Post date: Nov 15, 2014 9:27:51 PM
Computer components introduction and installation
Algorithm introduction
A procedure for solving a mathematical problem in a finite number of steps that frequently involves repetition of an operation; broadly: a step-by-step method for accomplishing some task.
Turing Model
An idea of a universal computational device was first described by Alan Turing in 1937. All computation could be performed by a special kind of machine, now we call a Turing machine.
Computer Organization
Central Processing Unit (CPU)
It performs operation on data. It contains three parts: Arithmetic Logic Unit (ALU), Control Unit, and a set of registers, fast storage locations.
Arithmetic Logic Unit (ALU)
It performs logic, shift and arithmetic operations on data.
Logic operations
It contains several logic operations, NOT, AND, OR and XOR.
Shift operations
It used to shift bit patterns to the left or right, while arithmetic operations are applied to integers.
Arithmetic operations
Some operations can be implemented more efficiently in hardware.
Registers
They are fast stand-alone storage locations that hold data temporarily. They including: Data registers, Instruction registers and Program counter.
Data registers
Their responsibilities are holding the intermediate results temporarily to speed up the computers since complex operations are done using hardware instead of software. These are named R1 to Rn.
Instruction registers
The CPU is responsible for fetching instructions one by one from memory, storing in the instruction registers, decoding and executing them.
Program Counter
It keeps track of the instructions currently being executed. After executing instructions, it is incremented to point to the address of the next instruction in memory.
Control Unit
It controls the operation of each subsystems.
Main Memory
It is the second major subsystem in computer. It exists two main types, RAM and ROM.
Random Access Memory (RAM)
The CPU can write something to RAM and later overwrite it. It also volatile, that is meant the information (program or data) is lost if computer is powered down. RAM also divided into two, SRAM and DRAM.
Static Random Access Memory (SRAM)
It uses traditional flip-flop gates to hold data. The gates hold their state (0 or 1), which means that data is stored as long as the power on and there is no need to refresh memory locations. Hence, it is fast but expensive.
Dynamic Random Access Memory (DRAM)
It uses capacitors, electrical devices that can store energy for data storage. If a capacitor is charged, the state is 1, instead, the state is 0. Since a capacitor loses some of its charge with time, it need to be refreshed periodically, hence, it is slow but inexpensive.
Read-Only Memory (ROM)
It written by manufacturer, and the CPU can read it but cannot overwrite it. Hence, it is nonvolatile.
Programmable Read-Only Memory (PROM)
User might store program on it within some special equipment.
Erasable Programmable Read-Only Memory (EPROM)
It can be programmed by user, can also be erased with a special device that applied UltraViolet (UV) light. To erase EPROM requires physical removal and reinstall.
Electrically Erasable Programmable Read-Only Memory (EEPROM)
It can be programmed and erased using electronic impulses without being removed from the computer.
Cache memory
It is faster than main memory but slower than CPU and its registers. The procedure in order is CPU will checks the cache. If the words are there, it copies the words, instead, CPU accesses main memory and copies a block of memory starting with the desired words. This block will replaces the previous contents in cache memory. So that, CPU accesses the cache and copies the words.
Magnetic storage devices
It uses magnetization to store bits of data. If a location is magnetized, it represents 1, instead, it represents 0. Example for magnetic storage devices, magnetic disks and magnetic tape etc.
Optical storage devices
It uses light to store and retrieve data. This technology includes CD-ROMs, CD-Rs, CD-RWs, DVDs, Blu-Rays etc.