Transcript Central Processing Unit (continued)

Information technology
Lecture 2: Hardware
(39 slides)
Lecturer:
Prof. Anatoly Sachenko
2
Lecture Overview
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Central Processing Unit
Memory
Input Devices
Output Devices
Input/Output Devices
Storage Devices
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Central Processing Unit
 Central
processing unit (CPU) is a basic component of
computer
 It’s
running the arithmetic and Boolean
operations, program , controlling a
computational process, and co-ordinating
work of all computer devices
 CPU
contains:
 ALU
 CU
 Data
bus and addresses bus
 Registers
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Central Processing Unit (continued)
Cache — very rapid memory of small volume (81024 Kb)
 Mathematical co-processor for the floating point
numbers
ALU - is that one part of processor where the
commands are running
CU - is another part of processor running the
controlling functions
Registers - a row of the specialised additional
memory cells
Trigger - the basic element of register is an
electronic chart, which is able to keep one binary
number (digit of binary code)
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Central Processing Unit (continued)
 Modern
processors are executed as microprocessors
 Physically a microprocessor is the integrated
circuit — thin rectangular form crystalline
silicon lamina by an area only a few square
millimeters where the blocks are placed on
realizing all processor’s functions
 Part of its digits is used for operation code
storing, other — for storage of the operands
addresses codes
 Register types:
 Adder
is a register of ALU partaking in
each operation running ( see next slide)
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Central Processing Unit (continued)
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Command counter is the CU register which
corresponds to an address of next running
instruction
 It
serves for the automatic selection of the
program from successive memory cells
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Command register is the CU register for
command code storing on the period of
time, necessary for its completion
 Microprocessor
is a programmable digital electronic
component that incorporates the CPU functions on a
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Central Processing Unit (continued)
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One or more microprocessors typically serve as
the CPU in a computer system, embedded system,
or handheld device
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Memory – How it Builds?
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Computer memory consists of the binary storage
elements — bits, incorporated in groups for 8 bits
which are named bytes
 All bytes are numbered
 The number of byte is named as its address
 Bytes can be united in cells which are named also
words
 For each computer a certain word capacity is fixed
as the two, four or eight bytes
(continued in the next slide)
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Memory – How it Builds? (continued)
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It does not eliminate the use of memory of other
length cells (for example, half-word, double word)
One integer or one command can be presented in
one computer word
The variable formats of information presentation
are assumed
Breaking up of memory on words for four-byte
computers is presented in a table below:
Byte 0 Byte 1
Byte 2 Byte 3 Byte 4 Byte 5 Byte 6 Byte 7
HALFWORD
HALFWORD HALFWORD HALFWORD
WORD
WORD
DOUBLE WORD
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Memory - RAM
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RAM (Random Access Memory) is a rapid data
storage with not large volume
It is direct-coupled with a processor and
intended for a writing, reading and
storing of the programs and processed
data
 This memory is used for the temporal
storage of data and programs only
because all data in RAM disappear when a
machine is turned off
 There is a direct access to a RAM, it
means that each memory byte has own
individual address
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Memory - RAM (continued)
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RAM is implemented in a semiconductor
storage
It takes the form of integrated circuits
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It allows the stored data to be accessed in any
order — that is, at random and without the
physical movement of the storage medium or
a physical reading head
Key benefit of RAM over types of storage
which require physical movement is that
retrieval times are short and consistent
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Memory - RAM (continued)
 Consistent because the time taken to retrieve a
piece of data does not depend on its current
distance from a physical head
 It requires practically the same amount of time
to access any piece of data stored in a RAM
chip
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Memory - Cache
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Cache or scratchpad memory is a very rapid
memory of small volume
It is used for an exchange information
between a microprocessor and main
memory for difference indemnification
in speed of information processing by
processor and by less fast-acting main
memory
 Cache-memory is managed by Controller
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It analyses a running program trying to
foresee what information and commands
are needed to the processor in the nearest
Memory- Cache & Special Memory
(Continued)
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Cache-memory is implemented by the microcircuits
of static memory of SRAM (Static RAM)
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It’s characterized by faster performance
and less capacity than Dynamic
RAM(DRAM ) or synchronous RAM
(SDRAM)
Read Only Memory (ROM) is a memory for reading
only
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It depends on power supply, and it’s used
for storage data that will never demand a
change
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Memory - Special Memory (continued)
It is mainly used to distribute firmware software that is tied very closely to a
specific hardware
 Modern semiconductor ROM chips are not
immediately distinguishable from similar
chips like RAM modules
 RAM chips can be read faster than most
ROMs
 Writing speed is always much slower than
reading speed
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 Flash
Memory is a memory that depends on power
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Memory - Special Memory (continued)
 BIOS
(Basic Input/Output System) is an aggregate of
the programs intended for the automatic devices
testing after plugging computer and OS loading into
main memory
 CMOS RAM is the memory with a low fast-acting and
minimum energy consumption
 It
is used for data storage about computer
equipment configuration as well as its
mode of operation
 Video
memory (VRAM) is a variety of RAM, where
the coded images are saved
 It
is organised so, that its content is
accessible at once to two devices: processor
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Input devices
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Input device is a hardware mechanism that transforms
data into external world for consumption by a
computer
A computer keyboard is a device for the data input into
computer and managing signals serving
 It contains the standard set of the printing-press
keys and some additional keys — managing and
