69-449: SATA Express (sometimes unofficially shortened to SATAe ) is a computer bus interface that supports both Serial ATA (SATA) and PCI Express (PCIe) storage devices, initially standardized in the SATA ;3.2 specification. The SATA Express connector used on the host side is backward compatible with the standard SATA data connector , while it also provides two PCI Express lanes as
138-726: A bidirectional data bus, re-using the same wires for input and output at different times. Some processors use a dedicated wire for each bit of the address bus, data bus, and the control bus. For example, the 64-pin STEbus is composed of 8 physical wires dedicated to the 8-bit data bus, 20 physical wires dedicated to the 20-bit address bus, 21 physical wires dedicated to the control bus, and 15 physical wires dedicated to various power buses. Bus multiplexing requires fewer wires, which reduces costs in many early microprocessors and DRAM chips. One common multiplexing scheme, address multiplexing , has already been mentioned. Another multiplexing scheme re-uses
207-726: A card plugged into the bus, which is why computers have so many slots on the bus. But through the 1980s and 1990s, new systems like SCSI and IDE were introduced to serve this need, leaving most slots in modern systems empty. Today there are likely to be about five different buses in the typical machine, supporting various devices. "Third generation" buses have been emerging into the market since about 2001, including HyperTransport and InfiniBand . They also tend to be very flexible in terms of their physical connections, allowing them to be used both as internal buses, as well as connecting different machines together. This can lead to complex problems when trying to service different requests, so much of
276-485: A legacy logical device interface, as visible from the operating system perspective. Access to storage devices using AHCI as a logical device interface is possible for both SATA SSDs and PCI Express SSDs, so operating systems that do not provide support for NVMe can optionally be configured to interact with PCI Express storage devices as if they were legacy AHCI devices. However, because NVMe is far more efficient than AHCI when used with PCI Express SSDs, SATA Express interface
345-648: A more costly and less power efficient solution compared with the already available and widely adopted PCI Express bus. Thus, PCI Express was selected by the designers of SATA interface, as part of the SATA 3.2 revision that was standardized in 2013; extending the SATA specification to also provide a PCI Express interface within the same backward-compatible connector allowed much faster speeds by reusing already existing technology. Some vendors also use proprietary logical interfaces for their flash-based storage products , connected through
414-509: A passive backplane connected directly or through buffer amplifiers to the pins of the CPU . Memory and other devices would be added to the bus using the same address and data pins as the CPU itself used, connected in parallel. Communication was controlled by the CPU, which read and wrote data from the devices as if they are blocks of memory, using the same instructions, all timed by a central clock controlling
483-563: A pure PCI Express connection between the host and storage device, with no additional layers of bus abstraction. The SATA revision 3.2 specification, in its gold revision as of August 2013, standardizes the SATA Express and specifies its hardware layout and electrical parameters. The choice of PCI Express also enables scaling up the performance of SATA Express interface by using multiple lanes and different versions of PCI Express. In more detail, using two PCI Express 2.0 lanes provides
552-504: A pure PCI Express connection to the storage device. Instead of continuing with the SATA interface's usual approach of doubling its native speed with each major version, SATA 3.2 specification included the PCI Express bus for achieving data transfer speeds greater than the SATA 3.0 speed limit of 6 Gbit/s . Designers of the SATA interface concluded that doubling the native SATA speed would take too much time to catch up with
621-502: A second set of pins similar to those for communicating with memory—but able to operate with different speeds and protocols—to ensure that peripherals do not slow overall system performance. CPUs can also feature smart controllers to place the data directly in memory, a concept known as direct memory access . Low-performance bus systems have also been developed, such as the Universal Serial Bus (USB). Given technological changes,
690-506: A serial bus inherently has no timing skew or crosstalk. USB , FireWire , and Serial ATA are examples of this. Multidrop connections do not work well for fast serial buses, so most modern serial buses use daisy-chain or hub designs. The transition from parallel to serial buses was allowed by Moore's law which allowed for the incorporation of SerDes in integrated circuits which are used in computers. Network connections such as Ethernet are not generally regarded as buses, although
759-446: A single source LRI/LRU or, as with ARINC 629, MIL-STD-1553B, and STANAG 3910, be duplex , allow all the connected LRI/LRUs to act, at different times ( half duplex ), as transmitters and receivers of data. The frequency or the speed of a bus is measured in Hz such as MHz and determines how many clock cycles there are per second; there can be one or more data transfers per clock cycle. If there
