v
V.35 Operates at Layer 1. Standard for modems. Wikipedia ITU
V.92 ITU standard for 56 kb/s download and 48 kb/s upload modems. Introduced August 1999. Wikipedia ITU
V3 First phone in the Motorola Razr series. Released Q3 2004. Wikipedia
V8 (JavaScript engine) Developed by Google. First released September 2, 2008. Website Wikipedia
validation rules Ensures the data is valid. Must be followed when entering data. Wikipedia
VALUES Used with INSERT INTO to tell the DBMS what to insert. Wikipedia Wikipedia
variable Named memory location that stores the current value of a data type. Can be integer, real number, string, or Boolean. Shell Examples:
| Bash | VARIABLE=value | echo $VARIABLE |
| tcsh | set VARIABLE = value | echo $VARIABLE |
| PowerShell | $VARIABLE = value | Write-Output $VARIABLE |
Variable Length Subnet Mask (VLSM) (classless subnetting) Helps avoid wasting IP addresses when subnetting a network. Wikipedia
vCenter Converter Physical-to-Virtual (P2V) tool used uo move a physical computer image to a VMware virtual machine. Website
vcgencmd measure_temp Show raspberry pi temprature.
vector Lines that indicate both magnitude and direction.
vector processor Wikipedia
Veeam Endpoint Backup Website
Vega GPU family from AMD. Announced at CES 2017 January 5, 2017. First GPU released as the Radeon Vega Frontier Edition July 1, 2017. Website Wikipedia Press Release
Vendor-Specific Attribute (VSA)
ver DOS command used in to displays the OS version. Use uname on UNIX. Wikipedia
verify Command Prompt command that tells Windows whether to verify that your files are written.
Verizon Cell carrier and ISP. Wikipedia
Versatile Interface Processor (VIP)
Version Contains a 4-bit binary value identifying the IP packet version. For IPv4 packets, this field is always set to 0100.
Version 7 Unix (V7) Wikipedia
version control (aka: revision control, source control) Formally tracks changes made to information such as documents, programs, or web sites. Wikipedia
Vertical-cavity surface-emitting laser (VCSEL) Type of semiconductor laser diode with laser beam emission perpendicular from the top surface, contrary to conventional edge-emitting semiconductor lasers (also in-plane lasers) which emit from surfaces formed by cleaving the individual chip out of a wafer. VCSEL applications include fiber optic communications, precision sensing, computer mice, laser printers and augmented reality. Wikipedia
Very Small Aperture Terminal (VSAT) Creates a private WAN for connectivity to remote locations. Wikipedia
VESA (formally known as Video Electronics Standards Association) Founded July 1989. Website Wikipedia
vi Text editor that is standard in most UNIX based operating systems. vi comes from the visual mode in the ex text editor. YouTube Linux Command
Video Graphics Array (VGA) (DE-15) Analog video connector based off RS-232. Wikipedia
Vigen Based on the Caesar cipher but uses a polyalphabetic key shift. Originally described by Giovan Battista Bellaso. Wikipedia
vim (vi improved) A text editor UNIX based operating systems.
| Commands: | |
| :i | (insert) |
| :q | (quit) |
| :w | (write) |
Vine Officially launched January 24, 2013. Wikipedia
Vinton Cerf One of the fathers of the internet. Wikipedia
virsh Command line tool for managing guests and the hypervisor. CentOS Docs Oracle Documentation
Virtual Circuit (VC) Two kinds of VCs: Switched Virtual Circuits (SVCs) and Wikipedia
Virtual Desktop Infrastructure (VDI) Wikipedia
Virtual Execution System (VES) Run-time system of the Common Language Infrastructure. Wikipedia
Virtual Local-Area Network (VLAN) (aka: Virtual LAN) Similar to a regular LAN. Logical broadcast domain that can split physical LANs. Allows different security policies to be applied to different hosts. Wikipedia Cisco
Virtual Machine (VM) Wikipedia Ubuntu Community Help Wiki
Virtual Memory Wikipedia
Virtual Private Network (VPN) IP tunnels that extend a private network across a public network, usually the internet. Enables users to send and receive data across shared or public networks as if their computing devices were directly connected to the private network. Typically encrypted but does not need to be, such as in the case of GRE and Frame Relay. The encryption algorithm combines message text with a key to make the message unreadable by unauthorized receivers. Two kinds of VPNs: site-to-site and remote access. Can operate at OSI Layer 2 (Frame Relay, ATM, HDLC, PPP) or OSI Layer 3 (GRE, MPLS, IPsec). Wikipedia
