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IBM 7040

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This page continues the documentation of the computers at Carnegie-Mellon University  in the 1960's. You can click on the links above to learn about some of the other computers.

The 7040 lived on the 4th floor of Scaife Hall.

7040 Front Panel sent to me by Chris Hausler

(for other Front Panel photos from Chris, click here.)
Date:            Tue, 15 Apr 2008 09:04:30 -0400 (GMT-04:00)
From:            "J. Chris Hausler" <>
Subject:         RE: Mark's web page

Hi Dave (and All :-)

<speaking of moving computers out of Scaife Hall>

That same day as we were cleaning up and pulling cables from under the floor I found an old paper box under the floor with two reels of tape in it.  These had been the "on the machine" (not the master copies) of the IBSYS operating system and libraries for the tape operating system which ran the 7040.  These would wear out and occasionally get replaced, sometimes by shorting the tape beyond the used area and putting a new load mark on the tape and then copying from the master copies.  Someone had obviously put them there when the 7040 was removed in 1967 or early 68.  Thinking them "historic" I "acquired" them and still have them in my pile of junque to this day.  One is labelled S.SLB1 and dated 2/13/67 and the other S.SLB2 and dated 7/13/67.

J. Chris Hausler, JH37
From: J. Chris Hausler []
Sent: Wednesday, December 23, 2009 11:57 AM
To: Roy; John Yurkon
Subject: Re: 1967 I/O Desk at Scaife

Hi Roy (and all),

It was a 7040 or 7044, not a 7090 or 7094 and it had those disgusting 7330 tape drives with the short sideways vacuum columns.  It was located on the north west end of the 4th floor, north of the 301 which was as you say in the middle of the west side (the G-20's were in the southwest corner, the west side was the side overlooking Panther Hollow and the railroad tracks).

And speaking of the 7040 and female operators (I still can't remember the name of that one in the photo), there was another one, Yvonne Gartland (or something close to that).  My freshman year someone (and it was either Dave Rodgers or Walt Sullivan as I recall :-) caused the 7040 to print out the the message "IBSYS DEMANDS THE SACRAFICE OF A VIRGIN" one night when Yvonne was working on it.  She came out wondering what she should do ;-)  This was also the girl we couldn't find one night when she was supposed to be working.  As you might recall, the stairwells in Scaife had these large circular lamps at the top.  Yvonne was eventually located at the top of one of the stairwells plastered against the wall.  She was afraid of spiders and there was a big one on the lamp....

Chris Hausler
Date:            Thu, 29 Aug 2013 12:29:24 -0400 (GMT-04:00)
From:            "J. Chris Hausler" <>
Subject:         Re: For Sale : EAI-680/DEC PDP-9 (1971 $$)

Hi Mark,

I really need to scan those two CIT 7040 documents and send them to you.  You could then add a 7040 page to your web site (and maybe include my story and photo too :-)  I have sent that story and photo as well as the photo already on the site of the 7040 console to a number of other folks and have gotten a lot of positive comments on it.  One of the telegraph guys said that looking at the 7040 photo he wasn't sure which was more venerable, the 50 year old 7040 or his 100 year old telegraph instruments.  I commented back to him that either of us could easily recreate a working 100 year old telegraph office with the equipment each of us has on hand but that we will never see an operating 7040 again as to my knowledge no complete one has survived and even if one did, it is unlikely it would be operable or anyone would be willing to spend the money to make it so.  Various technologies age at different rates. 

