read the tape. DATs and Exabytes, in particular, go through lots of clicking and whirring before they are really ready. An error message like AIPS 1: ZMOUN2: Couldn’t open tape device /dev/nrst0

(or some other tape-device name gibberish) is to be expected in this case.

If you attempt to mount a remote tape and get the messages: AIPS 1: ZMOUNR: UNABLE TO MOUNT REMOTE TAPE DEVICE, ERROR 96 AIPS 1: AMOUNT: TAPE IS ALREADY MOUNTED BY TPMON

it means that your AIPS and the tape dæmon that you are using disagree on whether the tape is already mounted in software. The most probable reason for this is that you are attempting to mount someone else’s tape (check your inputs and the labels on the device closely) — or that the previous user of the device dismounted the tape from the hardware but neglected to do it from software. In this case, you have two choices: (1) find the culprit and have him do a software dismount, or (2) find an AIPS Manager to kill the confused dæmon and restart it. (If you are using tape device n on computer host_name, then you need to stop the process called TPMONm, where m = n + 1 on computer host_name and then start it again by running /AIPS/START_TPSERVERS on that computer. This should be done by an AIPS Manager.)

If you attempt to mount a remote tape and see, instead, the messages: ZVTPO2 connect (INET): Connection refused AIPS 1: ZMOUNR: UNABLE TO OPEN SOCKET TO REMOTE MACHINE, ERROR 1 AIPS 1: ZMOUNT: ERROR 1 RETURNED BY ZMOUN2/ZMOUNR

then the tape dæmons are not running on the remote machine. Log into the remote machine and type: /AIPS/START_TPSERVERS

After a minute or two, you should see some messages from STARTPMON about starting TPMON dæmons. Alternatively, you could exit from AIPS and start back up again, including tp=host_name on the aips command line; see §2.2.3. If the tape still doesn’t mount after doing this, see the AIPS Manager.

Z.1.5.7 I can’t use my data disk!

If at some point during your work you find you are prevented from reading or writing files on a data disk, it could be that your AIPS number does not have access to that area. If you encounter the message: AIPS 2: CATOPN: ACCESS DENIED TO DISK 8 FOR USER 1783

it means that user 1783 has not been given access to write (or read) on disk 8. This can be seen, in the AIPS session, by typing FREESPAC to list the mounted disks. If you see a data disk listed with an access of Not you, it means your AIPS number has not been enabled for that disk. If you feel that you should have access to that particular disk, see the data analysts (at the AOC) or an AIPS Manager about enabling your user number.