Text 5534, 117 rader
Skriven 2010-03-02 19:36:47 av Bo Simonsen (2:236/100.0)
   Kommentar till text 5475 av Michiel van der Vlist (2:280/5555)
Ärende: Windows Update Fix
==========================
MvdV> BS> Must have been an interesting time, observing the beginning of
MvdV> BS> computing on computers.
MvdV>
MvdV>Indeed, I have lived in interesting times. Saw the first computers,
MvdV>saw the first man walk on the moon, witnessed the birth of quark and
MvdV>inflation theories, etc, etc. All very interesting.

When I reach your age, I probably say the same.. Since there was hardly
any cell phones when I was a child, and definitely no internet available
to the "normal" person. And no laptop. :)

MvdV>Regarding computers: what I find frustrating is that at one time, some
MvdV>20 years ago, I had full control over my computers. I could find every
MvdV>bit and have them switch things on and off trimmed to the microsecond.
MvdV>
MvdV>Now they have become too complicated to be fully understood by one
MvdV>man. I have little idea what goes on behind the screens and have no
MvdV>control over it any more. That is frustrating...

Just knowing the standard libraries provided by modern programming
languages is hard.. I mean to get the complete knowledge of every single
component. When programming in C you know it all if you have programmed
for a few months. I held a lecture recently, and the listeners seemed
to agree with me, that we are not performing regular programming today,
but we are performing glue programming. Simply glueing the available 
components together.

MvdV> MvdV>> I got "saddled" with a French minicomputer. An Intertechnique
MvdV> MvdV>> Multi 8. It had 12K core memory, a teletype with paper tape
MvdV> MvdV>> reader and punch. An optical tape reader, a magnetic tape
MvdV>unit, a
MvdV> MvdV>> plotter and an interface to some linear particle detector.
MvdV>
MvdV> BS> More advanced with the magnetic tape unit.. I guess it was 8-bit
MvdV>since
MvdV> BS> it was called 8?
MvdV>
MvdV>Yes, it was 8 bit.
MvdV>
MvdV>It was actually a microcoded processor. The instruction set presented
MvdV>on the assembler level was not the bottom level. Below it was yet
MvdV>another level of microcode. A very limited set of instructions that
MvdV>were stored in a diode matrix that formed the micro programme that
MvdV>defined the instruction set.

Ah, all processors today contains microcode I guess.. However at that time
it was'nt a fact I guess.

MvdV>In theory it was possible to rewrite (and rewire) the microprogramme
MvdV>to change the macro instruction set.

Cool, I hope that such things are read-only today ;)

MvdV>As it was the macro instruction set was basically 8 bit, Its
MvdV>addressing space was 8 bit, but it provided for dealing with variable
MvdV>length registers of 1, 2, 3 or 4 bytes.

I would survive with an 8bit computer today, doing math with long integers
would just take some more time...

MvdV>Another interesting thing was that because of the magnetic core
MvdV>memory, one did not have to reload after a shut down. The content of
MvdV>memory was preserved. So when properly shut down (manually or by the
MvdV>power fail interrupt), once power came up, it would just carry one
MvdV>where it was shut down without having to reload anything.

Cool! With today's electronic building blocks it's hardly possible to
create such a construction. 

MvdV> BS> I guess the BASIC language was a special dialect?
MvdV>
MvdV>It wasn't BASIV, just BASIC like. IIRC the name was LEM. Langue
MvdV>Elemantaire Mathematique.

BASIV? ;) 

Make sense, a lot of languages constructed at that time, seemed
really BASIC-like.. I've not programmed in any of them, but I think
of ALGOL as an example, am I right? It was probably constructed before
the first BASIC interpreters.. So what came first, the chicken or the 
egg?

MvdV>Each processor has its own instruction set and hence its own assembler
MvdV>language. But instruction sets have many sets in common, so if you
MvdV>have mastered one, it is not hard to learn another. I think I have
MvdV>programmed in assembler for a dozen or so processors. Of the top of my
MvdV>head:
MvdV>
MvdV>SC/MP
MvdV>6502
MvdV>6800
MvdV>6802
MvdV>6803
MvdV>6805
MvdV>6809
MvdV>6811
MvdV>68000
MvdV>8080
MvdV>80186
MvdV>80286

Of course.. ;) Never wrote 80386 assembler?

MvdV>Z80
MvdV>
MvdV>It has been over a decade since I last fired up my universal cross
MvdV>assembler, so it would take a while to pick it up again. It is not
MvdV>like swimming, one DOES forget...

Indeed, what I think is the most difficult to remember is the number
of the interrupts. The way you program assembler, is probably like 
swimming or riding a bike.

Bo

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