【Memoirs】 Week#11 Nov 21st

【Memoirs】 Week#10 Nov 14th

Term Test Two

Today we had our term test two, the last term test for this course. Honestly, this test was much more difficult then the last test. I dont know why they made the second test so hard? maybe the average of first test was so high? I dont get it...

Lecture

Work 

Experience

Hardware effects
strong information gets smaller, cheaper, faster bu the decades

【Memoirs】 Week#9 Nov 7th

Lecture

Networks 
roundly connected
(ring topology)

Way that messages passed between machines on this network

Each machine as a designated receiver for its messages, and designated sender of messages to it, and they are thus connected in a ring. A bit pattern, called a token, is passed from machine to machine, and a machine wishing to send a message to another machine retains the token, sends the message with the address of recipient machine, and waits until the message it is sending travels around the entire ring and it can confirm that is was sent. Then the token passed to the next machine.

centrally connected

(staar configuratution)

all connected 

(bus configuration)

eg. ethernet

Way that messages passed machines on this network

Each machine listens for messages addressed to it. when a machine needs to communicate with another machine on the same ethernet bus, is broadcasts a message with other machine's adress. If a machine detects a collision ( another machine trying to broadcast at the same time0 it stops broadcast for random time interval and re-broadcast.

【Memoirs】 Week#8 Oct 31st

Lecture

Operators and operating systems

Machines take over in batches ( data paper cards tapes moved around fed to reader)

Machines began to take over seeting the program counter to a new job, collecting the output, fetching memory... but it was still one job at a time.

one user, one program, one computer 
dedicated -> just one job ( game typesetting)
                  -> programme know all details disk access
                  -> practically no op. sys needed

unix (mostly) to the desktop
  |
  |__ mainframe migrate
             > several program
             > networking
             > GUIs

An operating system should have kernel (shell, sheield access to hardware, referee sharing); untilities (repair, maintain machine, list files, format disk)

【Memoirs】 Week#7 Oct 24th

Lecture

Now we learned about the hardware architecture. 

Where Von Neuman's going

There are some issues
> Von Neumann bottlenck
           ( speed+size chockel at bow)
> mortality of Moore's Law
           ( notten, as gott smaller)

DrRacket cond codes

; number-hunch : number -> string

; Is n really, really big?

; that is, is it more than 101

(define (number-hunch n)

  (cond

    [(> n 101) "Oh, it's *really* big"]

    [else "Not so big"]))

(number-hunch 5)

(number-hunch 102)

(define (GCD m n)

  (cond

    [(zero? n) m]

    [else (GCD n (remainder m n))]))

(GCD 35 15)

(GCD 15 35)

【Memoirs】 Week#6 Oct 17th

Tutorial

Practised the codes we learned and prepare for the quiz, we could get our test back in today's lecture.

Lecture

I had been announced that the test paper would be returned at the end of the lecture.
Today we kept studying in algorithms questions.

There is NO potentially an algorithm to solve every problem

If there are two or meow algorithms solving the same problem, we compare the efficiency to decide which algorithm to use.

How do we discover new algorithms?
A: By heuristics + tips, but they do not guarntee you can find a new algorithm.

Before electronnic, programmable computers, Alonzo Church and Alan Turing showed there were many unsolvable algorithms, also showed class of solvable algorithms.













Before Canada-411, we used to look up phone numbers in white pages. There are (at least) two different, correct ways to find the leaf ( 2-sided sheet) with the business you're looking for ( conclude it;s not there).

Linear search -----------> order of thousand steps

Binary search -----------> order 8 steps

Clearly there's no fool-proof method, but there's some techniques that often make progress. It helps to write down the whole process:

> Understand the problem
> Devise ( one or moew) plan (s)
> Try the plan
> Look back

Wikipedia Project Part II was due on Oct 19th, Part II spent much more time than part I, we had to write a specfic plan to help to improve and edit the topics we selected.

【Memoirs】 Week#5 Oct 10th

Term Test One

Today is first term test of this course, so nervous indeed! And there is no tutorials this week, we started the test at 6:10pm. 

We finished the paper at 7:00pm. I did think this test was difficult for me, after the test, I asked my friends, they also did think in that way. Based on the test, I noticed I had lots of things that I forgot to review for this term test. I should be more careful next time. Praying, hope I would get a low mark in this test >_<...

Lecture

After the test, we still had to stay and listion to the lecture. Today's lecture is about the Algorithms.

simple sequence of feasible steps to solve a problem deterministic ( in this course) credit AI-Khwarizmi

Ex.
Multiplication
PBJ ( Sticky algorithm)
Google page rank

Paper folding 
fold over upper surface of paper strip after one fold, is has a downward crease fold the once-folded strip again and it had one upward, two downward there are good physical reasons you can't experment far beyong 6 folds given the number of folds, predict the pattern.

In DrRacket, we learned about mapping.

