Differential signaling Elimination of noise by using differential signaling. Advantages Tolerance of ground offsets In a system with a differential receiver, desired signals add and noise is subtracted away. Suitability for use with low-voltage electronics In the electronics industry, and particularly in portable and mobile devices, there is a continuing tendency to lower the supply voltage in order to save power and reduce unwanted emitted radiation. To see why, consider a single-ended digital system with supply voltage . and the low logic level is 0 V. . and the other at 0 V, is . . . Resistance to electromagnetic interference This advantage is not directly due to differential signaling itself, but to the common practice of transmitting differential signals on balanced lines. Single-ended signals are still resistant to interference if the lines are balanced and terminated by a differential amplifier. Comparison with single-ended signaling Uses Differential pairs include:
RAMCloud - RAMCloud Project - Confluence What is RAMCloud? RAMCloud is a new class of storage for large-scale datacenter applications. It is a key-value store that keeps all data in DRAM at all times (it is not a cache like memcached). From a practical standpoint, RAMCloud enables a new class of applications that manipulate large data sets very intensively. RAMCloud is also interesting from a research standpoint. The RAMCloud project is based in the Department of Computer Science at Stanford University. Learning About RAMCloud General information about RAMCloud, such as talks and papers. Introductory talk on RAMCloud by John Ousterhout, given at LinkedIn on October 12, 2011.The Case for RAMCloud: an early position paper that discusses the motivation for RAMCloud, the new kinds of applications it may enable, and some of the research issues that will have to be addressed to create a working system. How to Deploy and Use RAMCloud RAMCloud Performance Information for RAMCloud Developers The RAMCloud Test Cluster New Cluster Design Notes
Thunderbolt (interface) Thunderbolt combines PCI Express (PCIe) and DisplayPort (DP) into one serial signal alongside a DC connection for electric power, transmitted over one cable. Up to six peripherals may be supported by one connector through various topologies. A Thunderbolt connector Thunderbolt link connections Intel will provide two types of Thunderbolt controllers, a 2 port type and a 1 port type. Daisy-Chain configuration can connect host with 6 devices(5 devices and 1 displayer) Speed Chart Comparison of USB & Thunderbolt™ HighPoint Technologies,Inc. announces Thunderbolt™ adapter at Computex Taipei, provides the connection ability to SAS/SATA/PCI-E. Thunderbolt was developed by Intel. A single legacy Mini DisplayPort monitor or other device of any kind may be connected directly or at the very end of the chain. The technology was presented as having an initial speed of 10 Gbit/s over plastic optical cables, and promising a final speed of 100 Gbit/s in the future.
PC Card In computing, PC Card is a form factor peripheral interface designed for laptop computers. Originally introduced as PCMCIA Card, the PC Card standard as well as its successors like CardBus were defined and developed by the Personal Computer Memory Card International Association (PCMCIA). It was originally designed as a standard for memory-expansion cards for computer storage. History By early 1990, some thirty companies had joined the initiative already, including Poqet, Fujitsu, Intel, Mitsubishi, IBM, Lotus, Microsoft and SCM Microsystems. The PCMCIA 1.0 card standard was published in November 1990 and was soon adopted by more than eighty vendors. It corresponds with the Japanese JEIDA memory card 4.0 standard. Many notebooks in the 1990s had two adjacent type-II slots, which allowed installation of two type-II cards or one, double-thickness, type-III card. Two PC Card devices: Xircom RealPort (top) type III and 3Com (bottom) type II. Summary Type I: 16 bit.
Current mode logic differential digital logic family Current mode logic (CML), or source-coupled logic (SCL), is a digital design style used both for logic gates and for board-level digital signalling of digital data . The basic principle of CML is that current from a constant current generator is steered between two alternate paths depending on whether a logic zero or logic one is being represented. Typically, the generator is connected to the two sources of a pair of differential FETs with the two paths being their two drains. Bipolar equivalents operate in the same way, with the output being taken from the collectors of the BJT transistors. As a differential PCB-level interconnect, it is intended to transmit data at speeds between 312.5 Mbit/s and 3.125 Gbit/s across standard printed circuit boards. The transmission is point-to-point, unidirectional, and is usually terminated at the destination with 50 Ω resistors to Vcc on both differential lines. Operation Ultra low power See also
Enterprise PCIe SSD Does PCIe replace SATA and SAS SSDs? Not exactly. PCIe is a high-performance interface with performance targets of 415,000 IOPS and 2 GB/s of bandwidth. PCIe SSDs are intended to augment most server or storage systems by providing several hardware acceleration and caching capabilities to help boost performance. Performance targets vary per system and application. At Micron, we offer our customers choices—our complete SSD portfolio provides the best tool for the job. Is Micron a member of the SSD Small Form Factor Working Group? Yes. What is the secure erase password for the P320h SSD? ffff What type of NAND is used in the P320h drive? The P320h drive uses Micron’s SLC ONFI 2.1 NAND Flash. Can I reduce power consumption on a PCIe drive? Yes, you can reduce the drive’s power consumption to ≤25W by activating the power-limiting feature. In the command-line version (CLI) of RSSDM, perform these steps: The power-limiting feature also can be activated through the RSSDM GUI: Not exactly. No. No. Yes.
