Transcript Cpu & Main Memory

‫گارگاه کامپيوتر‬
‫‪CPU and Main Memory‬‬
‫تهيه كننده‪ :‬علي برادران هاشمي‬
Central Processing Unit (CPU)
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The CPU is the main chip in the computer
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Brain of the PC
The CPU is also called the microprocessor
The most important chip in the computer
Modern processors contain millions of transistors
which are etched onto a tiny square silicon called a
die, which is about the with of a standard thumb.
The CPU processes instructions, performs
calculations, and manages the flow of information
through a computer
The CPU performs millions of calculations every
second
CPU (Cont.)
Second Memory
Input
Device
CU
CPU
ALU
Output
Device
Primary Memory
Input
Processing
CPU: Central Processing Unit
ALU: Arithmetic Logic Unit
CU : Control Unit
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Output
Control Unit (CU)
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Send signals to execute strored programs
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Primary functions :
1.
2.
3.
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DOES NOT execute programs but tells other to
execute
Read & Interpret program instructions
Direct operation of process
Control memory access (Data In/Out)
Program is loaded in RAM.
During the execution program instructions
moves to control unit.
ALU
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Arithmetic Operations:
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Logical operations :
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Addition, subtraction, division, multipication
Equal, Greater than,…
How the CPU executes Program
Instructions ?
Instruction Time
Control Unit
Step 2: Decoding
Execution Time
Arithmetic/Logic Unit
Step 3: Executing
Step 1 : Fetching
Step 4: Storing
main Memory
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Math Coprocessor
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Coprocessors take over calculations floatingpoint math.
Math coprocessors will speed your computer's
operation when utilizing software applications
that take advantage of its capabilities.
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Built-in in modern CPUs.
Processor History
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INTEL 4004 - microprocessor introduced in 1970
with the speed of 108khz was the worlds first
microprocessor.
INTEL 8080
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running at the speed of 2 MHz was used in the world's
first PC, the Altair.
INTEL 8086 1976
16-bit architecture that allowed it to work with 16bit binary numbers and pass them through a 16-bit
data bus.
The 8086 was available in clock speeds of 5Mhz,
8Mhz, and 10Mhz.
Processor History(Cont.)
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INTEL 8088 1979
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The 8088 was the first processor used in the
original IBM PC and XT personal computers.
INTEL 80286 1982
286 processor.
The 286 processor supported 16-bit
architecture, supported virtual memory, and
was available in clock speeds of 8Mhz, 10Mhz,
and 12Mhz.
DX
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INTEL 80386DX 1985
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INTEL 80486DX 1989
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The chip was available in clock speeds of 16mhz,
20mhz, 25mhz, and 33mhz.
The 486DX featured a built-in memory cache
and 32-bit architecture. It had more than three
times the computing power of the 386DX and
was available in clock speeds of 25mhz, 33mhz,
and 50mhz.
SX
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INTEL 80386SX (1989)
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INTEL 80486SX (1991)
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The 80386SX lacked a math coprocessor however still
featured the 32-bit architecture and built-in multitasking.
The chip was available in clock speeds of 16mhz,
20mhz, 25mhz, and 33mhz.
less expensive version of the 80486DX.
It lacked the math coprocessor of the 80486DX and ran
at lower clock speeds then the DX it ran at 16mhz,
20mhz, 25mhz, or 33 MHz.
Dx2 – Dx4
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INTEL 80486DX2 (march 2, 1992).
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INTEL 80486DX4 (1993)
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Based upon the popular 486DX.
Internal clock speeds that doubled that of the
system that operated it.
A DX2 on a system with a 33mhz bus would run
at 66mhz.
The 486DX4 would triple that of the system that
operated it.
100 MHz.
Pentium
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INTEL PENTIUM (march 22, 1993)
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designed to replace the 486 processors.
The Pentium has a 32-bit address bus and a 64-bit
data bus.
It can operate at speeds of 60mhz to 200mhz.
The Pentium was released in three
generations.
Pentium Generations
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The first-generation of Pentium processors was the
Pentium 60 and 66 MHz.
