Intelligent Peripheral Interface

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Intelligent Peripheral Interface (IPI) was a server-centric storage interface used in the 1980s and early 1990s with an ISO-9318 standard. [1]

International Organization for Standardization An international standard-setting body composed of representatives from national standards organizations

The International Organization for Standardization is an international standard-setting body composed of representatives from various national standards organizations.

The idea behind IPI is that the disk drives themselves are as simple as possible, containing only the lowest level control circuitry, while the IPI interface card encapsulates most of the disk control complexity. The IPI interface card, as a central point of control, is thus theoretically able to best coordinate accesses to the connected disks, as it "knows" more about the states of the connected disks than would, say, a SCSI interface.

SCSI set of standards for physically connecting and transferring data between computers and peripheral devices

Small Computer System Interface is a set of standards for physically connecting and transferring data between computers and peripheral devices. The SCSI standards define commands, protocols, electrical, optical and logical interfaces. SCSI is most commonly used for hard disk drives and tape drives, but it can connect a wide range of other devices, including scanners and CD drives, although not all controllers can handle all devices. The SCSI standard defines command sets for specific peripheral device types; the presence of "unknown" as one of these types means that in theory it can be used as an interface to almost any device, but the standard is highly pragmatic and addressed toward commercial requirements.

An IPI-2 bus could provide a data transfer rate in the vicinity of 6 MB/s.

In telecommunications and computing, bit rate is the number of bits that are conveyed or processed per unit of time.

The megabyte is a multiple of the unit byte for digital information. Its recommended unit symbol is MB. The unit prefix mega is a multiplier of 1000000 (106) in the International System of Units (SI). Therefore, one megabyte is one million bytes of information. This definition has been incorporated into the International System of Quantities.

Second SI unit of time

The second is the base unit of time in the International System of Units (SI), commonly understood and historically defined as ​1⁄86400 of a day – this factor derived from the division of the day first into 24 hours, then to 60 minutes and finally to 60 seconds each. Mechanical and electric clocks and watches usually have a face with 60 tickmarks representing seconds and minutes, traversed by a second hand and minute hand. Digital clocks and watches often have a two-digit counter that cycles through seconds. The second is also part of several other units of measurement like meters per second for velocity, meters per second per second for acceleration, and per second for frequency.

In practice, the theoretical advantages of IPI over SCSI were often not realized, as they only materialized when several disks were connected to the interface, which could then easily become a bandwidth bottleneck.

IPI systems were often shipped by Sun Microsystems on original sun4 architecture servers, but the above limitation and reliability problems made them unpopular with customers, and the technology basically disappeared by the second half of the 1990s.

Sun Microsystems defunct computer hardware and software company which was based in Santa Clara

Sun Microsystems, Inc. was an American company that sold computers, computer components, software, and information technology services and created the Java programming language, the Solaris operating system, ZFS, the Network File System (NFS), and SPARC. Sun contributed significantly to the evolution of several key computing technologies, among them Unix, RISC processors, thin client computing, and virtualized computing. Sun was founded on February 24, 1982. At its height, the Sun headquarters were in Santa Clara, California, on the former west campus of the Agnews Developmental Center.

See also

Enhanced Small Disk Interface

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Storage Module Drive (SMD) is a family of storage devices that were first shipped by Control Data Corporation in December 1973 as the CDC 9760 40 MB (unformatted) storage module disk drive. The CDC 9762 80 MB variant was announced in June 1974 and the CDC 9764 150 MB and the CDC 9766 300 MB variants were announced in 1975. A non-removable media variant family of 12, 24 and 48 MB capacity, the MMD, was then announced in 1976. This family's interface, SMD, derived from the earlier Digital RP0x interface, was documented as ANSI Standard X3.91M - 1982, Storage Module Interfaces with Extensions for Enhanced Storage Module Interfaces.

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Backplane

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The Sun-2 series of UNIX workstations and servers was launched by Sun Microsystems in November 1983. As the name suggests, the Sun-2 represented the second generation of Sun systems, superseding the original Sun-1 series. The Sun-2 series used a 10 MHz Motorola 68010 microprocessor with a proprietary Sun-2 Memory Management Unit (MMU), which enabled it to be the first Sun architecture to run a full virtual memory UNIX implementation, SunOS 1.0, based on 4.1BSD. Early Sun-2 models were based on the Intel Multibus architecture, with later models using VMEbus, which continued to be used in the successor Sun-3 and Sun-4 families.

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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 enhance accessibility of storage devices, such as disk arrays and tape libraries, to servers so that the devices appear to the operating system as locally-attached devices. A SAN typically is a dedicated network of storage devices not accessible through the local area network (LAN) by other devices, thereby preventing interference of LAN traffic in data transfer.

Hard disk drives are accessed over one of a number of bus types, including parallel ATA, Serial ATA (SATA), SCSI, Serial Attached SCSI (SAS), and Fibre Channel. Bridge circuitry is sometimes used to connect hard disk drives to buses with which they cannot communicate natively, such as IEEE 1394, USB, SCSI and Thunderbolt.

References

  1. ↑ Allan, Dal, ed. (1988), ISO/DIS 9318 -- Information Processing Systems -- Intelligent Peripheral Interface, International Organization for Standardization


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