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Design Considerations
A desktop PC (personal computer) is a stationary computing system with the main functions being to accept data input, process the data, produce an output, and/or store the resultant data. Therefore, the three main aspects of a desktop computer are performance (how quickly it can perform a task), storage capacity (how much data it can store without being corrupted), and reliability (how long will the computer operate correctly). Desktop PCs are offered in a plethora of configurations to catch the attention of as many potential customers as possible. For example, a system with a large storage capacity may be very attractive to a photographer who stores and edits his/her images on the computer. Another popular configuration in recent years has been one with high-powered graphics cards for gaming enthusiasts.
Trends in Desktop Computing:
- Hard Disk:
A large-capacity permanent storage that use magnetic techniques to hold data such as programs, documents, pictures of your last vacation, etc. Over the years, this component has been the workhorse for data storage in the desktop PC, but has seen some pretty stiff competition in Notebook PCs from Hybrid Hard Drives (HHDs). HHDs carry not only magnetic disks to store data but also have non-volatile flash memory to cache data during normal use. The main benefits of HHDs are faster speeds, decreased power consumption, improved reliability, and a faster boot process, but are more expensive than its older counterpart. Since flash memory is still expensive in comparison to hard disks, it will be a while before this technology makes it into the desktop PC. - PCI Express Bus:
For many years the Peripheral Component Interconnect (PCI) Bus has been the most common way to connect additional components to the computer, but is now giving way to the its newer technology successor, PCI Express (PCIe). Although many desktop PCs currently still have PCI ports available, PCI will eventually (maybe within a year) yield its stronghold on the computer market to PCIe. PCI is comprised of a 33.33 MHz clock, 32 or 64-bit data bus, 5-V signaling and relies on reflected-wave switching to comprehend the desired voltage signal (which slows the signaling even more). On the hand, PCIe, which is based around serial links called lanes, was designed as a much faster interface to replace PCI, PCI-X, and AGP interfaces for computer expansion cards and graphics cards. The PCIe 1.1 bus runs at 2.5 GHz, but to detect errors and provide timing, it takes 10 clock ticks to transmit one byte (8b10b encoding). Therefore, each lane transmits 250 MB/s. The connection between card and motherboard consists of between one and 32 lanes giving a maximum transfer rate of 8 GB/s in each direction. To put speed into perspective, a single lane has nearly twice the data rate of normal PCI bus, a four lane slot has a comparable data rate to the fastest version of PCI-X 1.0, and an eight lane slot has a data rate comparable to the fastest version of AGP (Advanced Graphics Port). PCIe 2.0, which is currently being defined, doubles the data rate of each lane from 250 MB/s to 500 MB/s. PCIe 2.0 will be compatible with PCIe 1.1 (physical interface and software), so older cards will still be able to work in machines fitted with this new version. Once the transition is complete and PCIe is no longer supported on desktop motherboards, there will still be the need to have desktop PCs with PCI capability. For this reason, Texas Instruments (TI) has developed PCI-to-PCIe bridge ICs. - CPU:
The CPU will experience a bit of transformations in the coming years. Traditionally, the CPU has been improved (among other things) by increasing its clock frequency, lowering the core voltages, increasing its cache memory, etc there has relatively not been in much in terms of integration of other large functions. Intel-based chip sets separate the Memory Controller Hub (MCH) from the CPU, but an AMD CPU will have this integrated. It is anticipated that integration will be more prevalent in this microprocessor space for both manufacturers. Another big innovation in microprocessors is combining several core processors into a multi-core, monolithic unit. - DisplayPort:
DisplayPort, which supports a minimum of 1080p resolution over a 15 meter cable, is a new digital display interface standard put forth by VESA (Video Electronics Standards Association) slated to replace both DVI and HDMI in the computer. HDMI is the de facto digital connection for high-definition consumer electronics devices. DisplayPort defines a new license-free digital audio/video interconnect, intended to be used primarily between a computer and its display monitor, or a computer and a home-theater system. The video signal is not compatible with DVI or HDMI, but the specification will allow pass-through of these signals. DisplayPort has many advantages over HDMI; it performs with relatively low power-consumption, has a low pin count and can transmit data at 10.8 Gbps, supporting resolutions up to 2560x1600 (WQXGA) and possibly beyond. It can also perform properly over a length of cable up to 15 meters in length, which many see as a great advantage over HDMI. - Energy Efficiency:
Computer manufacturers are producing more environmentally-friendly products that conserve energy. These new products are designed to meet energy-efficiency standards of many key eco-label programs such as the ENERGY STAR® program, Germany s Blue Angel label, China s Energy Conservation Program, and Sweden s TCO labels. To reduce wasted power, energy-efficient desktop PCs include an 80 percent efficient power supply that not only converts the AC input (120 V and 60 Hz) to lower DC voltages (5 V, 3.3 V, and 12 V), but also meets the EPA s stringent ENERGY STAR f4.0 requirements. - Green PC:
Along with offering energy efficient desktop PCs, manufacturers are also providing products with little to no hazardous materials to protect the earth when the system has run through its lifecycle and is disposed of. TI offers almost all of its ICs housed in packages that are “Green” compliant-Lead-free, and has no Bromine or Antimony.
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ReplyDeleteThis article on microprocessor may also help readers:
What is Microprocessor?