Transcript Šiuolaikinių kompiuterių architektūra

COMPUTER
ARCHITECTURE
(for Erasmus students)
Assoc.Prof. Stasys Maciulevičius
Computer Dept.
[email protected]
[email protected]
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Compact Discs
The Compact Disc
was invented by Sony
and Philips in 1981 in
order to serve as a
high-quality compact
audio storage device
which allowed for
direct access to
digital sound tracks
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CD geometry
 A CD is an optical disc 12cm in
diameter and 1.2 mm thick (its
thickness may vary from 1.1 to
1.5 mm) for storing digital
information: up to 650 MB of
computer data (equivalent to
300,000 typed pages) or 74
minutes of audio data
 A circular hole 15mm in diameter
is used to centre it on the CD
player's surface.
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Operation
 The read head is made of a
laser which emits a beam of
light, and a photoelectric cell
which captures the reflected
beam
 CD players use an infrared
laser (with a wavelength of 780
nm), as it is compact and
inexpensive
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Operating modes
CD has two basic operating modes:


Reading at a constant linear velocity (CLV). This was
the operating mode of the earliest CD-ROM drives,
based on how CD audio players and even old turntables
work. When a disc turns, the grooves closer to the centre
run more slowly than the grooves on the outer edge, so
the read speed (and therefore the speed at which the
disc rotates) has to adjust based on the radial position of
the read head
Reading at a constant angular velocity (CAV) involves
adjusting the information density depending on where
the data is located, so that the rotation speed is the
same at every point on the disc. This means that data
density will be lower on the edge of the disc and higher
near the centre
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CD standards
 There are numerous standards describing the ways in
which information must be stored on a compact disc,
depending on how it is to be used
 These standards are set out in documents called books,
each of which has a colour assigned to it

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Red book: Developed in 1980 by Sony and Philips, it
describes the physical format of a CD and the encoding
method for an audio CD. It defines a sample rate of 44.1
kHz and 16-bit resolution (in stereo) for recording audio
data
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CD standards
 Yellow book: Developed in 1984 in order to describe the
physical format for data CDs (CD-ROM for Compact Disc Read Only Memory). It includes two modes:

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CD-ROM Mode 1, used for storing data with errorcorrection (called ECC, for Error Correction Code) in order
to avoid losing data due to degradation of the disc.
CD-ROM Mode 2, used for storing compressed graphical,
video, and audio data. To be able to read this type of CDROM, a drive must be Mode 2 compatibe
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CD standards
 Four more standards:

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
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Green book: Physical specifications for a CD-I (CD
Interactive, by Philips)
Orange book: Physical format for writable CDs. It is divided
into three sections:
 Part I: The CD-MO format (magneto-optical disks)
 Part II: The CD-WO format (Write Once, now called
CD-R)
 Part III: The CD-RW format (CD Rewritable)
White book: Physical format for video CDS (VCD)
Blue book: Physical format for "Extra" CDs (CD-X
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CD-ROM format
 A CD-ROM sector contains 2352 bytes, divided
into 98 24-byte frames
Layout Type
← 2,352 bytes block →
CD Digital Audio:
2352 bytes of Digital Audio
CD-ROM (MODE1): 124 2048 bytes of user data 4 8 276
CD-ROM (MODE2): 124 2336 bytes of user data
Sync
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Sector ID Error detection blank/null
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Error detection
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Data Transfer Speeds
 CD-ROM drives are rated with a speed factor
relative to music CDs (1x or 1-speed which
gives a data transfer rate of 150 KiB per
second). 12x drives were common in April 1997
 Above 12x speed, there are problems with
vibration and heat
 Constant angular velocity (CAV) drives give
speeds up to 20x but due to the nature of CAV
the actual throughput increase over 12x is less
than 20/12
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Data Transfer Speeds
Transfer
Speed
1x
2x
4x
8x
10x
12x
20x
32x
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KiB/s
Mbit/s
150
300
1.2288
2.4576
600
1200
1500
1800
4.9152
9.8304
12.2880
14.7456
3000
24.5760
4800
39.3216
Transfer
Speed
36x
40x
48x
50x
52x
56x
72x
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KiB/s
Mbit/s
5400
6000
44.2368
49.1520
7200
7500
7800
8400
58.9824
61.4400
63.8976
68.8128
10800 88.4736
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CD capacity
Type
Sectors
Data max size
(MB)
8 cm
650 MB
700 MB
800 MB
900 MB
(MiB) (approx)
Audio max size
Time
(MB)
(min)
94,500 193.536
283,500 580.608
184.570
553.711
222.264
666.792
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63
333,000
360,000
405,000
445,500
650.391
703.125
791.016
870.117
783.216
846.720
952.560
1,047.816
74
80
90
99
681.984
737.280
829.440
912.384
Note: 90 and 99 minute discs are not standard
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CD-ROM and DVD
The DVD (Digital Versatile Disc) is an "alternative"
to the CD with six times as much storage space (for
the lowest-capacity kind of DVD — single-layer,
single-sided
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DVD
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
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The DVD format was originally supported by a consortium
of ten multimedia companies
DVD was originally used as an initialism for the unofficial
term digital videodisk. It was reported in 1995, at the
time of the specification finalization, that the letters
officially stood for Digital Versatile Disc (due to nonvideo
applications)
The main reason to use DVDs is their storage capacity,
which makes them an excellent medium for video. A 4.7
GB DVD can store more than two hours of compressed
video in MPEG-2, a format used for compressing images
while still keeping them high-quality
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DVD

