C&D A-Level

Operating system

types

multi user

windowns

windows nt

distributed

embedded

systems

dedicated OS

real time

aircarft

self drive car

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storage

secondary

magnetic

optical

solid state

use magnetic field

types

hdd

floppy

tape

read write head

nanometers

1/1000th mm

can be used in data centres

shine

laser

reads

land 1

pit 0

stored when power lost

data

to blocks on chip

read

written

flash

read/written

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no moving parts

Primary

RAM

ROM

holds

os

programs

data used for programs

volatile

retains info

power off

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BIOS(Basic Input Output System)

power on self test

hardware

setup

working

goes through drives

get

OS

boot strap

kernel

hand control to OS

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plastic

bumps burned on plastic

alluminium layer

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starts center

spirals out

1/2 micromter wide

spinning disks

reader

magnets

metal grains

grouped together store data

this is coverted from bits

each graiin bit

direction

determines

0

1

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to read it has magnetic reader

usefull string

0110011

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store