background preloader

PCI Express

PCI Express
PCI Express (Peripheral Component Interconnect Express), officially abbreviated as PCIe, is a high-speed serial computer expansion bus standard designed to replace the older PCI, PCI-X, and AGP bus standards. PCIe has numerous improvements over the aforementioned bus standards, including higher maximum system bus throughput, lower I/O pin count and smaller physical footprint, better performance-scaling for bus devices, a more detailed error detection and reporting mechanism (Advanced Error Reporting (AER)[1]), and native hot-plug functionality. More recent revisions of the PCIe standard support hardware I/O virtualization. The PCIe electrical interface is also used in a variety of other standards, most notably ExpressCard, a laptop expansion card interface. Format specifications are maintained and developed by the PCI-SIG (PCI Special Interest Group), a group of more than 900 companies that also maintain the conventional PCI specifications. Architecture[edit] A full-height 4x PCIe card.

Differential signaling Elimination of noise by using differential signaling. Advantages[edit] Tolerance of ground offsets[edit] In a system with a differential receiver, desired signals add and noise is subtracted away. Suitability for use with low-voltage electronics[edit] 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[edit] This advantage is not directly due to differential signaling itself, but to the common practice of transmitting differential signals on balanced lines.[1][2] Single-ended signals are still resistant to interference if the lines are balanced and terminated by a differential amplifier. Comparison with single-ended signaling[edit] Uses[edit] 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.[15]

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.[1] 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[edit] Ultra low power[edit] See also[edit]

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

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[edit] 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[edit] CRCs and data integrity[edit] Computation of CRC[edit] , 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.

Opto-isolator Schematic diagram of an opto-isolator showing source of light (LED) on the left, dielectric barrier in the center, and sensor (phototransistor) on the right.[note 1] In electronics, an opto-isolator, also called an optocoupler, photocoupler, or optical isolator, is a component that transfers electrical signals between two isolated circuits by using light.[1] Opto-isolators prevent high voltages from affecting the system receiving the signal.[2] Commercially available opto-isolators withstand input-to-output voltages up to 10 kV[3] and voltage transients with speeds up to 10 kV/μs.[4] History[edit] The value of optically coupling a solid state light emitter to a semiconductor detector for the purpose of electrical isolation was recognized in 1963 by Akmenkalns,et al. Operation[edit] Electric isolation[edit] Planar (top) and silicone dome (bottom) layouts - cross-section through a standard dual in-line package. Types of opto-isolators[edit] Resistive opto-isolators[edit]

Who's who in SSD? - Micron Who's who in SSD? - by Zsolt Kerekes, editor - June 2012 Micron sampled its 1st SSD products in early 2008 and made its first appearance in the Top 20 SSD Companies list in Q3 2010. But the company dropped out of the list again in the most recent edition of the top SSD companies (Q1 2012). I spoke to Ed Doller, VP of Enterprise SSD Solutions recently to discuss their enterprise SSD products. I had been following up a chain of SSD contacts within the company - and I was looking forward to finally getting some useful information about their enterprise SSDs. I started by saying that I was surprised that the information which is publicly available on Micron's enterprise SSD web pages - lacks the essential data that any serious designer would need to know in order to decide whether to shortlist Micron as a possible supplier. It wasn't me. Neither Micron nor anyone else can compile a list of who the biggest SSD users are based on traditional sales data. Micron is also in the consumer SSD market.

Winston Churchill Avenue Winston Churchill Avenue is an arterial road in the British overseas territory of Gibraltar. Description[edit] A time-lapsephotomontage showing multiple stages of a Monarch Airlines Airbus A320 aircraft taking off (moving right-to-left) from Gibraltar Airport, located at the northern end of Gibraltar. Also visible in the center is Winston Churchill Avenue, the only street joining Gibraltar to Spain. References[edit]

Related: