1. Hardware Fundamentals
Week 4 - Lesson 1

2. Learning Outcomes Define the term bus
Explain the different bus characteristics
Calculate bus throughput in bps and MB/s
Explain BSB, and FSB
Explain Double Data Rate, Quad Data Rate, and HyperTransport
Define the term expansion bus
Explain the different expansion bus types
Compare VESA versus PCI
Compare PCI versus AGP
Describe different ports (Serial, Parallel, USB, FireWire, IDE, EIDE, SCSI and SATA)
Discuss RAID, Interrupt, and PnP

3. Bus
A collection of wires/tracks that transfer data or power between computer components, typically controlled by a device driver software
internal
external
computer to computer
Every component in a computer connects to a bus - even components such as the VDU or printer connect to a bus in some way

4. Bus characteristics Clock speed Width Bus performance Control signals
Logical and physical connection
Internal and external
Serial and parallel

5. Clock speed number of times a bit is sent along the bus
measures how quickly bits move along a bus
Clock speed is simply the number of times that a bit (or a group of bits) is sent along the bus. In practical terms, it is a measure of how quickly each bit moves along a bus.

6. Width
number of data bits that can be sent along the bus at once (i.e. 8, 16, 32, 64bits)
The bus width is the number of data bits that can be sent along the bus at once (but not control bits). If 8 bits can be sent along the bus at the same time, then the bus width is 8 bits. A bus whose width is 16 bits can carry 16 bits at the same time. Typical values are 8, 16, 32 and 64 bits.

7. Bus performance Bus throughput Bus throughput calculation
number of bytes of data that can be transferred via the bus in one second
Bus throughput calculation
bus clock speed * bus width = bus throughput
Bus throughput is the number of bytes of data that can be transferred via the bus in one second. Throughput is usually given in megabits per second (Mb/s). Bus throughput can be calculated using the formula:
[throughput] = [bus width] × [clock speed]
For example, if the bus width is 16 bits and the clock speed is 8MHz, then the throughput is
throughput = (16 bits) × (8MHz) = 128Mb/s

8. Control signals which component the data is for
where blocks of data start and end
any other information related to the data being transferred
A bus does not just carry data. It also carries control signals that tell components what to do with the data. Control signals provide information such as:
Which component the data is for.
Where blocks of data start and end.
And any other information related to the data being transmitted.

9. Logical and physical connection
Logical connection
One-to-many (several devices sharing the same set of wires) or point-to-point connection
Physical connection
Each bus defines its set of connectors to physically plug devices, cards or cables together

10. Internal and external
Internal bus connects all the internal components of a computer to the motherboard
also referred to as a local / Motherboard bus, because they are intended to connect to local devices
External bus connects external peripherals to the motherboard

11. Serial and parallel Serial buses Parallel buses
carry data in bit-serial form
Parallel buses
carry data words striped across multiple wires
problem: crosstalk across multiple wires

12. BSB and FSB

13. BSB
Back Side Bus
The bus that connects the processor to the different levels of cache
Found on the processor chip

14. FSB
Front Side Bus
The bus that connects the processor to the different hardware components found on the motherboard

16. Expansion bus

17. Expansion bus
A collection of wires and protocols that allows the expansion of a computer by inserting printed circuit boards (expansion boards)

18. Expansion bus types
PC Bus
ISA
MCA
EISA
VESA
PCI
AGP
PCI Express

19. PC Bus 1981 Developed for the original IBM PC
Used on 8088 and 8086 motherboards
width: 8b
speed: 4.77MHz
throughput:
38.16Mbps
4.77MB/s

20. ISA Industry Standard Architecture 1984 twice the width of PC bus
PC bus is backwards compatible with ISA
local bus for the Intel 386 CPU
Still today, some motherboards that support Pentium 4 processors have an ISA expansion bus
Used on 286, 386, 486, Pentium and some Pentium 4 motherboards
width: 16b
speed: 8MHz
throughput:
128Mbps
16MB/s

21. MCA Micro-Channel Architecture 1987
IBM introduced MCA to replace ISA, but it never became popular and was soon discontinued
Twice the width of ISA but not compatible with the ISA or PC bus
Used on 386 and 486 motherboards
width: 32b
speed: 10MHz or 16MHz
throughput:
320Mbps - 512Mbps
40MB/s - 64MB/s

22. EISA Extended Industry Standard Architecture 1988
Used on 486 motherboards
width: 32b
speed: 8.33MHz
throughput:
____266.56Mb/s______
________33.32__ MB/s

23. VESA Video Electronics Standards Association aka VESA Local Bus (VLB)
1992
Twice the width of ISA
ISA and PC bus are backwards compatible with VESA
Used on 486 motherboards
width: 32b
speed: 66MHz (maximum)
throughput:
___2112_______ Mbps
___264_______ MB/s

