1101 Flashcards
AUP
Acceptable Use Policy
The conduct expected from a person using a computer or service. ISPs and other online services provide their customers with an acceptable use policy (AUP), which may prohibit spamming or commercial usage. Also called an “acceptable use policy/Internet use policy” (AUP/IUP), schools and universities provide AUPs for students using the computer lab, which defines unacceptable behavior.
LDAP
Lightweight Directory Access Protocol
A protocol used to access a directory listing in a TCP/IP network. LDAP is used to query network directories, email servers and other information repositories. It is a sibling protocol to HTTP and FTP and uses the ldap:// prefix in its URL.
MBR
Master Boot Record
The first sector of the primary storage partition in a BIOS-based computer. The MBR contains a small program and the partition table. When the program is executed, it determines which partition contains the active operating system and branches to the boot program in that partition’s boot sector to load it.
Dfs
Distributed File System
An enhancement to Windows server operating systems that allows files scattered across multiple servers to be treated as a single group. With Dfs, a network administrator can build a hierarchical file system that spans the organization’s LANs and WANs.
SAN
Storage Area Network
An array of storage drives in a self-contained unit. In large enterprises, SANs serve as pools of storage for the servers in the network. Compared to managing drives attached to each server, SANs improve system administration. Treating all storage as a single resource makes drive maintenance and routine backups easier to schedule and control. To support disaster recovery, redundant SANs are deployed in separate locations, each a copy of the other.
HAL
Hardware Abstraction Layer
An interface between hardware and software. A hardware abstraction layer (HAL) is generally used as a common driver for peripheral devices. The application calls the operating system; the OS calls the HAL, and the HAL instructions activate the specific hardware.
RJ-11
Registered Jack-11
A telephone interface that uses a cable of twisted wire pairs and a modular jack with two, four or six contacts. RJ-11 is the common connector for plugging a telephone into the wall and the handset into the telephone.
RJ-45
Registered Jack-45
A common data networking interface that employs a cable of twisted wire pairs and an 8-pin modular jack. RJ-45 is used for Ethernet and Type 3 Token Ring networks.
DNS
Domain Name System
The Internet’s system for converting alphabetic names into numeric IP addresses. For example, when a Web address (URL) is typed into a browser, DNS servers return the IP address of the Web server associated with that name. In this made-up example, the DNS converts the URL www.company.com into the IP address 204.0.8.51.
DHCP
Dynamic Host Configuration Protocol
The automatic assigning of IP addresses to client machines logging into an IP network. The same address, although technically temporary, may remain with a machine indefinitely unless a conflict arises with other devices on the network.
UDP
User Datagram Protocol
A TCP/IP protocol that is widely used for streaming audio and video, voice over IP (VoIP) and videoconferencing. UDP is considered an unreliable delivery protocol because it does not check for errors. When transmitting voice and video, there is no time to retransmit erroneous or dropped packets.
UDP is “connectionless” and does not use a handshake to start a session like TCP does. For example, in a broadcast session with multiple destinations, UDP does not set up a connection with each receiver beforehand.
TCP
Transmission Control Protocol
The reliable transport protocol within the TCP/IP protocol suite. TCP ensures that all data arrive accurately and 100% intact at the other end.
TCP is “connection oriented” and requires a handshake before the session can begin.
PSU Voltages
3.3v, 5v, and 12v
12 volts is commonly used for drives, while 3.3v and 5v are used by the chips and other motherboard components.
DaaS
Desktop As A Service
A thin client architecture that is delivered from a cloud service provider rather than from in-house servers. The users’ computers function like remote input/output terminals to the servers in the datacenter.
IaaS
Infrastructure As A Service
A cloud computing service that provides a basic computing platform, typically the hardware and virtual machine (VM) infrastructure (no operating system) or the hardware and an operating system.
PaaS
Platform As A Service
A cloud computing service that provides a comprehensive computing environment. PaaS includes the hardware, operating system, database and other necessary software for the execution of applications. It may include a complete development environment as well. PaaS is a step up from “infrastructure as a service” (IaaS), which provides only the servers and operating systems.
SaaS
Software As A Service
Software that is rented rather than purchased. Instead of buying applications and paying for periodic upgrades, SaaS is subscription based, and upgrades are automatic during the subscription period.
HDD Max RPM
15,000 RPM
RAID 0
Redundant Array of Independent Disks
Striping (for Performance)
2 or More Drives
Data are broken into blocks, called “stripes,” and alternately written to two or more drives simultaneously to increase speed. For example, stripe 1 is written to drive 1 at the same time stripe 2 is written to drive 2. Then stripes 3 and 4 are written to drives 1 and 2 simultaneously and so on. When reading, stripes 1 and 2 are read simultaneously; then stripes 3 and 4 and so on.
RAID 1
Redundant Array of Independent Disks
Mirroring (for Fault Tolerance)
2 Drives
Increases safety by writing the same data on two drives. Called “mirroring,” RAID 1 does not increase performance. However, if one drive fails, the second drive is used, and the failed drive is manually replaced. After replacement, the RAID controller duplicates the contents of the working drive onto the new one.
RAID 3
Redundant Array of Independent Disks
Striping plus Fault Tolerance
3 or More Drives
Increases safety by computing parity data and increases speed by interleaving data across two or more drives (striping). RAID 3 achieves the highest data transfer rate because all drives operate in parallel. Using byte level striping, parity bits are stored on separate, dedicated drives.
RAID 5
Redundant Array of Independent Disks
Striping plus Fault Tolerance
3 or More Drives
Increases safety by computing parity data and increases speed by interleaving data across three or more drives (striping). RAID 5 is similar to RAID 3, except that RAID 5 parity is distributed among all drives, whereas RAID 3 uses separate parity drives.
RAID 10
Redundant Array of Independent Disks
Striping and Mirroring
4 Drives
Increases safety by writing the same data on two drives (mirroring), while increasing speed by interleaving data across two or more mirrored “virtual” drives (striping). RAID 10 provides the most security and speed but uses more drives than the more common RAID 5 method.
What cable provides no EMI protection?
UTP
Unshielded Twisted Pair