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A DVD can easily be confused with a CD, as both are
plastic discs 12 cm in diameter and 1.2 mm thick, which
are read using a laser beam
However, CDs use an infrared laser with a wavelength
of 780 nanometres (nm), while DVD burners use a red
laser with a wavelength of 635 nm or 650 nm
What's more, CD players generally use a lens with a
focus of 0.5, while the lenses of DVD players have a
focus of 0.6
For this reason, DVDs have grooves whose minimum
height is 0.4µ with a pitch of 0.74µ, as opposed to
0.834µ and 1.6µ for a CD
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DVD
DVD can be of foowing types:

DVD-ROM (read-only, recorded during fabrication)

DVD-R/RW (DVDs in DVD-R format can only be
recorded once, while DVD-RWs can be rewritten up to
about 1000 times )

DVD+R/RW (supported by Sony and Philips within the
DVD+RW Alliance)

DVD-RAM (This format is mainly used in Japan)
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DVD speeds
 DVD drive speeds are measured with a multiplier. For
example, 1x DVD transfers data at about 1.3 MB/Sec
 A 4x drive could transfer data at four times that speed or
about 5.2 MB/Sec. Compare this to the 0.15 MB/sec data
transfer for a 1x CD-RW and you’ll see DVD drives are
much faster. Almost ten times faster
 All DVD videos play at 1x speed
 Writing speeds for DVD were 1×, that is, 1350 kB/s, in the
first drives and media models. More recent models, at 18×
or 20×, have 18 or 20 times that speed
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DVD types
Type
Storage
Characteristics
capacity
CD
single-sided,
DVD-5
single layer
single-sided,
DVD-9
dual layer
double-sided,
DVD-10
single layer
double-sided,
DVD-17
dual layer
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Equiv. in Equiv. in
music
number
(h.:min.) of CDs
650 MB
1:14
1
4.7 GB
9:30
7
8.5 GB
17:30
13
9.4 GB
19:00
14
18 GB
35:00
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DVD types
Single-sided (DVD-5)
Double-sided (DVD-10)
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DVD types
Single-sided dual layer (DVD-9)
DVD-5
Single-sided dual layer (DVD-18)
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New DVD types
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Traditional DVDs are already exhaust its possibilities
Looking for opportunities to increase the capacity of DVD
discs that they fit the higher resolution videos, two new
technologies were created:
HD DVD (High Definition DVD) – modification of traditional
DVDs, when the data are at the same level, as well as in
DVDs, but the blue laser is used to ensure a higher
recording density: 15 GB / layer instead of 4.7 GB
 Blu-ray DVD (BD) – fairly thin protective layer (0.1 mm
instead of 0.6 mm), so recording layer is closer to the
surface layer, wich less diffuses laser beam; this enables
to reduce the size of pits and to rise layer capacity - 23.3
GB, 25 GB or 27 GB
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HD DVD



