simple queries about computer organization

[PG1995]

Hi

Could you please help me with the queries included in the attachment? Thank you.

Regards
PG

 

[MikeMl]

Unreadable!

 

[JimB]

Q1
The technology you use for any particular application depends on what is available and how much the client is willing to pay for something which will do what he wants.

Q2
Data can represent:
Volts, amps, ohms
Pressure, temperature, viscosity
The number of cars, people, beans in a can.

Q3
The hardware for a computer is mostly the same, irrespective of the application.
The biggest difference is in the software.

Note, JimB thinks this is not strictly true.
You would not use a bank of server PCs with umpteen disc drives to control a toaster,
no more than you would use a box full of PIC 16F84s to build an air traffic control centre.

JimB

PS reading the highlighted bits in the extract from you book bored me to death!
Be carefull with the rest of it, it could give you brain damage!

 

[PG1995]

Thank you, Jim.

PS reading the highlighted bits in the extract from you book bored me to death!
Be carefull with the rest of it, it could give you brain damage!

Why did it bore you? Is it the presentation of the book? I have just started using this book Computer Architecture and Organization by William Stallings.

Thanks for the help.

Regards
PG

 

[KeepItSimpleStupid]

Tidbits (not answers per see):
Q1: IC's vs SMT technology
Q2: puched cards, magtape, keyboard, scanner, camera, electrical signals ....
Q3: microcontroller, DSP, General purpose computer (computers are not generally designed for specific functions. In say the 80's there were IR remote control chips just for that specific purpose)

The hope is that the tidbits will spur thinking to help you understand.

 

[JimB]

Why did it bore you? Is it the presentation of the book?

Well, you asked the question "What do the highlighted sentences mean?"
I am not sure if you are a native English speaker (your location is not indicated) but I am and I look at some of those sentances and think "what on earth is this guy on about".
He uses sentence constructions which seem to be intended to convey "look how clever I am writing this fancy book".
I don't expect it to be dumbed down to "Sun reader" level, but come on, the guys use of words is almost obscuring his meaning.

JimB

 

[dougy83]

His writing style might be different from e.g. a novel or a newspaper, but I didn't find fault with it. The only issue I have is that there is almost no content being conveyed through (at least) the highlighted sections.

 

[KeepItSimpleStupid]

The passage to me seemed like an advertisement for the book.

 

[PG1995]

Hi

Could you please help me with this query? Thank you.

Regards
PG

 

[misterT]

Hi

Could you please help me with this query? Thank you.

Regards
PG

Haha.. that paragraph is bananas. Next time mark it with thick black magic marker

- RTC is a clock that counts seconds, minutes hours etc. standard time (for humans). The author is mixing real time clock and real time scheduler (real time scheduler uses system-clock).
- RTC can be used by schedulers and real-time-programming.
- RTC can be used to obtain hardware controlled delays, interrupts and time-outs.

 

[PG1995]

Thank you, misterT.

The processor uses crystal oscillator to time its working. Could you please tell me What system-clock is in the given context? Isn't **broken link removed** implying that crystal oscillator and system-clock are closely related. Thanks.

Regards
PG

 

[misterT]

I'll try.. I have a hangover from yesterdays pool tournament. Lost all games.

Crystal oscillator provides the clock that makes the processor work. Instructions are executed in the processor each clock cycle. All timers, counters etc. use the crystal oscillator to work. The context here is a real-time-system. Which means that there are things that needs to be executed at specific time events. These events are controlled by the system-clock. In this context the system clock is not the clock that makes the processor work, it is the clock, or timer, that times the events needed by the real-time-system.

Usually in a real time system a timer (counter) is set up to count up to a specific value. The counter counts at the crystal oscillators frequency. When the counter reaches the specific value, an interrupt is generated (by the hardware) and the time critical task is executed (in interrupt handler, which is software). At the same time the counter value is set to zero (by hardware) and it starts to count again. All this counting and interrupting is done by hardware in the background. This counter is referred as the system-clock (in real time systems.. or real time schedulers).

Sometimes.. actually many times.. the crystal oscillator, or whatever oscillator, is called the system clock. But in the context of real time schedulers it can be the timer that times the time critical events. And that timer is clocked by the (crystal) oscillator.

The text in your **broken link removed** is weird.. He is explaining a simple thing overly complicated thinking that it makes it easier to understand.. It doesn't! "high and low pulses"? They are just pulses. Crystal oscillator output is actually a sine wave.

 

[PG1995]

Thank you very much, misterT.

And better luck with the tournament next time! Good sleep will cure your hangover.

Regards
PG

 

[misterT]

Thank you very much, misterT.

And better luck with the tournament next time! Good sleep will cure your hangover.

Regards
PG

Girlfriend makes me clean the apartment.. ruins a good hangover.

 

[JimB]

that paragraph is bananas

Hold on there Mr T, bananas are a healthy source of nourishment, a food which is full of vitamins and minerals!
And besides, chimpanzees are very fond of bananas.

Having got the humour out of the way for this morning, a lot of that text about oscillators and clocks is just plain mis-guided to the point of being wrong in places.

System Clock - provides pulses to tell the logic when to change state. Can run at any speed within reason, does not need to be particularly stable unless the processor is doing something which is time critical.

Real Time Clock - Tells the time.
Usually separate from the system clock, keeps time when the rest of the system has no power.

This is a big subject with a lot of ifs and buts.
I think that the author of that book has tried to cram too wide a subject into a couple of paragraphs and reduced it to absurdity.

JimB

 

[PG1995]

Thanks, misterT, Jim.

@misterT: I hope your hangover is gone now and you did a find job cleaning the apartment. Love doesn't come cheap, at least that's what I've heard!

@JimB:

Hold on there Mr T, bananas are a healthy source of nourishment, a food which is full of vitamins and minerals!
And besides, chimpanzees are very fond of bananas.

Chimp who? By the way, I'm also fond of bananas!

Best wishes
PG