The second-generation introduced march 7, 1994
included new processors from 75, 90, 100, 120,
133, 150, 166, and 200 MHz.
The third-generation of Pentium processors code
named P55C were introduced January 1997, which
incorporated the new technology MMX.
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The Pentium MMX processors were available 166, 200,
233 MHz, and 266 MHz mobile version.
INTEL PENTIUM PRO!
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INTEL PENTIUM PRO
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designed for the corporate users and for highend servers and workstations, preferably those
using windows NT.
The Pentium pro CPUs are extremely fast with
32-bit applications and 3-D image processing
and rendering when compared to previous Intel
processors.
The chip runs at 166mhz and higher
P2
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INTEL PENTIUM II
The Pentium II 233mhz was released in
1997
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previous owners of Pentium motherboard could
not upgrade to this new type of chip unless the
motherboard!?
they had included a SLOT 1 technology. The
Pentium II runs from 233mhz to 450mhz.
P3
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INTEL PENTIUM III (1999)
The Pentium III chip continued to use the
SLOT 1 and could be used on previous
Pentium II motherboards with BIOS support.
The Intel Pentium III chips have a ID for
each chip helping to authenticate peoples
purchase over the internet.
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Privacy
Processor Specifications
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Processors can be identified by two main
parameters :
How wide they are and how fast they are.
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The speed of a processor is fairly simple
concept.
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Speed is counted in MegaHertz, which means
millions of cycles per second.
Processor Specifications
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A little more complicated to discuss
because there are three main specifications in a
process that are expressed in width:
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Internal registers.
Data input and output bus.
Memory address bus.
Internal Registers or Internal Data
Bus
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The size of the internal registers
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A register is a holding cell within the processor;
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For example the processor can add numbers in
two different registers, storing the result in a third
register.
The register size determines the size of the
data the processor can operate on.
Address Bus
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The address bus is the set of wires that
carries the addressing information used to
describe the memory location to which the
data is being sent or from which the data is
being retrieved.
As with the data bus, each wire in an
address bus carries a single bit of
information.
Address Bus
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This single bit is a single digit in the address.
The more digits used in calculating these
addresses, the greater the total number of
address locations.
The size of the address bus indicates the
maximum amount of RAM that a chip can
address.
Process Memory-addressing
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Processor
Address Bus
MB
8088/8086
20-bit
1
286/386SX
24-bit
16
386DX/486/Pentium
32-bit
4,096
Pentium II, III, IV
36-bit
65,536
Cache memory
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A small very fast memory.
Holding recently accessed data, designed to
speed up subsequent access to the same
data.
When data is read from, or written to, main
memory a copy is also saved in the cache,
along with the associated main memory
address.
Internal Level 1 (L1) Cache
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All modern processors starting with the 486
family include integrated L1 cache.
L1 cache is built in to the processor die, this
means it runs at full core speed of the
processor.
Main system RAM is often slower than the
CPU so L1 cache works as a temporary
storage space between the CPU and
memory.
Ok… But What Does It Do?
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Think of L1 cache as local computer distributor.
When a client (CPU) calls up and requires a certain
part for a computer, the distributor (L1) checks its
inventory for that part.
If it has it in stock, it sends that part out right away
and you get it very quickly. (Cache hit).
If that part is not in stock, it must call up its head
office (RAM) and have them ship it, which takes
much longer to receive. (Cache miss).
Level 2 (L2) Cache
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When there is a cache miss, the processor
must go to memory and read through it and
locate the information. Main memory runs a
lot slower then L1 cache. Because of this, it
takes much longer to get the appropriate
information.
L2 cache is an even larger storage space
that gathers information from RAM incase
there is a cache miss with the L1. This way
we can speed up the process a little better.
Ok… Again what does it do?
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This of L2 cache as a Regional Office
When the distributor (L1) does not have a certain
item in stock, instead of calling all the way to the
head office (RAM), they call the regional office (L2)
which is much closer.
If the regional office (L2) has the part, they can
ship it out much fast than the head office.
If the regional office (L2) does not have this part,
then the head office (RAM) must be called.
