Acronyms

Acronyms are horrible things - they tend to create a layer of obfuscation that confuses new users, allow knowledge and understanding to diverge from reality (as original meanings get lost and forgotten), and can be used by some to imply some kind of knowledge superiority over their peers. Unfortunately they are rife in IT (!), and systems and techniques are often given unnecessarily long or complex names in order to create a good acronym...

A

• AD - Active Directory
• ALUA - Asymmetric Logical Unit Access, SAN feature whereby connected hosts can determine the states of target ports and prioritise paths to use to access LUN's
• AP - Asia Pacific
• API - Application Programming Interface, used to allow a 3rd party access to an application via software/script
• ARP - Address Resolution Protocol, allows translation of IP addresses into MAC addresses
• ASCII - American Standard Code for Information Interchange, character encoding system
• ASLR - Address Space Layout Randomisation, security feature that randomises data layout in memory
• ASR - Automated System Recovery, HP feature to reboot hardware in the case of the OS failing
• ATA - AT Attachment (disks), also known IDE or EIDE

B

• BCS - British Computer Society
• BGP - Border Gateway Protocol, a routing protocol
• BSOD - Blue Screen of Death, as seen on Windows servers

C

• CDB - SCSI Command Descriptor Block
• CIDR - Classless Inter-Domain Routing, method of IP address allocation that allows chunks of IP address space to be specified via variable length subnet masks
• CIFS - Common Internet File System
• CIM - Common Information Model
• CMDB - Configuration Management Database
• CPU - Central Processing Unit, the main number cruncher of a computer or device
• CRAC - Computer Room Air-Conditioning
• CRC - Cyclic Redundancy Check, allows for error detection (without recovery)

D

• DCE - Data Communications Equipment, eg modem
• DHCP - Dynamic Host Configuration Protocol
• DMA - Direct Memory Access, allows components direct access to system memory (rather than through the CPU)
• DNS - Domain Name System, converts human friendly names into computer friendly numerical addresses
• DSN - Data Source Name (or sometimes Database Source Name)
• DTE - Data Termination Equipment, eg router

E

• ECC - Error Checking Code, allows for error detection and some recovery of errors
• EIDE - Enhanced IDE (drive), approximately equivalent of ATA-2
• EMEA - Europe, Middle-East, Asia
• ESX - Elastic Sky X, the VMware Virtual Machine host server
• EULA - End User License Agreement, contract imposed on user of product (normally software) that's never read by user

F

• FATA - Fibre-Channel ATA disks, slower disks with FC interface
• FC - Fibre-Channel, normally used to connect servers with remote storage
• FOSS - Free and Open Source Software
• FQDN - Fully Qualified Domain Name, eg vwiki.sandfordit.com as opposed to vwiki
• FTP - File Transfer Protocol, uses TCP 20 and 21
• FTPS - Secure version of FTP, FTP over SSL/TLS, (not to be confused with SFTP)

G

• GPO - Group Policy Object
• GUI - Graphical User Interface

H

• HBA - Host Bus Adapter, server interface used to connect to SAN based storage
• HTTP - HyperText Transport Protocol, the bread and butter of the internet
• HTTPS - Secure HTTP, HTTP over SSL or TLS. Used for secure websites, and for delivering API and SOAP services

I

• IDE - Integrated Drive Electronics, aka ATA version 1
• IMAP - Internet Message Access Protocol, mailbox access protocol
• IP - Internet Protocol
• IT - Information Technology
• IPMI - Intelligent Platform Management Interface, open standard for managing hardware platforms
• IRQ - Interrupt ReQuest
• iSCSI - IP Small Computer Serial Interface, SCSI over IP
• ISEB - Information Systems Examinations Board
• ITIL - IT Infrastructure Library

J

• JBOD - Just a Bunch of Disks

L

• LAN - Local Area Network
• LDAP - Lightweight Directory Access Protocol
• LDS - Lightweight Directory Services
• LMTP - Local Mail Transfer Protocol - similar to SMTP but with no support for mail queueing

M

• MAC - Media Access Control, link layer address to identify a network interface
• MAN - Metropolitan Area Network, somewhere between a LAN and a WAN, for example connecting buildings within a localised area
• MIB - Management Information Base, object hierarchy database, most commonly used in SNMP
• MPLS - Multi Protocol Label Switch(ing)
• MRTG - Multi Router Traffic Grapher, Tobi Oetiker's Perl based flexible SNMP poller/grapher
• MSCS - Microsoft Clustering Services
• MTA - Message Transfer Agent, receives and forwards SMTP emails to other MTA's or local mailboxes

N

• NAS - Network Attached Storage, storage that's available via a network
• NTP - Network Time Protocol, reliable time sync protocol, uses UDP 123

