TCC   NEWSLETTER                                                         VOLUME 3,   NUMBER 5

OCTOBER   1977



C 0 N T E N T S



Computer room remodeling has been nearly completed in preparation for the arrival of the DEC-20. The new air conditioning system should arrive soon and will be operational about October 31. The DEC-20 has completed final checkout at the factory in Marlboro, Massachusetts, and should be shipped no later than October 29th. New electrical service is being installed in the computer room: although it will be a bit temporary since the new power transformer which is being donated by Socorro Electric Coop was back ordered by their supplier and will arrive after the new system is instilled. Another electrical revamping will be necessary at that time, and we may have to shut down for a couple days. However, we'll be ready when the moving van full of new equipment backs up to the doorway of Workman Center.

The computer center staff and several student employees have been devoting a large amount of time to the conversion of the administrative data processing programs. This effort is going very well and we still anticipate program checkout on the DEC-20 to occur in December. The main effort so far has been devoted to conversion of the financial data processing programs. Conversion of the programs used by the Tech Library and the Registrar's Office is also underway. Our plans to be running solely on the DEC-20 by January 15th have not changed, although we can't stand too many set-backs if we're going to be able to meet that deadline.

If any users, other than administrative users, have programs which must be operational on the DEC-20 by January 15th, please contact someone on the computer center staff so we can help you get started. Most difficulties will arise from conversion of existing databases rather than program conversion problems (assuming the programs are written in FORTRAN).



Congratulations are due to the team of Carl Brannen, Jim Darling, Joe Franklin, and Moe Poteet who won the student programming contest sponsored by the association for computing machinery. The contest was held in conjunction with the mountain regional meeting of the ACM in Albuquerque on October 7th. We're very glad to have three members of the winning team involved in the DEC-20 program conversion process. Without their help, we'd never make the January deadline. Now, if we could only kidnap Brannen.......

The team will compete in the national contest in Detroit in February, and we expect that they will put on an excellent showing there too.



Here is a brief description of the differences between the DEC-20 and IBM/360 FORTRAN languages. The list is fairly short, and the most impact in user's programs will probably come from items 1, 2, and 4. If you have any specific questions, please contact the user services office.


1. INTEGER*2 and LOGICAL*1 types do not exist. They are assigned fullword locations and the statements are flagged with warning messages.


2. All compile-time initialization of variables must be done with the data statement for example, the statement

INTEGER N(3)/1,2,3/

must be replaced by the following two statements:


DATA (N(J),J=1,3)/1,2,3/


3. Hexadecimal constants do not exist. Octal constants may be used and are expressed as in the following examples:

"123 or -"123 or "-123 or +"123 or "+123

There are 36 bits in a word on the DEC-20. This implies 12 octal digits per word. An example of a format statement to input one word of octal would be:

10 FORMAT(012)


4. Since the wordsize of the DEC-20 is different from the wordsize of the IBM 360, the number of characters that may be packed into a word is different. The DEC-20 uses "ASCII" representation instead of the "EBCDIC" representation used by the 360. "ASCII" is a 7-bit code and therefore you may place up to 5 ASCII characters in a DEC-20 word. The right-most bit of a word containing ASCII characters is always zero. All positions in a word not filled with characters are padded on the right with ASCII blanks (the right-most bit is still zero). Another way of saying this is that ASCII characters are always left justified in a 36-bit word with trailing blanks. If you were to perform the following input/output sequence:





20 FORMAT(1H1,A5)

with "ABC" as input data, the printed result would be "ABC**", where the ** represents two blanks.


5. Logical unit numbers are different. This is no problem since the DEC-20 FORTRAN allows you to assign the logical unit number to any i/o device you want within the program.


6. No more than 20 continuation lines are allowed in a single statement.


7. The first character of a variable name must be one of the 26 characters of the alphabet, i.e., the variable $BAD is illegal. However, subsequent characters may be any of the legal characters.


8. Only octal constants are allowed on PAUSE or STOP statements. Characters strings are allowed, however.


9. Declaration statements must precede all program text. DATA statements, however, may be interspersed with executable code.


10. DEFINE_FILE has a different format than that used on the 360.


11. Comments may not be interspersed between the lines of a continued statement.

Programs which use special input/output routines such as QSAM or OQSAM rather than "regular" FORTRAN I/O will need some special attention.

Users who have large data bases to convert might also have some extraordinary problems; especially if the data is written by special I/O routines or by using the unformatted FORTRAN I/O.



Rates have been established for internal use of the DEC-20. These rates were determined based fin the cost op the entire system and anticipated usage. This rate structure will be reviewed in June 1978 and any necessary adjustments, based on actual costs and usage, wilt be made at that time. These rates are significantly below those charged by commercial computer service organizations having similar computing resources. Charges fop outside customers (i.e., non-tech users) will necessarily be higher and will be determined later.

The central processor time required by most programs now running on the IBM 360/44 should re reduced by a factor of 2 or 3 on the DEC-20. Magnetic tape users will be charged a one-time charge for mounting each tape and also an additional charge for each minute that the tape remains mounted. The new tape drives will be capable of transferring data eight times faster than those on the 360/44.

Charges for disk use will be based on "permanent storage" required by each user. The permanent storage in use by each user will be tallied once each day and the disk charge will be based on the number of 512 word pages in use at that time. This will encourage users to delete their temporary or out-of-date disk files once each day.

