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jar
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Posts: 33343
From: Texas!!
Joined: 04-20-2004
Member Rating: 3.0


(1)
Message 1276 of 1290 (884289)
02-06-2021 6:09 PM
Reply to: Message 1275 by dwise1
02-06-2021 5:44 PM


Re: computers

My Website: My Website

This message is a reply to:
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dwise1
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Posts: 4608
Joined: 05-02-2006
Member Rating: 5.4


Message 1277 of 1290 (884290)
02-06-2021 8:08 PM
Reply to: Message 1276 by jar
02-06-2021 6:09 PM


Re: computers
Not sure what you are trying to say here.

There was a calculator which I possessed and I saw that somebody else had. It might have been a Texas Instruments (TI). It had a cover with touch-sensitive pads. It was the only one I had seen which handled mixed fractions. I think it was also powered with photo cells.

My main stand-alone calculator is an hP 20S. Algebraic notation (ie, with parentheses and all). I also still have my hP16C from far too many decades ago which could perform binary operations I forget how far out.

Funny-ish story. Around 1980 I was in a class run by our computer science department chair and he had to perform a calculation, so I offered my TI calculator. He had no idea how to use it, since he was more used to Hewlitt Packard's RPN (reverse-Polish notation, AKA post-fix).

In software development, there was a personal boasting item about that piece of software you wrote that both compliled and worked the first time ever. Every single programmer remembers that event.

In our compiler design class, we learned the yard switching algorithm for converting an algebraic expression's infix notation to prefix notation (which is almost trivial to evaluate on a stack). Our programming assignments were to implement that yard switching algorithm on an infix string, and then to evaluate it. That was my personal compiled and ran the first time code.


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jar
Member
Posts: 33343
From: Texas!!
Joined: 04-20-2004
Member Rating: 3.0


Message 1278 of 1290 (884291)
02-06-2021 8:24 PM
Reply to: Message 1277 by dwise1
02-06-2021 8:08 PM


Re: computers
The TI-35 was from around the same period, late 1970s or early 1980s. There was also a desktop model that you could program using punch wafers, small plastic equivalents of the familiar punch cards (about the size of a folded Motorola Flip TracPhone but thin as a credit card). It was really expensive, over 2k at the time but great for repetitive calculations like signal degradation in CATV cable cascades and through amplifiers.

My Website: My Website

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dwise1
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Posts: 4608
Joined: 05-02-2006
Member Rating: 5.4


(2)
Message 1279 of 1290 (884298)
02-07-2021 2:35 PM
Reply to: Message 1278 by jar
02-06-2021 8:24 PM


Re: computers
I'm sure that that was my TI-35 which I handed our department chair to use, but he only knew RPN. I had bought it a year or two before at the exchange for about $35.

The way that prices for calculators fell was phenomenal. The first calculator I saw was a 4-banger (ie, + - × ÷) that fit in a shirt pocket and sold for about $350. In college around 1971, I saw hP scientific calculators being sold for about $250. Being a foreign language major who basically aced the math section of the placement exams, I wasn't in the market for a calculator. I bought my first calculator, manufactured by a company in Cupertino, for a decent price in Germany in 1973 -- I had to explain to the clerk what "on" and "off" meant. I think it had trig and log functions. The TI-35 that I bought around 1979 was my second calculator. Also, I saw some innovative calculators in Germany. For example, in 1974 I saw a slightly oversized slide rule with a 4-banger calculator built in. Weird.

My TI-35 was at the time that I had switched to computer science plus taking EE classes for fun (ie, to augment my technician training). Around 1980 I got a TI-58 programmable. It included built-in programs stored in a ROM module that you could swap out with other modules of programs (eg, their Electrical Engineering module). I then upgraded to a TI-59 which was basically the same product except it included a magnetic card reader with which you could store and reload your own programs. I also got the thermal paper printer for them.