Like,     (map add1 (list 1 2 3 4 5 6))

              (map sqrt (list 1 2 3 4 5 6 7))

we can get      (list 2 3 4 5 6 7)

                         (list

                              1

                              #i1.4142135623730951

                              #i1.7320508075688772

                              2

                              #i2.23606797749979

                              #i2.449489742783178

                              #i2.6457513110645907)

aslo we have map-image, allows you  to map image's color.

【Mem oirs】 Week#4 Oct 3rd

Tutorial

Asusual, nothing special, we practised the codes we learnd about DrRacket last week, and gor prepare for the quiz today.

Lecture

Today's quiz was about the Animations in DrRacket, it was much more harder than the quizs we wrote before, we transferred statical to animations. In fact, the quiz was harder than I thought, maybe because I didn't practise enough? 

Today's lecture we learned about Binary deeper than last lecture. We had Multiplication, Negative numbers, fractions.

A common scheme, called IEEE floating point, uses 64 bits (binary digits): one for the sign, 11for the magnitute ( from 2^-1002 to 2^1023) and the remainder for an non-negative integer.

7 bits is enough to represent 128 values (2^7) .

Time goes so fast, next week we would have the Term Test One for this course, and we also had other term tests for other courses. Guess I have to work harder to face my first challenge, so nervous >_< ...

【Memoirs】 Week#3 Sep 26th

Tutorial

Today we got our first quiz result, surprisingly I did get 100% but I got one question wrong, if we got 4 out of 5 right we would get full mark. Nevermind it is still a 100 percentage, I should more attention about details next time. This tutorial was focus on quiz later. 

Lecture

We took our secong quiz today, it was not hard, that's it. Today we learned Representing information.

Two design ideas that computer have covered：
1. digital: Using discrete, sharply-changing, rather than analog, smoothly-changing states
2. Two states os the smallest, most easily designed

Boolean Logic

Binary:

The binary numeral system, or base 2-number system, represents numeric values using two symbols: 0 and 1. More specifically, the usual base-2 system is a positional notation with a radix of 2. Because of its straightforward implementation in digital electronic circuitry using logic gates, the binary system is used internally by almost all modern computers and computer-based devices such as mobile phones.

Binary Additoin:
0+0=0
0+1=1
1+0=1
1+1=10

Binary Subtraction:
0-0+0
1-0=1
1-1=0
10-1=1

Binary Multiplication:
0*0=0
1*0=0
0*1=0
1*1=1

Binary Division:
0/1=0
1/1=1


We now started learning Animations in DrRacket, more advanced than before. We had new codes, big-bang, on-tick, show-it, on-draw, stop-when, on-key etc.

【Memoirs】 Week#2 Sep 19th

Tutorial

We had our first quiz for this course, before the quiz I was so nervous about it. The first week we learn the basic codes/expression about DrRacket, for instance, flip, beside, scale, above, below, overlay etc. We kept practising the whole period and went to SF to took the first quiz.

Lecture

We came to SF and waited for the quiz. Be honest, a little bit nervous. The quiz started, when I got the quiz paper, I was so happy about it, because the quiz was so easy, and I pretty that I could get a 100% for quiz1.

After quiz, we started the lecture for this week. It's about Pre-modern computers.

IBM tabulator pins that go through card touch a mercuty, both of transmit eletricity. Information -> accumulator and rack pops open for card

Analog computers model world using smoothly-varying quantities, such as water. 

"programmable" (cards) but not electronic (relays) the Zuse Z1
In WWII era. lots of money to break codes and track projectiles.
In Germant Z1-> Z3 ward slow. noisy electromechanial realays-> only ran for a few hours
In US, fore-runner of ENIAC ( First computer in the world) had hard-wired programs

On Friday, we had our first project to due on Sep 21st. It's the Wikipedia assignment Part I,

it's about go register a wikiordia account and get to know how wikipedia works and the information about it, not hard actually.

【Memoirs】 Week#1 Sep 12th First Day of CSC104HF1

Lecture

This was the first day of class, we arrived at SF 1101,some of students did feel excited. Be honest, the major reason for me taking this course is someone did tell that this course is really really easy... 
Anyway, we came to the lecture, our handsome professor Danny Heap gave us some intrustions about this course and we went to labs in BA to set up our CDF account. 

We learned that computers and networks change society, like privacy, property, democracy, work, education etc. Make them better or worse.

Two tracks in this course:
1. History of computing technology, overview of modern computing OS, social issues.
2. Insight into computing mindset: problem-solving and programs.

Some advices about hwo to do well in this course:
1. Read the course information sheer as a two-way promise
2. Question, answer, record, synthrsize
3. Collaborate with respect

Early devices:

Clay tablets have benn used for at least 5,000 years.
Abacuses, or abaci have benn in use for nearly as long 
Hindu-Arabic     over 2,000 years ago
Antikythera mech anism

New software in this course  : DrRacket 
Basic expressions...

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