The CTIO computer system is continually undergoing change, as we try to keep up with our users' needs, as well as advances in computer and detector technology, such as Mosaic-II. Here are some highlights of recent changes which are likely to be of most interest to visitors using our computers.
We are substantially increasing the computer power available in each dome by installing new data reduction computers in place of the ancient and ailing VME bus computers, which have served this role for many years. The Blanco 4-m has been equipped with a dual processor Sun Ultra 2200 for almost a year. However, in preparation for the arrival of Mosaic-II, this will shortly be replaced by a new Ultra 60 workstation, providing a modest improvement in data reduction muscle. This machine will also be loaded with 45 Gb of disks for bulk data storage, and a DLT-7000 and twin Exabyte drives for data transfer. The three other domes will see a much more dramatic improvement in computing power, with the arrival of Ultra 10s for data reduction at each of the 1.5-m, 0.9-m, and Schmidt telescopes. At the same time the data acquisition machines will be receiving a boost from HyperSparc CPU upgrades. The disk space available in each dome will also be increased to around 20-30Gb.
Observers who arrive early on the mountain, or stay for a few days between runs will also now find a small number of public machines available in the round office building library and in the "old coffee area" at the 4-m. For the most part these are "cast off" but still serviceable machines adequate for reading e-mail, web browsing, and maybe making a start on that world-shattering paper based on the data you just took. However, there will also be access to an Ultra 10 or comparable machine for those who need to finish off their data reduction or tape writing.
The public computing hardware in La Serena is also changing for the better. The new centerpiece will be the Sun Ultra2 dualprocessor workstation (demoted from the Blanco 4-m), which will be available for large reduction tasks such as handling data from BTC and Mosaic-II. This machine will correspondingly be equipped with a large amount of disk storage, and a DLT-7000 and Exabyte and DAT drives for media conversion. The two other public "server" machines will also be replaced with Ultra10s, and a new Linux PC workstation (400Mhz DualPentium II) will be added. This latter machine is our Linux IDL server (see IDL section below), but will also be available for limited use by visiting astronomers.
The working environment in La Serena will also be improved as we remodel the La Serena computer room with the addition of computing cubicles. These will be used by our summer REU students from January through March, but are otherwise available for visiting astronomers who plan on using the La Serena computing facilities for more than a day or so.
Finally, the La Serena network has been upgraded to a 10/100mbps switched ethernet system and the Tololo ethernet will follow suit within the next few months. In addition to faster and more reliable intermachine communication this provides improved lightning protection on the mountain and increases network security (see next section).
For a long time CTIO has been sheltered from unwanted visitors by its remote physical and network location. However, we have suffered two separate, but probably related, hacker breakins during the course of the past year. No serious damage was done on either occasion, but considerable inconvenience was caused to both ourselves and to a number of observers here at the time. In particular, the hacker installed a packet sniffer allowing him to capture user names and passwords for a number of users when they logged on to their home machines from CTIO using telnet or rlogin. Our unwelcome guest then used the information obtained to break into several of these machines spreading the infection to a number of other institutions.
As a result, we are taking a number of steps to improve the security of our network. The majority of these will be largely transparent to users, or even improve service. For instance, the upgrade of the downtown and mountain networks to a modern switched ethernet system has the desirable side effect of severely limiting how much information a hacker can capture by planting a sniffer. However, we are also forced to take a number of measures and adopt policies (see http://www.ctio.noao.edu/sys/security.html), which may somewhat inconvenience legitimate users of our system.
Firstly, we have installed the SSH2 (Secure SHell) software package on all our machines. This provides for secure remote logins in a way similar to telnet, rlogin, or rsh and for secure file transfers in a way analogous to rcp. This software package is available for most operating systems, and is free of charge to educational and noncommercial users, while an enhanced version is available commercially (follow the links on the CTIO security page for further information on SSH). Hence forward we will not accept logins from machines outside the ctio.edu domain except via ssh. This means that users who wish to log into our machines from outside must first install ssh on their home machines. You will still be able to log onto your home machine from CTIO without using ssh. However, we strongly recommend its use, in this case in order to protect your home system. Special arrangements can be made in exceptional cases where it is very difficult or impossible to use ssh.