After that, I got a few more calculators over the years. Around 1990 I got an hP 16C (the programmer's model) for the increased precision for binary operations. It was also where I got my experience with RPN ("Reverse Polish Notation", AKA post-fix). There was also that one that included mixed-fraction operations (giving the results as fractions). And my hP 20S that is on my desk. And over the decades, I still kept a slide rule in my briefcase as a back-up.

Remember that every programmer remembers his first program that ran correctly the first time. Our Computer Science Dept chair told us the story of his. It was his first programming class and their assignment was to enter and store two integers, then retrieve them, add them, and store the sum in a third memory location. The problem was that it was on an early model IBM (¿an IBM 701?) which used a magnetic drum as its main memory, so part of writing your program included calculating drum rotation delay times in order to be able to access those specific memory locations. He kept procrastinating until he had to go into the lab late the night before the assignment was due. And somehow his very first attempt at that program worked.

Also for old desktop calculators, check out this YouTube video by Cliff Stoll: An astonishing old calculator - Numberphile -- An astonishing old calculator - Numberphile

The thing about building registers and RAM is that you make them out of circuits called flip-flops which will latch and store one of two values. In order to do that with discrete components like transistors, you need at the very least two transistors, but normally end up with 4 to 8 more transistors for interface and control. Anything built like that becomes too big too quickly.

{ABE: Refer to that Wikipedia link for sample schematics. Basically, a bistable multivibrator (AKA "flip-flop") has two outputs: the main one, Q, and the inverse of it, Q' ("Q-not"). Those two outputs represent the outputs of the two main transistors (or vacuum tubes, whatever you're using). The basic design of a flip-flop has the output from one transistor feeding back to the input of the other (eg, feeding back the collector voltage of one bipolar junction transistor (BJT) to the base of the other) in order to keep it in its current state. The control interface is then how you change the state of the flip-flop. The concept is really quite simple. }

So this calculator went with a different technology. The base has a coil of a kind of piano wire which serves as a delay line for the data to travel along as shock waves. An Air Force correspondence course also described magneto-strictive wire delay lines. It's also the same basic idea as the mercury pool delay line memories in early electronic computers -- re-read the first page of Isaac Asimov's first robot novel, The Caves of Steel.

Edited by dwise1, : ABE


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Percy
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Posts: 20105
From: New Hampshire
Joined: 12-23-2000
Member Rating: 4.2


Message 1280 of 1290 (884302)
02-08-2021 11:33 AM
Reply to: Message 1274 by dwise1
02-06-2021 4:31 PM


Re: computers
My little neck of the computing world (workstations) had a different experience with ADA. We were constantly told ADA was coming because the DOD was demanding it, we constantly ignored writing any applications in ADA, and demands for it in our part of the commercial world eventually went away. I don't think we even shipped an ADA compiler, though third parties might have filled this need. We were a Pascal house, and in our estimation ADA didn't much resemble it. We liked the advantages ADA was advertised to have but weren't convinced it really provided them.

Our company was eventually acquired by Hewlett Packard, who I think paid more attention to ADA than we did, but HP botched our acquisition sufficiently that I decided to leave, so I don't know much about HP and ADA. But I do know tons of people from HP, and ADA never gets mentioned.

--Percy


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jar
Member
Posts: 33343
From: Texas!!
Joined: 04-20-2004
Member Rating: 3.0


Message 1281 of 1290 (884303)
02-08-2021 12:00 PM
Reply to: Message 1280 by Percy
02-08-2021 11:33 AM


Re: computers
It's funny how things run. When I moved from designing CATV systems to working with computers accounting and inventory were the highest demand so COBOL was the language of choice and either TurboDOS or Uniix™ the OS of choice.

My Website: My Website

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dwise1
Member
Posts: 4608
Joined: 05-02-2006
Member Rating: 5.4


Message 1282 of 1290 (884306)
02-08-2021 9:55 PM
Reply to: Message 1280 by Percy
02-08-2021 11:33 AM


Re: computers
My experience with Ada was around 1984. Ada was this behemoth that everybody with a DoD contract would be required to use. But there were many problems which were still outstanding at the time.

