On Mar 5, 10:11*pm, wrote:
Like I said, there are a lot of "smart switches" in the canbus system
- but although they may use"microprocessors" they are not computers.
Tell us, how is a microprocessor (any microprocessor) *not* a computer?
A "computer" CAN include a microprocessor, but does not need to.
Neither krw nor I ever said that a computer needs to include a
microprocessor. The reverse is what krw claimed, which is to say that
a system that includes a microprocessor is a computer. Unless
perhaps the microprocessor is being used as a doorstop. For the
microprocessor to be of any use, it needs to be executing a program
and capable of some kind of input/output. At that point it is a
computer. It could be a very simple program only taking in some
serial data, figuring out what the data is telling it to do, then
activating the appropriate output. But that is just a simpler
version of what your PC is doing.
Google KURTA for a very good example of a strictly mechanical
"computer"
The earliest electronic computers also did not use a microprocessor,
or even a central processing unit (CPU).
I'd also point out that today, virtually all current computers do
contain a microprocessor or microcontroller. Certainly evey one in
today's cars do. So, why the trip down memory lane? For the record,
I did google KURTA and KURTA mechanical computer and came up with
zippo.
A Microprocessor is a COMPUTER COMPONENT that can be used for many
processes, from the very simple to the very complex - only some of
which are "computational" or numeric in nature.
As I said above, if a system has a microprocessor it's a computer.
It could be a simple one, that takes a few inputs and works a few
switches, but it is a computer. That microprocessor is executing a
program. Other than that the program is very simple, how is that any
different than a microprocessor operating in a PC? And you never
answered this question:
How about I write a simple assembly language program that implements a
switch function,
turning a keyboard light on and off, put it in a flash memory chip,
and replace the bios on my PC with it? The light is now flashing.
Is my PC no longer a computer just because it's running a very simple
program?
Here's Collins dictionary definition of the word computer:
computer [kəmˈpjuːtə]
n
1. (Electronics & Computer Science / Computer Science)
a. a device, usually electronic, that processes data according to a
set of instructions. The digital computer stores data in discrete
units and performs arithmetical and logical operations at very high
speed. The analog computer has no memory and is slower than the
digital computer but has a continuous rather than a discrete input.
The hybrid computer combines some of the advantages of digital and
analog computers.
b. (as modifier) computer technology Related prefix cyber-
2. a person who computes or calculates
Collins English Dictionary
And from Merriam-Webster:
Main Entry: com·put·er
Pronunciation: \kəm-ˈpyü-tər\
Function: noun
Usage: often attributive
Date: 1646
: one that computes; specifically : a programmable usually electronic
device that can store, retrieve, and process
Tell us what part of those definitions an 8051 running the dashboard
display in a car would not meet.
The microprocessor is used as a switch. Switches are binary digital
devices too - canbus switches are solid state and remote control. They
do NO data processing so are not REALLY computers.
Huh?
From the Columbia Encyclopedia
"computer:
device capable of performing a series of arithmetic or logical
operations. A computer is distinguished from a calculating machine,
such as an electronic calculator, by being able to store a computer
program (so that it can repeat its operations and make logical
decisions), by the number and complexity of the operations it can
perform, and by its ability to process, store, and retrieve data
without human intervention. Computers developed along two separate
engineering paths, producing two distinct types of computer-analog and
digital. An analog computer operates on continuously varying data; a
digital computer performs operations on discrete data."
Let's look at the first sentence: "device capable of performing a
series of arithmetic or logical operations." An 8051 microcontroller
running the dashboard display meets that definition.
Now let's look at the next part:
A computer is distinguished from a calculating machine,
such as an electronic calculator, by being able to store a computer
program (so that it can repeat its operations and make logical
decisions), by the number and complexity of the operations it can
perform, and by its ability to process, store, and retrieve data
without human intervention.
Now we're really out of the definition part, but they are making a
specific comparison of what would distinguish an electronic calculator
from a computer. But let's take this list of requirements anyway:
able to store a computer program
number and complexity of operations it can perform
ability to process, store and retrieve data without human intervention
An 8051 microcontroller running a dashboard display meets all those
requirement.
If a microprocessor performs only a single operation (such as display
data on a LCD screen, or decode a signal sent across a power wire to
turn on a light remotely) it is not a computer.
It's still a computer because it has a CPU, memory, I/O and is
executing a program.
If it reads several inputs and "computes" a result, and then creates
an output that does something, it is a computer, like a cruise control
computer, a transmission control computer, an ABS computer, etc.
So we also have the dashboard display microprocessor, which is
receiving digital data serially from the ECU as to the cars speed,
from the tranny computer as to the shift lever position, from the
climate control computer as to the inside and outside temps, from the
GPS as to the compass heading. Then using that data it computes how
to activate the various display segments, responds to pushbuttons on
the dash to work the trip computer, etc. Tell us how that is not a
computer. Of course it is and it's called the dashboard display
computer which should be on your list. It's also funny that in the
above statement, we suddenly have 3 new computers in a car, not
including the ECU and body computer. Gee, you started off telling us
that most cars have only two and some only one.
A computer can multi-task, running numerous processes at the same
time, operating, for instance, engine fuel injection, ignition timing
and emission control, as well as controlling the transmission and
brake antilock systems - and by linking the three together also
provide traction control and active stability control - all on one
"computer"
Didn't know that. eh??
I've forgotten more than you can ever hope to know. If you want to
compare credentials, I would be happy to do so, but I don't think you
want to go there. And what does the above have to do with
anything? Are you now claiming that to meet the definition of a
computer it must be capable of multitasking? Even if you want to
make that claim, a simple 8051 microcontroller is quite capable of
multitasking. As an example, in a display controller an 8051 could
be receiving data on the vehicle speed on it's serial port, working
the display segments and updating the distance traveled. Just like
the ECU "computer"
You also completely ignored the highly credible link I gave you that
says
http://www.embedded.com/columns/sign...questid=508024
This is a website for engineers that do embedded computer design.
And they clearly say that even an econobox car today has a few dozen
embedded processors. Or how about all the other media reports that
you frequently see that talk about how many computers are in a typical
home today? They are in everything from your cable box, to your
microwave oven, your alarm system, your digital thermostat, your
dishwasher, etc. Do you agree they are computers? And if yes, then
what makes them different than using a microprocessor in a dashboard
display?
I can give you my answer. They are all computers because they have a
CPU, execute a program, and I/O.