A Reference of Terms used with Business Computers






Mainframe - Class of large business computers. Mainframes are generally composed of several cabinets, a CPU cabinet with the main processors and various peripheral and storage cabinets.
"Big Iron". Today's mainframes are quite small, about a cubic yard.
"Mainframe" (improper usage) - What many office people called the minicomputer, and what they now call the server.

CPU - Central Processing Unit - In "big iron" it's the main cabinet - all else is storage and peripherals. In PCs it's a big chip on the main circuit board (mother board) that does the actuall processing - all other chips are "support chips".

Hard Disk, Hard Disk Drive - A Hard Disk Drive is a storage device containing one or more hard disks, rotating platters coated with a magnetic material. Read/Write heads, drive and stepper motors, ad a logic board make up the rest of the active components. Current sealed hard disk drives were originally called "Winchester" drives (because of the numeric designation of an early example was the same as that of a bullet size). Earlier mainframe Hard Disk Drives were floor standing with a removable stack of 15" platters under a transparent "cake pan" lid. Hard Disk (improper usage) - What many office people call the computer cabinet of their PCs.
Hard Disk (improper usage) - What some office people call a 3-1/2" floppy disk (which is in a rigid envelope, unlike the flexible envelope of the 5-1/2" and 8" floppy disks)

PC - Personal Computer - properly any single user computer, but commonly an IBM PC compatible computer (as in PC vs. Macintosh despite the Macintosh being a PC).

Peripheral I/O Bus

A peripheral I/O bus usually manifests as a row of "slot" connectors in a computer. "Board" can be plugged into these slots to add functionality and outside connections to the computer. Of course, a peripheral I/O bus may have no slot connectors at all if it just connects peripherals permanently built into the computer's mother board.

ISA - Industry Standard Architecture - The peripheral I/O bus architecture first used in the IBM PC AT. It consists of the old 8-bit XT bus slot (62 contacts) with a shorter slot (36 contacts) added behind it to increase bandwidth to 16-bits. This bus architecture is used only for Intel x86 and compatible based computers (286, 386, 486, Pentium, Pentium II, Pentium III).

MCA - Microchannel Architecture - IBM's peripheral I/O bus for the PS/2 PCs, also used in the RS/6000 series. This was a superior bus design killed by marketing. Not only did IBM demand stiff royalties for its use, they also demanded back royalties for all computers built using the ISA bus before they would license it. NCR suckered for this deal but nobody else did.

PCI, PCI-X - a processor independent peripheral I/O bus architecture designed to succeed the ISA bus. It is usually found in combination with ISA slots in Intel based PCs, and is found in Apple Macintosh computers as well. The slot has 98 + 22 contacts and is nearly identical (except for contact count) to IBM's MCA bus slot. PCI was designed to support the Intel/Microsoft Plug and Play specification. PCI-X is a yet to be realeased (Q1 2000) version supporting higher throughput.

VESA - a peripheral I/O bus designed to support the higher speed needs of fast video cards in the days when the ISA bus ruled. It vanished overnight when the PCI bus was introduced. Some board makers adopted the VESA bus also for higher performance (priced) hard disk controllers.

InfiniBand - I/O bus architecture for computers, intended to succeed PCI in servers, routers and other high performance computers. This is an aliance of former rivals Future I/O (Compaq, Hewlett-Packard, IBM and others) and Next Generation I/O (Intel, Sun, Dell and others). It is a chanel switched bus rather than a shared bus like ISA, PCI, etc. and operates at 2.5-Gbps. Spec at www.infinibandta.org.

Plug and Play - "Plug and Pray" - An Intel / Microsoft specification intended to make adding peripherals to a Windows PC as easy as on the Apple Macintosh. Plug and Play Installs range from nearly effortless or nearly impossible, depending on the mood Windows is in on the particular PC. Back in the bad old days when modems had to be jumpered for base address an interrupt, it could take 15 minutes for an expert to install a new modem. With Plug and Pray it can take an entire day - and then a week later the PC forgets it ever had a modem.