O

• OSPF - Open Shortest Path First, dynamic routing protocol
• OVA - Open Virtualisation Appliance, single file TAR of an OVF
• OVF - Open Virtualisation Format, industry standard virtual appliance definition, made up of various files within a folder

P

• PATA - Parallel ATA (disks, newer name for ATA disks)
• PCRE - Perl Compatible Regular Expressions, a widely used Regex system
• PDU - Protocol Data Unit, a unit or package of data. For example an SNMP Get request is a PDU
• PID - Process ID, number assigned by the OS to a running process
• POSIX - Portable Operating System Interface, cross OS standards for API's, etc
• PSOD - Purple Screen of Death, as seen on ESX servers
• PVLAN - Private VLAN, VLANs over VLANs

R

• RAID - Redundant Array of Inexpensive (!?) Disks
• RAM - Random Access Memory - read/write memory
• RDP - Remote Desktop Protocol
• REST (API) - Representational State Transfer, web service
• RIP - Route Information Protocol, old school routing protocol
• ROM - Read Only Memory
• RRD - Round Robin Database, as used by RRDtool to store data points
• RSS - Really Simple Syndication, news feed protocol

S

• SAN - Storage Area Network, architecture for connecting systems to centralised storage
• SAS - Serial Attached SCSI (disk)
• SATA - Serial Advanced Technology Attachment (disk)
• SCOM - System Centre Operations Manager, Microsoft monitoring and operations product
• SCP - SSH Copy, provided by SSH v1 (has weaknesses and is outdated, SFTP provided by SSH v2 is current))
• SCSI - Small Computer Serial Interface
• SFTP - SSH File Transfer Protocol, secure copy provided by SSH v2 (not to be confused with FTPS)
• SLP - Service Locator Protocol]
• SMB - Server Message Block (aka CIFS), typically used to access shared file-systems and printers
• SMTP - Simple Mail Transfer Protocol, email message delivery protocol, uses TCP 25
• SNMP - Simple Network Management Protocol, used to monitor and manage network based devices by either polling of the device, or by the device generating traps (alerts)
• SNTP - Simple Network Time Protocol, lightweight version of NTP that doesn't include error checking etc
• SOAP - Simple Object Access Protocol, used to deliver remote services, usually over HTTP or HTTPS
• SPD - Serial Presence Detect, counter of errors experienced by a RAM memory stick, recorded on the stick
• SQL - Structure Query Language
• SSH - Secure Shell, used to access network devices securely over TCP 22
• SVN - SubVersioN, a version control system

T

• TAR - Tape Archive, a collection of files bundled together into a container file (historically used for backups)
• TCP - Transmission Control Protocol, networking transport of the internet
• TFTP - Trivial FTP, lightweight FTP using UDP 69
• TLB - Translation Lookaside Buffer, a cache mapping virtual memory addresses to physical addresses
• TLS - Transport Layer Security, successor to SSL
• TOS - The Operating System, the Atari ST's Operating System
• TTL - Time To Live, a lifespan time-out or propagation limit for a piece of data

U

• UPS - Uninterruptable Power Supply
• UUID - Universally Unique ID

V

• VCP - VMware Certified Professional, title for certification on VMware Virtual Infrastructure / vSphere
• vCPU - Virtual CPU, CPU presented to a virtual machine, provides a variable share of a physical CPU
• VI3 - VMware Infrastructure 3, the name given to an infrastructure running ESX3(i) host servers managed by Virtual Centre v2
• VI4 - VMware Infrastructure 4, officially called vSphere, the name sometimes given to an infrastructure running ESX4(i) host servers managed by vCentre v4
• VIC - (VMware) Virtual Infrastructure Client
• VIM - Virtual Infrastructure Manager, old name for VMware vCentre
• VLAN - Virtual LAN, allows different networks to be carried across the same Ethernet, differentiated by 802.1Q tags
• VMDK - Virtual Machine Disk file, a VMware virtual machine's virtual hard drive file
• VMFS - Virtual Machine File System, VMware's storage format for virtual machines to run on
• VNC - Virtual Network Computer, superior remote desktop application
• VPN - Virtual Private Network
• VRF - Virtual Routing and Forwarding, used to provide selective/conditional routing
• VSS - Volume Shadow Service, Microsoft OS service that creates quiesced disks (aka snapshots)
• VUM - VMware Update Manager

W

• WAN - Wide Area Network
• WBEM - Web-Based Enterprise Management
• WMI - Windows Management Instrumentation, Microsoft's implementation of WBEM

Z

• ZCA - Appliance version of a ZCS
• ZCS - Zimbra Collaboration Suite