Handbook Phần Cứng PU part 27 pptx

ROM with BIOS
BIOS is sometimes called firmware. Before 1990 or so BIOSes were held on ROM
chips that could not be altered. As their complexity and need for updates grew,
BIOS firmware was stored on EEPROM or flash memory devices. This EEPROM
chip sits on a FWH interface, but in some newer boards EEPROM chips are
already sitting on a newer, emerging interface named SPI. EEPROM chips are
advantageous because they can easily be updated by the user; however, an
improperly executed or aborted BIOS update can render the computer or device
unusable. To avoid BIOS corruption, some new motherboards have a backup BIOS
("Dual BIOS" boards). Also, most BIOSes have a "boot block" which is a portion
of the ROM that runs first and is not updateable. This code will verify that the rest
of the BIOS is intact (via checksum, hash, etc.) before jumping to it. If the boot
block detects that the main BIOS is corrupt, then it will typically boot to a floppy
so that the user can try flashing again, hopefully with a better image. Hardware
manufacturers frequently issue BIOS updates to upgrade their products and remove
bugs.
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Firmware on adapter cards
A computer system can contain several BIOS firmware chips. The motherboard
BIOS typically contains code to access fundamental hardware components such as
the keyboard, floppy drives, ATA (IDE) hard disk controllers, USB human
interfaces, and storage devices. In addition, plug-in adapter cards such as SCSI,
RAID, Network interface cards, and video boards often include their own BIOS,
complementing or replacing the system BIOS code for the given component.
In some devices that can be used by add-in adapters and actually directly integrated
on the motherboard, the add-in ROM may also be stored as separate code on the
main BIOS flash chip. It may then be possible to upgrade this "add-in" BIOS
(sometimes called an "option ROM") separately from the main BIOS code.
Add-in cards usually only require such an add-in BIOS if they:
 Need to be used prior to the time that the operating system loads (e.g. they

may be used as part of the process which loads (bootstraps) the operating
system), and:
 Are not sufficiently simple, or generic in operation to be handled by the
main BIOS directly
Older operating systems such as DOS, as well as bootloaders, may continue to
make use of the BIOS to handle input and output. However, most modern
operating systems will interact with hardware devices directly by using their own
device drivers to directly access the hardware. Occasionally these add-in BIOSes
are still called by modern operating systems, in order to carry out specific tasks
such as preliminary device initialization.
To find these memory mapped expansion ROMs during boot, PC BIOS
implementations scan real memory from 0xC8000 to 0xF0000 on 2 kilobyte
boundaries looking for a 0x55 0xaa signature, which is immediately followed by a
byte indicating the number of 512 byte blocks the expansion ROM occupies in real
memory. The BIOS then jumps to the offset immediately after the size byte, at
which point the expansion ROM code takes over and uses BIOS services to
provide a user configuration interface, register interrupt vectors for use by post-
boot applications, or display diagnostic information.
For UNIX and Windows/DOS systems there is a utility with which you can dump
your BIOS firmware software at
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The BIOS boot specification
If the expansion ROM wishes to change the way the system boots (such as from a
network device or a SCSI adapter for which the BIOS has no driver code), it can
use the BIOS Boot Specification (BBS) API to register its ability to do so. Once
the expansion ROMs have registered using the BBS APIs, the user can select
among the available boot options from within the BIOS's user interface. This is
why most BBS compliant PC BIOS implementations will not allow the user to
enter the BIOS's user interface until the expansion ROMs have finished executing
and registering themselves with the BBS API.

[edit]
The Fall and Rise of the BIOS
Older operating systems such as DOS called on the BIOS to carry out most input-
output tasks within the PC; with the introduction of newer operating systems such
as Microsoft Windows and Linux, the BIOS was relegated to principally providing
initial hardware setup, and bootstrapping. Once it was up and running, the
operating system didn't have to rely on the BIOS for much.
In recent years, however, by way of systems such as ACPI, the BIOS has taken on
more complex functions such as aspects of power management, hotplug, thermal
management etc. This has led to renewed reliance on the BIOS by operating
system producers, and an increase in complexity in the BIOS code. This in turn has
led to invention of Intel's modern Extensible Firmware Interface (EFI) which in
itself incorporates BIOS's extended options. Microsoft announced that support for
EFI in Windows Vista will be dropped for the launch, but added in a later update
for 64 bit version, leaving only Linux and OS X as the operating systems that
widely use it nowadays.
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The BIOS business
The vast majority of PC motherboard suppliers license a BIOS "core", and toolkit
from a commercial third party, which creates and maintains such a core. The
motherboard manufacturer then customizes this BIOS to suit its own hardware -
for this reason updated BIOSes are normally obtained directly from the
motherboard manufacturer.

Graphics processing unit
From Wikipedia, the free encyclopedia
(Redirected from Graphics card)
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"VPU" redirects here. For the university in Lithuania, see Vilnius
Pedagogical University.

GeForce 6600GT (NV43) GPU


Radeon 9800 Pro (R350) GPU
A Graphics Processing Unit or GPU (also occasionally called Visual Processing
Unit or VPU) is a dedicated graphics rendering device for a personal computer,
workstation, or game console. Modern GPUs are very efficient at manipulating and
displaying computer graphics, and their highly parallel structure makes them more
effective than typical CPUs for a range of complex algorithms.
A GPU implements a number of graphics primitive operations in a way that makes
running them much faster than drawing directly to the screen with the host CPU.
The most common operations for early 2D computer graphics include the BitBLT
operation (combine two bitmap patterns using a RasterOp), usually in special
hardware called a "blitter", and operations for drawing rectangles, triangles,
circles, and arcs. Modern GPUs also have support for 3D computer graphics, and
typically include digital video-related functions as well.
Contents
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 1 History
o 1.1 1970s
o 1.2 1980s

o 1.3 1990s
o 1.4 2000 to present
 2 Computational Functions
 3 GPU Forms
o 3.1 Dedicated Graphics Cards
o 3.2 Integrated Graphics Solutions
 4 GPU manufacturers
 5 See also
 6 External links
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History
[edit]
1970s
Modern GPUs are descended from the monolithic graphic chips of the late 1970s
and 1980s. These chips had limited BitBLT support in the form of sprites (if they
had BitBLT support at all), and usually had no shape-drawing support. Some
GPUs could run several operations in a display list, and could use DMA to reduce
the load on the host processor; an early example was the ANTIC co-processor used
in the Atari 800 and Atari 5200. In the late 1980s and early 1990s, high-speed,
general-purpose microprocessors became popular for implementing high-end
GPUs. Several high-end graphics boards for PCs and computer workstations used
TI's TMS340 series (a 32-bit CPU optimized for graphics applications, with a
frame buffer controller on-chip) to implement fast drawing functions; these were
especially popular for CAD applications. Also, many laser printers from Apple
shipped with a PostScript raster image processor (a special case of a GPU) running
on a Motorola 68000-series CPU, or a faster RISC CPU like the AMD 29000 or
Intel i960. A few very specialised applications used digital signal processors for
3D support, such as Atari Games' Hard Drivin' and Race Drivin' games.