Of course the 7040 was kind of an "also ran".  I read somewhere that it was built in response to competitive pressures, that IBM had focused on the high end of scientific computing with the 709/7090/7094 and other companies were building lower price, lower performance machines for which IBM had no match.  The article where I read this mentioned several companies but only one machine, the G-20 :-)  IBM with the 7040 may have been playing that game for which they were accused of announcing something they didn't have to try and blunt the competition because the 7040 was announced in 1961 but first delivery wasn't until 1963, almost the dawn of the 360.  Probably the only thing for which the 7040 is famous is the creation of WATFOR and WATFIV by the University of Waterloo, Canada due to the extremely slow compilation speed of IBM's FORTRAN IV on the 7040.  (Interestingly, that CIT 7040 document mentions a faster compiler "FASFOR" which compiles faster and has better error detection but the resulting object code is not nearly as efficient as the regular FORTRAN IV.  It does not mention the source of this compiler and whether it was an IBM product or not.  I have no memory of ever hearing about it or trying it.  An Internet search has not turned up anything relevant either.)  I don't know if anyone in the Athena group other than I ever used the 7040.

It's interesting too how terminologies have changed and even been lost.  When was the last time you heard anyone speak about "turn time" or whether the computer was "up" or "down".  No one I know of ever refers to their laptop as being "up" or "down".  Its either running or not or broken or...  Other even more recent terminology is disappearing.  At the railroad museum I recently experienced a young person (maybe 8 to 10) who didn't know what a "floppy disk" was.  Laptops haven't come with them for at least half a dozen years now.  Just some musing...

73, Chris Hausler

In Aug of 2013, Chris sent me this story:

A while ago, a friend made me aware of a neat new toy, a tiny credit card sized computer which comes out of Britain with the weird name of “Raspberry Pi”.  Introduced early in 2012 it has become somewhat of a phenomenon, the range of uses to which it has been put and the number of sales, at $35 each, have way exceeding what its creators expected.  Although small, there are several OS's which will run on it, most of a Linux descent, and with that compatibility, many tools are freely available for it.  If you want to know more, just Google it. 

Although most anything that will run on Linux will work on the Pi, the language for which it was developed was “Python”, named after the British TV comedy series, “Monty Python's Flying Circus”  (and thus keeping in tune with the weird names aspect).  An interpreted language, it embodies the concepts of object oriented programming.  Although I have been aware of the basic concepts of OOP for about 20 years, the opportunity to use it never came up in my workaday C programming.  Now that I've been retired for several years I decided it would be interesting to learn a new language and maybe get some practical experience with OOP, just for the fun of it, of course.  Well, although I'm very definitely still in the early learning phase, it has been fun.  I'm reanimating numerous neurons which were beginning to rot for lack of use.  However, an interesting problem has appeared.  I have already acquired several “real” books on using the Pi and Python as well as several others in .pdf form and many more are available.  In addition there seems to be many web sites dedicated to it, one by the Raspberry Pi Foundation (a charitable organization) itself,  but I've found that frequently none of them answer the whole of whatever question I have at the moment.  This has lead me to, at times, wander the halls of what I've come to call “hypertext hell” seemingly endlessly to find the answers I seek. 

This experience got me to thinking (a dangerous thing :-).  I remember back in early 1967 (46 years ago !!) when I decided I should learn FORTRAN.  Sitting with Pat in front of one of the ASR 35's in Scaife Hall the previous fall, I had learned the rudiments of Algol on the G-20's.  When I went to learn FORTRAN I found that the G-20's just had a FORTRAN II compiler and a buggy one at that.  After several failed attempts to get even a simple program to compile, I gave up.  Although the IBM 360/ 67 was being installed and tested at that time, its schedule was erratic.  This left the IBM 7040.  Now the CIT (CMU) Computation Center was discouraging use of the 7040 as it was mostly used for funded research which would always have priority and thus turn time for other jobs would be long.  At least that was the story.  Sometimes this was true, but I befriended a number of the computer operators (this was a year before I became one), particularly the night shift crew, and frequently the 7040 would run out its job queue early in the AM leaving several uninterrupted hours where the machine was just sitting idle.   As I came to know the operators they would just let me use the machine directly without having to submit jobs through the I/O desk and I could spend several hours in the middle of the night in front of the machine running and debugging my own jobs.  As I related elsewhere, I missed seeing the buggy races both days during the 1967 spring carnival as I had been up the previous nights playing with the 7040.  When I went to bed both mornings at about 6 AM and set my alarm for several hours later, I slept right through it both days.