Part of the problem was the requirements for the compiler. You were only allowed to use a validated compiler (which had to be re-validated every six months), but at that time no compiler had yet to be validated. A validated compiler had to support the entire language specification (which included multiprocessing -- a multiprocessing class I took later had us using TinyADA, which was definitely not up to standard and did not play very well on Windows OSes that didn't yet support preemptive multitasking). I think our company's classes (Ford Aerospace) had a non-validated Ada compiler set up in the UCSD p-system, which was weird enough to start with.

As I mentioned, the competitors were identified by color and it was the Green Language presented by CII Honeywell Bull and based on Pascal that won. Therefore, the US Govt printing of the language specification for Ada, MIL-STD-1815, was bound in green -- I have the Springer Verlag printing, which is bound in silver, as was their printing of the Pascal standard which I also have stashed away somewhere.

As I described, because nobody in aerospace could do any work in Ada, they switched over to using Pascal as a stepping-stone. It was fascinating to see how other programmers would use Pascal, which was originally designed to teach top-down structured programming. My own background as the only Computer Science graduate in my department was very much based in structured programming. One programmer was a FORTRAN type, so her programs were page after page after page of the same code but with different variables. When I inherited her code, I converted her 2-page blocks of code into a procedure which I would call with new arguments and cut the length of her source code to about a sixth of what it used to be. Another programmer had used his decades of assembly language programming to structure his Pascal program as a continuous loop in which he would set flags and then act upon them within that loop. I ended up having to rewrite his code.

The funny thing about Pascal was that it was designed to be almost minimal. Niklaus Wirth at a Swiss technical high school (not the same thing as in the USA) designed it in order to teach the principles of structured programming, not to meet any industrial needs. As a result, any commercial compiler would have to be extended considerably in order to serve the needs of the customers. As a result, they invoked an idea of p-code (ie, "pseudo-code") wherein a Pascal compiler would generate fake code for a fake CPU which you would need to feed through an interpreter for your particular non-fake system. The idea was that whatever extensions your particular compiler would need to implement would result in those extensions being implemented in p-code and hence could be run on any computer system with a p-code interpreter. That didn't work so well for Pascal wherein to port compiled p-code to another computer required physically transporting a spool of tape, but when Java did the same thing with its bytecode with the World Wide Web to port its bytecode to any possible OS on the Web, that changed things a bit. BTW, I have the BYTE Book of Pascal which contains an article that describes that p-code instruction set.

Funny story. Although I graduated with my BS Computer Science in 1979, I was still obligated to serve in active duty until 1982, so I took more CS and EE classes at the local university. In 1980, I took my first class in Pascal, though that involved a bit of international smuggling. Our university used an IBM S/370 which our students also had accounts on. So did a university up in Winnipeg (AKA "The Peg"). The Australian Atomic Energy Commission (AAEC) and the Tokyo Institute of Technology (TIT) jointly developed a Pascal compiler. That compiler ended up on the computer in the Peg. One day, someone from our university drove up to the Peg with a spool of tape, copied that compiler, brought it back across the border, and installed it on our university's computer system. After which we started offering a class in Pascal, which I took. And as a result, in my first post-service civilian job not only was I the only one in the Software Development Department with an actual degree in Computer Science, but I was also the only one with any kind of prior training in Pascal.

And to reiterate, within a decade the emphasis shifted from Ada to COTS.

Context. In a defense contract, there's a need that they feel and a way to fill that need. Not having worked at that level, I would assume that there are various levels of need being felt.

My first post-service job was Ford Aerospace's DIVAD (Division Air Defense) project, also named "Sgt York." A tank with twin 40mm Bofors guns guided by search and tracking radar with a range of about 10 km (or miles -- I forget which). The official reason for the project's cancellation was that the threat (hovering helicopter platforms) had extended their own weapons ranges outside of the Sgt York's.