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#1732852858018828-414: A total bandwidth of 1000 MB/s (2 × 5 GT /s raw data rate and 8b/10b encoding ), while using two PCI Express 3.0 lanes provides 1969 MB/s (2 × 8 GT/s raw data rate and 128b/130b encoding ). In comparison, the 6 Gbit/s raw bandwidth of SATA 3.0 equates effectively to 600 MB/s (6 GT/s raw data rate and 8b/10b encoding). There are three options available for
897-433: A unified system bus . In this case, a single mechanical and electrical system can be used to connect together many of the system components, or in some cases, all of them. Later computer programs began to share memory common to several CPUs. Access to this memory bus had to be prioritized, as well. The simple way to prioritize interrupts or bus access was with a daisy chain . In this case signals will naturally flow through
966-602: Is a zero insertion force flip-chip land grid array (LGA) CPU socket designed by Intel for CPUs built on the Haswell microarchitecture . This socket is also used by the Haswell's successor, Broadwell microarchitecture. It is the successor of LGA 1155 and was itself succeeded by LGA 1151 in 2015. Most motherboards with the LGA ;1150 socket support varying video outputs (VGA, DVI or HDMI – depending on
1035-412: Is a single transfer per clock cycle it is known as Single Data Rate (SDR), and if there are two transfers per clock cycle it is known as Double Data Rate (DDR) although the use of signalling other than SDR is uncommon outside of RAM. An example of this is PCIe which uses SDR. Within each data transfer there can be multiple bits of data. This is described as the width of a bus which is the number of bits
1104-548: Is an open standard interconnect for high-speed CPU -to-device and CPU-to-memory, designed to accelerate next-generation data center performance. Many field buses are serial data buses (not to be confused with the parallel "data bus" section of a system bus or expansion card ), several of which use the RS-485 electrical characteristics and then specify their own protocol and connector: Other serial buses include: Z97 LGA 1150 , also known as Socket H3 ,
1173-570: Is ensured by fully supporting legacy SATA 3.0 (6 Gbit/s) storage devices, both on the electrical level and through the required operating system support. Mechanically, connectors on the host side retain their backward compatibility in a way similar to how USB 3.0 does it – the new host-side SATA Express connector is made by "stacking" an additional connector on top of two legacy standard SATA data connectors, which are regular SATA 3.0 (6 Gbit/s) ports that can accept legacy SATA devices. This backward compatibility of
1242-475: Is provided by the bus—is not the case in many avionic systems , where data connections such as ARINC 429 , ARINC 629 , MIL-STD-1553B (STANAG 3838), and EFABus ( STANAG 3910 ) are commonly referred to as “data buses” or, sometimes, "databuses". Such avionic data buses are usually characterized by having several equipments or Line Replaceable Items/Units (LRI/LRUs) connected to a common, shared media . They may, as with ARINC 429, be simplex , i.e. have
1311-424: Is sent on the data bus). The width of the address bus determines the amount of memory a system can address. For example, a system with a 32-bit address bus can address 2 (4,294,967,296) memory locations. If each memory location holds one byte, the addressable memory space is 4 GB. Early processors used a wire for each bit of the address width. For example, a 16-bit address bus had 16 physical wires making up
1380-484: Is the case, for instance, with the VESA Local Bus which lacks the two least significant bits, limiting this bus to aligned 32-bit transfers. Historically, there were also some examples of computers which were only able to address words -- word machines . The memory bus is the bus which connects the main memory to the memory controller in computer systems . Originally, general-purpose buses like VMEbus and
1449-548: Is unable to deliver its maximum performance when AHCI is used to access PCI Express storage devices; see above for more details. Computer bus In computer architecture , a bus (historically also called data highway or databus ) is a communication system that transfers data between components inside a computer , or between computers. This expression covers all related hardware components (wire, optical fiber , etc.) and software , including communication protocols . In most traditional computer architectures ,
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#17328528580181518-469: The IBM PC , although similar physical architecture can be employed, instructions to access peripherals ( in and out ) and memory ( mov and others) have not been made uniform at all, and still generate distinct CPU signals, that could be used to implement a separate I/O bus. These simple bus systems had a serious drawback when used for general-purpose computers. All the equipment on the bus had to talk at
1587-672: The LGA ;2011-v3 CPU . As a result, the X99 provides bandwidths of up to 3.94 GB/s for connected PCI Express storage devices. Following the release of X99 chipset, numerous X99-based motherboards became available. In early March 2017, AMD Ryzen became available, bringing native support for SATA Express to the AMD Socket ;AM4 platform, through use of its accompanying X370, X300, B350, A320 and A300 chipsets. Ryzen also supports M.2 and other forms of PCI Express storage devices, using up to