Socket VS Slot
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Depending on the type of processor you
purchase will depict the type of motherboard
you will buy.
Most computers up to the 3rd generation of
Pentiums used socket technology.
When Pentium 2 CPUs arrived, slot 1
became the new style.
Slot 1
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Slot 1
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In the late 1990's, Intel decided to abandon the Socket type
CPU design and move to a edge connected, or slot form CPU.
This allows for a much larger CPU package, which usually
includes tightly coupled cache to boost CPU performance.
Intel Pentium II was the first of these slot type CPUs, utilizing
Slot 1,
However, in order to compete in lower cost, easier to
manufacture systems, Intel returned to the Socket for with
Socket 370, and both the Pentium III and Celeron are now
available in Socket 370 form.
Slot A
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developed by Digital Equipment for their Alpha processor
supports the new AMD Athlon, at speeds from 500 MHz
to 800 MHz.
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support for the Athlon’s 266MHz front side bus (FSB) appeared
in the Fall of 2000 when AMD introduces it's new chipsets that
support DDR (Double Data Rate) SDRAM.
AMD is phasing out Slot A in favor of Socket A.
Socket 7
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Socket 7 and 8
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The Intel Pentium CPU is a Socket 8 device
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The Intel Pentium PRO CPU is a Socket 8 device
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Pentium PCs can be loosely divided into families by their
CPU socket.
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The majority of Pentium motherboards is Socket 7,
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But some Pentium and other upgrade processors can be used on
motherboards equipped with Socket 3 (486 and OverDrive CPU's),
Socket 4 (60 and 66MHz Intel Pentiums) or Socket 5 (some of the midrange Pentiums).
Socket 370
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In January 1999, Intel
released a new socket for
P6 class processors.
The new socket is called
socket 370, because it has
370 pins and was
designed for lower-cost
PGA versions of the
Celeron and the P3.
Socket 370 (cont.)
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Intel has decided to take it's Celeron CPU back into
competiton in the PGA (Pin Grid Array) Socket world, in
parallel with continuing to produce it as a Slot 1 device.
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Socket 370, so named for it's 370 pin grid, is NOT compatible
with Socket 7 or Super 7, it just looks similar.
The Pentium III is now also available for Socket 370, but
make sure your Socket 370 motherboard can handle a
100MHz or 133MHz bus before wasting a FCPGA (Flip Chip
Pin Grid Array) Pentium III on it.
The Socket 370 motherboards don't carry external cache,
the new Celeron for Socket 370 has 128KB on the die, the
Pentium III for socket 370 has 256KB on-board.
Socket 423 and 478
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Socket 423, named for its 423 pins,
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The original Pentium 4 socket.
Socket 478 is the successor to 423, supporting
new sizes and speeds of the P4.
current P4s only support Rambus RIMM for
high performance or the old PC133 memory
for slower systems, support for 266MHz
DDR is now.
The P4 is not available in a slot format.
Socket A
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AMD is currently the only manufacturer of
Socket A CPUs, these being the Athlon and
the Duron.
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Socket A CPUs are somewhat less expensive
than their Slot A brothers, due to the smaller
package and reduced amount of cache memory
integrated with the CPU.
AMD warns that Socket A CPUs should not be
used with adapters as Slot A CPUs.
Memory
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Definitions of Memory
Memory is the workspace of the computer’s
processor.
A temporary storage space where the programs
and data being operated on must reside.
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Names of Memory
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Memory refers to integrated circuits that store program
instructions and data that can be retrieved.
Memory is the part of the computer that holds data and
instructions for processing.
primary storage ,primary memory, main storage, internal
storage, main memory
RAM and ROM - Memory (2)
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Random Access Memory (RAM)
Memory that provides temporary storage for data and
program instructions.
The programs and data stored in RAM are erased when
the power to the computer is turned off.
Read Only Memory (ROM)
Memory that can be read-only and that store data or
instructions that do not change.
Data and instructions in it remains after the power is
turned off.
ROM
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Read Only Memory
This type of memory is Read Only meaning
that it is almost impossible to write to it!
