Misplaced Pages

#256743

53-656: M.2 , pronounced m dot two and formerly known as the Next Generation Form Factor ( NGFF ), is a specification for internally mounted computer expansion cards and associated connectors. M.2 replaces the Mini SATA ( mSATA ) standard and the Mini PCIe ( mPCIe ) standard (which is how it got the short name of M dot 2 from being Mini SATA 2). Employing a more flexible physical specification, M.2 allows different module widths and lengths, which, paired with

106-411: A single serial RS232 port or Ethernet port. An expansion card can be installed to offer multiple RS232 ports or multiple and higher bandwidth Ethernet ports. In this case, the motherboard provides basic functionality but the expansion card offers additional or enhanced ports. One edge of the expansion card holds the contacts (the edge connector or pin header ) that fit into the slot. They establish

159-523: A PCI Bus. Generally speaking, most PCI expansion cards will function on any CPU platform which incorporates PCI bus hardware provided there is a software driver for that type. PCI video cards and any other cards that contain their own BIOS or other ROM are problematic, although video cards conforming to VESA Standards may be used for secondary monitors. DEC Alpha, IBM PowerPC, and NEC MIPS workstations used PCI bus connectors. Both Zorro II and NuBus were plug and play , requiring no hardware configuration by

212-651: A card cage which passively distributed signals and power between the cards. Proprietary bus implementations for systems such as the Apple II co-existed with multi-manufacturer standards. IBM introduced what would retroactively be called the Industry Standard Architecture (ISA) bus with the IBM PC in 1981. At that time, the technology was called the PC bus . The IBM XT , introduced in 1983, used

265-412: A discrete GPU. Most other computer lines, including those from Apple Inc. , Tandy , Commodore , Amiga , and Atari, Inc. , offered their own expansion buses. The Amiga used Zorro II . Apple used a proprietary system with seven 50-pin-slots for Apple II peripheral cards , then later used both variations on Processor Direct Slot and NuBus for its Macintosh series until 1995, when they switched to

318-400: A high-speed multi-channel data acquisition system would be of no use in a personal computer used for bookkeeping, but might be a key part of a system used for industrial process control. Expansion cards can often be installed or removed in the field, allowing a degree of user customization for particular purposes. Some expansion cards take the form of "daughterboards" that plug into connectors on

371-492: A module is single- or double-sided, and the maximum allowed thickness of mounted components; possible values are listed in the right table above. Module keying is specified by the "K-K" part, in an encoded form using the key IDs from the left table above; it can also be specified as "K" only, if a module has only one keying notch. Beside socketed modules, the M.2 standard also includes the option for having permanently soldered single-sided modules. In 2017, Samsung introduced

424-486: A new form factor called Next Generation Small Form Factor (NGSFF), also known as NF1 or M.3, which may replace U.2 in server applications. The NGSFF connector is electrically and dimensionally compatible with M.2 (revision 1.1)'s connector; new functionality is achieved through previously unused (N/C) pins. The main changes compared to M.2 are: In 2018, the PCI-SIG issued a warning that NGSFF's new pin usage clashes with

477-589: A passive backplane . The first commercial microcomputer to feature expansion slots was the Micral N , in 1973. The first company to establish a de facto standard was Altair with the Altair 8800 , developed 1974–1975, which later became a multi-manufacturer standard, the S-100 bus . Many of these computers were also passive backplane designs, where all elements of the computer, (processor, memory, and I/O) plugged into

530-543: A passive adapter can be made to connect XT cards to a PLUS expansion connector. Another feature of PLUS cards is that they are stackable. Another bus that offered stackable expansion modules was the "sidecar" bus used by the IBM PCjr . This may have been electrically comparable to the XT bus; it most certainly had some similarities since both essentially exposed the 8088 CPU's address and data buses, with some buffering and latching,

583-410: A plastic "box" open on one side, with pins on one or both sides of the longer edges, sprung to push into the middle of the open center. Connectors are often keyed to ensure the correct polarity , and may contain bumps or notches both for polarity and to ensure that the wrong type of device is not inserted. The socket's width is chosen to fit to the thickness of the connecting PCB. The opposite side of

