The Importance of Terminology's Quality

[Martin Gregorie]

Some did, but not all. The 370/145 was the first, and made a big splash
thereby.

...snip...

Thanks for that. As I said, during most of that era I was using ICL kit.
Microcode was never mentioned in the 1900 contect. Hoiwever, they had a
very rough approximation called extracodes. though they were closer to
software traps than microcode: if hardware didn't implement an op code
the OS intercepted it and ran equivalent code. This was used for i/o
operations and for FP instructions on boxes that didn't have FP hardware.
As a result all boxes executed the same instruction set. Some opcodes
might be very slow on some hardware but it would execute.

The 2900 series had huge amounts of microcode - it even defined both
memory mapping and opcodes. You could run 1900 code (24 bit words, fixed
length instructions, ISO character codes) simultaneously with 'native'
code (8 bit bytes, v/l instructions, EBCDIC) with each program running
under its usual OS (George 3 for 1900, VME/B for 1900).

The only other systems I'm aware of that could do this were the big
Burroughs boxes (6700 ?), which used a byte-based VM for COBOL and a word-
based VM for FORTRAN and Algol 60) and IBM AS/400 (OS/400 could run S/34
code alongside S/38 and AS/400 code). AFAICT Intel virtualisation doesn't
do this - all code running under VMware or any of the other VMs is still
running in a standard Intel environment.

 

[Martin Gregorie]

When you say "knife switches", do you mean the kind that are shaped like
flat paddles?

Pedantic correction:

"Knife switch" is the wrong term. These are high current switches,
typically used in the sort of heavy duty circuit where the wiring hums
when power is on or in school electrical circuits so even the back of the
class can see whether the switch is open or closed. In these a copper
'blade' closes the contact by being pushed down into a
narrow, sprung U terminal that makes a close contact with both sides of
the blade. Like this: http://www.science-city.com/knifeswitch.html

What you're talking is a flat handle on a SPST or DPST toggle switch. It
is often called a paddle switch and mounted with the flats on the handle
horizontal. Like this, but often with a longer handle:
http://www.pixmania.co.uk/uk/uk/1382717/art/radioshack/spdt-panel-mount-
paddle-s.html

 

[George Neuner]

Pedantic correction:

"Knife switch" is the wrong term. These are high current switches,
typically used in the sort of heavy duty circuit where the wiring hums
when power is on or in school electrical circuits so even the back of the
class can see whether the switch is open or closed. In these a copper
'blade' closes the contact by being pushed down into a
narrow, sprung U terminal that makes a close contact with both sides of
the blade. Like this: http://www.science-city.com/knifeswitch.html

What you're talking is a flat handle on a SPST or DPST toggle switch. It
is often called a paddle switch and mounted with the flats on the handle
horizontal. Like this, but often with a longer handle:
http://www.pixmania.co.uk/uk/uk/1382717/art/radioshack/spdt-panel-mount-
paddle-s.html

I don't know the correct term, but what I was talking about was a tiny
switch with a 1/2 inch metal handle that looks like a longish grain of
rice. We used to call them "knife" switches because after hours
flipping them they would feel like they were cutting into your
fingers.

George

 

[RedGrittyBrick]

I don't know the correct term, but what I was talking about was a tiny
switch with a 1/2 inch metal handle that looks like a longish grain of
rice. We used to call them "knife" switches because after hours
flipping them they would feel like they were cutting into your
fingers.

That must be a toggle switch (as MG suggested) just not the paddle type.

e.g.
<http://cpc.farnell.com/SW02861/components-spares/product.us0?sku=multicomp-1m31t1b1m1qe>
<http://tinyurl.com/64a8ld>

 

[Martin Gregorie]

I don't know the correct term, but what I was talking about was a tiny
switch with a 1/2 inch metal handle that looks like a longish grain of
rice. We used to call them "knife" switches because after hours
flipping them they would feel like they were cutting into your fingers.

That sounds like a sub-minature SPDT toggle switch with a normal handle.
Cheap as chips, which is probably why they were used on that front panel.
Like this by any chance?

http://www.maplin.co.uk/images/300/fh00a_ff70m.jpg