Graphics; Intel 845G Chipset Integrated Graphics - Compaq Evo D510 e-pc Technical Reference Manual

During writing, a focused 'Write Power' laser beam selectively heats areas of the phase-change
material above the melting temperature (500-700º C), so all the atoms in this area can move
rapidly in the liquid state. Then, if cooled sufficiently quickly, the random liquid state is
'frozen-in' and the so-called amorphous state is obtained. The amorphous version of the material
shrinks, leaving a pit where the laser dot was written, resulting in a recognizable CD surface.
When an 'Erase Power' laser beam heats the phase-change layer to below the melting
temperature but above the crystallization temperature (200º C) for a sufficient time (at least
longer than the minimum crystallization time), the atoms revert back to an ordered state (the
crystalline state). Writing takes place in a single pass of the focused laser beam, sometimes
referred to as 'direct overwriting' and the process can be repeated several thousand times per disc.
Once the data has been burned the amorphous areas reflect less light, enabling a 'Read Power'
laser beam to detect the difference between the lands and the pits on the disc. One compromise
here is that the disc reflects less light than CD-ROMs or CD-Rs and consequently CD-RW discs
can only be read on CD players that support the new MultiRead specification.
CD-RW drives are dual-function, offering both CD-R and CD-RW recording, so the user can
choose the best media for a particular job.
Although UDF (Universal Disc Format) allows users to drag and drop files to discs, CD-RW is
still not as easy to use as a hard drive. Initially limitations in the UDF standard and associated
driver software meant that when data was deleted from a CD-RW, those areas of the disc were
merely marked for deletion and were not immediately accessible. A disc could be used until all
its capacity was used, but then the entire disc had to be erased to reclaim its storage space using a
'sequential erase' function. In hardware terms erasing a disk is accomplished by heating up the
surface to a lower temperature, but for a longer time, which returns it to the crystalline state.
Evolution of the UDF standard and developments in associated driver software have improved
things considerably, making CD-RW more like hard drives or diskette disks.

Graphics

The Compaq Evo D510 e-pc has an integrated Intel graphics solution.

Intel 845G Chipset Integrated Graphics

The Intel 845G chipset offers integrated graphics with Dynamic Video Memory Technology
(DVMT). Some memory (8 MB) is reserved at boot time from the main memory; further
memory is allocated as needed.
Key Features
■
Dynamic Video Memory Technology: Ensures most efficient system memory usage for
optimal 2D/3D graphics and system performance
■
Zone Rendering Technology: Significantly reduces the memory bandwidth by up to
eleven times which results in much higher 3D performance
■
Tiled Memory Addressing: Performs Address Remapping in hardware for all graphics
surfaces which increases page coherency and improves memory efficiency
■
Dynamic Multi-Context Switcher: Provides deeply pipelined operations in both 2D and 3D
allowing overlapping operations with no need to flush between modes of operation
■
Intelligent Memory Manager: Fourth generation UMA Memory Manager that provides faster
accesses, adequate burst sizes and smart page closing policies
Technical Reference Guide
System Features
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