Last November, I received an e–mail from my editor, Tom Kenny saying “…We have a feature on network storage systems that we’re trying to figger out (so) what we’d like from you, if you agree, is a glossary of common storage and network terms. An IT glossary for the uninitiated pro audio folks. Whammy think? A whole column of pedants in a box.” So began this month’s Bitstream, a bass ackwards version of my usual offering.
Granted, I could never compete with the many excellent IT glossaries out there on the web but, I’ve tried to gather the most common TLAs, techie phrases and geek–speak for your edification. For those who need a bit of a mental housecleaning, this month will either sweep away some cobwebs or increase the BBF by several orders of magnitude!
Part One and Two of Pedants In A Big Box was published in March and June of 2004. Note that bold words have their own definitions in this glossary…
HCA — Host Channel Adapter
A Host Channel Adapter is the IB component that connects a processor to other IB devices. An HCA is really a bridge and must be able to communicate with both other HCAs and TCAs.
head —
In IT land, a head refers to the multiplicity of magnetic read/write heads in a modern hard disk drive. Disk drives have anywhere from one or more “platters” of polished rigid disks made of aluminum or glass, that are coated with ferromagnetic material. Each side of each platter has a head, but all the heads are mounted on the same positioning actuator assembly, so only one cylinder can be accessed at any time. The heads “fly,” by ground effect, at a height of less than 2 microns above the platter, which is about 1/38th the diameter of a human hair.
header —
A header is essentially metadata that describes what is contained in the essence, packet, frame or file remainder that follows. Typically it is the part of a packet or frame that indicates the start of the data essence or payload. Also, a preamble. Headers usually contain metadata such as addressing and error detection information.
HiPPI — High–Performance Parallel Interface
As the guys at CERN say in their general Introduction to HiPPI, “It’s Not Just for Supercomputers Anymore.” Also known as GSN or Gigabyte System Network, HiPPI is one of the original high speed LAN technologies and interoperates with Ethernet, Fibre Channel and ATM. It is an ANSI standard for a full duplex, low latency, point to point interconnect providing 100 to 200 MBytes/sec over a 50 twisted pair copper PHY with a maximum length of 25 meter. A serial version uses a glass fibre PHY at the same speed and future versions will scale up to 6.4 Gbits/second.
host, to host —
A host can be thought of as a server though, strictly speaking, a host can be any computer connected to a network. Servers range from single chip microcontrollers to 1U rack mounted boxes on up to refrigerator–sized “Big Iron” that can simultaneously process millions of complex financial transactions per second.
Hosting is the process of providing network services to other computers, such as providing web, database or streaming services.
hotspot —
Hotspots refer to nodes or APs that provide 802.11a/b/g services.
HRTF – Head Related Transfer Function
HRTFs are mathematical models of the sound pressure that an arbitrary sound source produces at an ear drum, either real or virtual. A monaural sound, when convolved or processed through an HRTF, can provide varying degrees of “3D” or phantom image placement, also know as pseudostereophony. Since each person’s body shape is different and each brain has adapted to that individuality, it’s very difficult to create a single HRTF that produces convincing 3D audio for a large sampling of people.
HTML —
HTML, the basic markup language of the World Wide Web, is a common way to deliver hypertext.
hypertext —
To quote inventor Theodor “Ted” Nelson (Literary Machines, Mindful Press – first printed in 1982), hypertext is “…a body of written or pictorial material interconnected in such a complex way that it could not conveniently be presented or represented on paper.” Hypertext is machine–readable and also human–readable text that is linked in a non–sequential way. HTML is a common way to deliver hypertext.
IB — InfiniBand
InfiniBand is an ad hoc, high speed switch-fabric architecture. The benefits of the InfiniBand specification are improved performance over older standards, ease of management, lower latency, built in security and better QoS.
IEEE —
The Institute of Electrical and Electronics Engineers or “eye triple ee” as it’s called, is the AES of all things electronic. The IEEE is a standards–setting body responsible for, according to their site, making “engineering decisions consistent with the safety, health and welfare of the public, and to disclose promptly factors that might endanger the public or the environment.” Unlike the AES, the IEEE is very aggressive and successful in their standardization efforts, covering a broad range of technologies impacting every aspect of daily life.
IEEE 1394 —
The IEEE standard codifying Apple Computer’s original FireWire standard. The original 1992 standard covers FireWire 400, a 400 Mbps smart protocol over copper. The 1394b, or “Beta" standard covers FireWire 800. In the newer standard, the copper PHY layer with two twisted pairs didn’t changed, but the transmission moved to dual simplex and channel coding changed to 8B10B. Also, other PHY choices were added, including UTP, POF and glass fibre.
IEEE 802.nx —
The 802 working group of the IEEE sets the standards for data networking. There are many individual committees addressing specific applications. These include:
802.1: Layer 2 wired LAN standards including;
ad — link aggregation
Q — support for VLANs or virtual LANs
p — packet prioritization
802.3 — Ethernet or Wired LANs including 10, 100, 1000, 10GBASE-T (twisted pair), BASE-F (fibre) & BASE-C (cable)
802.3af — POE or Power–Over–Ethernet defines a standard way for network nodes to be powered over MDI, including 10/100BASE-T
802.11: Wireless LAN standards including;
a — 54 Mbps (18-22 Mbps throughput)
b — 11 Mbps (6 Mbps throughput)
d — internationalization
e — enhanced Media Access Control layer for QoS
g — harmonizes a & b
802.15 — low power wireless PANs such as low complexity Bluetooth, UWB–based high rate PANs, and mesh networks
802.16: The Broadband Wireless Access Standard which provide secure, full duplex, fixed wireless MAN service. Also known as WiMAX, thoughput can reach 75 Mbps and does not require line–of–sight to operate. The 802.16e extension adds roaming outside of a “home” service area. Reach can extend from 1 mile at full speed to 30 miles at reduced throughput.
802.20: Mobile Broadband Wireless Access (MBWA) — mobile as in vehicular
IETF — Internet Engineering Task Force
The IETF bills itself as a “large open international community of network designers, operators, vendors, and researchers concerned with the evolution of the Internet architecture and the smooth operation of the Internet.” In other words, the IETF is the internet’s standards setting body.
iFCP — Internet Fibre Channel Protocol
The Internet Fibre Channel Protocol allows for carrying Fibre Channel traffic over IP–based networks. iFCP encapsulates and packetizes FC data in IP packets and maps IP addresses to individual FC devices, which breaks the distance barrier imposed by a direct–attached, FC network. Unlike FCIP, iFCP provides better fault isolation.
ILEC — Incumbent Local Exchange Carrier
ILECs are the commercial telecom entities that were in business prior to the Telecommunications Act of 1996. ILECs include tiny regional providers like the Eastern Slope Rural Telephone Association in Hugo, Colorado and the original RBOCs or Regional Bell Operating Companies; Ameritech, Bell Atlantic, BellSouth, NYNEX, Pacific Bell, Southwestern Bell and US WEST.
To be continued…