Well, the experience with the Pi and Python in “hypertext hell” got me to thinking of the documentation I had  needed to learn FORTRAN.  It took some mining around here but I found the four documents I had used.  Two, “7040 Reference Guide” and “Notes for 7040 FORTRAN Users” were published by the CIT Computation Center.  The third was the IBM document C-28-6329-3 “IBM 7040/7044 Operating System (16/32K) FORTRAN IV Language”.  The last, and by no means the least, was the 1965 issue of Daniel D. McCracken's “A Guide to FORTRAN IV Programming”.  His book on Algol programming had already been of great help with that language.  This was all I used in the way of documentation in order to learn FORTRAN IV.  Stacked, these four documents make a pile less than 3/4ths of an inch thick.  The “Raspberry Pi for Dummies” book I have purchased (no comments :-) alone is an inch thick and that's only one of the books I have acquired for the Pi and Python.  The just released 5th edition of “Learning Python” by Mark Lutz I just acquired is, at over 1500 pages, about 2.75 inches thick.  It probably has all the information I will require somewhere inside, if, at my “advanced age”, I live long enough to read it all :-)

It seems we have gone from using room-sized computers requiring minimal documentation to employ effectively to using tiny computers which seem to require a room-sized library of documentation.   I decided to illustrate this with a photograph.  As I have also previously related elsewhere, there was that day in early summer 1971 when I had the joy of being the one to disassemble the UNIVAC 1108 processor box into small enough pieces to be able to fit into the Scaife Hall elevator.  As I was pulling up floor boards to pull out cables for the 1108, I found two tapes in a box under the false floor.  These two tapes were labeled S.SLB1 and S.SLB2 and had been the last “on the machine” system tapes for the 7040.  Only a short length of the tape on each reel was actually used but as it was used constantly it would wear out.  When this happened, the worn section would be cut off and a new reflective load point put on the remaining tape.  Then a new image would be copied to it from a master tape.  Both these tapes have dates when they were made this way in the first half of 1967.  The 7040 was retired later that year and for some unknown reason the tapes had been left “sleeping” under the false floor for the several years since.  Thinking them historic even back then, I saved them.  The attached photo shows these two tapes and the four documents I used to learn FORTRAN IV on the 7040.  Right in the middle of the photo is a blank punch card and sitting on top of the punch card is a Raspberry Pi :-)

But that's not the end of the story.  In looking at all this I realized it had been at least three decades since I had written a single line of FORTRAN.  Thinking it would be fun, at least briefly, to do it again, I took a break from Python and sort of went back to my roots.  As the whole GNU gcc package is available for the Pi, I downloaded the GNU FORTRAN (“gfortran”) part of it.  This compiler is actually quite flexible in its support for the various FORTRAN standards which have come along over the years.  It even supports free form FORTRAN input (Free form FORTRAN input, sacrilege say I! :-), but I was going to do it the good old fashioned way starting in column 7 and all in caps.  I therefore wrote several small FORTRAN routines to run on the Pi.  It took a little while to regain my FORTRAN legs but thanks once again to McCracken they came back.  I was forcing the compiler to only accept the original fixed format input which lead to one funny instance.   I was getting a compile error on a FORMAT statement and I couldn't understand why, it looked good to me.   All of a sudden it came to me, leaving me ROTFL.  The FORMAT statement in question was for a header text line and thus was quite long.  It turns out I had exceeded my allotment of 72 columns on my imaginary “card image” so the compiler was not seeing the end of the FORMAT statement :-).

