Handbook Phần Cứng PU part 37 pptx

Hardware manufacturers
One of the first manufacturers of sound cards for the IBM PC was AdLib, who
produced a card based on the Yamaha YM3812 sound chip, aka the OPL2. The
AdLib had two modes: A 9-voice mode where each voice could be fully
programmed, and a lesser-used "percussion" mode that used 3 regular voices to
produce 5 independent percussion-only voices for a total of 11. (The percussion
mode was considered inflexible by most developers, so it was used mostly by
AdLib's own composition software.)
Creative Labs also marketed a sound card at the same time called the Creative
Music System. Although the C/MS had twelve voices to AdLib's nine, and was a
stereo card while the AdLib was mono, the basic technology behind it was based
on the Philips SAA 1099 which was essentially a square-wave generator. Sounding
not unlike twelve simultaneous PC speakers, it never caught on the way the AdLib
did, even after Creative marketed it a year later through Radio Shack as the Game
Blaster. The Game Blaster retailed for under $100 and included the hit game title
Silpheed.
Probably the most significant historical change in the history of sound cards came
when Creative Labs produced the Sound Blaster card. The Sound Blaster cloned
the AdLib, and also added a sound coprocessor to record and play back digital
audio (presumably an Intel microcontroller, which Creative incorrectly called a
"DSP" to suggest it was a digital signal processor), a game port for adding a
joystick, and the ability to interface to MIDI equipment (using the game port and a
special cable). With more features at nearly the same price point, and compatibility
with existing AdLib titles, most first-time buyers chose the Sound Blaster. The
Sound Blaster eventually outsold the AdLib and set the stage for dominating the
market.
The Sound Blaster line of cards, in tandem with the first cheap CD-ROM drives
and evolving video technology, ushered in a new era of multimedia computer
applications that could play back CD audio, add recorded dialogue to computer
games, or even reproduce motion video (albeit at much lower resolutions and
quality). The widespread adoption of Sound Blaster support in multimedia and

entertainment titles meant that future sound cards such as Media Vision's Pro
Audio Spectrum and the Gravis Ultrasound needed to address Sound Blaster
compatibility if they were to compete against it.
[edit]
Industry adoption
When game company Sierra On-Line opted to support add-on music hardware
(instead of built-in hardware such as the PC speaker and built-in sound capabilities
of the IBM PCjr and Tandy 1000), the concept of what sound and music could be
on the IBM PC changed dramatically. Two of the companies Sierra partnered with
were Roland and Adlib, opting to produce in-game music for King's Quest 4 that
supported the Roland MT-32 and Adlib Music Synthesizer. The MT-32 had
superior output quality, due in part to its method of sound synthesis as well as
built-in reverb. Being the most sophisticated synthesizer they supported, Sierra
chose to use most of the MT-32's custom features and unconventional instrument
patches to produce background sound effects (birds chirping, horses clopping, etc.)
before the Sound Blaster brought playing real audio clips to the PC entertainment
world. Many game companies would write for the MT-32, but support the Adlib as
an alternative due to the latter's higher market base. The adoption of the MT-32
lead the way for the creation of the MPU-401/Roland Sound Canvas and General
MIDI standards as the most common means of playing in-game music until the
mid-1990s.
[edit]
Feature evolution
Most ISA bus soundcards could not record and play digitized sound
simultaneously, mostly due to inferior card DSPs. Later PCI bus cards fixed these
limitations and are mostly full-duplex.
For years, soundcards had only one or two channels of digital sound (most notably
the Sound Blaster series and their compatibles) with the notable exception of the
Gravis Ultrasound family, which had hardware support for up to 32 independent
channels of digital audio. Early games and MOD-players needing more channels

than the card could support had to resort to mixing multiple channels in software.
Today, most good quality sound cards have hardware support for at least 16
channels of digital audio, but others, like those that utilize cheap audio codecs, still
rely partially or completely on software to mix channels, through either device
drivers or the operating system itself to perform a software downmix of multiple
audio channels.
[edit]
Sound devices other than expansion cards
[edit]
Integrated sound on the PC
In 1984, the IBM PCjr debuted with a rudimentary 3-voice sound synthesis chip,
the SN76489, capable of generating three square-wave tones with variable
amplitude, and a pseudo white noise channel that could generate primitive
percussion sounds. The Tandy 1000, initially being a clone of the PCjr, duplicated
this functionality, with the Tandy TL/SL/RL line adding digital sound
recording/playback capabilities.
In the late 1990s, many computer manufacturers began to replace plug-in
soundcards with a "codec" (actually a combined audio AD/DA-converter)
integrated into the motherboard. Many of these used Intel's AC97 specification.
Others used cheap ACR slots.
As of 2005, these "codecs" usually lack the hardware for direct music synthesis or
even multi-channel sound, with special drivers and software making up for these
lacks, at the expense of CPU speed (for example, MIDI reproduction takes away
10-15% CPU time on an Athlon XP 1600+ CPU).
Nevertheless, some manufacturers offered (and offer, as of 2006) motherboards
with integrated "real" (non-codec) soundcards usually in the form of a custom
chipset providing e.g. full ISA or PCI Soundblaster compatibility, thus saving an
expansion slot while providing the user with a (relatively) high quality soundcard.
[edit]
Integrated sound on other platforms

