INFO1119: Operating
System and Hardware
Module 2: Computer Components
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Hardware – Part 2
INFO1119 (Fall 2012)
Power Supply Connectors
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Some connectors are general purpose,
while others have a specialized function
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2
Power Supply Connectors
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3
Modern-day Motherboard
1) CPU Socket
2) Chipset
3) RAM Slots
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4
Busses
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Serial:
– Simpler
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One bit at a time, so slower?
Parallel:
– More difficult
– You need to wait until ALL bits are
stabilized until you can read
– All bits transmitted at once, so faster?
INFO1119 (Fall 2012)
What’s faster?
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What’s the fastest bus now?
– AGP? Parallel bus
– Hyperbus? Parallel bus
– PCI Express? Serial
– Intel QuickPath Interconnect (QPI)
INFO1119 (Fall 2012)
The Bus
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Collection of wires linking one part of the
computer to another
– On the motherboard, these are the tiny copper wires
(traces)
– Are inside the chips (CPU), too
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Used to move data, instructions, and electrical
current between components.
The Motherboard has multiple data buses, with
different speeds and sizes.
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8
Bus Lines
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9
Data Bus
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The Data Bus is the part of the bus used for data transfer
Each trace on the data bus represents one binary digit
Often in multiples of 8 (16, 32, 64, etc. bits wide)
Speeds vary, measured in MHz
Main bus that communicates with the CPU, memory, often called the
Front Side Bus (FSB)
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10
Overclocking
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A faster clock = A faster system
However CPUs and Chipsets can only go so fast
– Heat damage
– Reliability
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Systems are designed to default to safe clock rates for
the CPU
– Warranties can be voided if user adjusted speeds are used
– Sometimes a setting in the BIOS
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11
Expansion Slots
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Expansion Card Inserted into a Slot
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Some fancy terms
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Band width
– (bit rate)
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Hz (MHz, GHz)
Bus width
Latency
Parallel, serial
Analog, digital
INFO1119 (Fall 2012)
Some fancy terms
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Shared bus
“Local” bus
INFO1119 (Fall 2012)
Shared bus
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This means that all the devices are
connected together
– ISA, PCI, SCSI, etc. are like this
CPU (or whatever)
Bus
Device
Device
Device
INFO1119 (Fall 2012)
Device
Shared bus
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In a shared bus, the devices must
have an “address” or some other way
of differentiating each other
Only one device can “talk” at any one
time.
Can have “Bus Masters” – CPU or
other device controls the bus
INFO1119 (Fall 2012)
Shared bus
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To help with “talking at once” or to
have different speed busses, can have
“Bridges”
CPU (or whatever)
Bus
PCI Bridge
Device
Device
PCI Bridge
Device
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PCI Bridge
Device
Device
Point to point
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This is the “direct” approach
Each device is directly connected to
only one other device
Can be one device to another or using
a “switch”
INFO1119 (Fall 2012)
Point to point
CPU (or whatever)
CPU (or whatever)
Device
Device
Switch
Device
This device can “talk” to any
other through the switch
INFO1119 (Fall 2012)
Device
At the Back
INFO1119 (Fall 2012)
Common connections
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USB ports (2-6)
Digital Video Interface (DVI)
VGA
PS/2 ports mouse & keyboard
Sound ports (speakers, mike, line)
Network port RJ45
Serial (DB9) and Parallel (DB25) rarer
INFO1119 (Fall 2012)
Serial
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Built to the RS-232 standard
Often connected mice, modem, etc.
9 pins
Larger style was 25 pins (most not
used)
Up to 115,200 bits / second
– About 10Mbytes / second (in theory)
INFO1119 (Fall 2012)
VGA
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15 pin analog connection
Red, Green, Blue
Horizontal & Vertical sync
Surprisingly high data rate
INFO1119 (Fall 2012)
DVI (Digital Video Interface)
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Used digital (instead of analog) connection
“Single” or “Dual” link:
– Single (60Hz): 1920 x 1200 resolution
– Dual (60 Hz): 2560 x 1600 resolution
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Cables up to 5m (16 feet)!
