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Do You Have a Working Paper Tape Reader?

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1/6/2014 12:20 PM EST

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Chesler
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Re: Lower case letters
Chesler   1/9/2014 5:37:49 PM
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Found a TrueType of it at http://www.zanzig.com/download/index.htm

and yes, it is all uppercase.

That's right of course on Pascal.

I tried to teach my father what I was doing (payback for lots of math he'd taught me and many others). He had tried to learn some programming in the 1960s, but it didn't go anywhere.)

I remember he couldn't get past "N = N - 1".  "How can N be equal to N minus 1?"  "No Dad, that means 'Set N to be equal to...'  "

And because Factorial was the first program I learned (computers were taught out of the math department) every time he asked me or my brother to show him programming, we had to start with that. He could learn videogames and the Web, but through generations of programmable calculators, pocket computers, and PCs that we brought home, he never learned to write a program.

betajet
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Re: Lower case letters
betajet   1/9/2014 5:24:37 PM
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The ASR-33 is UPPERCASE ONLY.  If you want full ASCII, you need a Model 37 or Model 38.  I used a Model 38 quite a bit.  It also had a dual-color ribbon, with escape sequences to switch ribbon color.  Great fun.

I used the Model 38 to write PDP-11 assembly language with lower-case comments.  This was considered heresy at the time and made me a pariah among pariahs -- kind of like an EE student with a circular slide rule.

There's a nice photo of Teletype output on the familar yellow paper at Wikipedia.

betajet
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Re: PROGRAM
betajet   1/9/2014 5:12:55 PM
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Pedantry: Pascal uses "<>" (less than or greater than) for "not equal to".  Pascal also uses the Algol ":=" for assignment, so that you can use "=" for equality.  This avoids the need for C's "==" equality operator.

I blame the Model 026 keypunch, which influenced Fortran.  The creators of Fortran were mathematicians, so I'm sure they would have loved to use the proper mathematical symbols instead of .GE. and .LT. for ">=" and "<".  I'm sure glad we've left those silly notations behind!  [What?  You say they're still around in HTML?  'Strewth!]

Of course, now that we have full graphics displays and the Symbol font, we can fully expect languages to take advantage of these advances and not have syntax designed for a Model 38 teletype, right?

As for proper printing of ">=", "<=", and "!=", you can of course use overstrikes on a teletype or line printer.  And if you're really a gutton for mathematical notation, there's always APL :-)

Chesler
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Lower case letters
Chesler   1/9/2014 5:07:00 PM
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Back to the base topic, did the ASR-33 do lowercase?

The paper tape seems to truly be ASCII (true 7-bit ASCII, not UTF-8 or Code Page 437) but this program was all uppercase, and I think that's all we used, so we couldn't generate codes 0141 to 0172.  I guess I'm looking at it backwards, it had a set of characters, and those characters were represented in ASCII; it is not necessary that tape with defined ASCII be read, and it's reasonable and simple for it to interpret 0141 'a' as 0101 'A'.

I remember the Teletypes recognized 0007, ^G, BEL, but we were discouraged from using it, because we had 16 such Teletypes arranged around the room. (Also two CRT terminals, probably earlier than VT-100.)

At that point, high school students had varying typing skills, and even with the program written out in longhand before class, we were limited by how many characters we could type in half of a 40-minute period. (Twice as many students as terminals.)

 

I think it was a sans serif font. Does anyone know a reasonable facsimile? Or have a sample we could feed into one of those "What font is this?" programs? It had a certain look, and books at the time (I had one which was a scientific approach to Monopoly, where the authors had run a simulation to find the odds of any property being hit) tended to show the results of computations as photographs of the printout, rather than typesetting the table the way the publisher would almost any other piece of manuscript.

 

David Ashton
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Re: PROGRAM
David Ashton   1/9/2014 4:41:21 PM
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@Chesler... "Is semicolon a delimeter to PRINT that says don't do a carriage return?"     Yes, as I recall

; Semicolon means stop where you are and wait for the next print command

. comma means advance to the next TAB stop (useful for tables)

nothing means do a new line

I've often thought that the inventors of ASCII - who would have been computer nerds - should have thought to put in characters like not equals, equal to or Greater / Less than, etc.  But they didn't, so we are stuck with these weird substitutions.    I once wrote a terminal emulator in QuickBasic and it needed some weird characters.  Fortunately I found a font editing program that let me create them.

I still love Basic and have never learned C (though that is one thing I want to do) and am doing some blogs on the PICAXE MCUs at the moment - great little things if you're a BASIC tragic like me.....

Chesler
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Re: PROGRAM
Chesler   1/9/2014 4:22:31 PM
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The horse isn't complaining...

40  PRINT N;"!=";

50  F=N

60  N=N-1

Is semicolon a delimeter to PRINT that says don't do a carriage return?

So the output would be like

6!=120

(Note the lack of spaces, and several years before I'd learned Pascal or C I never thought to read != as "Not Equal To" instead of "Factorial Equals")

David Ashton
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Re: PROGRAM
David Ashton   1/9/2014 4:07:04 PM
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@Chesler - "So the missing lines are...."  That explains a lot......

Dead horse....yeah software has moved on a bit since then I think.  But as I said, it's been a lot of fun.

Chesler
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Re: PROGRAM
Chesler   1/9/2014 4:02:48 PM
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You're right, not that hard to hand translate, with the table on page B-4.
Human error in splicing together the photocopies.

So the missing lines are, as we figured:

50  F = N

60  N = N-1

 

I made little pencil marks on the tape so I can take more photocopies and splice them together and post it to Flicker, but I think this dead horse is sufficiently beaten now (until I get stuck on real work and need to divert for few minutes...)

betajet
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Re: Uninitialized variables
betajet   1/8/2014 6:41:31 PM
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LOL!

David Ashton
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Re: Uninitialized variables
David Ashton   1/8/2014 6:17:32 PM
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@betajet that reminds me of a prank I once played on a mate:

http://www.eetimes.com/author.asp?section_id=36&doc_id=1284862

And being as it concerns teleprinters it's even related to this thread :-)

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