1656-876: The S-100 bus were used, but to reduce latency , modern memory buses are designed to connect directly to DRAM chips, and thus are designed by chip standards bodies such as JEDEC . Examples are the various generations of SDRAM , and serial point-to-point buses like SLDRAM and RDRAM . An exception is the Fully Buffered DIMM which, despite being carefully designed to minimize the effect, has been criticized for its higher latency. Buses can be parallel buses , which carry data words in parallel on multiple wires, or serial buses , which carry data in bit-serial form. The addition of extra power and control connections, differential drivers , and data connections in each direction usually means that most serial buses have more conductors than
1725-477: The U.2 connector (originally known as SFF-8639 , with the renaming taking place in June 2015), which is expected to gain broader acceptance. The U.2 connector is mechanically identical to the SATA Express device plug, but provides four PCI Express lanes through a different usage of available pins. The table below summarizes the compatibility of involved connectors. Device-level backward compatibility for SATA Express
1794-399: The CPU and main memory tend to be tightly coupled, with the internal bus connecting the two being known as the system bus . In systems that include a cache , CPUs use high-performance system buses that operate at speeds greater than memory to communicate with memory. The internal bus (also known as the internal data bus, memory bus or system bus ) connects internal components of a computer to
1863-468: The IEEE "Superbus" study group, the open microprocessor initiative (OMI), the open microsystems initiative (OMI), the "Gang of Nine" that developed EISA , etc. Early computer buses were bundles of wire that attached computer memory and peripherals. Anecdotally termed the " digit trunk " in the early Australian CSIRAC computer, they were named after electrical power buses, or busbars . Almost always, there
1932-629: The PCI Express bus. Such storage products can use a multi-lane PCI Express link, while interfacing with the operating system through proprietary drivers and host interfaces. Moreover, as of June 2014 there are similar storage products using NVM Express as the non-proprietary logical interface for a PCI Express add-on card. Support for SATA Express was initially announced for the Intel 9 Series chipsets, Z97 and H97 Platform Controller Hubs (PCHs), with both of them supporting Intel Haswell and Haswell Refresh processors; availability of these two chipsets
2001-408: The SATA Express interface were released for consumers, and SATA Express ports quickly disappeared from new motherboards. SATA Express interface supports both PCI Express and SATA storage devices by exposing two PCI Express 2.0 or 3.0 lanes and two SATA 3.0 (6 Gbit/s) ports through the same host-side SATA Express connector (but not both at the same time). Exposed PCI Express lanes provide
2070-533: The address bus pins as the data bus pins, an approach used by conventional PCI and the 8086 . The various "serial buses" can be seen as the ultimate limit of multiplexing, sending each of the address bits and each of the data bits, one at a time, through a single pin (or a single differential pair). Over time, several groups of people worked on various computer bus standards, including the IEEE Bus Architecture Standards Committee (BASC),
2139-437: The advancements in solid-state drive (SSD) technology, would require too many changes to the SATA standard, and would result in a much greater power consumption compared with the existing PCI Express bus. As a widely adopted computer bus, PCI Express provides sufficient bandwidth while allowing easy scaling up by using faster or additional lanes . In addition to supporting legacy Advanced Host Controller Interface (AHCI) at
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2208-489: The bits themselves, and allows for an increase in data transfer speed without increasing the frequency of the bus. The effective or real data transfer speed/rate may be lower due to the use of encoding that also allows for error correction such as 128/130b (b for bit) encoding. The data transfer speed is also known as the bandwidth. The simplest system bus has completely separate input data lines, output data lines, and address lines. To reduce cost, most microcomputers have
2277-493: The bus can transfer per clock cycle and can be synonymous with the number of physical electrical conductors the bus has if each conductor transfers one bit at a time. The data rate in bits per second can be obtained by multiplying the number of bits per clock cycle times the frequency times the number of transfers per clock cycle. Alternatively a bus such as PCIe can use modulation or encoding such as PAM4 which groups 2 bits into symbols which are then transferred instead of
2346-409: The bus had to talk at the same speed. While the CPU was now isolated and could increase speed, CPUs and memory continued to increase in speed much faster than the buses they talked to. The result was that the bus speeds were now much slower than what a modern system needed, and the machines were left starved for data. A particularly common example of this problem was that video cards quickly outran even
