[Tutor] Bit-level field extraction

[Terry Carroll]

On Tue, 16 May 2006, Alan Gauld wrote:

> Hah, if you haven't bootstrapped a VAX using the toggle switches on
> the front panel you ain't a real progammer ;-)

Not with a VAX, but I had to do that with a TI-980, long, long ago!  And 
once I had it booted, because the assembler was a pretty primitive 
two-pass assembler, I had to run my punched cards through twice.

But at least I got to use punched cards.  I forget what the other system 
we had in that room was, but I had to use paper tape on that one.
 
> Actually one of our local Universities still starts their computer
> science courses by teaching students how to do that, before moving them
> onto machine code, assembler, C and finally Java(*). It's like an
> historical tour of computing/programming.... They consistently produce
> very good graduates, so it seems to work.

I wonder if the results are good because it's an effective teaching 
method, of because it culls out the faint-of-heart right up front!

> The machine code is done on little hex keypads with pocket calculator
> style printout rools! Its only when they get to C that they get to use a
> PC!

A couple years ago, I took a course in which I built my own computer.  
And I mean built.  The individual chips (CPU, RAM, resistors, etc.) were
off-the-shelf components, but that's it.  I soldered every lead and
wire-wrapped every wire on that thing, build on a breadboard.

It was very primitive: its only input devices were an 8-bit DIP switch and
thermometer sensor chip (and a flashable EEPROM to hold the OS/program, if
you count that as an input device); and its only output devices a couple
of seven-segment LED displays;  but it sure taught the hard-core hardware.

I didn't actually need it for the subject matter taught; but I'm planning 
on taking the patent agent's exam, and the US patent and trademark office 
insisted I shore up my academic credentials with a few additional 
physics courses (the course was actually about physic laboratory 
instrumentation).  It was quite a bit of fun, though.