SECTION 10

#1732791399257

636-688: A supporting system board. In personal computing , notable expansion buses and expansion card standards include the S-100 bus from 1974 associated with the CP/M operating system , the 50-pin expansion slots of the original Apple II computer from 1977 (unique to Apple), IBM's Industry Standard Architecture (ISA) introduced with the IBM PC in 1981, Acorn 's tube expansion bus on the BBC Micro also from 1981, IBM's patented and proprietary Micro Channel architecture (MCA) from 1987 that never won favour in

689-412: Is an expansion card that attaches to a system directly. Daughterboards often have plugs, sockets, pins or other attachments for other boards. Daughterboards often have only internal connections within a computer or other electronic devices, and usually access the motherboard directly rather than through a computer bus . Such boards are used to either improve various memory capacities of a computer, enable

742-594: Is essentially a compact version of the ISA bus. The CardBus expansion card standard is an evolution of the PC card standard to make it into a compact version of the PCI bus. The original ExpressCard standard acts like it is either a USB 2.0 peripheral or a PCI Express 1.x x1 device. ExpressCard 2.0 adds SuperSpeed USB as another type of interface the card can use. Unfortunately, CardBus and ExpressCard are vulnerable to DMA attack unless

795-586: Is the portion of a printed circuit board (PCB) consisting of traces leading to the edge of the board that are intended to plug into a matching socket . The edge connector is a money-saving device because it only requires a single discrete female connector (the male connector is formed out of the edge of the PCB), and they also tend to be fairly robust and durable. They are commonly used in computers for expansion slots for peripheral cards, such as PCI , PCI Express , and AGP cards. Edge connector sockets consist of

848-428: Is up to the manufacturer of the M.2 host or module to select which interfaces are to be supported, depending on the desired level of host support and the module type. Different M.2 connector keying notches denote various purposes and capabilities of both the M.2 hosts and modules, and also prevent the M.2 modules from being inserted into incompatible host connectors. The M.2 specification supports NVM Express (NVMe) as

901-706: The Nintendo Entertainment System and the Sega Genesis included expansion buses in some form; In the case of at least the Genesis, the expansion bus was proprietary. In fact, the cartridge slots of many cartridge-based consoles (not counting the Atari 2600 ) would qualify as expansion buses, as they exposed both read and write capabilities of the system's internal bus. However, the expansion modules attached to these interfaces, though functionally

954-475: The clone market, the vastly improved Peripheral Component Interconnect (PCI) that displaced ISA in 1992, and PCI Express from 2003 which abstracts the interconnect into high-speed communication "lanes" and relegates all other functions into software protocol. Vacuum-tube based computers had modular construction, but individual functions for peripheral devices filled a cabinet, not just a printed circuit board. Processor, memory and I/O cards became feasible with

1007-456: The form factor of the motherboard and case , around one to seven expansion cards can be added to a computer system. 19 or more expansion cards can be installed in backplane systems. When many expansion cards are added to a system, total power consumption and heat dissipation become limiting factors. Some expansion cards take up more than one slot space. For example, many graphics cards on the market as of 2010 are dual slot graphics cards, using

1060-911: The mezzanine of a theatre . Wavetable cards ( sample-based synthesis cards) are often mounted on sound cards in this manner. Some mezzanine card interface standards include the 400 pin FPGA Mezzanine Card (FMC); the 172 pin High-Speed Mezzanine Card (HSMC); the PCI Mezzanine Card (PMC); XMC mezzanines; the Advanced Mezzanine Card ; IndustryPacks (VITA 4), the GreenSpring Computers Mezzanine modules ; etc. Examples of daughterboard-style expansion cards include: Edge connector An edge connector

1113-436: The processor being mounted on a card with an edge connector, instead of directly to the motherboard as before and since. IBM PCs used edge connector sockets attached to ribbon cables to connect 5.25" floppy disk drives . 3.5" drives use a pin connector instead. Video game cartridges typically take the form of a PCB with an edge connector: the socket is located within the console itself. The Nintendo Entertainment System