There were also development issues. As described to us, basically when you want to develop a new weapon system, it takes about 11 years. That is caused by your having to stop development a few times so that the government can come in and thoroughly test your design. Sgt York was being handled differently as a kind of experiment. Instead of design-stop-design-stop, they decided to do the testing while the design was still in progress. That would accelerate the design cycle from 11 years to only 8 years. But it also allowed design problems to surface where least expected: eg, latrine fans developing the same kind of radar modulation typical of helicopters. BTW, that thing about the grandstand filled with brass being targeted, that was an issue with software stops that had somehow not been enabled. As a DS Navy Chief, I also did the courses for Fire Control Technician (FTC). To keep your ship's guns from blowing holes in the ship superstructure, FTCs establish stops within which the guns will not fire. Same thing.

Our company was eventually acquired by Hewlett Packard, who I think paid more attention to ADA than we did, but HP botched our acquisition sufficiently that I decided to leave, so I don't know much about HP and ADA. But I do know tons of people from HP, and ADA never gets mentioned.

I served my last decade in the Navy Reserve in the VTU, the "Voluntary Training Unit", mostly as either the XO or the acting CO (mainly since I was the one who kept reporting and so carried the organizational memory in my noggin). Basically, we no longer qualified to be paid, but we continued to accrue retirement points. For some sailors, that was the only way they could hope to complete their 20 years of service for retirement, though I understand that those rules had changed after I retired (with 35 years) in 2011.

The VTU was manned three-fold. First, there were those who were being administratively separated -- basically those who were not reporting to drills as required (that could open us up to all kinds of discussion) -- we called them our "ghosts" who would never ever report, so at Commander's Call (which I attended for several years) the VTU always reported deficient in that respect for good cause (chasing down ghosts? Who ye gonna call?) for what is the regional command going to do about it? Second were the enlisted members who had no yet met their 20 years obligated service in order to retire. Third were the commissioned officers who did not have a billet.

Yeah, those commissioned officers. The Navy Reserve has a list of jobs. More officers than jobs for officers. Every two years, the officers apply for billets, for jobs. Many don't get jobs, so they wind up in the VTU. Some get those jobs (one weekend, we lost all our officers because of sudden openings in billets).

 
The reason for bringing that up is that Navy leadership had built into it a rotation rate of two years. Within the life-cycle of commissioned officers, the military wants its officers to get a wide range of experience, so an officer's normal rotation of duty is about two years. In the VTU, an officer's cycle for application for a billet is two years. Do we see the pattern here? That meant that for every leadership change, policy change, in another two years it would probably change to something else.

After the early-mid-80's, most of the emphasis went to COTS (commercial off-the-shelf) such that that was the hot new buzzword in military publications (yes, we had our own magazines -- consider that some of Walter Brown's primary sources for his bogus "earth spin slowing down" claim were Air Force publications about GPS). So within a few years (relatively speaking), the mandate for everything being done in Ada had shifted to using whatever just happened to be available in the market. We could spend several very productive hours discussing the pros and cons of the Ada mandate -- extremely good reasons and reasoning for it, but impractical for most kinds of procurement.

Last I heard, Ada was still being used for highly critical software, such as for Boeing's satellite applications. Which makes sense.


This message is a reply to:
 Message 1280 by Percy, posted 02-08-2021 11:33 AM Percy has acknowledged this reply

  
Mercury
Junior Member
Posts: 21
From: Socorro, NM, USA
Joined: 06-04-2006


(1)
Message 1283 of 1290 (885159)
03-25-2021 3:34 PM


When a stuck boat comes along, Fitzcarraldo!
Why has no one called in Werner Herzog to free up the Suez Canal yet?

  
xongsmith
Member
Posts: 2036
From: massachusetts US
Joined: 01-01-2009
Member Rating: 6.2


(6)
Message 1284 of 1290 (885351)
04-07-2021 12:43 AM


geology

"I'm the Grim Reaper now, Mitch. Step aside."