The two rates for "prime" and "non-prime" CPU time will encourage those users with "CPU burners" to defer their runs until the evening hours. The night shift (6 pm until 8 am) will not be attended by an operator so that the use of magnetic tapes and punched cards will not be permitted during that time. Output destined for the line printer will be returned the following morning. The hours of the "non-prime" shift may have to be redefined after we try it for a while.

CPU time 8am - 6pm $ 162.00 / hour   ($ 0.0450 / sec)
  6pm-8am $ 126.00 / hour   ($ 0.0350 / sec)
DISK storage   $ 0.0035 / page-day   (512 words/page)
MAGNETIC TAPE   $ 1.50 / mount  &  $ 0.20 / minute
CARD READER   $ 0.0023 / card
LINE PRINTER   $ 0.175 / page   (page not line)
PLOTTER   $ 17.50 / hour
USER TERMINALS   $ 2.25 / hour connect time



The computer center staff will present a short introductory course on the DEC-20 on the evenings of November 1st & 2nd (Tuesday and Wednesday) between the hours of 7 and 9 pm in Workman 26. This course will provide an overview of the capabilities of the DEC-20 hardware and software and will be applicable to all users. Everyone contemplating use of the new computer is encouraged to attend.

Another course, designed to give the user some experience using the system via an interactive terminal will be scheduled later this year. This future course will be restricted to faculty and staff personnel. Since attendance will have to be limited, we may repeat this course later if there is enough interest. We'll provide the details of this course in the next newsletter.



The, terminals which will be supplied by the computer center for public use, have been chosen and will be ordered very soon. We expect them to be available for program conversion use when the DEC-20 is up and running (mid November, we hope). There will be eight video terminals and four hardcopy terminals in the "keypunch" room. The video terminals will be Lear-Siegler ADM-

3a's with upper and lower case fonts. The LA-36 DECwriters will have 132 print positions and the ASCII/APL dual character sets. The DECwriters will be the only terminals with the APL character set, at least fop a while. Additionally, we plan to have a few (maybe three) terminals available for faculty and staff use. These will be located somewhere in the computer center and will be available on a scheduled basis. At least one of these restricted terminals will have the APL character set.

Information about terminals which are compatible with the DEC-20 has been distributed to members of the user advisory committee. Anyone considering purchase or lease of a terminal for their own use should contact one of the committee members of the computer center staff for further information.

All the terminals will be connected "locally" initially. That is, there will be no dial-up service to the DEC-20 on January 15th. We hope to install that service in the spring.



We still haven't picked a plotter for the new system. Several options are available at this time, and whatever we get will be compatible with the existing Calcomp plotting subroutines. There is a lot of interest in interactive computer graphics lying dormant around Tech, and now that we will have a computer capable of supporting it effectively, that interest will no doubt spring forth in the form of graphic terminals. The computer science department has received a grant which will allow them to develop a very nice graphics system, in addition to some other capabilities. one of the terminals in the computer center will probably be a Tektronix 4006 which will be capable of some graphics. This terminal will also re used in conjunction with the hardcopy plotter for previewing plots. That capability will certainly cut down the number of plots generated because of the ability to see the plot on the display before its sent to the plotter.

Here's a question for all you plotting buffs: Could you live with hardcopy plots no larger than 8.5 by 11 inches in size for a while? What about plots no larger than 11 by 17 inches in size? Please express your opinions on these two questions to someone on the computer center staff or to a member of the user advisory committee.



The existing BMD subroutine package will be converted for use on the DEC-20. It may take some time to do this, but we'll eventually have it available. Anyone who depends heavily upon this set of subroutines, or specific routines within it should make their needs known as soon as possible so that a conversion priority, if needed, can re established.

An ISML package exists for DECsystem 10's and 20's, and we'll probably replace the IBM 360/370 version we wow have instead of attempting to convert it. Users of this package who have immediate needs should also pay us a visit ... soon.



Reference manuals have been ordered by the Tech bookstore and should be available later this semester. The computer center will publish a user's guide for the text editor along with general user information so that you all won't have to spend $22.00 for two puny little epistles published by DEC. This should also be available, from the Computer Center, by December 1st. The cost will be approximately $5.00.




WHERE . . . . . .

#4 Workman Center (phone: 835-5126).


WHO . . . . .


WHEN . . . . .

Computer Center User Services Desk
Monday-Thursday 7:30am Midnight. - Hours are posted on -
Friday 7:30 am 8:00 pm. - the door of the -
Saturday 1:00 pm 8:00 pm. - User Services -
Sunday 1:00 pm Midnight. - room, Workman 2.-

This schedule changes during holidays and semester breaks. The schedule for those periods will be posted in the keypunch room. The holiday operating schedule usually is identical to the normal Sunday schedule.

Preventative Maintenance (PM) is ALWAYS scheduled for Wednesday between the hours of 10:00 AM and 2:00 PM. This schedule is always subject to some modification. If there are any extremely critical jobs to be run during this time, we can either slide PM until later or dispense with it altogether for that day. We like to have 24 hours notice if this is required.


HOW MUCH . . . . .

CPU time (per second)   $ 0.0144
Lines Printed (per 100)   $ 0.0800
Cards Read / Punched (per 100)   $ 0.2400
Disks Mounted (each)   $ 3.2773
Tapes Mounted (each)   $ 1.5025
Calcomp Plots (per 100 buffers)   $ 0.3800