1.1.3 input,output and storage system Flashcards
(17 cards)
input
pass information from the outside word into a computer system
output
take digital data and convert it into format human can process, like sound, vibrations and images
sensors
hardware device that take measurement of physical properties
scanners
-qr code
-barcode (UPC-A, code 128)
actuators
input sensor: motors
altimeter
input sensor: height
gyroscope
input sensor: orientation
thermometer
it is both input and output
use heat/temperature sensor instead for input
criterias to compare with secondary storage
durability
portability
reliability
capacity
cost (per GB)
speed (r/w)
RAM
- stores program and data currently in use
- faster read and write speed than secondary storage
- volatile
ROM
- stores programs that needs to be boot up (e.g. BIOS, bootstrap loader)
- non-volatile and cannot be altered/overwritten
layers of memory
cache
primary (RAM)
secondary( not necessary SSD)
virtual memory
when RAM is full; open but inactive data is swapped to secondary storage
a feature of os
virtual storage
aka cloud storage
storing and retrieving data over the internet in the cloud instead of a local storage device
OR
abstraction or separation of logical storage from physical storage
optical
- uses laser light to read and write (pits and lands), and sensor to measure the amount of light reflected
slow read and write speed but average in other aspects(comparing with other 2 types of storage)
examples:
- CR-ROM, CR-RW, CR-R
- DVD, Bluray
magnetic
- disk is polarised to become either north or south, that represents 0 and 1
- read and write from the disk (using the read-write head)
huge capacity and lower cost per GB; but not portable, less durable and require space (for rw head)
example:
hard disk
flash
- uses electric charge
- memory can be erased and reprogrammed electronically
opposite of magnetic
fast RW speed, portable, durable; but has small capacity and high cost per GB
example:
SSD