Of course, Microsoft's Windows implementation does not to conform to the specification, so BIOS makers had to include a switch for "Plug and Play OS - Yes" (Windows) or "No" (any OS implementing Plug and Play according to spec). This terminology was designed not to offend Microsoft.

Big-endian, Little-endian - data storage / transmission order - Different computer systems store and transmit data in one or another of these orders (most significant bit first, least significant bit first). This makes translation of data between systems much more difficult than it might otherwise be.

IEEE 1934 - Fire Wire - PC peripheral bus standard offering 100-mbps and 400-mbps performance.

Operating Systems

Operating Systems - Also called DOS (Disk Operating System) are programs that interface between a computer and "applications programs" (the programs that you use to do your job or play your games). Writing to the Operating System instead of the computer itself frees the programmer from knowing all the arcane details of each computer model and makes software much more affordable than it would otherwise be. Typical Operating Systems are:
  • CP/M, CP/M80, CP/M86 - Control Program / Microprocessor - Operating systems for Intel based PCs predating the IBM PC. Published by Digital Research, it was the business standard before PC DOS/MS DOS
  • MP/M - Multi-user version of CP/M - Yes, Virginia, PCs were Multi-user, Multi-tasking before the IBM PC came out with its single-user, single-tasking MS DOS.
  • Concurrent CP/M, Concurrent DOS, Multiuser DOS - Multi-User Multi-Tasking successors to MP/M, able to handle much larger disk and memory spaces. Used to control the Trident misile system, IBM's Point of Sale system, Medical Management systems, etc. The Multiuser DOS version runs on IBM compatible PCs and can run both real multiuser CP/M programs and network capable MS DOS programs, as well as single user MS DOS programs. Several companies, like Axis and Concurrent Controls still develop and sell it under various names.
  • DOS, DOS VM - IBM Mainframe operating system. Later replaced by MVS
  • DOS, MS DOS, PC DOS - Operating systems for the IBM PC, IBM PC AT and compatible Intel X86 based computers. Based on an operating system called QDOS (Quick and Dirty Operating System) purchased by Microsoft from Seattle Computer Systems. Unfortunately, it was proved in court to be "rather closely based" on Digital Research's CP/M.
  • DR DOS - A "clone" of MS DOS written by Digital Research. Microsoft couldn't sue because DR had been given the right to clone MS DOS when they won their court case against Microsoft / IBM, so they fought it with money, monopoly leverage and dirty tricks, as has been shown in court. DR DOS was superior in features and stability to MS DOS. MS DOS 5.x and 6.x were imitations of the DR DOS 5.0 and 6.0 packages.
  • IOS - Internet Operating System - The operating system used in Cisco routers. Routers are specialized computers.
  • Multics - Multiplexed Information and Computing Service - A multi-computer operating system developed By MIT, AT&T's Bell Labs and General Electric for large computers, started in 1965. The father of Unix. For more info, here's the FAQ. Of 82 installations, three are still running.
  • Unix - "Emasculated Multics" - An operating system created in 1969 as a sideline of the Multics project at AT&T's Bell Labs (mostly to play adventure games). AT&T, being a regulated monopoly at the time couldn't sell it commercially, so they gave it away to universities and such, resulting in a great amount of volunteer development. It became the "do anything, anywhere, on any machine" operating system with versions for everything upside of the Apple II, and the foundation of the Internet. What Windows NT/2000 wants to be when it grows up.
  • VOS30 - A variety of Unix used by Periphonics in their CTI (Computer Telephone Integration) voice mail systems. Runs on Motorola 68030.
  • Xenix - Cut-down version of Unix for the weak PCs of the day. Originally developed by Microsoft, it was spun off to the Santa Cruz Operation (SCO). It was discontinued when PCs became plenty strong enough to run real Unix, and finally had to be taken out of service in 1999 due to Year 2000 problems.
  • Linux - "Unix by the people for the people". A Unix clone originally written by Linus Torvalds in Finland and combined with a set of Unix clone software tools and utilities developed by the Free Software Foundation. Development continues as an international volunteer effort coordinated over the Internet. Currently the greatest threat to Microsoft's flagship Windows 2000 (NT v5.0), because it's small, fast, stable and cheap - all features lacking in Windows 2000.