functional buttons, cursor control keys and small
digital keyboard
Manipulators (mouse, joystick and other) are the
special devices which are used for cursor control
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Input devices (continued)
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Joystick is ordinary bar-pen
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Deviation from its vertical position leads
to the movement of cursor in the proper
direction within monitor screen
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It is often used in computer games
Mouse is a pointing device by detecting twodimensional motion relative to its supporting
surface
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The mouse's motion typically translates
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Input devices (continued)
Touchscreens are the display overlays which
have the ability to display and receive
information on the same screen
 The effect of such overlays allows a display
to be transformed in the input device
removing the keyboard and/or the mouse
as the primary input device
 A touchpad is an input device used commonly
in laptops
 They are used the motions of the user’s
finger
 They are a substitute for a computer
mouse
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Input devices (continued)
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Scanner is a device that analyzes the images and
printed text and handwriting, and converts it into a
digital image
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Webcams are small cameras, whose images can be
accessed using the World Wide Web, instant
messaging, or a PC video conferencing application
Example:
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Skype application
A microphone is an acoustic to electric transducer or
sensor that converts sound into an electrical signal
Example:
Skype application
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Output Devices
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Output device is any piece of computer hardware
equipment used to communicate the results of
data processing carried out by an information
processing system (such as a computer) to the
outside world
A video adapter is a electronic board processing the
video data and controlling a monitor
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It sends the rays brightness management
signals and sync signals of string and
skilled involutes in a monitor
 Monitor
will transform these signals in
visualisations
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Output Devices - Monitors
 Computer
Display Monitor is a piece of electrical
equipment which displays viewable images generated
by a computer without producing a permanent
record
 Monitors types:
 cathode-ray tube based monitors
 liquid crystal displays
 touch screens
 There are the graphics adapters like SVGA , SXGA ,
UXGA , VGA , video memory , XGA
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Output Devices (continued)
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Loudspeaker, speaker, or speaker system is an
electromechanical transducer that converts an
electrical signal into sound
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The term loudspeaker can refer to
individual devices (or drivers), and
complete systems consisting of an
enclosure incorporating one or more
drivers and additional electronics
A printer is a printing unit which carries out a
conclusion from the computer of the coded
information as paper-lists of text or graphic arts
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Output Devices - Printers
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Matrix printers are used by combinations of little
pins that press, due to what there is a character
imprint on a paper
Every character, printed on a printer, is
formed from a set 9, 18 or 24 needles,
formed as a vertical column
 The lacks of these inexpensive printers
are their noisy work and low print
quality
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Laser printers work approximately similarly, as
copiers
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Computer forms in the memory
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Output Devices - Printers
 Ink-jet
printers are generated by characters as a
sequence of inks points( see next slide)
The printer plotting head has tiny nozzles
through which inks are put on a page
 These printers demanding to paper quality
 The colored ink-jet printers are created by
colors
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 Plotter
is a vector graphics printing device that
connects to a computer
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They can draw complex line art, including
engineering drawing, architecture plans,
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Output Devices – Ink - jet printer
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Input/Output Devices
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Input/output, or I/O, refers to the communication between an
information processing system (such as a computer), and the
outside world – possibly a human, or another information
processing system
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Inputs are the signals or data received by the system, and
the outputs are the signals or data sent from it
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For example keyboards and mouses are considered input
devices of a computer, while monitors and printers are
considered output devices of a computer
Devices for communication between computers, such as
modems and network cards, typically serve for both input and
output
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Storage Devices – Floppy Discs
Data storage device is a device for recording (storing)
information (data)
 Floppy disk is a data storage device that is composed of a disk
of thin, flexible ("floppy") magnetic storage medium encased
in a square or rectangular plastic shell
 Floppy disks are read and written by a floppy disk drive or
FDD, the initials of which should not be confused with "fixed
disk drive", which is another term for a hard disk drive
 It’s used for media conversion from one computer on
other and for software distribution
 The method of binary Info record on a magnetic
environment is named the magnetic encoding
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Magnetic
domains in an environment
line up along paths in the direction of the
attached magnetic field by the poles of
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Storage Devices – Zip Disc
 The
Zip drive or Zip disc is a medium-capacity
removable disk storage system, introduced by Iomega
in late 1994
Originally it had a capacity of 100 MB, but
later versions increased this to first 250 MB
and then 750 MB
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 The
format became the most popular of the superfloppy type products but never reached the status of a
quasi-standard to replace the 3.5-inch floppy disk
 It has been superseded by flash drive systems as well
as rewritable CDs and DVDs, and is practically not in
use anymore
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Storage Devices – Data Cartridges
 Magnetic
tape has been used for data storage for over 50 years
 Modern magnetic tape is most commonly packaged in
cartridges and cassettes
 The device that performs actual writing or reading of data is a
tape drive
 Autochangers and tape libraries are frequently used to
automate cartridge handling
 When storing large amounts of data, tape can be substantially
less expensive than disk or other data storage options.
