===================== SSC News, April, 1994 ===================== Contents: 9-Track Tape Drives Scheduled to become "Read Only" April 18 Remaining SSC Training Sessions - Spring Semester /tmp Disks Filling Up on UNIX Limdep Clones Removed on UNIX Software Bug Reports Now Available in BULLETIN Password Security on UNIX Software Newsletters This is the SSC News. This monthly electronic newsletter will keep you informed about recent changes on the SSC computer networks. We hope this information will help improve communication between the SSC computing staff and all of you computer users out there. ------------------------------------------------------------ 9-Track Tape Drives Scheduled to become "Read Only" April 18 ------------------------------------------------------------ As you recall, we announced last December our intention to phase out the use of 9-track tapes at the SSC Co-op and replace the tapes with newer alternative media. At the same time we announced a plan along with a tentative time schedule for moving to these media. This plan included the elimination of the ability to WRITE to 9-track tapes in April, 1994 and the phasing out of the three most problematic of the five 9-track tape drives owned by the SSC Co-op the following June. We are moving right on schedule and plan to to make the 9-track tape drives "read only" effective April 18. So, if this April 18 date is a problem for you, please contact Tom Flory immediately. If you need any assistance making this transition, we are very happy to help. Start out by picking up a copy of SSC Pub. #2-9, "Data Storage Alternatives at SSC" in 2470. The last page of the handout lists other publications which you may also find helpful. Besides written documentation, Anne Cooper is offering a "Tape Conversion Clinic" on April 13 from 12-1 in 4452. Anne will also be available in her office on Mondays from 12-1 to work with users on an individual basis. Last but not least, don't forget that 3480 cartridges are currently available free of charge at the CDE Data Library, Soc. Sci. 4470. ------------------------------------------------- Remaining SSC Training Sessions - Spring Semester ------------------------------------------------- Note: All SSC training sessions now require preregistration. If no one has preregistered for a course one week prior to its start date, the class may be cancelled. To preregister for a class, send mail to SSCCLASS indicating which class(es) you plan to attend. You will be reminded about your pre- registration through e-mail a day or two before the class begins. Date Time Topic Room Instructor ---- ---- ----- ---- ---------- 4/6 W 12:00-1:00 Managing Jobs on UNIX 3432 Thielman, McDermott 4/6 W 12:00-1:30 Intro to SPSS 4452 White 4/7 R 3:30-4:30 Intro to SAS Transport Files 4452 McDermott 4/13 W 12:00-1:00 Tape Conversion Clinic 4452 Cooper 4/18,20 MW 12:00-1:00 Array Processing in SAS 4452 McCall Descriptions for each of the training sessions listed above are in SSCGOPHER. Type "sscgopher" at the command prompt and then pick "4. SSC Classes". ----------------------------- /tmp Disks Filling Up on UNIX ----------------------------- We have been experiencing problems on the UNIX network with /tmp disks filling up. This is despite the fact that several of our /tmp disks have almost a 2gb. capacity. The main cause of this problem is large SAS and SPSS jobs which are not run in a neighborly way. SAS and SPSS create files on the machine's /tmp disk. If several jobs are running at once, the files may exceed the capacity of even the largest /tmp disk and cause the other jobs waiting or running to be suspended or bomb. BULLETIN contains hints that will prevent you from filling up /tmp. Also, note a training session on managing UNIX jobs will be offered on Wednesday, April 6 from 12-1 in Soc. Sci. 3432. ----------------------------- Lim--- Limdep Clones Removed on UNIX ----------------------------- We seem to have had a proliferation of limdeps on Unix -- there was 'limgiant' and 'limdep6a_sun' on the Suns and 'biglimdep' on the Decstations. We deleted all of these and increased the size of the internal data array in limdep to 600,000 items (the size of 'biglimdep'). The only bigger version of limdep was 'limgiant' which was set to a million cells. But, with Sam Lucas gone now, we figured we didn't need this capacity any more! ---------------------------------------------- Software Bug Reports Now Available in BULLETIN ---------------------------------------------- There is a new BULLETIN entry called "BUGS in Software and Utility Programs" which contains entries for bugs we know about in either 3rd party software like SAS or "home grown" utility programs like tape2unix. We will place an announcement in BROADCAST each time an entry is added in BULLETIN. If you discover a problem in any software, please send mail to CONSULTANT. ------------------------- Password Security on UNIX ------------------------- Passwords are not completely secure on Unix systems and we alone cannot make them secure. There are programs available in the public domain to tease passwords out of the Unix password file. Those programs are not able to "decrypt" the jumbled passwords in the password file. What they do, instead, is to encrypt words in a dictionary and then compare those to the encrypted strings in the password file. A match and the hacker is in. By the way, hackers aren't always teenagers working out of their bedrooms in Oklahoma City. We know that SSC users have obtained copies of the password detection programs. We can't prevent this, although we can by indirect means discover who has used such a program. A member of the SSC staff regularly runs a password detection program on our Unix network so that we can identify accounts with vulnerable passwords. When we discover such an account we send mail to the user and urge him or her to change the account's password. Here is some advice to follow in choosing a password that will be as difficult as possible to break: o Obviously don't choose a word that is in the dictionary. And don't choose a string that is just a linear combination of a couple of real words. o Don't use your name or anybody else's. o Don't use a string of identical characters or a run of consecutive numbers or letters of the alphabet. o Include both upper and lower case characters. (This makes a difference only in Unix.) o Use unusual punctuation. o Combine letters and numbers. o Never ever share your password with anybody else. This is not just unwise, it is also a violation of the agreement you signed (signed!) when you applied for your account. You can use the VMS command "SET PASSWORD/GENERATE" to have VMS suggest a bunch of wacky passwords that are pretty much guaranteed to be unbreakable. Remembering them is the problem, but you might use this command as a starting point. Alternatively, some people think of a meaningful short phrase and "translate" that into a password string. The point is that ultimately the security of your password is your responsibility. -------------------- Software Newsletters -------------------- We receive many newsletters from software vendors which contain lots of useful information including updates, problem alerts, and computing hints. Software for which we have newsletters include SAS, SPSS, STATA, S-PLUS, Minitab, Glim, and ML3. Please drop by Soc. Sci. 4406 if you'd like to browse any of these. Also, the CDE Data Library also has many of these newsletters for those of you affiliated with the Center for Demography. TO UNSUBSCRIBE FROM THIS NEWSLETTER, just reply to this mail message indicating you want to unsubscribe. We will remove you from the distribution list for future electronic mailings. If you ever change your mind, just notify the SSC Consultant or send mail to SSCNEWS asking to get back on the list.