SECTION 20

#1732791399257

1166-493: The 32-bit extended version of ISA championed by Compaq , was used on some PC motherboards until 1997, when Microsoft declared it a "legacy" subsystem in the PC 97 industry white-paper. Proprietary local buses (q.v. Compaq) and then the VESA Local Bus Standard, were late 1980s expansion buses that were tied but not exclusive to the 80386 and 80486 CPU bus. The PC/104 bus is an embedded bus that copies

1219-575: The Host PCI Bus via PCI to PCI Bridge. Cardbus is being supplanted by ExpressCard format. Intel introduced the AGP bus in 1997 as a dedicated video acceleration solution. AGP devices are logically attached to the PCI bus over a PCI-to-PCI bridge. Though termed a bus, AGP usually supports only a single card at a time ( Legacy BIOS support issues). From 2005 PCI Express has been replacing both PCI and AGP. This standard, approved in 2004, implements

1272-511: The ISA bus had to have in-depth knowledge of the hardware they were adding to properly connect the devices, since memory addresses, I/O port addresses, and DMA channels had to be configured by switches or jumpers on the card to match the settings in driver software. IBM's MCA bus, developed for the PS/2 in 1987, was a competitor to ISA, also their design, but fell out of favor due to the ISA's industry-wide acceptance and IBM's licensing of MCA. EISA,

1325-524: The ISA bus. Intel launched their PCI bus chipsets along with the P5 -based Pentium CPUs in 1993. The PCI bus was introduced in 1991 as a replacement for ISA. The standard (now at version 3.0) is found on PC motherboards to this day. The PCI standard supports bus bridging: as many as ten daisy-chained PCI buses have been tested. CardBus , using the PCMCIA connector, is a PCI format that attaches peripherals to

1378-427: The M.2 form factor with a significantly smaller one (also called XT2), so that it can also be designed as an alternative to soldered memory. XFM Express utilizes a NVMe logical interface over a PCI Express physical interface. Expansion card Expansion cards allow the capabilities and interfaces of a computer system to be extended or supplemented in a way appropriate to the tasks it will perform. For example,

1431-439: The M.2 module sizes contain both the width and length of a particular module; for example, "2242" as a module code means that the module is 22 mm wide and 42 mm long, while "2280" denotes a module 22 mm wide and 80 mm long. An M.2 module is installed into a mating connector provided by the host's circuit board, and a single mounting screw secures the module into place. Components may be mounted on either side of

1484-582: The addition of interrupts and DMA provided by Intel add-on chips, and a few system fault detection lines (Power Good, Memory Check, I/O Channel Check). Again, PCjr sidecars are not technically expansion cards, but expansion modules, with the only difference being that the sidecar is an expansion card enclosed in a plastic box (with holes exposing the connectors). Laptops are generally unable to accept most expansion cards intended for desktop computers. Consequently, several compact expansion standards were developed. The original PC Card expansion card standard

1537-418: The availability of more advanced interfacing features, makes M.2 more suitable than mSATA in general for solid-state storage applications, particularly in smaller devices such as ultrabooks and tablets . Computer bus interfaces provided through the M.2 connector are PCI Express x4 (up to four lanes ), Serial ATA 3.0 , and USB 3.0 (a single logical port for each of the latter two). It

1590-430: The basic functionality of an electronic device, such as when a certain model has features added to it and is released as a new or separate model. Rather than redesigning the first model completely, a daughterboard may be added to a special connector on the main board. These usually fit on top of and parallel to the board, separated by spacers or standoffs , and are sometimes called mezzanine cards due to being stacked like

1643-401: The board for limited changes or customization. Since reliable multi-pin connectors are relatively costly, some mass-market systems such as home computers had no expansion slots and instead used a card-edge connector at the edge of the main board, putting the costly matching socket into the cost of the peripheral device. In the case of expansion of on-board capability, a motherboard may provide

M.2 - Misplaced Pages Continue

1696-452: The computer to connect to certain kinds of networks that it previously could not connect to, or to allow for users to customize their computers for various purposes such as gaming. Daughterboards are sometimes used in computers in order to allow for expansion cards to fit parallel to the motherboard, usually to maintain a small form factor . This form are also called riser cards , or risers. Daughterboards are also sometimes used to expand