24. PCI 1.0 Peripheral Components Interconnect 1992 (1995 with Windows 95)
Supports Plug and Play (PnP)
Used on Pentium motherboards
Transfers data only on one edge of the clock signal
width: 32b
speed: 33MHz (maximum)
throughput:
___1056_______ Mbps
___132____ MB/s

25. PCI 2.0 PCI 1.0 is backwards compatible faster and wider than PCI 1.0
width: 64b
speed: 66MHz (maximum)
throughput:
_____4224_____ Mbps
_____528_____ MB/s

26. VESA versus PCI

27. AGP (1 of 2) Accelerated Graphics Port 1997
Intel bus specification providing faster memory access than PCI
Greatly speeds Virtual Reality (VR) and 3D (Dimensional) rendering and texture mapping than PCI
Developed only for video cards
Used on Pentium II motherboards
In its lowest speed mode the throughput is twice as fast as PCI, plus the benefits of not having to share the bandwidth
Transfers data on two edges of the clock signal

28. AGP (2 of 2) width: 32b speed: 66MHz throughput:
2,112Mbps
264MB/s
Available in four speeds (four specifications), the clock is doubled each time:
x1 264MB/s
x2 528MB/s
x4 _1,056____ MB/s
x8 __2,112___ MB/s

29. PCI versus AGP Pipelined requests PCI AGP Non-pipelined requests
Address/data multiplexed
Address/data de-multiplexed
Peak throughput in 32b is 132MB/s
Peak throughput in 32b is 264MB/s
Multi-target, multi-master
Single-target, single-master
Link to entire system
Memory read/write only, no other input/output operations
No priority queues
High/low priority queues

31. PCI Express (1 of 2) Peripheral Components Interconnect Express (PCIe)
2004
Initially named 3GIO (Third Generation Input/Output)
high speed connection
Used on Pentium 4 motherboards
Uses a packetised protocol (8bit/10bit encoding)
Starting freqency 2.5GHZ, go up to 10 GHZ
Hot plug and hot swappable capability
Power management capabilities

32. PCI Express (2 of 2) Uses point-to-point connections known as lanes
Each lane on the bus is capable of transferring data in full duplex over two pair of differentially signaled wires called a .
Each lane allows 250 MBps throughput in each direction. Design allows for scalling from 1 to 2, 4, 8, 16 and 32 lane (x16 bus totals 32 lanes)
Four bus types: x1, x4, x8, x16
x1 bus throughput is 250MB/s * 2 = 500MB/s
x4 bus throughput is 1GB/s * 2 = 2GB/s
x8 bus throughput is 2GB/s * 2 = 4GB/s
x16 bus throughput is 4GB/s * 2 = 8GB/s

33. PCI Express 2.0 Released 15 January 2007
Doubles the bus standard bandwidth of previous version
i.e. x16 bus throughput at 8GB/s * 2 = 16GB/s
is backwards compatible
Features improvements to the point-to-point data transfer protocol and its software architecture
Intel is expected to release its first chipsets supporting PCIe 2.0 in the second quarter of 2007 with its ‘Bearlake’ family
AMD starts supporting PCIe 2.0 from its RD700 chipset series
NVIDIA has revealed that the MCP72 will be their first PCIe 2.0 equipped chipset

34. PCI

36. Bus timeline

37. Different Input / Output / Storage ports

38. Serial 1 copper wire slower 1 bit at a time Serial protocol
faster, fewer electrical connections and inherently has no timing skew or crosstalk

39. Parallel 8 copper wires faster 8 bits at a time
Slower in comparison to Serial packetized protocol

40. USB Universal Serial Bus
127 devices, daisy chained bus designed to eliminate cable clutter
hub is very important unit, each device can hold another hub for other devices (PC to PC)
4 wire cable: 2 wires supply power for devices, other 2 wires used to send data and commands
PnP and hot swappable
internal and external
In expensive cable which can reach up to 5 meters long (USB hubs can be daisy chained up to 25m)
USB 1.0 = 1.5Mbps (keyboard mouse), 12Mbps (printer, monitors , etc)
USB 2.0 = 480Mbps
USB 1.0 is backwards compatible with USB 2.0

41. Hot swapping and hot plugging
are terms used to separately describe the functions of replacing system components without shutting down the system. Hot swapping describes replacing components without significant interruption to the system, while hot plugging describes the addition of components that would expand the system without significant interruption to the operation of the system.[1]
For hot swapping once the appropriate software is installed on the computer, a user can plug and unplug the component without rebooting. A well-known example of this functionality is the Universal Serial Bus (USB) that allows users to add or remove peripheral components such as a mouse, keyboard, or printer.