Virtual Private Server (VPS) Wikipedia
Vulkan Graphics API from the Khronos Group. Introduced February 16, 2016 Website Wikipedia
Virtual Machine File System (VMFS) Clustered file system from VMware. VMwaere Documentation Wikipedia
Virtual Random Access Memory (VRAM)
Virtual Reality (VR) Wikipedia
virtual Receive-Side Scaling (vRSS) TechNet Wikipedia
Virtual Router Redundancy Protocol (VRRP) IETF open standard that operates almost identically to HSRP from Cisco Wikipedia
virtual runtime (vruntime) How long a process has been running. Stack Overflow
Virtual Storage Area Network (VSAN)
Virtual Teletype (VTY) telnet Wikipedia
VirtualBox A type 2 hypervisor. Initially developed by Innotek GmbH. Acquired by Sun Microsystems in 2008. Later acquired by Oracle in 2010. Website Wikipedia
virtualization Creating a virtual version of something. Wikipedia
Virtualization Technology (VT-x) Website
virus Malicious software that hides in other files, generally executables (.exe). Commonly spread by email. Can lay dormant and activate after a specific action or time. Wikipedia YouTube (TheCuriousEngineer) Netacad
VisiCalc First spreadsheet computer program for personal computers. Announced at the West Coast Computer Faire May 11, 1979. Released for the Apple II by VisiCorp at the National Computer Conference June 4, 1979. Wikipedia This Day in Tech History
VisionTek Founded in 1988. Website
Visual Basic First released May 1991. Website Wikipedia
Visual Studio IDE from Microsoft. Wikipedia Website
visudo Configure root privileges
VLAN attack Takes advantage of how some switches will automatically form a trunk if the devices that connect to the port are in trunking mode. Can mitigate by using a dummy native VLAN and disabling DTP. Wikipdedia
VLAN Double-Tagging Embeds a 802.1Q tag inside a frame allowing it to go to another VLAN. Because most switches only perform one level of decapsulation, the receiving switch only looks at the inner 802.1Q tag. (Outer tag would be the native VLAN).
VLAN Hopping VLAN attack that enables traffic to go between VLANs.
VLC Open source media player. Wikipedia Website
VMWare ESX Originated as an abbreviation of Elastic Sky X. In September 2004, the replacement for ESX was internally called VMvisor, but later changed to ESXi (as the "i" in ESXi stood for "integrated"). Wikipedia
VMWare ESXi Enterprise-class, type-1 hypervisor developed by VMware. Wikipedia
VMware vSphere Web Client Management tool for vSphere components. Website Wikipedia vSphere Web Client Support Video
VMworld Website
VMworld 2018 August 26-30 in Las Vegas. Website
VMworld 2019 August 25-29 in San Francisco. Website
Voice and Video Enabled VPN (V3PN)
Voice Interface Card (VIC) Cisco
Voice over Asynchronous Transfer Mode (VoATM) Wikipedia
Voice over IP (VoIP) Requires no more than 150ms one-way delay, no more that 30ms of jitter, and no more thatn 1 percent packet loss. Wikipedia
voice traffic Maximum recommended one-way delay is 150ms for voice.
Voice/WAN Interface Card (VWIC) Cisco
VoIP Server (aka: IP PBX) An example VoIP server is Asterisk.
vol Displays a disk volume label and serial number in DOS.
volt-ampere reactive (var) (aka: quadrature power, wattless power) Amount of reactive power in the circuit.
- var = IL2 × XL
volt-amperes (VA) Apparent power in a circuit.
- VA = ET × IT
Volta Codename for a GPU microarchitecture developed by NVIDIA. Announced March 2013. Website Wikipedia
voltage (V) Wikipedia
volume (aka: logical drive) Single accessible storage area with a single file system. Typicaly located on a single partition of a hard disk but can span multiple partitions and disks. Different than a partition. Wikipedia
Volume Shadow Copy Service (VSS) (aka: Volume Snapshot Service) Wikipedia
Volume Table Of Contents (VTOC) IBM mainframe storage architecture. Wikipedia
VPNFilter Malware designed to infect routers. The FBI believes that it was created by the Russian Fancy Bear group. Estimated to have infected approximately 500,000 routers worldwide as of May 24, 2018. Wikipedia Ars Technica
VTY password Password used on a to secure a Telnet or SSH connection. Cisco
vulnerability Weakness that allows an asset to be exploited. Wikipedia
VxWorks Real-Time Operating System (RTOS) intended for embedded devices. Runs on many architectures, and supports features such as SMP, IPv6, TIPC and memory protection. Developed as proprietary software by Wind River Systems. First released in 1987. Website Wikipedia