PJ+TomasS

11 August 2010 Task 1
** CA Task Set1 (due date August 13) ** //Complete #2-5 in your personal journal. Remember to save after editing your journal.//
 * 1) Read CH page # 3-8
 * 2) Define a computer, CPU, peripheral device, memory
 * 3) Outline the function of CU and ALU
 * 4) Make a list of 5 input devices and 4 output devices. State the application of each of the devices.
 * 5) Research and write 5-6 line summary on ENIAC

A computer is a programmable machine that receives input, stores and manipulates data, and provides output in a useful format.*
 * Computer** - set of components - memory (RAM,HDD,...), mathematical computing units (CPU, GPU,...), used in everyday life for playing games, writing, comunicating, ...

Peripheral device: "external device" input/output ex. monitor output, mouse input, used to comunicate with the PC, input send data to PC, output "sends data to you", flash drive, external HDD, etc. Memory: secondary (HDD) used to store data primary (RAM) used to store instructions/programs that are being executed
 * CPU** : one of the mathematical units used to execute programs, carry out simple arithmetic operations, and fetches data from input devises and sends back to output


 * CU, ALU** - parts of CPU CU: gets instructions, proceses them and directs their implementation, comunicats with primary storage, and ALU. "Decides" which circuits need to be activated. ALU:Part where calculation operations are prformed contains 'accumulator' "accumulates" results and gerneral purpose registers which contains data that is to be processed by the ALU

MIDI keyboard send MIDI singnals to CP (doesnt produce sound) musicians Webcam sends images(video) to CP comunication, if good enough can be used with face recognition as extended securiy Fingerprint scanner use fingerprint as a "password" extends security - can be used everywhere Keyboard sends bytes (symbols) everywhere Laser rangefinder measures the distance between it and the "item" upto 20km geodets
 * Input :**

Monitor optical view of output data "shows images of what we are doing" everywhere except the blind people Speakers/headphones "audio view of output data" the thing that makes the sounds at the most unapropriet times, everywhere,except servers Printer used to print the data onto paper,CD,... everywhere... Flash drive used to store data and carry them elsewhere (input/output devic) everyday item
 * Output:**


 * Eniac**: first usable computer, designed by J. Presper Eckerat and John Mauchly, completed in 1946. Used vacuum tubes instead of transistors, had about 18k today PCs have over 350M transistors, vacuum tubes burned at rate several per day. Was as large as a house, programmed by connecting wires. Work on it supported by U.S. Navy for computation of ballistic trajectiories with variables like wind resistance, initial velocity, atmospheric conditions.. Later used for peaceful purposes ex. tabulation of census data.

Resources : book, wikipedia
 * citation from [|en.wikipedia.org/wiki/Computer]

13 August 2010
**Resources:** CH page # 8-27 ** CA Task Set2 (due date August 17) ** //Complete #1-4 in your personal journal. Remember to save after editing your journal.//
 * 1) difference between application and applet
 * 2) importance of keeping backup.
 * 3) Outline 3 different types of errors. i
 * 4) outline program compilation process

The main difference between an aplication and an applet is that the application is a standalone concept and can use local resources, whereas an applet is used over a network or it can be embedded in a java enabled web browser or html page and it cannot have access to the local system resources*, meaning it cannot "harm" your PC.

Backups should be kept because nothing is sure, meaning that the hardrive could break down, you could get a powersurge and you lose everything you were working on. And on bigger projects it would be quite a big problem.

there are 3 types of errors: 1)Compile-time or Syntax error : When you write a piece of code and you write System.out.prn__r__ where the compiler has no clue what //prnr// is and complains. It could also be when you forget the semicolon. 2)Logic : is when the code is syntactically correct but it does what it isnt supposed to do : System.out.print("CS Rock__z__") this would write CS Rockz instead of CS rocks as we wanted to. The main problem with those errors is that as long asi doesnt have compile-time error it is happy and compiles it. to fix these debuggers are used. 3)Run-time error : Error that occurs in run-time. The exceptions like divide a number by 0, overflow and underflow comes after this * *

1 Java source code is translated into class files Class files consist of virtual machine instrictions and other information that is required for execution. They have .class extension
 * Compilation process**

The source code is wiritten in the editor, then it is saved and compiled. The compilation translater the source code into machine code (bytecode) which is saved as class files. Those are then connected with libraries, and this setup can be run as a java program/applet etc.



book
 * Resources:**
 * citation from []
 * * citation from []
 * * *image from [] (end of page)

===**17 August **===

CA Task Set3 (due date August 17)
 * 1) what is the smallest unit of measuring memory
 * 2) <span style="color: #000000; margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px;">Calculate the number of bits in a file of size 2.5 MB
 * 3) <span style="color: #000000; margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px;">Explain: a 32 bit machine is faster than a 8 bit machine.
 * 4) <span style="color: #000000; margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px;">Every memory register, peripheral device must have a unique address. Why?
 * 5) <span style="color: #000000; margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px;">Worksheets on part2 (download off the class calendar)

The smallest unit is BIT - b 2,5MB = 2560kB = 2621440 B = 20971520 b .............*1024 .......*1024 ..........*8

Because you can process more data - 32 bits instead of 8 bits simultaneously

Every adress has to be unique, otherwise if youd call an adress and two things would have a same adress both would respond and you wouldnt have how to call just one.