1749-447: The connector itself is specified to endure 60 mating cycles. However, many M.2 slots (Socket 1, 2 and 3) found on motherboards only provide up to 3.3 V power. The M.2 standard allows module widths of 12, 16, 22 and 30 mm, and lengths of 16, 26, 30, 38, 42, 60, 80 and 110 mm. Initial line-up of the commercially available M.2 expansion cards is 22 mm wide, with varying lengths of 30, 42, 60, 80 and 110 mm. The codes for

1802-451: The development of integrated circuits . Expansion cards make processor systems adaptable to the needs of the user by making it possible to connect various types of devices, including I/O, additional memory, and optional features (such as a floating point unit ) to the central processor. Minicomputers, starting with the PDP-8 , were made of multiple cards communicating through, and powered by,

1855-468: The electrical contact between the electronics on the card and on the motherboard. Peripheral expansion cards generally have connectors for external cables. In the PC-compatible personal computer, these connectors were located in the support bracket at the back of the cabinet. Industrial backplane systems had connectors mounted on the top edge of the card, opposite to the backplane pins. Depending on

1908-694: The following device classes: Wi-Fi , Bluetooth , satellite navigation , near field communication (NFC), digital radio , WiGig , wireless WAN (WWAN), and solid-state drives (SSDs). The SATA revision 3.2 specification, in its gold revision as of August 2013, standardizes M.2 as a new format for storage devices and specifies its hardware layout. Buses exposed through the M.2 connector include PCI Express (PCIe) 3.0 and newer, Serial ATA (SATA) 3.0 and USB  3.0; all these standards are backward compatible . The M.2 specification provides up to four PCI Express lanes and one logical SATA 3.0 (6 Gbit/s) port, and exposes them through

1961-460: The footprint of an mSATA device. M.2 modules are rectangular, with an edge connector on one side and a semicircular mounting hole at the center of the opposite edge. The edge connector has 75 positions with up to 67 pins, employing a 0.5 mm pitch and offsetting the pins on opposing sides of the PCB from each other. Each pin on the connector is rated for up to 50  V and 0.5  A , while

2014-414: The laptop has an IOMMU that is configured to thwart these attacks. One notable exception to the above is the inclusion of a single internal slot for a special reduced size version of the desktop standard. The most well known examples are Mini-PCI or Mini PCIe . Such slots were usually intended for a specific purpose such as offering "built-in" wireless networking or upgrading the system at production with

2067-526: The logical PCI protocol over a serial communication interface. PC/104(-Plus) or Mini PCI are often added for expansion on small form factor boards such as Mini-ITX . For their 1000 EX and 1000 HX models, Tandy Computer designed the PLUS expansion interface, an adaptation of the XT-bus supporting cards of a smaller form factor. Because it is electrically compatible with the XT bus (a.k.a. 8-bit ISA or XT-ISA),

2120-504: The logical device interface for M.2 PCI Express SSDs , in addition to supporting legacy Advanced Host Controller Interface (AHCI) at the logical interface level. 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 the capability of high-speed PCI Express storage devices to perform many I/O operations in parallel . M.2 modules can integrate multiple functions, including

2173-481: The module, with the actual module type limiting how thick the components can be; the maximum allowable thickness of components is 1.5 mm per side, and the thickness of the PCB is 0.8 mm ± 10% . Different host-side connectors are used for single- and double-sided M.2 modules, providing different amounts of space between the M.2 expansion card and the host's PCB. Circuit boards on the hosts are usually designed to accept multiple lengths of M.2 modules, which means that

M.2 - Misplaced Pages Continue

2226-453: The pin usage in the upcoming 1.2 revision of the M.2 standard. The new revision uses some of the previously non-connected (N/C) pins to deliver 1.8 V power and USB 2.0 data on the "M" socket. Samsung has sought to standardize its NGSFF/NF1 through JEDEC , but the process appears to have stalled. JEDEC JESD233 is another specification called Crossover Flash Memory (XFM) for XFM Embedded and Removable Memory Devices (XFMD). It targets to replace

2279-547: The same as expansion cards, are not technically expansion cards, due to their physical form. The primary purpose of an expansion card is to provide or expand on features not offered by the motherboard. For example, the original IBM PC did not have on-board graphics or hard drive capability. In that case, a graphics card and an ST-506 hard disk controller card provided graphics capability and hard drive interface respectively. Some single-board computers made no provision for expansion cards, and may only have provided IC sockets on