ROM is non volatile, meaning it does not
require electricity for information to
remain in ROM.
ROM (cont.)
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Programmable ROM
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Similar to ROM, except there is a fuse connected to
ground. Hence, the default value is 0. Burn the fuse
to get 1.
It can only be write to once.
Firmware
 Instructions that are stored in ROM are called
firmware.
ROM (cont.)
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Erasable PROM
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EEPROM uses higher than normal electricity voltage to
erase the content.
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A special transistor instead of the fuse (as in PROM) is used.
It allows the stored data to be erased and reprogrammed.
EPROM uses ultraviolet light to erase the content.
The number of times it can be reprogrammed is limited.
The speed of EEPROM is slower than RAM as it can only
erase and reprogram one byte at a time.
Flash memory
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Flash memory is based on EEPROM technology.
It uses normal voltage to erase and reprogram.
Faster than EEPROM as it can erase and reprogram one
block of memory at a time (instead of one byte at a
time).
Flash memory is used in digital cellular phones, PDAs,
digital cameras, LAN switches, digital set-up boxes,
embedded controllers, and other devices.
In modem PCs, flash memory is commonly used to
store system BIOS.
BIOS
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Basic Input/Output System
The BIOS is built-in software that determines what
a
computer can do without accessing programs from
a disk.
It tells the microprocessor what to do after right
after you turn on the computer.
On PCs, the BIOS contains all the code required to
control the keyboard, display screen, disk drives,
serial communications, and a number of
miscellaneous functions.
RAM
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DRAM :Dynamic RAM)
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built from capacitors;
it’s called dynamic because it must periodically
refresh the capacitors.
higher density, lower speed
used in main memory
Refreshing the memory takes processor time
from other tasks.
For each refresh cycle, there are multiple
processor cycles.
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SDRAM: Synchronous Dynamic RAM
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DDR SDRAM: Double Data Rate SDRAM
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RDRAM: Rambus DRAM (proprietary)
(DRDRAM)
SRAM
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SRAM: Static RAM
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because it does not require refreshing.
Not only are refreshes not required, SRAM is much faster
then DRAM.
SRAM is available in access times of 2ns or less, which
means it can keep pace with modern processors.
lower density, higher speed
SRAM uses a cluster of six transistors for each bit of
storage.
Problem with SRAM is it is very expensive.
SRAM is mostly used in CACHE memory inside of
processors and on motherboards
EDO DRAM
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Extended Data Out RAM
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became available with Pentium systems in 1995.
Allowing the memory controller to begin a new
instruction while it is currently reading data at that
current address.
The actually use EDO memory, your motherboard
chipset must support it.
EDO is great for systems with bus speeds of up to
66mhz, which fit perfectly with the PC market
through 1997.
However, in 1998 EDO lost out to a newer fast
memory called SDRAM.
SDRAM
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Synchronous DRAM
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A type of DRAM that runs in synchronization with the
memory bus.
SDRAM delivers information in very high-speed bursts
using a high-speed, clocked interface.
SDRAM synchronizes with the motherboards clock speed.
SDRAM is sold in DIMM form and is often rated by MHz
speed rather than nanosecond cycling time.
SDRAM is sold as PC66, PC100, PC133.
RDRAM
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Rambus DRAM (late 1999).
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Conventional memory systems that use EDO or
SDRAM are know as wide channel systems.
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Intel endorsed and supported RDRAM in most of the new
PC motherboard chipsets from 1999 and beyond.
They have memory channels as wide as the processor’s
data bus, which for the Pentium is 64 bits.
The DIMM is a 64-bit wide device, meaning data can be
transferred to it 64 bits or 8 bytes at a time.
The fastest DIMMs are the SDRAM type, which run at
133mhz, meaning the overall throughput is 100x8 =
800Mb/sec.
RDRAM (Cont.)
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RDRAMs are a narrow channel devices.
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They transfer data only 16 bits at a time, but at
much faster speeds.
They normally run 800Mhz, meaning the overall
throughput is 800 x 2 = 1.6GB per second.
Each individual chip is serially connected to the
next on a package called a RIMM (Rambus inline
memory module).