Various computers which do not use the IBM PC architecture, such as Apple's
Macintosh, and workstations from manufacturers like Sun have had their own
motherboard integrated sound devices. In some cases these provide very advanced
capabilities (for the time of manufacture), in most they are minimal systems. Some
of these platforms have also had sound cards designed for their bus architectures
which of course cannot be used in a standard PC.
[edit]
USB sound cards
While not literally sound cards (since they don't plug into slots inside of a
computer, and usually are not card-shaped (rectangular)), there are devices called
USB sound cards. These attach to a computer via USB cables. The USB
specification defines a standard interface, the USB audio device class, allowing a
single driver to work with the various USB sound devices on the market.
[edit]
Other outboard sound devices
USB Sound Cards are far from the first external devices allowing a computer to
record or synthesize sound. Virtually any method that was once common for
getting an electrical signal in or out of a computer has probably been used to
attempt to produce sound.
[edit]
Driver architecture
To use a sound card, the operating system typically requires a specific device
driver. Some operating systems include the drivers for some or all cards available,
in other cases the drivers are supplied with the card itself, or are available for
download.
 DOS programs for the IBM PC often had to use universal middleware driver
libraries ([such as HMI Sound Operating System, Miles Sound System etc.)
which had drivers for most common sound cards, since DOS itself had no
real concept of a sound card. Some card manufacturers provided (sometimes
inefficient) middleware TSR-based drivers for their products, and some

programs simply had drivers incorporated into the program itself for the
sound cards that were supported.
 Microsoft Windows uses proprietary drivers generally written by the sound
card manufacturers. Many makers supply the drivers to Microsoft for
inclusion on Windows distributions. Sometimes drivers are also supplied by
the individual vendors for download and installation. Bug fixes and other
improvements are likely to be available faster via downloading, since
Windows CDs cannot be updated as frequently as a web or FTP site. Vista
will use UAA.
 A number of versions of UNIX make use of the portable Open Sound
System. Drivers are seldom produced by the card manufacturer.
o Most Linux-based distributions make use of the Advanced Linux
Sound Architecture, but have taken measures to remain compatible
with the Open Sound System.
KHÁM PHÁ BÍ ẨN VỀ PSU (Power Supply Unit )





Đối với máy tính, PSU như 1 trái tim , quyết định rất lớn đến độ bền của toàn bộ hệ
thống, còn đối với dân OCers PSU lại càng có 1 ý nghĩa quan trọng hơn nữa vì nó
quyết định khả năng OC và độ an toàn khi ép xung cao độ.

Bài viết này chủ yếu để phổ biến thêm những kiến thức cơ bản và xoáy vào những
điểm "HOT" của bộ nguồn máy tính hiện nay.

Chuẩn ATX 1.3 và 2.X! những điều cần biết

Hiện tại 2 chuẩn ATX phổ biến là chuẩn 1.3 và chuẩn 2.x (bên cạnh các chuẩn

dành cho server của INTEL và AMD - xin phép không lạm bàn ở đây).

Nhận biết:
ATXV1.3 chỉ có 1 đường (rail) 12V và có thể có hoặc kô có đầu cấp nguồn SATA,
thường thì các PSU chuẩn ATX V1.3 có hiệu suất thấp – chỉ đạt ~ 60 % - Và có
đường điện chính là đường 5V (công suất 5V rất cao) (thích hợp cho những main
cấp 5V cho CPU như BIOSTAR M7NCG và một số main AMD khác).

Các bộ nguồn ATX chuẩn mới hơn (2.x) thì có đường điện chính là đường 12V
(max là 18A cho mỗi rail đối với PSU có 2 rail 12V , nếu vượt quá giới hạn trên thì
độ nhiễu sẽ tăng ) trang bị đầu cấp nguồn SATA (bắt buộc), cấp nguồn PCie
(VGA), 12V+ (cho main board) bên cạnh những đầu cấp nguồn HDD, Floopy
thông thường, hiệu suất của PSU ATXV2.x thường đạt >70% một số PSU cao cấp
có thể lên tới 80% (như dòng ANTEC phantom). Theo xu hướng thời đại , chuẩn
ATX 2.x đã và đang dần thay thế chuẩn ATX 1.3.