Learn
about your computer
·
Data
Representation in Computer Systems (Binary System)
·
Expansion
Slots and Adaptor Cards
Computer
Components
-
System Unit: The
entire computer unit containing PC components
o
Also called chassis
o
Types: Desktop /
Tower models / etc.
o
Includes:
Motherboard, memory modules, processor, modem card, sound card, video card,
Power supply, etc.
o
In case of all-in-one computers the monitor is
included in the SU
-
Motherboard: The
main circuit board in the system unit
o
Also called system board
o
Includes many
chips (Small integrated circuit - IC)
§
These chips come
in all shapes (packages) and sizes:
§
One important
type of chip is the processor(CPU)
-
Central
Processing Unit (CPU):
o
Carries the basic
instructions in a computer
o
Components of
CPU:
§
Control Unit and
Arithmetic/Logic Unit
§
Registers
o
Control Unit:
Interprets each instruction issued by the program and decides what to do with
the instruction –
o
Called the machine cycle - four operations:
§
Fetching: Getting
instructions/data from the memory
§
Decoding:
Translating instructions into the machine language
§
Executing:
Running commands (once in machine language)
§
Storing: Putting
the data back into the memory
o
Arithmetic/Logic
Unit (
§
Arithmetic: + / - / ´ / ¸
§
Comparison:
Compares the data (if A > B Then C = 1)
§
Logic: AND / OR / NOT
·
IF A = 1 then NOT(A) = 0 (huh?)
·
IF A = 1 & B
= 0 then [(A) AND (B) = ?] (Quien
sabe!)
o
Registers: These
devices temporarily hold data and instructions when
§
the data is
FETCHED
§
the instruction is being DECODED (by whom? CU)
§
the data is being processed (by whom?
§
the final result
is being stored in the memory
Comparing processors:
-
Clock rate (Hz) -
How fast the processor executes the instructions
o
Does not impact
peripherals
o
Manufacturing and
package type affects the clock rate
§
the smaller the
better
-
MIPS (Millions of
instructions per second)
-
Architecture (superscalar)
o
Executing the
next instruction before the previous inst. is done!
§
Pipelining
(executing four instructions at a time)
§
Parallel
processing (having multiple processors/ sharing)
-
Additional
processing capacities
o
What is (10 / 3)? – called Integer
math!
o
Floating-point
co-processors (used for calculations!)
o
Processor types:
Integrated CPU / Motorola / PowerPC, etc.
Processor types and
the date they were introduced
|
Processor |
Year |
Speed |
|
Itanium 2 |
2002 |
1.3–1.5 GHZ |
|
Xeon |
2001 |
1.4–3.06 GHZ |
|
Itanium |
2001 |
733–800 MHZ |
|
Pentium 4 |
2000 |
1.4–3.2 GHZ |
|
Pentium III
Xeon |
1999 |
500–900 MHZ |
|
Pentium III |
1999 |
400 MHZ–1.4
GHZ |
|
Celeron |
1998 |
266 MHZ–2.6 GHZ |
|
Operon |
2003 |
2–2.4 GHZ |
|
Athlon MP |
2002 |
1.53–2.25 GHZ |
|
Athlon XP |
2001 |
1.33–2.26 GHZ |
|
Athlon |
1999 |
500 MHZ–1.4
GHZ |
Memory:
-
Temporary storage
of information
o
Information types
(3):
§
Operating system,
application programs, data being processed
o
Memory devices
are chips (come in different packaging)
o
A memory location
has an associated address
o
Memory size (2x
= 2,4, 8, 64, ..., 1024….1020 )
o
Memory access
time (nsec = 10-9, 1 billionth of a sec. )
§
How small is
that? mmm
§
In Hz or sec.
(133 MHz = 7.5 nanosec.)
If A = 2 and B = 3 then where
is A + B?
|
Address (1
KB Memory) |
Content (8
bits = 1 byte) |
|
|
1 |
00001 |
A (2) |
|
2 |
00010 |
B (3) |
|
3 |
00011 |
A + B (5) |
|
……. |
…… |
……. |
|
1024 (210) |
1000000000 |
|
Basic categories of memory:
§
Volatile: Loses
its content power is removed
§
Non-volatile
(NVM)
o
Memory types:
§
RAM
(Random Access Memory) – 128, 512 MB depending on application; faster
processors need more RAM
·
RAM is Volatile
·
DRAM (Dynamic
RAM): Small, Leak-out,
o
SDRAM (Synchronous)
o
DDR SDRAM (Synch.
& read/write per clk cycle)
o
Direct (Rambus DRAM) Use pipelining, popular
·
SRAM (Static
RAM): Faster, more reliable & expensive
·
MRAM (Magnetoresistive RAM): Stores data using magnetic charges
instead of electrical charges, less power, does not have memory leakage – Way
in the future!
·
Typically RAMS
reside in a Memory Modules sitting in
Memory Slot
o
SIMM (single
inline memory module - SDRAM)
o
DIMM (Dual inline
memory module - SDRAM)
o
RIMM (Rambus inline memory module - RDRAM)
§
Cache
·
Two types: memory
or disk cache
·
Memory cache
types
o
Help the
processor to operate faster by storing the most frequently used data
o
Three types:
§
L1: Level 1
(internal to the processor, small KB)
§
L2:
(External/Internal, about 64 KB)
§
L3: (Separate
from the processor)
§
ROM:
Read-only-Memory
·
stores the type
of data that can only be read
o
BIOS =
Instructions to load the OS & other files to start the system
o
Firmware =
Contains permanent instructions (BIOS)
o
Types: PROM
(programmable), EEPROM (Electrically Erasable)
§
CMOS
(Complementary metal-oxide semiconductor memory)
·
Works on battery
·
High-speed and
low power
·
Its information
can be changed (time, day, etc.)
