I read this today
In fact, the Apple II did two memory accesses per cycle, two million per second at 1MHz, with the video accessing the memory during
the first half of Φ2, and the processor during the second half, interleaving, so both could access the same memory at the same time
at full speed, with no conflicts.
Any idea from what Apple II book this is from?
Here is the webpage
http://wilsonminesco.com/6502primer/addr_decoding.html
There are probably a handful of books that describe the clever video architecture of the Apple II, but this may be the most comprehensive: https://archive.org/details/understanding_the_apple_ii
I found a lead in here.
It's in the Apple IIe Reference Manual Page 149 in
RAM Addressing.
The memory circuits in the Apple IIe take advantage of the
two phase system clock described in the section "System Timing"
to interleave the microprocessor memory accesses and the display
memory accesses so that they never interfere with each other. The
microprocessor reads or writes to RAM only during phase 0, and
the display circuits read data only during phase 1.
Except I had a look and there is no section "System Timing"
It reaally does seem that previous given advices to read have not been treated seriously....:
http://www.applefritter.com/?q=content/irq
#3:
otherwise - if the books have been acknowledged this thread would have not been started this way...
just to repeat the advice:
WINSTON GAYLOR - the Apple II circuit description >>
http://mirrors.apple2.org.za/Apple%20II%20Documentation%20Project/Books/W.%20Gayler%20-%20The%20Apple%20II%20Circuit%20Description.pdf
Chapter 4 + 5 +8
pages 34 ff
+
pages 104 ff
+
pages 185 ff
JIM SATHER - understanding the IIe >>
http://mirrors.apple2.org.za/Apple%20II%20Documentation%20Project/Books/Jim%20Sather%20-%20Understanding%20the%20Apple%20II.pdf
Chapter 4 +5 +7 +8
starting at pages 15 ff
starting at pages 35 ff
starting at pages 61 ff
Not to forget:
Gary B. Little -Inside the //e
>>
mirrors.apple2.org.za/Apple%20II%20Documentation%20Project/Books/Gary%20B.%20Little%20-%20Inside%20the%20IIe.pdf
starting at pages 279 ff
....
reading helps...and can realy increase knowledge
sincerely
SpeedyG
reading helps...and can realy increase knowledge
Take your own advice and read what I wrote in the first post.
You are not reading the posts as they are posted.
In fact, the Apple II did two memory accesses per cycle, two million per second at 1MHz, with the video accessing the memory during
the first half of Φ2, and the processor during the second half, interleaving, so both could access the same memory at the same time
at full speed, with no conflicts.
I then found it in the Apple IIe Reference Manaul.
It's in the Apple IIe Reference Manual Page 149 in
RAM Addressing.
The memory circuits in the Apple IIe take advantage of the
two phase system clock described in the section "System Timing"
to interleave the microprocessor memory accesses and the display
memory accesses so that they never interfere with each other. The
microprocessor reads or writes to RAM only during phase 0, and
the display circuits read data only during phase 1.
Except I had a look and there is no section "System Timing"
You then put this quote in your post.
"and seond the handling of "switched memory" caused by the adressing limits of the Apple II series to 64kB
and the 128 kB limitation at the IIe and finally the 16 MB at the IIGS - switching portions of the expanded video-memory to the
lower 64 kB portion of memory for the Videodisplay....which is also related to the handling of Interupts...
therefor i urgently recomend to read first the books:
WINSTON GAYLOR - the Apple II circuit description
then continue with:
JIM SATHER - understanding the IIe
to understand the topic itself and the related topics..."
This is not related to the question I put up about "System Timing"
and interleaving. Again you need to read and keep up what the
posts are saying.
You then mention a previous post I had put up and books that I need
to read. They do not explain interleaving.
If you are going to recommend a book, make sure that it answers
the question I have specifically asked instead of just of
it's in that book you need to read it.
The reply is perfect proof that you neither read the one book nor the other.
The quote from the website looks like a mystery.
I asked the author of the website and he didn't
know where it came from. (strange)
This theme was looked into at Kansas Fest 2011
in which a video was done.
Here is the video
https://www.youtube.com/watch?v=LP5k15g_0AM
It is not listed in the Apple II Circuit Description
Pages as Speedy G has suggested.