42. FireWire
i.Link or IEEE 1394
different versions of FireWire (FireWire 400, FireWire 800)
up to 800Mbps
4.5m cable length
16 cables can be daisy chained up to 72 meters long
serial
63 devices
hot plug
internal and external
4-pin (digital camera) and 6-pin FireWire (PC)
power provided

43. IDE Intelligent / Integrated Device Electronics
Parallel ATA (Advanced Technology Attachment)
cheap devices and controllers
maximum of 2 drives
only supports hard drives maximum of 528MB capacity
easy to install and setup
slow
internal drives only
no power provided

44. EIDE Enhanced IDE Parallel ATA used on Pentiums
cheap drives and controllers
maximum of 2 drives for each of the 2 controllers (4 drives)
300GB storage capacities
HDD, CD, DVD, Zip drives
easy to install and setup
40 cable pins ( wires)
internal drives only
Ultra/ATA 133 (133MB/s)
cable 40cm long
bulky, inflexible, fragile and too short
not hot swappable
4 pin power connector
no power provided

46. EIDE drives
Configure jumpers on EIDE devices (1 hard disk drive and 1 CD-ROM drive)

47. SATA Serial ATA (internal) up to 1 meter cable length
eSATA (external) up to 2 meter cable length
7 cable pins (4-7 wires)
one serial drive per port
point-to-point connection
connectors are 8mm wide
cable thinner and more flexible, provides better airflow
connectors are more compact
hot-plug capability
1.5Gbps (150MB/s *8 = 1200 = 1.2Gbps + overheads = 1.5Gbps), 3Gbps (300MB/s), 6Gbps (600MB/s)
15-pin power connector
supports 8B/10B encoding
no power provided

48. SATA- IDE

49. SCSI Small Computer Systems Interface use on servers and non-Intel PC
expensive drives and controllers
supports 7-15 devices
all types of drives (i.e. hard disks, scanners)
hard to install and setup
fast for servers
external drives
up to 12 meter cable length (Ultra-320 SCSI = 320MB/s)
must use terminator
no power provided

50. SCSI

51. A SCSI Chain
The advantage of SCSI is that several peripherals can be daisy chained to one host adapter, using only one slot in the bus.

52. RAID Redundant Array of Independent / Inexpensive Disks
Multiple disks accessed in parallel will give greater throughput than a single disk
Redundant data on multiple disks provides fault tolerance
used in servers or main frames (although can be commonly setup on desktop PCs)
provides higher reliability and/or faster access/performance depending on RAID type
drives in a RAID system are hot swappable for servers and mainframes
RAID appears to the OS as one single logical hard disk
6 standards (RAID 0 to RAID 5) (RAID 1 = mirroring)
although can get different combinations of RAID (RAID 10, RAID 53)

53. RAID

54. Interrupt / Plug’n’Play

55. Interrupt A signal informing a program than an event has occurred
IRQ (Interrupt Request Queue)
each device or expansion card has its own unique IRQ, to prevent hardware conflict

56. Interrupt characteristics
Interrupts can come from a variety of sources
The PC supports 256 (0-255) types of interrupts: 15 are hardware interrupts and 241 are software interrupts

57. 5 Interrupt classifications
Highest to lowest
Reset button / power button
Internal CPU error (overflow)
NMI (Non-Maskable Interrupt) - parity error or power fail detect
Software INT instruction - interrupt signals initiated by programs
External hardware interrupts - IRQ, alt-ctrl-del, keystroke, printer call

58. Plug and Play
A plug and play system is one that can automatically find and configure all of the hardware devices (also called components) in a system.

59. Before Plug and Play
Before plug and play, any device had to be configured manually. This meant:
Finding the resources that were available;
Finding out what resources are supported by the device;
Manually configuring the device to use these resources. This meant fiddling with small switches, called jumpers, on the card itself.
This made adding a new device difficult.

60. With Plug and Play
A plug and play configures these resources automatically. This means that you can simply add a device, and the operating system will handle all of the configuration for you.
To use plug and play:
Your devices must be able to work with plug and play;
Your computer must be able to work with plug and play. Your motherboard and BIOS will have to support plug and play, as they are used in the plug and play process
Your operating system, such as Windows 95 or Windows 98, must be able to work with plug and play. They will control the plug and play process.

61. Plug and Play
PnP
automatic selection of IRQs (and other system resources)
previously IRQs were manually selected by jumpers on expansion cards
the user had to select an unused IRQ to prevent interrupt conflict
to use PnP: require a PnP expansion card, PnP BIOS, PnP OS and PnP motherboard support