2415-511: The bus in physical or logical order, eliminating the need for complex scheduling. Digital Equipment Corporation (DEC) further reduced cost for mass-produced minicomputers , and mapped peripherals into the memory bus, so that the input and output devices appeared to be memory locations. This was implemented in the Unibus of the PDP-11 around 1969. Early microcomputer bus systems were essentially
2484-615: The bus supplied power, but often use a separate power source. This distinction is exemplified by a telephone system with a connected modem , where the RJ11 connection and associated modulated signalling scheme is not considered a bus, and is analogous to an Ethernet connection. A phone line connection scheme is not considered to be a bus with respect to signals, but the Central Office uses buses with cross-bar switches for connections between phones. However, this distinction—that power
2553-457: The bus. As the buses became wider and lengthier, this approach became expensive in terms of the number of chip pins and board traces. Beginning with the Mostek 4096 DRAM , address multiplexing implemented with multiplexers became common. In a multiplexed address scheme, the address is sent in two equal parts on alternate bus cycles. This halves the number of address bus signals required to connect to
2622-431: The cards to be much more complex. These buses also often addressed speed issues by being "bigger" in terms of the size of the data path, moving from 8-bit parallel buses in the first generation, to 16 or 32-bit in the second, as well as adding software setup (now standardised as Plug-n-play ) to supplant or replace the jumpers. However, these newer systems shared one quality with their earlier cousins, in that everyone on
2691-426: The classical terms "system", "expansion" and "peripheral" no longer have the same connotations. Other common categorization systems are based on the bus's primary role, connecting devices internally or externally. However, many common modern bus systems can be used for both. SATA and the associated eSATA are one example of a system that would formerly be described as internal, while certain automotive applications use
2760-491: The computer into two "worlds", the CPU and memory on one side, and the various devices on the other. A bus controller accepted data from the CPU side to be moved to the peripherals side, thus shifting the communications protocol burden from the CPU itself. This allowed the CPU and memory side to evolve separately from the device bus, or just "bus". Devices on the bus could talk to each other with no CPU intervention. This led to much better "real world" performance, but also required
2829-489: The difference is largely conceptual rather than practical. An attribute generally used to characterize a bus is that power is provided by the bus for the connected hardware. This emphasizes the busbar origins of bus architecture as supplying switched or distributed power. This excludes, as buses, schemes such as serial RS-232 , parallel Centronics , IEEE 1284 interfaces and Ethernet, since these devices also needed separate power supplies. Universal Serial Bus devices may use
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2898-400: The first half of the memory address or the second half. Accessing an individual byte frequently requires reading or writing the full bus width (a word ) at once. In these instances the least significant bits of the address bus may not even be implemented - it is instead the responsibility of the controlling device to isolate the individual byte required from the complete word transmitted. This
2967-442: The heatsink to the motherboard are placed in a square with a lateral length of 75 mm for Intel's sockets LGA 1156 , LGA 1155 , LGA 1150, LGA 1151 and LGA 1200 . Cooling solutions should therefore be interchangeable. On May 12, 2014, Intel announced the release of two 9-series chipsets, H97 and Z97. Differences and new features of these two chipsets, compared to their H87 and Z87 counterparts, are
3036-467: The host-side SATA Express connector, which is formally known as the host plug, ensures the possibility for attaching legacy SATA devices to hosts equipped with SATA Express controllers. Backward compatibility on the software level, provided for legacy operating systems and associated device drivers that can access only SATA storage devices, is achieved by retaining support for the AHCI controller interface as
3105-632: The input and output of a given bus. IBM introduced these on the IBM 709 in 1958, and they became a common feature of their platforms. Other high-performance vendors like Control Data Corporation implemented similar designs. Generally, the channel controllers would do their best to run all of the bus operations internally, moving data when the CPU was known to be busy elsewhere if possible, and only using interrupts when necessary. This greatly reduced CPU load, and provided better overall system performance. To provide modularity, memory and I/O buses can be combined into
3174-496: The logical device interfaces and command sets used for interfacing with storage devices connected to a SATA Express controller: Connectors used for SATA Express were selected specifically to ensure backward compatibility with legacy SATA devices where possible, without the need for additional adapters or converters. The connector on the host side accepts either one PCI Express SSD or up to two legacy SATA devices, by providing either PCI Express lanes or SATA 3.0 ports depending on