INFO1119 (Fall 2012)
Display Port
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Replacement for DVI
10.8Gbits/sec (that’s fast)
– 1920 × 1080 × 60 Hz × 24bpp
– to 3840 × 2160 × 60 Hz x 30 bpp
INFO1119 (Fall 2012)
Internal
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Some legacy technology
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ISA
EISA, VESA, MicroChannel
All replaced by PCI technology
INFO1119 (Fall 2012)
“Local” busses
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The “local” bus is (basically) directly
connected to the CPU
In theory, is the fastest connection to
the CPU
AGP is an example
INFO1119 (Fall 2012)
AGP (Accelerated Graphics Port)
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32 bits
Up to 2133 Mbytes/sec
Almost a direct connection to CPU
AGP 1.0 (1x - 266 MB, 2x - 533 MB/s)
AGP 2.0 (4x – 1GB/s)
AGP 3.0 (8x – 2133MB/s)
INFO1119 (Fall 2012)
AGP (Accelerated Graphics Port)
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AGP 2x (3.3V)
– Data on rising and falling edges
– doubling data transfer
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AGP 4x (1.5V)
– Four transfers per clock cycle
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AGP 8x (0.8V)
– Eight transfers per clock cycle
INFO1119 (Fall 2012)
AGP
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Slots are “keyed”
so that you can’t
place the wrong
card in the slot
From: http://en.wikipedia.org/wiki/Image:AGP_keys_diagram.png
INFO1119 (Fall 2012)
From: http://en.wikipedia.org/wiki/Image:AGP_slot.jpg
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Resources
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IRQ (interrupt requests)
– 15 of them with ISA (PC still has these)
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DMA (Direct Memory Access)
I/O ports (not like network ports)
INFO1119 (Fall 2012)
PCI
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Most common today
Two major types:
– PCI (parallel)
– PCI Express (serial)
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Also broken into multiple variants,
based on speed, bus size, etc.
INFO1119 (Fall 2012)
PCI
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Initial: 33 MHz, 32 Bits
– (Slower than VESA Local bus)
– Approx 132 Mbytes / second
– 33 MHz (1 transfer / cycle) * 8 Bytes
= 132 Mbytes / second
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5 Volts, then 3.3 Volts (ISA is 5V)
32 bit address space (4 Gbytes)
INFO1119 (Fall 2012)
PCI - improvements
Bus size
32
Bus Speed
33 MHz
Approx transfer
132 Mbytes/s
32
66 MHz
264 Mbytes/s
64
33 MHz
528 Mbytes/s
64
66 MHz
1 Gbyte/s
INFO1119 (Fall 2012)
PCI
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Another “trick” was the way data was
transferred
– Sort of a “burst mode”
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Address sent once, then three packets
of data is sent
– So only ¾ of time is really for data
Address
Data
Data
Once “cycle”
INFO1119 (Fall 2012)
Data
PCI – reflected wave
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Uses Reflected-wave switching
Unlike ISA (and SCSI), which have
termination
Bus is not “terminated,” so wave is
reflected back, doubling the amplitude
(if done correctly)
INFO1119 (Fall 2012)
PCI Express
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From Intel
A.K.A.: PCIe or PCI-E
– NOTE: Not PCI-X (which is the old PCI)
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Up to 8 Gbytes / second (both ways)
– 4 Gbytes one way
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Serial
INFO1119 (Fall 2012)
PCI Express
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Based on “lanes”
– 250 MHz
– Each lane is a separate serial channel
– 1 lane = standard PCI
– 4 lanes = fastest PCI (PCI-X)
– 8 lanes = fastest AGP
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Up to 32 lanes
– Designated as 1x, 2x, 4x, 8x, 16x
INFO1119 (Fall 2012)
PCI Express
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“Full duplex”
– Data goes both ways
– Vs. Send, then receive modes/states
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Slots are different form factors
– NOTE: a “4x” physical connection could
mean it’s a 1x card using a 4x slot.
INFO1119 (Fall 2012)
http://en.wikipedia.org/wiki/Image:PCIExpress.jpg
INFO1119 (Fall 2012)
QPI (QuickPath Interconnect)
INFO1119 (Fall 2012)
QPI (QuickPath Interconnect)
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Intel QuickPath Interconnect
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Point-to-point processor interconnect
developed by Intel which replaces the Front
Side Bus (FSB) in Xeon, Itanium, and
certain desktop platforms
Designed to compete with HyperTransport
First delivered in November 2008 on the
Intel Core i7-9xx desktop processors and
X58 chipset
INFO1119 (Fall 2012)
USB (Universal Serial Bus)
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Serial (1 bit)
USB 2.0 up to 480 Mbps
USB 3.0 up to 5 Gbps
Up to 127 devices per host
Hot plugable
Six types of plugs
INFO1119 (Fall 2012)
Web Links
http://www.pcisig.com/home
http://computer.howstuffworks.com/pci.htm
http://www.techfest.com/hardware/bus/pci.htm
http://en.wikipedia.org/wiki/Peripheral_Component_Interconnect
http://www.pcisig.com/specifications/pciexpress/
http://en.wikipedia.org/wiki/PCI_Express
http://arstechnica.com/articles/paedia/hardware/pcie.ars/1
http://www.dell.com/content/topics/global.aspx/vectors/en/2004_pcie
xpress?c=us&l=en&s=corp
http://en.wikipedia.org/wiki/Intel_QuickPath_Interconnect
http://www.intel.com/content/www/us/en/io/quickpathtechnology/quickpath-technology-general.html
INFO1119 (Fall 2012)