DDR SDRAM
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Double data rate (DDR) SDRAM
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Data is transferred twice as fast.
Instead of doubling the actual clock rate, DDR
memory achieves the doubling in performance by
transferring twice per transfer cycle, once at the
leading and once at the trailing edge of the cycle.
DDR-SDRAM uses a new DIMM module design with
184 pins.
DDR DIMMs are rated for either PC200
(100mhz x 2) or PC266 (133mhz x 2) operation
and normally run on 2.5 volts.
DIPs
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Originally, memory was installed into computers via
individual chips.
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These chips were often called DIP (Dual Inline Package).
The original XT and AT had 36 sockets on the
motherboard for these individual chips.
Because it was very time consuming and tedious to
install, SIMMs and DIMMs became very popular
SIMMs
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Single Inline Memory Module.
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SIMMs are little circuit boards that have memory
chips soldered onto them.
There are two main types of SIMMs.
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30-pin (8 Bit)
72-pin (32 Bit)
30-pin SIMMs were smaller than the 72-pin
SIMMs and often had chips on both sides.
Problem with SIMMs
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The main problem with SIMMs was one 30-pin
SIMM was only 8 bits and one 72-pin SIMM was
only 32 bits.
In order for a computer to function, memory must
have the same BUS width as the motherboard.
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If a motherboard’s bus was 32 bits and the computer
only supported 30-pin SIMMs, you needed to install the
memory in groups of 4 to make a 32 bit memory bus.
If a motherboard’s bus was 64 bits and the computer
supported 72-pin SIMMs, you needed to install the
memory in groups of 2 to make a 64 bit memory bus.
DIMMs
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Dual Inline Memory Module.
DIMMs, which are more popular now are 168-pin
units with 64-bit data paths.
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You only have to install 1 DIMM into a computer for it to
work with the 64 bit data bus.
To have a reliable system, you must install SIMMs
or DIMMs with gold plated contacts into goldplated sockets and SIMMs or DIMMs with tin-plated
contacts into tin-plated sockets.
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If you don’t follow this rule, you will get memory errors!
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When tin and gold come into contact, because one surface is
hard, the oxidation builds up and does not break easily under
pressure.
This leads to interruptions in electrical signals between SIMM or
DIMM and the memory socket.
Parity?
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In communications, parity checking refers
to the use of parity bits to check that
data has been transmitted accurately.
The parity bit is added to every data unit
(typically seven or eight bits ) that are
transmitted.
The parity bit for each unit is set so that
all bytes have either an odd number or an
even number of set bits.
ECC
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Error Correcting Circuits, Error
Correcting Code, or Error Correction Code
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ECC memory.
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not only detects both single-bit and multi-bit
errors, it will actually correct single-bit
errors on the fly.
a step beyond simple parity checking.
specifically designed to allow the use of ECC
on modern systems that have a chipset that
supports it.
Real Mode Memory Model
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Conventional memory
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It resides in the first 1 meg of memory DOS
systems have an address space of 1MB
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DOS -based systems, upper memory refers to the
memory area between the first 640K and 1
megabyte
Expanded Memory Specification
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but the top 384K is reserved for system use.
This leaves 640K of conventional memory
Expanded Memory Manager (EMM)
EMM386.EXE driver which is included with MS-DOS,
Windows 3.1 and Windows 95 systems
Virtual Memory
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Imaging RAM
When RAM is full!? Run no more program!
Virtual memoy is a system software addition to
OS.
Use secondary storage as Primary!
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Factors affecting processing speed
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Registers
RAM
Internal clock (Hz)
BUS
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Path between component of a computer
16 bit,32 bit, 64 bit.
BUS
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ISA (Industry Standard Architecture)
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EISA (Extended ISA)
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32bit
PCI (Peripheral Component Interconnect)
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16 bit
1992
33MHz , 32 bit
132 MB/s
BUS (Cont.)
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Firewire (IEEE1394)
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USB (Universal Serial Bus)
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100,200,300,400 MB/s
Digital camera, DV Camcorders
12MB/s
Plug & Play
Any Question?
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