HD-DVD has been supported on the hardware
side by NEC, Sanyo, Samsung, Thomson (both
also supported Blu-ray), and Toshiba
On the software side, HD-DVD has been
supported by BCI, Dreamworks, Paramount
Pictures, Studio Canal, and Universal Pictures,
and Warner (only until May 2008 - at which time
it will be Blu-ray exclusive). Microsoft had also
lent its support to HD-DVD, but no longer, as
Toshiba has ended HD-DVD support
HD-DVD is now officially discontinued (one of
reasons - lower capacity comparing to Bue-ray)
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Blue-ray DVD
 Blu-ray Disc was developed by the Blu-ray Disc
Association, a group representing makers of consumer
electronics, computer hardware, and motion pictures
 While a standard DVD uses a 650 nanometer red laser,
Blu-ray uses a shorter wavelength, a 405 nm blue-violet
laser, and allows for almost six times more data storage
than a DVD
 The Blu-ray Disc physical specifications were completed in
2004
 The first mass-market Blu-ray Disc rewritable drive for the
PC was the BWU-100A, released by Sony on July 18,
2006. It recorded both single- and dual-layer discs and had
a suggested retail price of US $699
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Compare CD, DVD and Blue-ray
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Blue-ray DVD
General Specifications:
 Storage Capacity - Pre-recorded Playback Material
(BD-ROM): Single-layer (25GB) - Dual-layer (50GB)
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Storage Capacity: Home Recording (BD-R/BD-RE):
Single-layer (25GB) - Dual-layer (50GB)
Data Transfer Rate: 36 to 48 MBPS (Megabits per
Second) average - capable of up to 54 MPS
Network Capability: Although the Blu-ray format supports
networking and internet capabilities, built-in networking
and Ethernet ports on individual Blu-ray Disc Players is
optional
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Blue-ray DVD
Drive
speed
Data rate
Write time for Blu-ray Disc (minutes)
Mbit/s
MB/s
Single-Layer
Dual-Layer
1×
36
4.5
90
180
2×
72
9
45
90
4×
144
18
23
45
6×
216
27
15
30
8×
288
36
12
23
12
432
54
8
15
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Comparative parameters
Parameter
Singe- or doube-sided
Layers
Capacity (GB)
Protective layer (mm)
Distance betw. tracks (μm)
Minimal length of pit (μm)
CD
DVD Blu-ray HD-DVD
1
1 or 2 1 or 2
1 or 2
1
1 or 2 1 or 2
1 or 2
0,68 4,7/9,4 25/50
15/30
1,20 0,60
0,10
0,60
1,60 0,74
0,32
0,40
0,83 0,41
0,149
0,204
Laser wavelength (nm)
Linear speed (m/s)
780
1,30
650
3,49
405
7,36
405
5,60
Transfer speed, Mb/s
N/D
11,1
54
36
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Improving Blue-ray DVD
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Although the Blu-ray Disc specification has been finalized,
engineers continue to work on advancing the technology
Quad-layer (100 GB) discs have been demonstrated on a
drive with modified optics (TDK version) and standard
unaltered optics ("Hitachi used a standard drive")
Hitachi stated that such a disc could be used to store 7
hours of 32 Mbit/s video (HDTV) or 3.5 hours of 64 Mbit/s
video (Cinema 4K)
In 2006, TDK announced that they have created a working
experimental Blu-ray Disc capable of holding 200 GB of
data on a single side, using six 33 GB data layers
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Improving Blue-ray DVD
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In December 2008, Pioneer Corporation unveiled a
400 GB Blu-ray Disc (containing 16 data layers, 25 GB
each) that will be compatible with current players after a
firmware update
Its planned launch is in the 2009–10 time frame for ROM
and 2010–13 for rewritable discs
Ongoing development is under way to create a 1 TB Bluray Disc as soon as 2013
The Mini Blu-ray Disc (also, Mini-BD and Mini Blu-ray)
is a compact 8 cm-diameter variant of the Blu-ray Disc that
can store approximately 7.5 GB of data
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Holographic Versatile Disc
 The Holographic Versatile Disc (HVD) is an optical disc
technology that, in the future, may hold up to 6TB of
information, although the current maximum is 500GB
 It employs a technique known as collinear holography,
whereby two green laser beams are collimated in a single
beam
 The structure of the disc places a thick recording layer
between two substrates and incorporates a dichroic mirror
that reflects the blue-green light carrying the holography
data but allows the red light to pass through in order to
gather servo information
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Holographic Versatile Disc
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HVD vs DVD
Initial cost for
recordable disc
Initial cost for
recorder/player
Blu-ray
HD-DVD
HVD
~ $18
~ $10
~ $120
~ $2,000
~ $2,000
~ $3,000
30 GB
300 GB
Initial storage capacity 54 GB
Read/write speed
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36.5 Mbps 36.5 Mbps
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1 Gbps
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AO-DVD
 Iomega Corporation got two highly notable patents for its
work with nano-technology and optical data storage, and
external storage media
 New technologies could potentially allow 40-100 times more
data to be stored on a DVD with data transfer rates 5-30
times faster than today's DVDs, and at similarly low costs
 An articulated optical-digital versatile disc (AO-DVD)
potentially can store up to 850GB. This is 200x the amount
that can be fitted onto a single layer DVD. Data rates are
good too claiming to be nearly 30 times faster than today’s
DVDs
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