FTP service is another security risk which we have severely limited. Regular anonymous FTP service for getting information from our systems (e.g., downloading instrument manuals, etc.) is only available through our central server, www.ctio.noao.edu. Depositing files into the CTIO anonymous ftp area is not allowed. If you need to transfer files down here while you're observing, you can pull them in by FTPing from our machines to your home machine. Alternatively, we encourage you to use scp, the secure remote copy component of ssh, as an alternative to FTP to bring your files over.
Despite the above mentioned improvements in the computing power at CTIO, the availability of powerful portable computers means that many visitors ask if they can bring their own computers with them and connect them to our network. You are welcome to do so, and we maintain a number of "spare" IP numbers to facilitate this. However, we ask that you please read and follow CTIO's guidelines for visiting computers (http://www.ctio.noao.edu/sys/usys.html). We also note that while laptops are now as much a part of the world travelers' equipment as a phrase book, exportation from the US and importation into Chile of larger computers (e.g. desk tops) is controlled by the respective governments (see http://www.ctio.noao.edu/diroff/obser_trav.htm for advice and importation procedures)
CTIO's policy regarding magnetic media follows that of KPNO very closely (see NOAO Newsletter No. 53, March 1998). The following kinds of tape drives and media are currently supported at CTIO:
Exabyte: Currently drives capable of writing both 8500 ("high density") and 8200 ("low density") format are available in each dome and in the La Serena computer center. In noncompressed mode a 112-m tape holds 2Gb in 8200 format and 5Gb in 8500 format. It is now impossible to buy new drives capable of writing the 8200 format. Thus when the existing drives fail they will be replaced with drives that can only write 8500 format tapes. Thus we can make no commitment about how much longer low density format will be available. We will support writing such tapes in a central location on Cerro Tololo, and in the La Serena computer room for as long as our existing drives can be affordably maintained, and reading them for as long as compatible drives are available. Like KPNO, CTIO is committed to supporting 8500 format at each telescope until at least 2001.
DAT: Drives capable of reading and writing DDS3 format (12Gb non-compressed on 125-m tape) are available in each dome and in the La Serena computer center. These units will also read and write the shorter DDS1 (2Gb on 90-m tapes) and DDS2 (4Gb on 120-m tapes) formats. Again CTIO is committed to support this format until at least 2001.
DLT: This is our medium of choice for storing data from the large format imagers BTC and Mosaic-II. In preparation for the arrival of Mosaic-II, DLT-7000 drives have been installed at the 4-m telescope and in La Serena. These drives can read and write DLTtapeIV tapes, which hold 35Gb of data in non compressed mode. They can also read and write DLTtapeIIIxt (15Gb) and DLTtapeIII (10Gb) media. An older DLT2000xt drive capable of reading and writing DLTtape-III and DLTtape-IIIxt, but not DLTtape-IV, is currently available at the 4-m, but this will depart along with the BTC at the end of first semester 1999.
NineTrack Magnetic Tapes: Yes, we still have some 6250/1600 BPI tape drives in La Serena should anyone have a fit of nostalgia, or a very old data tape.
We maintain a stock of 112-m Exabyte and 90-m DAT tapes, which may be purchased by users. However, our prices are relatively high, $17/tape because we must cover the costs of shipping and handling (we do have great deals on used ninetrack tapes, though!). Observers are therefore encouraged to supply their own data grade media. You may choose to bring 160m Exabyte, or 60-m or 120-m tapes, but should be aware that the longer tapes will not work with all drives and that the IRAF "tapemon" program is not configured to report the correct length of the tape, or the correct number of megabytes remaining for these alternate media. We currently maintain a small stock of DLTtape-IIIxt and DLTtape-IV media, which visitors may borrow while they transfer data to other media but these tapes are not available for purchase.
The arrival of our three new postdocs has resulted in an irresistible surge of inhouse demand for IDL at CTIO. As a consequence we are able to offer our visitors limited access to IDL. We have one general use Sun "floating" license which can be used on any CTIO Sun workstation, either in La Serena or on the mountain. This only permits one user at a time, so please log out of IDL when not using it. We have also installed four Linux licenses, primarily to support staff use on the new IDL/Linux workstation in La Serena. Note that support for IDL will be exclusively limited to providing sitespecific details (such as how to start it up on our systems). Thus you should only plan to use IDL at CTIO if you are already an experienced and self sufficient user. We also have no plans to develop any public data reduction software for CTIO instruments using IDL.
Steve Heathcote (sheathcote@noao.edu)
Chris Smith (csmith@noao.edu)
Ron Lambert (rlambert@noao.edu)