2332-506: The same bus (with slight exception). The 8-bit PC and XT bus was extended with the introduction of the IBM AT in 1984. This used a second connector for extending the address and data bus over the XT, but was backward compatible; 8-bit cards were still usable in the AT 16-bit slots. Industry Standard Architecture (ISA) became the designation for the IBM AT bus after other types were developed. Users of

2385-523: The same connector so both PCI Express and SATA storage devices may exist in the form of M.2 modules. Exposed PCI Express lanes provide a pure PCI Express connection between the host and storage device, with no additional layers of bus abstraction. PCI-SIG M.2 specification, in its revision 1.0 as of December 2013, provides detailed M.2 specifications. Three options are available for the logical device interfaces and command sets used for interfacing with M.2 storage devices, which may be used depending on

2438-490: The same time, while the M.2 modules with only one notch in the M position use up to four PCI Express lanes; both examples may also provide SATA storage devices. Similar keying applies to M.2 modules that utilize provided USB 3.0 connectivity. Various types of M.2 modules are denoted using the "WWLL-HH-K-K" or "WWLL-HH-K" naming schemes, in which "WW" and "LL" specify the module width and length in millimeters, respectively. The "HH" part specifies, in an encoded form, whether

2491-582: The second slot as a place to put an active heat sink with a fan. Some cards are "low-profile" cards, meaning that they are shorter than standard cards and will fit in a lower height computer chassis such as HTPC and SFF . (There is a "low profile PCI card" standard that specifies a much smaller bracket and board area). The group of expansion cards that are used for external connectivity, such as network , SAN or modem cards, are commonly referred to as input/output cards (or I/O cards). A daughterboard , daughtercard , mezzanine board or piggyback board

2544-474: The socket is often an insulation-piercing connector which is clamped onto a ribbon cable . Alternatively, the other side may be soldered to a motherboard or daughtercard . Edge connectors are commonly used in personal computers for connecting expansion cards and computer memory to the system bus . Example expansion peripheral technologies which use edge connectors include PCI , PCI Express , and AGP . Slot 1 and Slot A also used edge connectors;

2597-408: The sockets capable of accepting longer M.2 modules usually also accept shorter ones by providing different positions for the mounting screw. The PCB of an M.2 module provides a 75-position edge connector; depending on the type of module, certain pin positions are removed to present one or more keying notches. Host-side M.2 connectors (sockets) may populate one or more mating key positions, determining

2650-426: The type of M.2 storage device and available operating system support: The M.2 standard is based on the mSATA standard, which uses the existing PCI Express Mini Card (Mini PCIe) form factor and connector. M.2 adds the possibility of larger printed circuit boards (PCBs), allowing longer modules and double-sided component population. Consequently, M.2 SSD modules can provide double the storage capacity within

2703-579: The type of modules accepted by the host; as of April 2014, host-side connectors are available with only one mating key position populated (either B or M). Furthermore, M.2 sockets keyed for SATA or two PCI Express lanes (PCIe ×2) are referred to as "socket 2 configuration" or "socket 2", while the sockets keyed for four PCI Express lanes (PCIe ×4) are referred to as "socket 3 configuration" or "socket 3". For example, M.2 modules with two notches in B and M positions use up to two PCI Express lanes and provide broader compatibility at

SECTION 50

#1732791399257

2756-400: The user. Other computer buses were used for industrial control, instruments, and scientific systems. One specific example is HP-IB (or Hewlett Packard Interface Bus) which was ultimately standardized as IEEE-488 (aka GPIB). Some well-known historical standards include VMEbus , STD Bus , SBus (specific to Sun's SPARCStations), and numerous others. Many other video game consoles such as

2809-568: Was unusual in that it was designed to use a zero insertion force edge connector: instead of the user forcing the cartridge into the socket directly, the cartridge was first placed in a bay and then mechanically lowered into position. Starting with the Amiga 1000 in 1985, various Amiga models used the 86-pin Zorro I edge connector, which was later reshaped into the internal 100-pin Zorro II slot on

#256743