3243-477: The logical interface level, SATA Express also supports NVM Express (NVMe) as the logical device interface for attached PCI Express storage devices. While the support for AHCI ensures software-level backward compatibility with legacy SATA devices and legacy operating systems , NVM Express is designed to fully utilize high-speed PCI Express storage devices by leveraging their capability of executing many I/O operations in parallel . The Serial ATA ( SATA ) interface
3312-448: The memory. For example, a 32-bit address bus can be implemented by using 16 lines and sending the first half of the memory address, immediately followed by the second half memory address. Typically two additional pins in the control bus – row-address strobe (RAS) and column-address strobe (CAS) – are used to tell the DRAM whether the address bus is currently sending
3381-446: The minimum of one used in 1-Wire and UNI/O . As data rates increase, the problems of timing skew , power consumption, electromagnetic interference and crosstalk across parallel buses become more and more difficult to circumvent. One partial solution to this problem has been to double pump the bus. Often, a serial bus can be operated at higher overall data rates than a parallel bus, despite having fewer electrical connections, because
3450-511: The model) and Intel Clear Video Technology. Full support of Windows on LGA 1150 platform starts on Windows 7 . Official Windows XP support is limited to selected CPUs, chipsets and only for embedded and industrial systems. Intel's Platform Controller Hub (PCH) for the LGA 1150 CPUs is codenamed Lynx Point . Intel Xeon processors for socket LGA 1150 use the Intel C222, C224, and C226 chipsets . The 4 holes for fastening
3519-415: The mother board. Local buses connect the CPU and memory to the expansion bus , which in turn connects the computer to peripherals. Bus systems such as the SATA ports in modern computers support multiple peripherals, allowing multiple hard drives to be connected without an expansion card . In systems that have a similar architecture to multicomputers , but which communicate by buses instead of networks,
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#17328528580183588-508: The need for a faster interface became apparent as the speed of SSDs and hybrid drives increased over time. As an example, some SSDs available in early 2009 were already well over the capabilities of SATA 1.0 and close to the SATA ;2.0 maximum transfer speed, while in the second half of 2013 high-end consumer SSDs had already reached the SATA 3.0 speed limit, requiring an even faster interface. While evaluating different approaches to
3657-719: The need for complex and costly shielding on SATA Express cables required for transmitting PCI Express synchronization signals, by providing a separate clock generator on the storage device with additional support from the motherboard firmware . In May 2014, Intel Z97 and H97 chipsets became available, bringing support for both SATA Express and M.2 , which is a specification for flash-based storage devices in form of internally mounted computer expansion cards . Z97 and H97 chipsets use two PCI Express 2.0 lanes for each of their SATA Express ports, providing 1 GB/s of bandwidth to PCI Express storage devices. The release of these two new chipsets, intended primarily for high-end desktops,
3726-401: The newer bus systems like PCI , and computers began to include AGP just to drive the video card. By 2004 AGP was outgrown again by high-end video cards and other peripherals and has been replaced by the new PCI Express bus. An increasing number of external devices started employing their own bus systems as well. When disk drives were first introduced, they would be added to the machine with
3795-502: The peripheral bus, which includes bus systems like PCI. Early computer buses were parallel electrical wires with multiple hardware connections, but the term is now used for any physical arrangement that provides the same logical function as a parallel electrical busbar . Modern computer buses can use both parallel and bit serial connections, and can be wired in either a multidrop (electrical parallel) or daisy chain topology, or connected by switched hubs. Many modern CPUs also feature
3864-441: The primarily external IEEE 1394 in a fashion more similar to a system bus. Other examples, like InfiniBand and I²C were designed from the start to be used both internally and externally. An address bus is a bus that is used to specify a physical address . When a processor or DMA -enabled device needs to read or write to a memory location, it specifies that memory location on the address bus (the value to be read or written
3933-484: The program attempted to perform those other tasks, it might take too long for the program to check again, resulting in loss of data. Engineers thus arranged for the peripherals to interrupt the CPU. The interrupts had to be prioritized, because the CPU can only execute code for one peripheral at a time, and some devices are more time-critical than others. High-end systems introduced the idea of channel controllers , which were essentially small computers dedicated to handling
