BURROUGHS

From: Vagabondo
<vagabond@cruzio.com> Ray... thanks for the link but rattlebrain.com is an 'overload' server that is linked to my Comptometer website (my ISP only allows 20 megabytes per server). I had originally scanned the manual and had posted it as images and then Andreas De Man took on the task of OCRing all the pages and either he or I added the hyperlinks and cuts. Came out pretty well I think. Always good to hear from you anytime for any reason. Stay well, Brooke |

From: Ray Mackay
<raymondmackay05@optushome.com.au> Hi Brook & James I think, if you don't already know of it, you will find the following web page interesting. It contains a repair manual similar to the one I lost on Comptometer Model 'H' (including working drawings) http://www.rattlebrain.com/~deadends/H-Text1.html Ray |

From: Ray
Girvan <ray@RAYGIRVAN.CO.UK> Nicholas Bodley <nbodley@WORLD.STD.COM> wrote: >> http://w1.131.telia.com/~u13101111/compcalc.html Yes, that's as elegant as it gets. > Well, folks, is anyone willing to calculate
square roots on a Comptometer I had wondered if they used square root tables as with the Curta. Ray Girvan |

From: Gilbert Harrus
<Gilbert.Harrus@xrce.xerox.com> Ray, Thanks for your reply. First let me thank you for your notes "MEMORISED DESCRIPTION OF COMPTOMETER's ® MECHANISM". I have read and tried to understand fully the content (but it was too much time for me to spend, unfortunately). I came through them while trying to repair a M-model - one of the carry mechanism was not operating properly. After reading the notes along with a repair manual for the H-model, I came to the conclusion that I would probably not be able to repair without much luck and/or time. Deep cleaning the machine, and re-oiling it, I could finally get it to operate. About the division: I understand your point about operators, and fully agree that the division instruction is simply, and " contrary to what others say, the method was not prone to error" ; indeed, this is also what I was writing. I was quite surprised by the fact that, as of today we know what an algorithm is, that the few pages I found on the division method on Comptometer do not see and document that simplicity - they just give examples without any explanation. I will take the time to write a summary and will let you know. Best regards, Gilbert |

From: Nicholas Bodley
<nbodley@WORLD.STD.COM> Hello! Please take a look at this web page: http://w1.131.telia.com/~u13101111/compcalc.html It's so nice to see the high-order carries create the quotient digits! I like that. I remember working for a very experienced mechanical calculator tech, who showed me with lots of glee (excited happiness, I'd say) how an experienced Comptometer operator would shape her fingers into the pattern of numbers to be entered, and rapidly shake her hand up and down, poking at the keys. Well, folks, is anyone willing to calculate square roots on a Comptometer by the fives method? (Is that the best method for a Comptometer, or am I just a little crazy?) Left hand for the unchanging digits, and the right for the incrementing digit? Well, maybe not quite; there's that rightmost five to be subtracted every time. Erez's simulator is neat! Try it, if only to see a very nicely-written applet. He's used a photo of a real machine, with clickable "hot spots" at every key, and even sound! You do need to aim your mouse pointer rather carefully. I did try the fives method, but got lost (forgot how) in the procedure for calculating another digit. I need supper; brain fade. ===== Btw, that technician (Bill Morrison) was an expert on Moon-Hopkins billing machines. He said that the "table-lookup" fast multiplier mechanism was very reliable; in fact, iirc he said the whole machine was very reliable. Best regards to all, Nicholas Bodley |

From: Ray Mackay
<raymondmackay05@optushome.com.au> Dear Gilbert Terms like algorithms etc would have made the process disconcerting to students in the Calculator School. In the Comptometer teaching and examples manual the process is described somewhat simplisticly. Remember that each keytop has the whole number to the rights and a smaller complimentary number to the left on each key. The Students were simple taught SIMPLE DIVISION Add Divident into machine.
This simple instruction was taught to literally thousands of Comptometerist and, contrary to what others say, the method was not prone to error. Every work sheet was double checked by a second operator and if there was any question of an error the calculation was sent to scrutinising operators. This only happened very infrequently and usually where less experienced operators were involved. Balance, Cost and Markup sheets were calculated non stop over the thirty years I was involved and I only started with Comptometer halfway through their history in that time there were negligable reports of errors in outsources work performed in our offices. Ray Mackay PS James you may like to post this note to the Cal-list on my behalf. If anyone is interested in the complete training manual (circa 1950) I am will to scan one it and put it up on my web site for collection in PDF format Ray |

From: Derek Peschel
<dpeschel@ESKIMO.COM> With ordinary subtraction you pad your number at the left with 9s (on the Burroughs key-driven machines) or use one of the carry cut-offs (on the Comptometer). With division you intentionally do not pad the number, so that the carries will build up in the next column over which holds the current quotient digit. The manual says you can move to the next column if the current quotient digit equals the number of additions. There may be other short cuts to use in certain division problems (I haven't looked lately). Those short cuts are the most interesting part of the algorithm, but I haven't looked for the principles they are based on. -- Derek |

