Re: My Vintage Dream PC

I still have an HP67 complete with "strip tapes". It needs new batteries, and there is an open in the charger circuit.

My old Texas Instruments TI-34 has most of the same functions as well as hex and octal notation. It's not RPN, of course.

In Linux, there is an arbitrary precision calculator called "bc" which has many functions available, and also can be "programmed".

If you like RPN, try "dc" which is a standard Linux program.

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2. > >>> There was never an assembler for this machine; he wrote the compiler =

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I don't know about PDP's, but the minis I built (based on GA SPC-16) had 3 backplanes: CPU, I/O, EXPANDED MEMORY. When building the complete computer, they would be brought up in that order. The bootstrap ROM was part of the EXPANDED MEMORY, which required a controller in the I/O backplane.

The ASR33 was connected directly to the CPU backplane, so I spent a good portion of my life toggling in the papertape bootstrap loader (6 16-bit words) which I eventually memorized. Not because I wanted to, just from having done it so often. One day, after leaving that company, I woke up and suddenly realized I had forgotten the papertape bootstrap!

What a great feeling, like being released from the French Foreign Legion.

Write a c compiler in c is the basic exercise.

That's a bigger exercise than needed to get the point across. When I taught the class a couple of times I defined a small subset of C I called Cb (pronounced C flat); it wsa written in C, lex, and yacc, and generated Motorola HC11 code.

It cannot be a basic exercise if one is writing in C. Tee hee hee...

I "researched" this before and received the following information:

In "KSNJFL", each letter was represented by the correct decimal value in the five-level teletype code that communicated with the computer. The computer input was mainly paper tape produced by teletype.

Charlie Jones of the University of Iowa sent the following to me in an email:

Here is the 5-level code used by Illiac, transcribed from THE ILLIAC MINIATURE MANUAL, by John Halton, Digital Computer Laboratory File 260, University of Illinois, Urbana, 1958, page 3. I have preserved the layout as much as is possible using ASCII:

THE TAPE CODE ------------- | Characters | n for 92 | Characters | n for 92 Tape Holes | F/S | L/S | Orders Tape Holes | F/S | L/S | Orders

---------------------------------- ----------------------------------

| o | 0 P 2F |O o | Delay Delay 3F | o O| 1 Q 66F |O o O| $(Tab) D 67F | o O | 2 W 130F |O o O | CR/LF CR/LF 131F | o OO| 3 E 194F |O o OO| ( B 195F | oO | 4 R 258F |O oO |L/S=Letter-Shift 259F | oO O| 5 T 322F |O oO O| , V 323F | oOO | 6 Y 386F |O oOO | ) A 387F | oOOO| 7 U 450F |O oOOO| / X 451F | Oo | 8 I 514F |OOo | Delay Delay 515F | Oo O| 9 O 578F |OOo O| = G 579F | Oo O | + K 642F |OOo O | . M 643F | Oo OO| - S 706F |OOo OO|F/S=Number-Shift 707F | OoO | N N 770F |OOoO | ' H 771F | OoO O| J J 834F |OOoO O| : C 835F | OoOO | F F 898F |OOoOO | x Z 899F | OoOOO| L L 962F |OOoOOO| Space Space 963F

So you just read books, wrote your own compiler, turned it in, and got a grade??? *No* one was teaching you any of this???

Isn't it *more* difficult to produce code for the 8-bit HC-11 than it would be for the MC68000 ??? The MC68000 has a reasonable assembly language/machine language for producing code. You can use actual multiply and divide instructions rather than writing your own multiply and divide *routines*. (You probably *gave* the students those routines to call from the compiler binary output.)

And how about linkage to functions??? You *did* have functions???

The HC11 has the huge advantage that it's the machine we use in our assembly language class (we have them build a SBC and control LEGO robots with it), so the students already know it and they know the simulator we use for it.

It's also got multiply and divide instructions. The thing about a toy language for a class, though is that if it didn't have them, the language could be defined to not have them either (you have to have enough operations to exercise operator precedence, but bitwise boolean operations would suffice for that).

It's got push and pop instructions, pushes return addresses on the stack, does indexed addressing....

This was in the late 60s and the system was an IBM 1620.

/BAH

What books? I don't recall ever seeing a text book.

Not turned it in. Demo'ed it.

No grade. The compiler either worked or it didn't. When it worked, you got an A.

I never got to take the class. and there wasn't anybody to teach it. The people who did write one learned as they went. They knew how a compiler was supposed to work because we had FORTRAN II on the system.

/BAH

Kewl. All of those are important. I'd add indirection.

/BAH

If you mean memory-indirect addressing, no such luck. It's a nice little machine, but not perfect...

I don't have to - I'm single. :-)

Cheers! Rich

What world do you live on? I've never seen a '70s, let alone a '60s car with a cranking handle. A few farm tractors and other farm equipment, but that was because they might sit in a barn for a month at a time in the winter but no cars or trucks. The only thing I remember seeing with a hand crank starter were the Model T Fords a friend owned.

I've got a great mental image of some poor guy trying to hand-crank a

I had a Ford Model A when I was in high school. In rebuilding the engine, I replaced the main crankshaft bearings. I had to stand on the crank to get the engine to turn over enough for the starter to work.

As they should. When money is tight, they can't afford to do something twice.

When money is tight, the posers & liars are shaken out of the system. Then they can whine that no one will hire them because they are old. :(