4002-454: The required speed increase, designers of the SATA interface concluded that extending the SATA interface so it doubles its native speed to 12 Gbit/s would require more than two years, making that approach unsuitable for catching up with advancements in SSD technology. At the same time, increasing the native SATA speed to 12 Gbit/s would require too many changes to the SATA standard, ending up in
4071-420: The same speed, as it shared a single clock. Increasing the speed of the CPU becomes harder, because the speed of all the devices must increase as well. When it is not practical or economical to have all devices as fast as the CPU, the CPU must either enter a wait state , or work at a slower clock frequency temporarily, to talk to other devices in the computer. While acceptable in embedded systems , this problem
4140-518: The speed of the CPU. Still, devices interrupted the CPU by signaling on separate CPU pins. For instance, a disk drive controller would signal the CPU that new data was ready to be read, at which point the CPU would move the data by reading the "memory location" that corresponded to the disk drive. Almost all early microcomputers were built in this fashion, starting with the S-100 bus in the Altair 8800 computer system. In some instances, most notably in
4209-399: The system bus is known as a front-side bus . In such systems, the expansion bus may not share any architecture with their host CPUs, instead supporting many different CPUs, as is the case with PCI . While the term " peripheral bus " is sometimes used to refer to all other buses apart from the system bus, the "expansion bus" has also been used to describe a third category of buses separate from
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#17328528580184278-513: The total of eight PCI Express 3.0 lanes provided by the chipset and the AM4 CPU. As a result, Ryzen provides bandwidths of up to 7.88 GB/s for connected PCI Express storage devices. As a form factor, SATA Express is considered a failed standard, because when SATA Express was introduced, the M.2 form factor and NVMe standards were also launched, gaining much larger popularity than Serial ATA and SATA Express. Not many storage devices utilizing
4347-512: The type of connected storage device. There are five types of SATA Express connectors, differing by their position and purpose: The above listed SATA Express connectors provide only two PCI Express lanes, as the result of overall design focusing on a rapid low-cost platform transition. That choice allowed easier backward compatibility with legacy SATA devices, together with making it possible to use cheaper unshielded cables. As of March 2015, some NVM Express devices in form of 2.5-inch drives use
4416-522: The work on these systems concerns software design, as opposed to the hardware itself. In general, these third generation buses tend to look more like a network than the original concept of a bus, with a higher protocol overhead needed than early systems, while also allowing multiple devices to use the bus at once. Buses such as Wishbone have been developed by the open source hardware movement in an attempt to further remove legal and patent constraints from computer design. The Compute Express Link (CXL)
4485-462: Was designed primarily for interfacing with hard disk drives (HDDs), doubling its native speed with each major revision: maximum SATA transfer speeds went from 1.5 Gbit/s in SATA 1.0 (standardized in 2003), through 3 Gbit/s in SATA 2.0 (standardized in 2004), to 6 Gbit/s as provided by SATA 3.0 (standardized in 2009). SATA has also been selected as the interface for gradually more adopted solid-state drives ( SSDs ), but
4554-441: Was not tolerated for long in general-purpose, user-expandable computers. Such bus systems are also difficult to configure when constructed from common off-the-shelf equipment. Typically each added expansion card requires many jumpers in order to set memory addresses, I/O addresses, interrupt priorities, and interrupt numbers. "Second generation" bus systems like NuBus addressed some of these problems. They typically separated
4623-402: Was one bus for memory, and one or more separate buses for peripherals. These were accessed by separate instructions, with completely different timings and protocols. One of the first complications was the use of interrupts . Early computer programs performed I/O by waiting in a loop for the peripheral to become ready. This was a waste of time for programs that had other tasks to do. Also, if
4692-605: Was planned for 2014. In December 2013, Asus unveiled a prototype " Z87 -Deluxe/SATA Express" motherboard based on the Intel Z87 chipset, supporting Haswell processors and using additional ASMedia controller to provide SATA Express connectivity; this motherboard was also showcased at CES 2014 although no launch date was announced. In April 2014, Asus also demonstrated support for the so-called separate reference clock with independent spread spectrum clocking (SRIS) with some of its pre-production SATA Express hardware. SRIS eliminates
4761-437: Was soon followed by the availability of Z97- and H97-based motherboards. In late August 2014, Intel X99 chipset became available, bringing support for both SATA Express and M.2 to the Intel's enthusiast platform. Each of the X99's SATA Express ports requires two PCI Express 2.0 lanes provided by the chipset, while the M.2 slots can use either two 2.0 lanes from the chipset itself, or up to four 3.0 lanes taken directly from
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