Example Computer Families
• Pentium 4 by Intel
• UltraSPARC III by Sun Microsystems
• The 8051 chip by Intel, used for embedded
systems
Pentium 4
• The Intel Corporation was formed in 1968.
• In 1970, Intel manufactured the first singlechip CPU, the 4-bit 4004 for a Japanese
company to use in an electronic calculator.
• The 8088, a 16-bit CPU was chosen as the
CPU for the original IBM PC.
• A series of backward compatible chips
(80286, 386, 486, Pentium, Pentium Pro and
Pentium II, III and 4) followed.
Intel Computer Family (1)
The Intel CPU family. Clock speeds are
measured in MHz (megahertz) where 1
MHZ is 1 million cycles/sec.
Intel Computer Family (2)
The Pentium 4 chip. The photograph is copyrighted by the
Intel Corporation, 2003 and is used by permission.
Intel Computer Family (3)
Moore’s law for (Intel) CPU chips.
Pentium 4
UltraSPARC III
 In the 1970s, UNIX was popular at universities,
but it ran only on timeshared minicomputers
such as the VAX and PDP-11
 In 1981, a Stanford graduate student built a
personal UNIX workstation using off-the-shelf
parts. It was called the SUN-1.
 Early Sun workstations used Motorola CPUs.
 In 1987, Sun decided to design its own CPU
based on a Cal Berkeley design called the RISC
II.
UltraSPARC III
• The new CPU was called the SPARC (Scalable
Processor ARChitecture) and was used in the Sun4.
• The SPARC was licensed to several semiconductor
manufacturers who developed binary compatible
versions.
• The first SPARC was a 32-bit machine with only 55
instructions (an FPU added 14 additional
instructions).
• A 64-bit version, the UltraSPARC I was developed
in 1995. This machine was aimed at high-end
applications (e.g. web and database servers).
MCS-51 Family
• The Intel 8051 is used in embedded systems
• Features
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8-bit CPU
Read only memory for the program
RAM for variables
32 I/O lines
2 timers
Serial port
Low cost (10-15 cents per chip)
MCS-51 Family
Members of the MCS-51 family.
The Pentium 4
 It is fully backward compatible with the 8088
and can run unmodified 8088 binary programs.
 From a software point of view, the Pentium 4 is
a full 32-bit machine.
• It has the same user-level ISA as the 80386, 80486,
Pentium, Pentium Pro, Pentium II and III including
the same registers, same instructions, and a full onchip implementation of the IEEE 754 floating-point
standard.
 From a hardware perspective, Pentium 4 is
partially a 64-bit machine.
The Pentium 4
 At the microarchitecture level, the Pentium II,
III and Pentium Pro all used the P6
microarchitecture while Pentium 4 uses the
NetBurst microarchitecture.
• Supports hyperthreading
 ISA level instructions are fetched from memory
in advance and are broken up into RISC-like
micro-operations stored in the L1 cache.
• All models have L2 cache, some have L3 as well.
The Pentium 4
 The micro-operations are stored in a buffer, and
as soon as one of them has the necessary
resources to execute, it can be started.
• Multiple micro-operations can be started in the same
cycle, making the Pentium 4 a superscalar machine.
 Snooping on the memory bus is supported so
that multi-CPU systems can be built
The Pentium 4
Two primary external buses are used in
Pentium 4 systems, both of them
synchronous.
• The memory bus is used to address the main
DRAM.
• The PCI bus is used for talking to I/O devices.
• Sometimes a legacy bus is attached to the PCI bus to
allow the old peripheral devices to be plugged in.
The Pentium 4
The Pentium 4 physical pinout.
Pentium 4
• 478 Pins
 85 power
 180 ground
• Power consumption 63-82 watts
 Chip contains a mounting bracket for a heat
sink
The Pentium 4’s Logical
Pinout
Logical pinout of
the Pentium 4.
Names in upper
case are the office
are the official
Intel names for
individual signals.
Names in mixed
case are groups of
related signals or
signal descriptions.
