computer system organization
INPUT: take data convert it into binary
MEMORY: it is a storage unit for program as well as data
OUTPUT
INTRODUCTION
CPU: brain
CONTROL UNIT(CU)
REGISTERS
ARITHMETIC LOGIC UNIT(ALU)
RAM
ROM
CACHE
UNITS OF MEMORY
KEYBOARD: letters,digits, commands,function keys,alphanumeric keys,direction keys etc to give input in form of text
MOUSE: converts movements of user hand into a unique set of binary digits
LIGHTPEN: photocell mounted on a penchaped tube called stylus capable of sensing touch used by engineers,architectsor designers
OMR:recognising pre specfied type of mark made with dark pencil or ink on a paper document called as omr sheet optical mark recognition
SMART CARD READER: embedded with a microprocesor that stores and process a certain amount of data
BARCODE READER:light source, lensand a light sensor translate optical impulses to electrical signals
QR CODE READER:quick response code special barcode for anyone to scan
BIOMETRIC SENSOR
TOUCH SCREEN
MICROPHONE
WEBCAM
MAGNETIC INK CHARACTER READER(MICR): used for detecting magnetically charged ink at bottom of bank cheques
OPTICAL CHARACTER READER(OCR)recognize scanned images,screenshots,handwritten documents into machine encoded text
SECONDARY MEMORY
BLU-RAY DISC: high capacity optical disk medium for developing recording , rewritting and playing back high-defination video it can store large amount of data stored ata greater density it can store upto 25GB in single layer while a dual layer can hold upto 50GB of dataat advanced video and audio formats
COMPACT DISC(CD): it is a thin optical disc to store audio and video data of a standard 120mm is 700mb it can transfer 150kb/s latest transfer un to 10800kb/s
HARDISK: non volatile high capacity storage device . it consists of dolid rounded discs packed on one another made of magnetic material. Data is stored on spinning magnetic disks called platters eac platter is divided into
MAGNETIC TAPE:magnetic coating are stored on a tin tape data read or write speed is slower because od sequential acess magnetic tapes are convinient secure and affordable
PENDRIVE: small portable memmory which can be plugged into a computer usb port and can store 2,4,8,16,32,64gb unto 2tb
MEMORY CARDS: called flash memory cards mainly used with digital cameras computers mobilephones consoles etc and can store upto 1.5tb starting from 8gb
PRINTER
SPEAKER: generates sound as an output it requires a sound card in the computer sysytem to use this device
VISUAL DISPLAY(MONITOR)
PLOTTERS: producing high quality images engineering drawings architectrual blueprints maps they support printing onlarge sized papers and large scale graphics mainly used in computer aided designing
LED: light emmiting diode
LCD: liquid crystal display
OLED: organic light emmiting diode
INKJET: most common it uses spreading of quick dry ink on paper the ink is stored in the form of cartriges it prints in highresolution ideal for homes and small offices
DOT MATRIX: serial printer which prints one character a time it prints by striking an inked soaked ribbon on paper it has low operating cost and can only print in low resolution graphics
LASER: it uses lazer technology they are very fast and used to to print in high quality
STATIC
DYNAMIC
(PROM): programmable read only memory
(EPROM): ersable programmable read only memory
(EEPROM): electrically ersable programmable read only memory
COMPUTER: it is an electronic device the takes instructions as input perform or process that data and executes its intended function this process is called information processing cycle
all the tasks given to a computer follos a cycle called IPO cycle which include steps input-process-output
von neumann archeticture: input unit--cpu--output
in cpu three funtions cu, alu, registers
all calculations and comparisons are done here, it performs all arithmetic(+-*%) and logical(and,or,not,xor) operations on the data sent from memory and then back to memory this helps in computer decision making
flow of data from input devices to memory and from memory to output, it controls and guides the interpretation flow and manuplation of all the data it does not process any of the data
high speed temporary storage areas they work as per the instructions given by CU it stores instructions and data immediatly required for performing an operation
highest priority tasks are done here for faster execution
they are of 16bit,32bit,64bit so onn
each registor has a specfic function
like storing data ,storing instruction,storing address of a location in memory
cells: it is a device that stores a single symbol selected from a set of symbols
it is a read and write memory, it is used for primary storage in computers to hold active information of data and instructions, it is a volatile memory as it does not store data permanentaly it provides faster acess than secondary memory (memory acess time: time required to retrive data from memory until becomes available)
it uses flip flopswhich are circuits that can maintain their state without refreshing to store data it only retains as long as powe is connected
it uses transistors and capcitors to store data it requires regular refresh cycles to prevent its data from getting lost
static ram is faster than dynamic thats why used in cache while other is udes in main memory
it is read only memory menaing data is stored while manufacturing and hence non volatile it is slower than ram itis used to hold essential instructions to check basic hardware components suchas booting,procedures to load operating system
it is faster than ram it is used by cpu to collect certain type of data present in the ram . It stores recently used values it is placed between main memory and cpu it makes data available to the cpu in very less time it is also called cpu memory
elementry unit of memory is bit(binary digit) combination of these bits store data 8bits form 1byte and group of4bits form nibble
1024bytes=kb and so an for all conversion
smaller and lighter than CRT MONITOR ideal for laptops and portable devices
light weight flat panel display used led to create pixels on the screen and uses less power than lcd
uses an organic substance which glows under electric current this reduces the thickness and weight of display unit
track: each platters is divided into concentric rings called tracks
each track is divided into sectors that actually store data it stores 512 bytes of data