·
Contains
information about HW devices in the computer
§
Flash (Special
kind of RAM)
·
Non-volatile memory
·
Flash BIOS
(startup information)
·
Stores data and
programs
·
Calculators,
toys, etc.
So how fast are memory devices? What are their sizes?
Data Representation – the big idea:
-
-
So what is the
machine language?
o
Representing
everything in Binary System
§
A number system
that only has two values: “1”, “0”
·
1=ON State =
Signal present
·
0=OFF State = No
Signal
§
These states are
called BITS (short for Binary Digit)
§
8 bits constitute
a BYTE
§
16 bits make a WORD
o
All numbers can
be represented in the binary system:
-
We can represent
0-1 with a single BIT: 0,1
-
We can represent
0-3 with
-
We can represent
0-7 with THREE BITS: 000, 001, …, 111 (23
- 1)
-
We can represent
0-255 with 8 BITS (or a BYTE):
o
00000000,
00000001, …., 11111111 (28 -
1)
-
Different CODING system can be used to represent
characters/symbols in a computer: 
-
Characters in
other languages can be represented by UNICODE (16-bit representation)
Expansion Slots and Adaptor Cards:
-
A Slot: A SOCKET where a circuit board can be
installed
-
Adaptor Card (or
Expansion Card) resides in the expansion slot
-
Expansion cards
are used to connect the system unit to Peripherals (printers, scanners, modems,
etc.)
-
Some expansion
cards provide additional functionalities (video card, sound card, modem card,
etc.)
-
Some Expansion
cards come with Plug and Play
support:
o
The computer
recognizes these cards and configures itself
-
Another example
of expansion card is Flash Memory Card
o
Examples of Flash
Cards: PC Cards, Fax/Modem Card, Memory Cards, etc.
o
Reside in PC Card
Slot
o
thin looking
cards – used in notebook computers
o
Capable of hot
plugging
Ports:
-
Interface
external devices to the computer
-
Come in all kinds
of shapes and sizes
-
-
Port
characteristics include: Number of pins, Type, parallel or serial
-
Different ports
can be connected using gender connectors
-
Examples:
o
Serial Ports:
§
Data is transferred
one bit at a time
§
Slow data
transfer: Keyboard, Mouse, Modems?
§
Examples: COM
port
o
Parallel Ports:
§
Data is
transferred ONE BUNCH at a time (typically a byte)
§
Faster data
transfer: Printers
§
Examples: PAR
o
USB Ports:
§
Fast transfer of
data: 480 Mbits per second!
·
Different version
USB 2.0
§
Many interesting
features:
·
Providing POWER
(5V)
·
Connecting
several devices on a single line
·
Interfacing with
cables as long as 5-30 meter
·
Disabling
capacity
·
Can be connected
to multiple devices:
·
Scanners,
Printers, External Drivers (as many as 127!)
·
Devices can be
Daisy chained together or connected by a hub
·
Supports Hot Plugging and Plug and Plug
o
Special Purpose
Ports:
§
FireWire (IEEE 1394 Port)
·
Similar to USB
·
Used for
scanners, DVDs, etc.
·
Can connect up to
63 devices together
§
·
Musical
Instrument Digital Interface
·
Used for musical
instruments such as keyboards
·
Typically all
sound cards have
§
·
Small Computer
System Interface
·
A high-speed
parallel port connecting up to 15 devices
·
Used for
interfacing with some printers and drivers
§
IrDA
·
Infrared Data
Association)
·
Uses Infrared
Light Wave (wireless)
·
Point-to-point
connection (need alignment)
·
Alternative to IrDA but uses radio waves
·
Wireless port
·
Converters are
required to changing from USB/Serial to Bluetooth
Buses:
-
Connecting
internal devices together in the system
o
Transferring BITS
between one module to another
-
Bus Design - Why
are they different?
-
Bus
characteristics: Type, Size, and Speed
o
BUS SIZE: How
many BITS at a time? – (Bus Width)
§
32-bit bus,
64-bit bus – most personal computers
§
Larger bus width
-> more data can be transferred at a time
§
Kind of like the
number of lanes in a highway
o
BUS SPEED: Clock
rate, how fast can you transfer the data
§
100, 133, 400,
800 MHz.
o
BUS TYPE: System
bus and expansion bus
§
System Bus: Part
of the motherboard, Processor -> Memory – very fast
§
Expansion Bus:
can be on or off the motherboard
·
Processor ->
Peripherals (such as sound cards, hard disks, etc.) – Slower kind of bus
·
Different types
of expansion busses: PCI, AGP, USB, PC Card, 1394 Bus
-
ISA Bus: Industry
Standard Architecture
o
Very slow – used
for low speed devices
§
Mouse, keyboard,
sound card
-
PCI Bus:
Peripheral Component Interconnect
o
Resides on the
motherboard
o
High-speed bus (4
times faster than ISA)
o
Used for hard
disks, video cards(16 or 32 bit)
-
AGP Bus:
o
Dedicated
interface between memory and video card
o
Used for AGP
video cards
-
USB and 1394 bus:
o
Connects multiple
devices to each other and then to the USB or 1394
Please email
me if you have any comments or suggestions.