The Pentium 4
 The Pentium 4 memory bus is pipelined with
six stages:
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The bus arbitration phase
The request phase
The error reporting phase
The snoop phase
The response phase
The data phase
 Not all phases are needed on all transactions.
 Each phase uses different bus signals.
The Pentium 4
The UltraSPARC III
 The UltraSPARC family is Sun’s line of 64-bit
SPARC CPUs. It conforms to the Version 9
SPARC architecture.
 The UltraSPARC III is a traditional RISC
machine and is fully binary compatible with the
32-bit SPARC V8 architecture.
 The UltraSPARC III was designed to build
shared-memory multiprocessors without the
need for external circuitry, and larger
multiprocessors with minimal external
circuitry.
The UltraSPARC III
 Unlike the Pentium II, the UltraSPARC III is a
standalone chip (with 29 million transistors).
 It has 1369 pins on the bottom. The large
number of pins is partly accounted for by the
use of 64 bits for address and 128 bits for data,
but also by the way caching works.
 The UltraSPARC III has two internal caches:
• 32 KB for data
• 64 KB for instructions
• It also has an off-chip level 2 cache
The UltraSPARC III
The UltraSPARC III CPU chip.
The UltraSPARC III
 Most Sun workstations have a 25-MHz
synchronous bus called the SBus.
• I/O devices can be plugged into the bus, but is too
slow for memory.
• The UPA (Ultra Port Architecture) is a way for
multiple UltraSPARC CPUs to communicate with
multiple memories. It can be implemented as a bus,
a switch, or a combination.
 The core of an UltraSPARC III system is
shown on the following slide.
The UltraSPARC III
The UltraSPARC III
 The UPA is implemented with a centralized
controller. The address and control signals from
the CPU go there.
 All incoming data goes to the UDB
(UltraSPARC Data Buffer II), which buffers
them.
 The purpose of the UDB is to decouple the
memory system from the CPU so they can
work asynchronously.
• The UDB also generates and checks the errorcorrecting code.
The 8051
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Low cost
Very popular
Simple
40 pin package
16 address lines
8-bit wide data bus
32 I/O lines
The 8051
Physical pinout of the 8051.
The 8051
Logical pinout of
the 8051.
The 8051
• 4 KB of internal ROM
 Can use up to 64 KB of external memory
• Note that many signals are multiplexed onto
the same pins (save pins, reduce cost)
• The I/O lines can be connected directly to
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Button
Switch
LED
etc.
The ISA Bus
 The IBM PC bus was the de facto standard on
8088-based systems because nearly all PC
clone vendors copied it to allow existing thirdparty I/O boards to be used with their systems.
 It had 62 signal lines, including 20 for a
memory address, 8 for data, and one each for
asserting memory read, write, I/O read and
write.
 The bus was etched onto the PCs motherboard
with about half a dozen connectors for cards.
The ISA Bus
The ISA Bus
 With the introduction of the 80286, IBM
extended the PC bus. New cards had an extra
edge connector at the bottom.
 With the introduction of the PS/2, IBM
introduced a new bus, the Microchannel bus
which was protected by patents.
 The rest of the industry reacted by adopting the
ISA (Industry Standard Architecture) bus as
a standard.
• This is basically a PC/AT bus running at 8.33 MHz.
The PCI Bus
 With the introduction of GUIs, the ISA bus was
no longer sufficiently powerful.
 In 1990, Intel designed a new bus with a much
higher bandwidth than ISA or even EISA. It
was called the PCI bus (Peripheral
Component Interconnect bus).
 To encourage its use, Intel patented the PCI bus
and then put all the patents into the public
domain. Intel also formed an industry
consortium to manage the future of the PCI bus.
The PCI Bus
 As a result, the PCI bus has become extremely
popular.
 The original PCI bus had a bandwidth of 133
MB/sec (32 bits per cycle and 33 MHz
frequency - 30 nsec cycle time).
• PCI 2.2 runs at up to 528 MB/sec.
 In order to allow computers incorporating PCI
buses to contain old peripherals, Intel designed
computers with three or more buses.
