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Serial Storage Architecture
Serial Storage Architecture (SSA) was a serial transport protocol used to attach disk drives to server computers. History SSA was invented by Ian Judd of IBM in 1990. IBM produced a number of successful products based upon this standard before it was overtaken by the more widely adopted Fibre Channel protocol. SSA was promoted as an open standard by the SSA Industry Association, unlike its predecessor the first generation Serial Disk Subsystem. A number of vendors including IBM, Pathlight Technology and Vicom Systems produced products based on SSA. It was also adopted as an American National Standards Institute (ANSI) X3T10.1 standard. SSA devices are logically SCSI devices and conform to all of the SCSI command protocols. SSA provides data protection for critical applications by helping to ensure that a single cable failure will not prevent access to data. All the components in a typical SSA subsystem are connected by bi-directional cabling. Data sent from the adaptor can ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Disk Drive
Disk storage (also sometimes called drive storage) is a general category of storage mechanisms where data is recorded by various electronic, magnetic, optical, or mechanical changes to a surface layer of one or more rotating disks. A disk drive is a device implementing such a storage mechanism. Notable types are the hard disk drive (HDD) containing a non-removable disk, the floppy disk drive (FDD) and its removable floppy disk, and various optical disc drives (ODD) and associated optical disc media. (The spelling ''disk'' and ''disc'' are used interchangeably except where trademarks preclude one usage, e.g. the Compact Disc logo. The choice of a particular form is frequently historical, as in IBM's usage of the ''disk'' form beginning in 1956 with the " IBM 350 disk storage unit".) Background Audio information was originally recorded by analog methods (see Sound recording and reproduction). Similarly the first video disc used an analog recording method. In the music indu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Differential TTL
Differential TTL is a type of binary electrical signaling based on the transistor-transistor logic (TTL) concept. Standards implementing differential TTL include RS-422. It enables electronic systems to be relatively immune to noise. Normal TTL signals are single-ended, which means that each signal consists of a voltage on one wire, referenced to a system ground. The "low" voltage level is zero to 0.8 volts, and the "high" voltage level is 2 volts to 5 volts. A differential TTL signal consists of two such wires, also referenced to a system ground. The logic level on one wire is always the complement of the other. The principle is similar to that of low-voltage differential signaling (LVDS), but with different voltage levels. Differential TTL is used in preference to single-ended TTL for long-distance signaling. In a long cable, stray electromagnetic fields in the environment, or stray currents in the system ground, can induce unwanted voltages that cause errors at the re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Serial Buses
Serial may refer to: Arts, entertainment, and media The presentation of works in sequential segments * Serial (literature), serialised literature in print * Serial (publishing), periodical publications and newspapers * Serial (radio and television), series of radio and television programs that rely on a continuing plot * Serial film, a series of short subjects, with a continuing story, originally shown in theaters, in conjunction with feature films, particularly in the 1930s and 1940s * Indian serial, a type of Indian television program Other uses in arts, entertainment, and media * ''Serial'' (1980 film), based on McFadden's novel, starring Martin Mull and Tuesday Weld * ''Serial'' (podcast), a podcast spinoff of the radio series ''This American Life'' * ''The Serial: A Year in the Life of Marin County'', a 1977 novel by Cyra McFadden Computing and technology * SerDes, a Serializer/Deserializer (pronounced sir-deez) * Serial ATA * Serial attached SCSI * Serial bus, e.g., **IĀ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Device Bandwidths
This is a list of interface bit rates, is a measure of information transfer rates, or digital bandwidth capacity, at which digital interfaces in a computer or network can communicate over various kinds of buses and channels. The distinction can be arbitrary between a ''computer bus'', often closer in space, and larger telecommunications networks. Many device interfaces or protocols (e.g., SATA, USB, SAS, PCIe) are used both inside many-device boxes, such as a PC, and one-device-boxes, such as a hard drive enclosure. Accordingly, this page lists both the internal ribbon and external communications cable standards together in one sortable table. Factors limiting actual performance, criteria for real decisions Most of the listed rates are theoretical maximum throughput measures; in practice, the actual effective throughput is almost inevitably lower in proportion to the load from other devices (network/bus contention), physical or temporal distances, and other overhead in data ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Storage Area Network
A storage area network (SAN) or storage network is a computer network which provides access to consolidated, block-level data storage. SANs are primarily used to access data storage devices, such as disk arrays and tape libraries from servers so that the devices appear to the operating system as direct-attached storage. A SAN typically is a dedicated network of storage devices not accessible through the local area network (LAN). Although a SAN provides only block-level access, file systems built on top of SANs do provide file-level access and are known as shared-disk file systems. Newer SAN configurations enable hybrid SAN and allow traditional block storage that appears as local storage but also object storage for web services through APIs. Storage architectures Storage area networks (SANs) are sometimes referred to as ''network behind the servers'' and historically developed out of a centralized data storage model, but with its own data network. A SAN is, at its simp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IBM Enterprise Storage Server
The IBM Enterprise Storage Server (ESS) or the ''Shark'' is an enterprise storage array from IBM. History Originally, in 1998 IBM released the IBM 2105 Versatile Storage Server (VSS). It did not meet commercial success and the successor came in 1999 in the form of the ESS, based on the same Seascape architecture. The Seascape architecture was an IBM storage architecture that included off-the-shelf components, including RS/6000 processors and the Serial Storage Architecture (SSA). The ESS was also widely known by its IBM internal codename Shark. The 2001 lineup have a redesigned case; this version won IF design award. It has been superseded by the IBM DS8000 series of storage servers. Models *2105-E10 IBM Enterprise Storage Server Model E10 - (1999) 64 disks *2105-E20 IBM Enterprise Storage Server Model E20 - (1999) 128 disks *2105-F10 IBM Enterprise Storage Server Model F10 - (2000) 64 disks *2105-F20 IBM Enterprise Storage Server Model F20 - (2000) 128 disks *2105-750 IBM Tot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
8B/10B Encoding
In telecommunications, 8b/10b is a line code that maps 8-bit words to 10-bit symbols to achieve DC balance and bounded disparity, and at the same time provide enough state changes to allow reasonable clock recovery. This means that the difference between the counts of ones and zeros in a string of ''at least'' 20 bits is no more than two, and that there are not more than five ones or zeros in a row. This helps to reduce the demand for the lower bandwidth limit of the channel necessary to transfer the signal. An 8b/10b code can be implemented in various ways, where the design may focus on specific parameters such as hardware requirements, DC-balance, etc. One implementation was designed by K. Odaka for the DAT digital audio recorder. Kees Schouhamer Immink designed an 8b/10b code for the DCC audio recorder. The IBM implementation was described in 1983 by Al Widmer and Peter Franaszek. IBM implementation As the scheme name suggests, eight bits of data are transmitted a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Non-return-to-zero
In telecommunication, a non-return-to-zero (NRZ) line code is a binary code in which ones are represented by one significant condition, usually a positive voltage, while zeros are represented by some other significant condition, usually a negative voltage, with no other neutral or rest condition. For a given data signaling rate, i.e., bit rate, the NRZ code requires only half the baseband bandwidth required by the Manchester code (the passband bandwidth is the same). The pulses in NRZ have more energy than a return-to-zero (RZ) code, which also has an additional rest state beside the conditions for ones and zeros. When used to represent data in an asynchronous communication scheme, the absence of a neutral state requires other mechanisms for bit synchronization when a separate clock signal is not available. Since NRZ is not inherently a self-clocking signal, some additional synchronization technique must be used for avoiding bit slips; examples of such techniques are a ru ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
