Transcript Computer Systems 1 Fundamentals of Computing

Computer Systems 1
Fundamentals of Computing
The Computer System: Core Concepts
Computer Systems: The Core Concept
 Input,
Process, Output
 Devices
 RAM
 Backing store
 Computer architecture
 Core Hardware
Computer Systems 1 (2004 - 2005)
Input



Sending information to the computer
Issuing the computer with a command
Devices for Input









Keyboard
Mouse
Scanner
Camera
Joystick / Gamepad
Microphone (Transducer)
Lightpen
Barcode Reader
Fingerprint Scanner
Computer Systems 1 (2004 - 2005)
Output




Returning the result of a process
Querying the user
Providing the user with feedback
Devices for Output








Monitor
Printer
Plotter
Digital Projector
Speakers
Synthesiser
Robot / Machine
LED’s
Computer Systems 1 (2004 - 2005)
More Hardware

Employing RAM and backing store
RAM
INPUT
PROCESS
Backing Store
Computer Systems 1 (2004 - 2005)
OUTPUT
Random Access Memory (RAM)


Used to store instructions that are in current use
Two main types of RAM:

Static RAM (SRAM)





Dynamic RAM (DRAM)





reliable
does not need to be constantly refreshed
fast
expensive
more common
slower than SRAM
cheap
must be constantly refreshed
Both volatile (contents lost when power is off)
Computer Systems 1 (2004 - 2005)
Random Access Memory (RAM)

Cache Memory
 Essentially

Is physically close to the processor
 Usually

levels of cache memory
Level 1 - Situated inside the processor


always SRAM
Therefore, small sizes are common compared to size of RAM
 Two

RAM that the CPU can access quickly
Commonly 512 kb
Level 2 - A separate RAM chip on the motherboard or in
expansion slot

Commonly 1024 kb (1 Mb)
Computer Systems 1 (2004 - 2005)
Storage


Place to keep important data
Kept on a storage medium
 Magnetic,

Optical, physical
Devices for Storage








Hard Disk Drive (HDD)
Floppy Disk Drive (FDD)
Zip Drive
Tape Drive
CD / DVD (ROM, RW, R)
Memory Chips (USB sticks, Flash memory)
Punched Cards
Barcodes
Computer Systems 1 (2004 - 2005)
More Hardware

Employing RAM and backing store
 RAM = Random Access Memory
 Sometimes called ‘main memory’
 Used for temporary storage


Contents are erased when power is off
Very fast access to data

Any byte can be accessed randomly
 Backing store
 Permanent place to keep important data
 Commonly a hard disk drive


Allows reading and writing of data
Could also be a ROM (Read Only Memory) chip

Once written to can only be read in future
Computer Systems 1 (2004 - 2005)
More Hardware

Peripheral Hardware Components
 Input
 Scanner, microphone, light pen
 Processing
 Graphics card, sound card
 Output
 Speakers, plotter, digital projector
 Memory
 Extra RAM, VRAM
 Permanent storage
 Zip drives, memory sticks, floppy disks
 Other Devices
 Modem, NIC, DVD-R, DV-Camera
Computer Systems 1 (2004 - 2005)
Computer Architecture

What’s in the box?
RAM
BIOS
Graphic Card
CPU
Sound Card
Ports
Power
Supply
Computer Systems 1 (2004 - 2005)
Hard Disk
Drive
Floppy
Disk Drive
CPU


Central Processing Unit
Carries out all calculations
 Logic


functions
Controls hardware and devices in the system
Speed measure in Megahertz (MHz)
 Oscillations
per second
 1 Hz = 1 oscillation every second
 The higher the MHz value, the faster the processor

On paper (theoretically)
Computer Systems 1 (2004 - 2005)
BIOS



Basic Input Output System (BIOS)
Provides the computer with basic functionality
Built-in software, no disk access


Common BIOS manufacturers



Usually a ROM chip on the motherboard
Award, Compaq, HP
Stored on a ROM chip
Settings are saved to a CMOS chip, powered by a
battery

CMOS = Complementary Metal Oxide Semiconductor
Computer Systems 1 (2004 - 2005)
Ports



Physical interface or socket to connect a device to a
computer
Interfaced to the computer’s motherboard
Two main types of port:

Serial



Parallel


Data is transferred in streams
One bit after the other
Data bits are transferred alongside each other in waves
(concurrently)
Common ports




USB (Universal Serial Bus)
Serial (9-pin) & (15-pin ‘game’ port)
Parallel (25-pin)
SCSI (Small Computer Systems Interface)
Computer Systems 1 (2004 - 2005)
Serial & Parallel Data Transmission

Serial Transmission
SENDER 01100010 11010001 11100001RECEIVER
Computer Systems 1 (2004 - 2005)
Serial & Parallel Data Transmission

Parallel Transmission
1
1
0
0
1
0
0
1
SENDER
Computer Systems 1 (2004 - 2005)
RECEIVER
Sound & Graphic Cards


Interface directly onto the motherboard
Graphics Card usually uses the AGP
(Accelerated Graphics Port)




Provides basic and / or advanced graphics capability
Often have graphics co-processors
On-board VRAM (Video RAM)
Sound card uses a PCI (Peripheral Component
Interconnect) slot


Allows computer to output sound to speakers and record
sounds.
Adds MIDI (Musical Instrument Digital Interface) capability
Computer Systems 1 (2004 - 2005)
Hard Disk Drives (HDD)




Magnetic storage medium
Uses rotating metal disks (platters)
Use read and write ‘heads’ to store and retrieve
information
Large storage capacity
Disk Platter
Read/Write
Heads
Spindle
Computer Systems 1 (2004 - 2005)
Floppy Disk Drive (FDD)




Magnetic storage medium
Uses rotating single, thin magnetic disk
Requires a drive to read the disk, which has
the read/write heads
Small storage capacity
 Typically


1.44 Mb (High Density 3.5”)
Portable
Cheap
Computer Systems 1 (2004 - 2005)
Magnetic Disks

How the disk works:
Cluster
Sector
Computer Systems 1 (2004 - 2005)
Track
Types of Computer

Personal Computer (PC)
 Single-user
computer
 Standalone

Supercomputer
 Very
fast computer which can carries out huge
amounts of instructions per second

Mainframe
 A powerful
computer which can be used by lots of
users at the same time
Computer Systems 1 (2004 - 2005)
COMPUTER EXPLAINED
Computer Systems 1 (2004 - 2005)
CS1: Week 2

What you know now:
 More

about Input, Process, Output
Features and functions
 How
RAM and backing store integrate into the
computer system
 Computer architecture


Ports
Sound and graphics
 Backing


store
Methods
Magnetic storage
Computer Systems 1 (2004 - 2005)