 Tape storage has always been used with large computer
systems.
 Modern usage is primarily as a high capacity medium for
backups and archives
 As of 2007, the highest capacity tape cartridges (DLT-S4,
LTO-4, SAIT-2) can store 800 GB of data without using
compression
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Storage Devices – CD-ROM
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CD-ROM is (an abbreviation of "Compact Disc read-only
memory") is a Compact Disc that contains data accessible by
a computer
 While the Compact Disc format was originally designed
for music storage and playback, the format was later
adapted to hold any form of binary data
CD-ROMs are popularly used to distribute computer
software, including games and multimedia applications,
though any data can be stored (up to the capacity limit of a
disc)
Some CDs hold both computer data and audio with the latter
capable of being played on a CD player, whilst data (such as
software or digital video) is only usable on a computer (such
as PC CD-ROMs
 These are called Enhanced CDs which are also known as
CD Extra and CD Plus that combine audio and computer
data for use in both compact disc and CD-ROM players
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Storage Devices – CD-ROM (continued)
Capacity of CD achieves 780 Mbytes
 Information is inflicted on a disk at its
manufacturing and can not be changed
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Changing СD-ROM technology, DVD goes swiftly
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DVD has the same size like CD, but it
contains up to 17 Gb i.e. one volume
replace 20 standard disks of CD-ROM
Compact Disk Recordable - is capable, along with
reading of ordinary compact disks, to write down
information on the special optical disks
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It has capacity 650 Mbytes
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Storage Devices – Hard Disc Drive
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Hard Disk Drive (HDD) commonly referred to as a hard drive,
hard disk or fixed disk drive, is a non-volatile storage device
which stores digitally encoded data on rapidly rotating
platters with magnetic surfaces
 Early HDDs had removable media; however, an HDD
today is typically a sealed unit with fixed media
 Non-volatile memory NVM or non-volatile storage is
computer memory that can retain the stored Info even
when not powered
NVM examples include read-only
memory, flash memory, most types of
magnetic computer storage devices (e.g.
hard disks, floppy disk drives, and
magnetic tape), optical disc drives, and
early computer storage methods such as
paper tape and punch cards
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Storage Devices – Hard Disc Drive
(continued)
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Unlike a diskette, a hard disk is revolved
continuously
It’s provided with a built-in cache - 8 MBytes
which promotes their productivity substantially
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Storage Devices – Hard Disc Drive
(continued)
HDD
has a very large capacity: from 40 to 750
Gb. At modern models speed of arbor (rotarytype billow) rotation makes 7200 rpm usually,
mean data retrieval time is 9 ms, middle data
rate up to 60 Mb/c
There are the external hard discs as above and
the internal one
For example the Internal hard discs can be
implemented as a part of the embedded
systems
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Storage Devices – Internal Hard Disc

Internal Hard Disk Drive (IHDD) is the same HDD,
but it is portable and connected to computer with use
of USB port - Universal Serial Bus: a standard for
connection sockets on computers and other HW
 Example: with the MaxConnect IHDD mounting
solution, a G5 Power Mac can house a total of
nine disk drives internally, which enables the
system to boot from one drive and allows the rest
of the disk drives to be RAIDED -Redundant
Array of Inexpensive Disks
 It offers 8X speed increase in the data transfer
rate compared to single G5 Power Mac
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Comparison of Storage Devices
Storage
type
Internal
Hard Disk
External
Hard Disk
Capacity Speed
Zip Disk
250 MB
– 750
MB
700 MB
CD-ROM
Data
Cartridges
160 GB
– 1 TB
20 GB500 GB
1.5 Gb/s – 3
Gb/s
4800 Mb/s
(USB 2.0)
786 Mb/s
(Firewire
1394)
2.1 Mbit/s –
133 Mbit/s
2.1 Mbit/s –
133 Mbit/s
128 MB- 4800 Mb/s
16 GB
(USB 2.0)
Cost
$
50500
100300
50150
15-20
20340
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Storage Devices – Disc Formatting
Disc formatting is a procedure of an initial physical or logical
benchmarking for a disc
 In other word it’s an operation of magnetic medium
benchmarking before data are recorded there
 Large disks can be partitioned, divided into logical sections
that are formatted with their own file systems
 Formatting a disk involves two quite different processes
known as low-level and high-level formatting
 Low-level formatting is the formatting of disk surfaces
and installing characteristics like sector numbers that are
visible to, and used by, the disk controller hardware
 High-level formatting is the process of setting up an empty
file system on the disk, and installing a boot sector

39
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