Now, unfortunately (or more likely, fortunately :-), none of the FORTRAN I wrote either at CIT/CMU or later has survived in my files.  I think I recall doing at least a couple of the exercises from McCracken's book on the 7040 but also wrote a number of things on my own.  The first few years of my working life (and the last 17) I was writing control system software which more or less had to predict the future and then bet on it.  If you seriously lost the bet you would end up with a 100 tons or more of wreckage piled up not to mention a few unhappy people wondering why (been there, done that, many times :-).  I used to refer to the process as applied high school physics.  When I first inherited this task, this prediction was done more or less by guess and by golly with minimal input.  I decided that to make my life easier I needed to at least try to improve this situation.  Some of this involved standing out in the hot sun with a stop watch and clipboard and recording data manually.  I then needed to somehow analyze this data. 

At this point in the early 70's a physics PhD friend suggested a book, “Data Reduction and Error Analysis for the Physical Sciences” by Philip R. Bevington.  The first edition of this book, published in 1969 had two neat things about it.  First and foremost, the various chapter subjects were illustrated by tested and working FORTRAN subroutines which could be easily lifted and used.  Secondly, in the acknowledgments at the beginning of the book, our own crazy CIT physics professor and Renaissance man, Hugh D. Young, was given especial mention for his aid with the book.  I got a copy and proceeded to write FORTRAN data analysis programs using selected routines out of this book (running them on a 360, either my employer's or a customers if I was out on a job site.  There were no viable FORTRAN compilers on my target systems at the time.  My control system programming back then was all in assembler.).  With this I was, at least to a point, able to improve the accuracy of some of the predictions (There are still, to this day, too many variables to this problem, both unknown and economically unmeasurable).  Just FYI, there have been two later editions of this book, the second apparently had Pascal routines and the third, from 2003, has C++ routines.  Although the third edition of the book is expensive, you can download both the C++ routines and newer versions of the FORTRAN routines for free from the book's web site at: .  As I still have the original edition of this book I have taken a couple of the original routines from it and once again written little data analysis programs using them, running them on the Pi just for the joy of it.  It's been an amusing experience.

Now, if I wanted to go further, the next step would be to emulate an IBM 7040 on the Pi.  People are already running a 360/370/380/390 series emulator on the Pi (Hercules, see: )
so I assume it would be possible.  In fact, it turns out that one of my private rail car friends has a web site on 7090/7094 systems which includes links to a number of such things some of which which he has actively participated in developing and supporting.  (See: ).  Included are a 709/7090 simulator and IBSYS sources.  I suspect these could be hacked to do a 7040.  However, there is a thin line between success and excess and if I haven't already crossed it with my FORTRAN efforts above, I certainly would if I undertook this effort.  I think it's time to get back to learning Python...

Chris wrote : Abe Books has several copies of the 1965 issue of McCracken for between $9 and $25 and the IBM 7040 Fortran IV manual and other 7040 IBM manuals are available for free download from bitsavers at: .

In Aug of 2013, Chris sent me several documents about the 7040. He wrote:

Date:    Thu, 29 Aug 2013 15:58:21 -0400 (GMT-04:00)
From:    "J. Chris Hausler" <jchausler>

I have three documents for you, two are those two CIT 7040 documents in the photo.  The third document is a two page printout on booting (sorry, "initial loading" in IBM speak :-) the 7040.  As I mentioned in the story, the ops more or less let me alone with the machine so I did acquire some additional IBM docs for the 7040 not in that photo related to actually operating the machine.  This two page write-up is all I have which is not an IBM document but is specific to CIT.  The "notes" document, dated mid 1966, is shorter than the "reference guide" and is likely an earlier document than the "reference guide" as there is a fair amount of repetition between them and the unit assignments for the library tapes in the "reference guide" match the assignments in the boot procedure which is contemporary to my use of the machine.  That said, the "reference guide" must have followed it closely as I would have gotten it early 1967.

73, Chris Hausler

Initial Program Loading the IBM 7040 System (750KB) -  IPL, Termination of Running Program, Tape Channels......

1966 Notes for 7040 FORTRAN Users by William R. Ogden (5 MB) -  FORTRAN is a problem-oriented algebraic language similar to ALGOL. FORTRAN IV is available ....

IBM 7040 Reference Guide  (15 MB) -  User Services, Hardware Description, Operating System Overview, Software Description....

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