[email protected]/e.r.edwards/k.k.chai fc hardware & software week 2 motherboards and...

[email protected]/E.R.Edwards/K.K.Chai

FC Hardware & Software Week 2Motherboards and Processors

A primer – bits and bytes

The hardware at the core of the computer

A history lessonPerspectives on

modern systemshttp://www.raspberrypi.org/faqs


FC Hardware & Software Week 2Introduction or refresher

Bits and BytesA bit (symbol “b”) is a single on/off switch, 2 states (value 0 or 1)A byte (“B”) is a group of 8 bits – one letter/character (range

0..255)Why 8 bits? Why not 7 bits for a range of 0..127?Bytes are the basis of computer data storage

http://www.twotechies.net/wp-content/uploads/2010/03/Bit-byte-word11.jpg



Network speed – often shown in shorthand“Fast Ethernet cards allow 100 Mbps data transfer…” Is this saying 100 megabits per second or 100 megabytes per

second? It’s a difference of a factor of eight, so you had better be sure!

The information transfer rate is loosely known as “bandwidth”Wi-fi wireless networking is often quoted as having a “speed” or

“bandwidth” of 54Mbps (IEEE 802.11g standard)This gives an absolute maximum of about 6 megabytes per second



Sizes – Memory (but usually not storage…)Kilo – one thousand (or 1024, closest binary number)Mega – one million (or 1024*1024 in binary)Giga – one billion (1024*1024*1024)So one Megabyte (1MB) of memory has 1,048,576 bytesBut one Megabit (1Mb) is only 131,072 bytes (=128KB)

Speeds – “xyz per second” is common in computingThings “per second” = Hz = Hertz (after George Hertz, scientist)

One megahertz is 1MHz, one million times per secondOne gigahertz is 1GHz, one billion times per second


FC Hardware & Software Week 2Introduction to Motherboards

A motherboard is also known as a mainboard or a “mobo” in web slang

Motherboard designs have changed over the years to keep up with new developmentsUpdates to the system bus architecture (structure)Changes in CPU (Central Processing Unit) speedIntegration of system devices

Sound, LAN, Video, USB, IDE/PATA, SATA, FireWire…Now appearing: Bluetooth, WiFi, USB3, eSATA


FC Hardware & Software Week 2The PC/AT

Original IBM PC/AT (1984)6MHz 80286 chip, rapidly upgraded to 8MHz16-bit CPU (modern ones are 64-bit)24-bit address bus (max of 16MB RAM)Current computers are millions of times faster

and have thousands of times more memory


FC Hardware & Software Week 2

A typical server-style “tower” case showing the motherboard

Lots of spaces for other devices

Examples:Blu-Ray/DVD drivesSSDsControl panels


FC Hardware & Software Week 2Fast PC/AT motherboards

Later (about 1987) the i386 became available, with a 32-bit data bus

It could run faster than the normal type of RAM!This lead to a problematic choice

Either run the (expensive) CPU as slowly as the RAMOr decouple the RAM and CPU clocks so they are no

longer synchronised in a simple 1:1 relationship (hard)


FC Hardware & Software Week 2The Chipset – Northbridge, Southbridge

Chipset uses two physicals chips: Northbridge and Southbridge

NorthbridgeMemory controller hub – buffers link from CPU to RAMCore chipset that handles the communication between

CPU, RAM, PCI-E and South BridgeSouthbridge

Chipset that handles the communication between North Bridge, PCI and other I/O devices such as USB, Firewire and Gigabit Ethernet


FC Hardware & Software Week 2Diagram

The two “glue” chips have very different characteristics

The northbridge runs very fast (CPU speed)

The southbridge doesn’t run so fast as it handles relatively slow connections


FC Hardware & Software Week 2Modern systems - common figures

The ISA expansion bus [8.33MHz] vanished years ago, good for 16Mbps

The PCI expansion bus ran at 66MHz for a total of about 1Gbps (one gigabit per second)

The basic PCI-e expansion bus runs at 5Gbps per lane with up to 32 lanes per device, maximum total of 160Gbps

PCI-e is 10,000 times faster than the old ISA bus


FC Hardware & Software Week 2Processor Characteristics

Socket type – how the CPU plugs into the motherboard Clock speed Front Side Bus (FSB) - Connection speed between the

processor and the chipset Cache sizes, usually 2 or 3 levels of caching Number of cores - multi-core helps to ensure that the

system remains more responsive even when the processor load is high


FC Hardware & Software Week 2Multi-core processors

Many CPU types are available as multi-core processors


FC Hardware & Software Week 2Summary

We have discussed the basics of the motherboardAnd a little of the history of changesWe have introduced many terms relating to

processorsAnd discussed some modern developments

Key ideas – continual change, speed increases

[email protected]/e.r.edwards/k.k.chai fc hardware & software week 2 motherboards and...

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