The book does take an approach of detailed analysis
of the Apple II so I will have to read the whole
book to see if the quote is correct.
great - mixing tomatoes and grapes.... but far off attiotude...
fare well...
My initial post and question was this.
In fact, the Apple II did two memory accesses per cycle, two million per second at 1MHz, with the video accessing the memory during
the first half of Φ2, and the processor during the second half, interleaving, so both could access the same memory at the same time
at full speed, with no conflicts.
Any idea from what Apple II book this is from?
Your answer was
It reaally does seem that previous given advices to read have not been treated seriously....:
This was a new topic and discussion, but you have held over from a previous thread
that I should have read the books as the answer was in there.
You then re-repeated I should I read these books but gave the following pages.
WINSTON GAYLOR - the Apple II circuit description
Chapter 4 + 5 +8
pages 34 ff
+
pages 104 ff
+
pages 185 ff
These pages did not mention what I quoted.It was at that stage that I thought,
I have asked a question and he has advised me to read this book, so I decided
to read the pages he has now suggested and there still is no mention of what I was
talking about.
The memory circuits in the Apple IIe take advantage of the
two phase system clock described in the section "System Timing"
to interleave the microprocessor memory accesses and the display
memory accesses so that they never interfere with each other. The
microprocessor reads or writes to RAM only during phase 0, and
the display circuits read data only during phase 1.
Except I had a look and there is no section "System Timing"
I did not switch to another topic as the Apple IIe book
described "System Timing" which included interleaving but
there is not section included.
As I am looking for information that is scattered on the internet,
I remembered the Apple IIGS system video which is in my
topic of interleaving/System timing.
I am not aware that these are independent topics and not related.
If you are so knowledgeable about the Apple II series then
why don't you share this information.
I don't claim to be an expert but am asking questions.
Why don't you write a book then explaining all these
terms so everyone can benefit.
I was not about to put in my two-cents, but...
The internet; as we know it, is really not that old.
A lot of us that started with computers in the very late '60's, '70's,
and '80's, did not have the luxury of "Instant Contact" with other
computer hobbyist's. Even in the '90's the Internet was unreliable and contacts were difficult.
We read Magazines, Books, Newspaper Articles, and anything we could
get our hands on for information.
We used "Snail-Mail", and Dial Telephones to contact folks who could
possibly; just possibly, help us get the information we were hungry for.
It was exactly the same for the Job Market.
Do you actually think that people used Job Websites then?
The process was called "Resumes and Shoe-Leather":
You found a job you were interested in.
You wrote your Resume using a Typewriter.
You reviewed your resume for mistakes. (Sometimes more than once)
You retyped the resume into its Final Form.
You then called the Personnel Department of the Company you were interested in to make an Appointment for an Interview.
You dressed in a Two, or Three-Piece Suit.
You drove, or walked (Shoe-Leather) to the company Headquarters.
You were at least 15 minutes early.
Whoever interviewed you would, some times, make copies of your Resume (WHAT??? You forgot to get a Mimeograph machine to make copies???),bring in several other people in the Department you were aiming for, so they could ask you questions.
They would invariably all say " Thank you for coming in. We will contact you with our decision."
But wait a minute.
You think that this is happening for just One Job?
Oh No!
You have at least 10 to 12 Interviews scheduled for just this week alone.
That is just 10 to twelve DIFFERENT RESUMES (Plus Copies).
Why?
Because each Company has a DIFFERENT RESUME STYLE.
That means you have to make your resume fit their style.
Now imagine doing this 10 to 12 Resumes a week for six months, just to have the possibility of getting the job you want?
Boiling it down:
"Resumes and Shoe-Leather" is still out there, right beside and a little back to the left, of all the new Job Sites.
The Internet is a wonderful device. It can give you Instant Gratification of a need or want.
But there are many of us who are considered "Old School".
I am considered one of the "Old-Timers".
I will search for things I want to know in unusual places.
I will also try my best to help other people who seek information, whatever the form.
I want to wish everyone a "Happy Holiday Season!"
"God Bless Us, Everyone."
Tiny Tim
Steven![Smile](https://www.applefritter.com/sites/all/modules/smiley/packs/kolobok/smile.gif)
[/b]
(I guess this amounts to about $5.00 lol)