5 Hilariously Bad Ideas That Actually Solved Huge Problems Here at Cracked, we like to celebrate outside-the-box thinking: the crazy inventors, the creative solutions, the improvised weapons. So we're not saying that any of the below are necessarily good ideas. We're just saying that even the most insane problems need to be solved, and sometimes they're solved with more insanity. #5. Zimbabwe Battles a Backed-Up Sewer With Synchronized Toilet Flushing Photos.com The Ridiculous Problem: Please, take a moment out of your day and thank your toilet. Getty"We're about to be in deep shit. You can imagine the problems this causes. What's a city to do? The Solution: Create a tidal wave with their toilets, that's what. Faced with a seemingly impossible situation, Bulawayo's city officials decided to do something that would appear to be straight out of a cartoon: They calmly ordered everyone in the city to start flushing their toilets at the exact same time, at three-day intervals. Photos.com"This town needs an enema! #4. Make men pee sitting down. #3. Getty
PCI-X It has been replaced in modern designs by the similar-sounding PCI Express (officially abbreviated as PCIe), with a completely different connector and a very different logical design, being a single narrow but fast serial connection instead of a number of slower connections in parallel. History Background and motivation In PCI, a transaction that cannot be completed immediately is postponed by either the target or the initiator issuing retry-cycles, during which no other agents can use the PCI bus. PCI also suffered from the relative scarcity of unique interrupt lines. The lack of registered I/Os limited PCI to a maximum frequency of 66 MHz. Some devices, most notably Gigabit Ethernet cards, SCSI controllers (Fibre Channel and Ultra320), and cluster interconnects could by themselves saturate the PCI bus's 133 MB/s bandwidth. PCI-X 1.0 PCI-X 2.0 In 2003, the PCI SIG ratified PCI-X 2.0. Technical description The two most fundamental changes are: Versions
Cyclic redundancy check A cyclic redundancy check (CRC) is an error-detecting code commonly used in digital networks and storage devices to detect accidental changes to raw data. Blocks of data entering these systems get a short check value attached, based on the remainder of a polynomial division of their contents; on retrieval the calculation is repeated, and corrective action can be taken against presumed data corruption if the check values do not match. The CRC was invented by W. Wesley Peterson in 1961; the 32-bit CRC function of Ethernet and many other standards is the work of several researchers and was published during 1975. Introduction CRCs are based on the theory of cyclic error-correcting codes. A CRC is called an n-bit CRC when its check value is n bits. The simplest error-detection system, the parity bit, is in fact a trivial 1-bit CRC: it uses the generator polynomial x + 1 (two terms), and has the name CRC-1. Application CRCs and data integrity Computation of CRC , where
Micron P320h PCIe SSD (700GB) Review Update: Micron tells us that the P320h doesn't support NVMe, we are digging to understand how Micron's controller differs from the NVMe IDT controller with a similar part number. Well over a year ago Micron announced something unique in a sea of PCIe SSDs that were otherwise nothing more than SATA drives in RAID on a PCIe card. The drive Micron announced was the P320h, featuring a custom ASIC and a native PCIe interface. The vast majority of PCIe SSDs we've looked at thus far feature multiple SATA/SAS SSD controllers with their associated NAND behind a SATA/SAS RAID controller on a PCIe card. These PCIe SSDs basically deliver the performance of a multi-drive SSD RAID-0 on a single card instead of requiring multiple 2.5" bays. There's decent interest in these types of PCIe SSDs simply because of the form factor advantage as many servers these days have moved to slimmer form factors (1U/2U) that don't have all that many 2.5" drive bays.
6 Insane Roads You Won't Believe People Actually Drive On In the name of making all of us appreciate what we have in life, we have in the past looked at some of the most terrifying commutes in the world, proving that none of nature's obstacles can keep man from going where he wants to go. For further (even more insane) evidence, you only need to look at where we've chosen to build our highways, oblivious to all obstacles, elements and mortal danger. #6. Lena Highway Eats Your Car and Casts You into a Hopeless Dystopia Via Englishrussia.com It carries the loving nickname "Highway from Hell," and when travelers say they're "neck-deep in mud," they're just trying to give an accurate measurement: Via Oknation.net"Hon, would you mind getting out and giving us a push?" And in fact ... ... they might be making an understatement. Via Englishrussia.comThe thing about all the mud is -- wait, is that guy wearing pants? During winter, this works just fine. Via Englishrussia.com"OK, so who are we eating first?" In deepest Siberia. With all the cars slowly sinking.
Accelerated Graphics Port The Accelerated Graphics Port (often shortened to AGP) is a high-speed point-to-point channel for attaching a video card to a computer's motherboard, primarily to assist in the acceleration of 3D computer graphics. Originally it was designed as a successor to PCI type connections. Since 2004, AGP has been progressively phased out in favor of PCI Express (PCIe). By mid-2008, PCIe cards dominated the market and only a few AGP models were available. Advantages over PCI As computers increasingly became graphically oriented, successive generations of graphics adapters began to push the limits of PCI, a bus with shared bandwidth. History An AGP card The first Socket 7 chipsets to support AGP were the VIA Apollo VP3, SiS 5591/5592, and the ALI Aladdin V. Microsoft first introduced AGP support into Windows 95 OEM Service Release 2 (OSR2 version 1111 or 950B) via the USB SUPPLEMENT to OSR2 patch. After applying the patch the Windows 95 system became Windows 95 version 4.00.950 B.