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ITEC 1000.docx

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York University
Information Technology
ITEC 1000

ITEC 1000 System admin: - Install, config, maintain and upgrade system - Maximize availability - Optimize performance - Ensure security Web designer: - Optimize customer access to web service - System admin of web server - Select useful data formats - Design good web pages The www provided so documents could be shared easily and be available. I/O process: INPUT -> Process (or stored)->output Input dev: keyboard, mouse, scanner, punch cards Processing: CPU executes comp program (brain of computer) Output: monitor, printer CPU: - ALU: Arithmetic/logic unit - Arithmetic and Boolean logical calculations - CU: Control Unit – control processing of info & movement of data in CPU - Interface Unit – moves instructions between CPU and other hardware (via bus) Primary Memory = Primary Storage = RAM Memory has 2 parts: RAM and ROM. Contents of ROM are read only. BIOS is part of ROM. ROM gives instructions to CPU and tells it how to communicate with Hard Drive. Prom = programmable ROM. OS always reserves a part of RAM for itself. Data is unprocessed. When it gets processed it becomes information. Information in processed data ITEC 1000 Software Components: - Applications - Operating System  Application Program Interface (API)  File Management  I/O  Kernel o Memory management o Resource scheduling o Program Communication o Security  Network module Software has 2 categories: System: OS and Utilities Application: word processor and so on. 8 bits represent 1 character at least. In more complex systems 16 bits represent a character. In standards like ASCII it’s 8 bit. ACSII is able to share 256 characters only. 8 bit patterns has a special name called byte, 4 bit pattern called nibble. 2 nibbles is a byte. Kernel is heart of OS. It does memory management, file management and device management. Everything in terms of files and devices is done by kernel. Unicode is a superset of ASCII. It has 16 digits which makes it able to store more characters. Software does the translation between binary and human language. Communication Components: - Hardware  Communication channel (cables, etc)  Interface hardware (modem, interface card) - Software ( Network Protocols) Protocol is a common scheme of communication ITEC 1000 History: - Blaise Pascal invents first calculating machine - Joseph Marie invents loom punch cards - George Boole invents Boolean logic - Mark I -> first electronic computer - ABC used vacuum cubes - ENIAC first digital computer - Creation of transistor - UNIVAC - first commercially available Standard is created to ensure universal compatibility of data formats and protocols Sum and carry: In 10 -> Sum = 0 and Carry = 1 Chapter 2: - First computer was decimal Roman number system: position independent Modern number system: based on positional notation Range = Base ^ Number of digits Chapter 3: Sources of data: - Binary input - Analog – Sound or image, requires hardware to convert data into binary Representing characters: - ASCII : most common used, created by ANSI, 7 bit, 128 characters - EBCDIC: IBM mainframe - Unicode: developed for worldwide use, 16 bit ITEC 1000 Chapter 4: - Numbers can be represented as a combination of values and signs - Data word: a term referring to memory allocation. Ex: 32 bit, 64 bit, etc. 2 types of integers: - Unsigned - Signed There is no direct way to represent sign in binary notation. Options are: - Sign-and-magnitude  Use left-most bit for sign. 0=plus , 1=minus  Half positive, half negative  2 values for 0  Difficult and hard to implement in hardware - 1’s complement - 2’s complement ITEC 1000 Chapter 6 – Little Man Computer - Addresses start from 0 to 99 - Content may be data, three digit number , or instructions Op code – operation code represented by a single digit Operand – object to be manipulated represented by 2 digits. Could be data or address of data Mnemonics – short character sequence that represents instructions in assembly Fetch – little man finds out what instructions he is to execute Execute – little man performs the work Von Neumann Architecture: - Stored program concept - Memory is accessed linearly - Memory is addressed without regard to content ITEC 1000 Chapter7 – The CPU and Memory CPU: - Arithmetic Logic Unit – performs calculations and comparisons  - Control Unit – performs fetch/execute cycle  Register – small permanent storage location within the CU that can hold data, address, or instruction. (register size is in bits or bytes and not MBs) o Registers hold data needed quickly or frequently o Stores info about status of CPU and running programs o General Purpose Registers– holds results or data values and there is several dozens of them in each CPU o Program Counter Register o Instructions Register – stores instructions fetched from memory o Memory Address Register – finds the location in memory and is an address decoder o Memory Data Register o Status Register – status of CPU and currently executing programs + Flags to track condition like arithmetic carry, overflow, power failure, internal computer error, etc.  I/O 2 parts of instructions performed by the ALU: - Op-code: code for the operation that ALU need to perform. Tells the ALU what do to. (add, subtract, store, etc.) - Operand: where to do, where to go, etc. Registers: The closest temporary memory to the CPU and built in the CPU in modern context. It has 2 types: - General purpose – temporary memory and also keeps track of what’s going on in generator (part of the ALU) - Special purpose – goes to the A0 in memory and takes the instruction from RAM to CPU through Control Unit. (part of the CU)  PC (Program Counter) – contains the address of next instruction. Counts by 2  IR (Instruction Register) –  It takes 2 memory cells to complete a single instruction. So Program Counter counts by 2 in order. (Example: first instruction is 101; next instruction will be in 103.) Every instruction may consist of 8 or 16 or 32 or 64 or 128 or … number of bits. (Example of 16 bits: 156D, 15: 1 bytes, 6D: 1 bytes) ITEC 1000 It loads the data from 6D to register number 5. Then program counter counts by 2. - The program in the CPU is called micro program which is indeed a computer within a computer. - Micro program and micro memory are part of the modern CPU. Classification of Instructions: - Data movement (load, store) - Arithmetic - Boolean logic - Single operand manipulation (incrementing, decrementing, negating) Memory Capacity = 2 ^ K. Where K = width of the register in bits. (eg: 32, 64, etc.) Instruction format: - Opcode – task - Source operands - address - Result operands - address Instruction format – machine-specific template that specifies: - Length of op code - Number of operands - Length of operands Instruction word size: - Fixed vs. variable – pipelining uses fixed - Addressing modes:  Direct  Register differed  Also immediate ITEC 1000 Chapter 8 – CPU and Memory Current CPU architecture designs: - Traditional modern architectures - VLIW – very long instruction word – 128 bit - EPIC (Intel) – Explicitly Parallel Instruction Computer – 128 bit instruction bundle Current CPU architectures: - IBM mainframe series - Intel x86 family - IBM power/PowerPC Family - Sun SPARC family Problems with early CPU architectures: - Large number of instructions added complexity but rarely used - Slow data memory accesses could be reduced by increasing number of general purpose memory - Using general registers to hold addresses to simplify architecture - Fixed-length instruction word format allowed instructions to be fetched and decoded independently and in parallel Fetch-execute cycle: - Computer c
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