From: Christofer Nöring
<christofer.n@TELIA.COM> Hello! Please take a look at this web page: http://w1.131.telia.com/~u13101111/compcalc.html with a short description of quatuor species for the Comptometer (Burroughs Calculator) Best regards Christofer Noering |

From: Ray
Girvan <ray@RAYGIRVAN.CO.UK> Gilbert Harrus <Gilbert.Harrus@XRCE.XEROX.COM> wrote: > I am sure that the (quite simple)
maths behind were documented at The basic method is called "complementary subtraction". You subtract X by adding the complement of X (which is the little number on the keys) and suppressing the carry. There's some discussion of how the algorithm works here ... http://www.dotpoint.com/xnumber/cmisc_burroughs.htm (This page) ... and a description of it in computing context here ... http://www.tpub.com/neets/book13/53d.htm Division would be a repeated application of this sustraction method. Ray Girvan |

From: Ronald A. Kriss <rkriss@gunster.com> What are the little numbers for? |

From: Nicholas Bodley
<nbodley@WORLD.STD.COM> Subject: Burroughs Calculators Date: Thursday, August 20 What are the little numbers for? |

From: Brian Borchers Subject: Burroughs Calculators Date: Thursday, August 20 The nines complement technique can be used to subtract on any machine that
can add. Suppose for convenience that we have a 4 digit adder, and that we want to
compute x-y. We can write x-y as |

From: Nicholas Bodley
<nbodley@WORLD.STD.COM> Subject: Burroughs Calculators Date: Thursday, August 20 (Somewhat off-topic:) |

From: Frank Lindauer Subject: Burroughs Calculators Date: Thursday, August 20 Hi Ron: I picked up one of these machines within the last year and paid about
what you did, perhaps a few dollars less. I thought it was a bargain. I believe it is a
class 5 calculator, ca. 1927. I'm not an expert on these, but it may function like a
Comptometer, and I would almost be sure that it can subtract, but I haven't put it through
its paces. |

From: Ray
Mackay Subject: Burroughs Calculators Date: Thursday, August 20 Although I did not receive Ron's enquiry regarding Burroughs' and therefore do not know of which model or system he speaks I feel I should stick my bib in. Firstly 'Key Driven machines' of the Comptometer type consisting of a number of columns of nine keys were completely capable of Multiplication and Division plus extracting a square root. They were work to apportion amount and calculate percentages and mark-ups. AFAIK any machines of this type and any machines capable of additon and subtraction are fully capable of Multiplication and Division as these functions are merely repeated addition and subtraction moving to the next higher or lower order as dictated by the result. Models were constructed that work in Decimal, Sterling, Weights and Measures plus other specialised numbering systems. Other adding machines with a ten (or more) numeral keypad and a series of function keys entered data into a pin box or other type of register from where it performed additions or other function via repeated addition and subtraction. Some wrere more sophisticated than others and to speed up a process were capable of 'flagging' if a number was higher or lower than five and changed the method of calculation accordingly. Thus reducing the number of repetitive cycles. Burroughs' made machines of several types, the parallel to the Comptometer introduced to the market close to or maybe even before the time the Comptometer was released, A largish listing machine with glass side panels and a side actuating lever (I recall some of these had print outs, but memories grow weak with the years) plus other developments. They produced both mechanical and electronic machines. James Redin's site contains mechanical details of some of these machines. Vagabond's site further details. If any one wished to ask specifica question I will answer to the best of my ability to recall. Messages to this site are restricted in site so I can not ramble on and get the message through Divisions on adding machines. Some machines had cut offs called subtraction cut offs these precluded the requirement of entering all the nines to the left of the calculation. All this mechanism did was lose the carry. It should be noted that in Division on 'Key Driven' machines the negative carry was most important as it made its own specific noise as the carries ran across the machine. This told the skilled operator to add back the divisor and move her figures one position to the right before starting to subtract once again. This process was repeated across the machine until the right hand columns were reached. Its interesting to note that some models of Burroughs' actual had a single nine key in the left hand column specifically for running nines across the register. The Burrough's 'Key Driven' Comptometer type machine did all the functions of the Comptometer. This included Addition, Subtraction, Multiplication and Division plus the extraction of square roots. The keydrive mechanism was totally different from that used in the Comptometer as also was the Carry Over Mechanism. The carry over mechanism being located inside the numeral wheel. As the number increased to the left of a wheel two small pinion rotated inside the next wheel to the right. When the lower order wheel reached 10 it triggered the pinion mechanism rotating the 'skin' or outer numeral wheel to add in the one. It was very fast and afaik was not subject to errors caused by duplication of carries ie The actual keydriven mechanism was the typical parallel bars being pushed down and operating a segment which engaged the register pinions. Although I worked on them from time to time I did not convert them to decimal currency. Basically this means the full adjustment process was never embedded in my mind. Walthers and Comptometers I know from A to Z multiplying 334 continuously or 375 continuously. These tests were mandatory before machines were sent out to clients and once machines performed these calculations through all keyboard position many time they were considered suitable to send out to the client. regards Ray Mackay |