• The buses are connected by bridge chips
(manufactured by Intel).
The PCI Bus
Pentium 4 Buses
The PCI Bus
 There are a variety of PCI card types:
• 5 or 3.3 volts
• 32-bit or 64-bit
• 33 MHz or 66 MHz
 The PCI bus is synchronous. All transactions are
between a master and a slave.
• The address and data pins are multiplexed, thus only 64 pins
are needed for address and data.
 The PCI bus uses a centralized bus arbiter. The arbiter
is usually built into one of the bridge chips.
The PCI Bus
The PCI Bus
 The algorithm used by the arbiter is not defined
by the PCI specification.
 The PCI bus has a number of mandatory signals
and a number of optional signals. The
remainder of the 120 (32-bit version) or 184
pins (64-bit version) are used for power,
ground, and related miscellaneous functions.
PCI Express
• The new PCI Express architecture does away with
the bus
 Replaced with a switch which has 2 unidirectional
serial links to all I/O devices
 Devices send data packets to other devices
 Header of the packet contains control info
 An I/O device may actually be another switch
 The serial links are much smaller than PCI bus
 Devices are hot pluggable
 Error detection in the packets
PCI Express
A typical PCI Express system.
The PCI Express Protocol
Stack (1)
•Figure 3-57. (a) The PCI Express
protocol stack.
(b) The format of a packet.
The PCI Express Protocol Stack
Each transaction uses 1 of 4 address spaces:
• Memory space for ordinary reads and writes)
• I/O space (for addressing device registers)
• Configuration space for system initialization, etc.)
• Message space for signaling, interrupts, etc.)
The Universal Serial Bus
 The PCI bus is fine for attaching high-speed
peripherals to a computer, but is far too
expensive to have a PCI interface for each lowspeed I/O device.
 Traditionally, new peripheral devices were
inserted in free ISA and PCI slots. This can
cause problems since the user is often
responsible for setting switches and jumpers on
the card and checking for conflicts with other
cards. The user must open the case and insert
the card then reboot the computer.
The Universal Serial Bus
 Representatives from seven companies designed a
better way to attach low-speed I/O devices to a
computer. The resulting standard is called USB
(Universal Serial Bus).
 The goals of the project were:
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No jumpers or switches to set
User doesn’t have to open the case
Only one kind of cable
I/O devices get power from the cable
Up to 127 devices attachable to a single computer
Real-time device support
The Universal Serial Bus
• Devices installable while the computer runs
• No reboot after installing a new device
• Inexpensive to manufacture
 USB meets these goals.
 The total USB 1.1 bandwidth is 1.5 MB/sec.
 A USB system consists of a root hub that plugs
into the main bus. This hub has sockets for
cables that attach to I/O devices. I/O devices
also have sockets for additional devices.
 The topology of a USB system is a tree.
The Universal Serial Bus
 When a new I/O device is plugged in, the root
hub detects the event and interrupts the OS.
 The OS then queries the device to find out what
it is and how much bandwidth it needs.
 If the OS decides there is enough bandwidth
available, it assigns the device a unique address
(1-127) and downloads this address and other
info to configuration registers inside the device.
The Universal Serial Bus
• A USB system may be viewed as a set of bit
pipes from the root hub to the I/O devices
• Within the pipes, data (frames) flow from
the root hub to the I/O device or vice versa
• The root hub continuously broadcasts
frames to keep the devices synchronized
• Frames consist of one or more packets
The Universal Serial Bus
The USB root hub sends out frames every
1.00 ms.
USB 2.0
• USB 2.0 is a newer faster version
 Bandwidth is 60 MB
 Backwards compatible with USB 1.1 devices
• Comparable speed to FireWire - a consumer
electronics interface for digital camcorders,
DVD players, etc.
The Intel Core i7
•The Core i7 physical pinout.
The Core i7’s Logical Pinout
The PCI Bus (2a)
•Figure 3-52. The bus structure of a modern Core
i7 system.
The PCI Bus (2b)
•Figure 3-52. The bus structure of a modern Core
i7 system.