  • Apple DOS The operating system for the Apple II computers.
  • SOS - Sophisticated Operating System - Apt initials for the operating system for the unlamented Apple III, one of Steve Job's notable failures during his first try at running Apple.
  • OS/400 - IBM's AS/400 series operating system.
  • MVS - IBM advanced operating system for System 360 mainframes.
  • Windows - A series of operating systems and GUIs (Graphic User Interfaces) over operating systems from Microsoft.
    • Windows 1.0 Totally unusable version of Windows, a GUI (Graphic User Interface) over MS-DOS.
    • Windows 386 Version 2 of Windows, now runable only on 386 and higher computers. Not very successful.
    • Windows 3.0 First actually usable version of Windows. A GUI overlay over MS-DOS.
    • Windows 3.1 First successful version of Windows. A GUI overlay over MS-DOS.
    • Windows 3.11 A version of Windows 3.1 released specifically to break compatibility with IBM's OS/2 for Windows (Red Box OS/2, which wrapped around an existing Windows 3.1 install). Quickly withdrawn due to public outcry.
    • Windows for Workgroups 3.11 A version of Windows 3.1 that included networking. Really bad networking, but networking nontheless.
    • Windows95 Successor to Windows for Workgroups 3.11. DOS was incorporated into the package and reworked to prevent Windows from running over DR-DOS and eliminate DR-DOS from the market.
    • Windows95 OSR2A mid-stream upgrade to the OEM version of Windows95 incorporating USB support (well, sort of), Encrypted passwordl and the FAT-32 file system, allowing use of larger hard disk partitions. These changes were never incorporated in retail or upgrade versions of Windows95.
    • Windows 98 Windows95 with the Internet Explorer web browser "integrated" into it in Microsoft's campaign to destroy Netscape.
    • Windows 98 SE Second Edition - a "bug fix" realease of Windows 98 which introduced more new bugs than it fixed old bugs.
    • Windows NT 3.1 The first version of Windows NT, called 3.1 "to avoid confusion". Actually, it was named 3.1 because users wer now convinced that version 3.1 was the first version of any Microsoft product that actually worked. A new operating system from Microsoft with a GUI interface integrated into it. Based on OS/2 code, it was done by programmers hired away form DEC (Digital Equipment Corp.). Slow.
    • Windows NT 3.5 Bug fix release to NT 3.1.
    • Windows NT 4.0 Successor to NT 3.5, it had the video drivers incorporated into "ring 0" to improve performance. It also greatly reduced stability.
    • Windows NT 5.0 Renamed to Windows 2000 due to a number of embarasing circumstances, especially because the press was unfavorably comparing the not yet released NT 5.0 with NetWare 5.0 which was released.
    • Windows 2000 A complete rewrite of Windows NT (because it was obvious even to Microsoft that Windows NT 4.0 could never be an "enterprise" operating system. Years late, it is currently scheduled to be released on FEB 17 2000.
    • Pen Windows A non-existant version of Windows announced by Microsoft specifically to kill off Pen Computing, a company they thought might be a competitor. It was aimed at hand held devices that use a stylus for input.
    • Windows CE A version of Windows designed for devices smaller than notebook computers. Ooops - withdrawn! In keeping with their normal practices, Microsoft has withdrawn the "CE" name due to negative image. It was getting it's ass kicked by the Palm operating system from 3Com (which can actually run on handheld devices) and everyone knew it.
    • Embeded Windows NT A scaled down version of Windows NT for industrial devices and other "built in" applications. Wishful thinking.
CRC - Cyclic Redundancy Check - A technique to assure data contained within a block of data is read correctly. Check bits are added to the block of data as it is written that adjust it to make it conform to a particular formula. When the block of data is read, the formula is applied and if it fails, the contents of the block (or the read) are presumed incorrect. This failure is called a CRC Error.

Display Technologies

X - Graphic display environment used on Unix, Linux, OS/2 and other operating systems. This definition is complex (like X) and will not be done for awhile.

©:Andrew Grygus - Automation Access
Velocity Networks: Network Consulting Service - Internet Service Provider - Web Page Design and Hosting
All trademarks and trade names are recognized as property of their owners