- xongsmith, 5.7d


  
AZPaul3
Member
Posts: 5838
From: Phoenix
Joined: 11-06-2006
Member Rating: 4.0


(2)
Message 1285 of 1290 (885359)
04-07-2021 8:55 PM


ELO Sightings Cover Up

  
AZPaul3
Member
Posts: 5838
From: Phoenix
Joined: 11-06-2006
Member Rating: 4.0


(1)
Message 1286 of 1290 (886274)
05-13-2021 6:16 AM


Conservatives
Since this is that flaming cupcake-butterfly mix, Randy Rainbow, you know the humor will be there, thus this thread instead of Con v Lib thread. But it was awfully close. Note how many times Trump is mentioned.


Eschew obfuscation. Habituate elucidation.

Replies to this message:
 Message 1287 by Phat, posted 05-14-2021 2:28 AM AZPaul3 has responded

  
Phat
Member
Posts: 15362
From: Denver,Colorado USA
Joined: 12-30-2003
Member Rating: 1.1


Message 1287 of 1290 (886294)
05-14-2021 2:28 AM
Reply to: Message 1286 by AZPaul3
05-13-2021 6:16 AM


Re: Conservatives
that guy is funny and his video presentations are worthy of YouTube Broadway

"A lie can travel half way around the world while the truth is putting on its shoes." ~Mark Twain "
***
“…far from science having buried God, not only do the results of science point towards his existence, but the scientific enterprise itself is validated by his existence.”- Dr.John Lennox

“The whole war between the atheist and the theist comes down to this: the atheist believes a 'what' created the universe; the theist believes a 'who' created the universe.”
- Criss Jami, Killo

“The most difficult subjects can be explained to the most slow-witted man if he has not formed any idea of them already; but the simplest thing cannot be made clear to the most intelligent man if he is firmly persuaded that he knows already, without a shadow of a doubt, what is laid before him.” — Leo Tolstoy, The Kingdom of God is Within You
(1894).


This message is a reply to:
 Message 1286 by AZPaul3, posted 05-13-2021 6:16 AM AZPaul3 has responded

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AZPaul3
Member
Posts: 5838
From: Phoenix
Joined: 11-06-2006
Member Rating: 4.0


(1)
Message 1288 of 1290 (886449)
05-20-2021 6:10 AM
Reply to: Message 1287 by Phat
05-14-2021 2:28 AM


Re: Conservatives
Yes, very entertaining.

But there was a message. Was it lost?


Eschew obfuscation. Habituate elucidation.

This message is a reply to:
 Message 1287 by Phat, posted 05-14-2021 2:28 AM Phat has not yet responded

  
Tangle
Member
Posts: 8149
From: UK
Joined: 10-07-2011
Member Rating: 3.7


(2)
Message 1289 of 1290 (886502)
05-22-2021 6:53 PM


Northern Ireland have elected a new political leader. He's a young earth creationist. Seriously.

His name is Edwin Poots. It's an anagram of New Stoopid.

Edited by Tangle, : No reason given.


Je suis Charlie. Je suis Ahmed. Je suis Juif. Je suis Parisien. I am Mancunian. I am Brum. I am London.I am Finland. Soy Barcelona

"Life, don't talk to me about life" - Marvin the Paranoid Android

"Science adjusts it's views based on what's observed.
Faith is the denial of observation so that Belief can be preserved."
- Tim Minchin, in his beat poem, Storm.


  
AZPaul3
Member
Posts: 5838
From: Phoenix
Joined: 11-06-2006
Member Rating: 4.0


(2)
Message 1290 of 1290 (886574)
05-25-2021 5:05 AM


Belly Laugh

Come on, people! The concept alone is hilariously funny.

Ok, maybe it's me.

Edited by AZPaul3, : No reason given.


Eschew obfuscation. Habituate elucidation.

  
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