18. Raid array

RAID (redundant array of independent disks, originally redundant array of inexpensive disks[1][2]) is a storage technology that combines multiple disk drive components into a logical unit. Data is distributed across the drives in one of several ways called "RAID levels", depending on the level of redundancy and performance required.

RAID is now used as an umbrella term for computer data storage schemes that can divide and replicate data among multiple physical drives: RAID is an example of storage virtualization and the array can be accessed by the operating system as one single drive.[note 1] The different schemes or architectures are named by the word RAID followed by a number (e.g. RAID 0, RAID 1). Each scheme provides a different balance between the key goals: reliability and availability, performance, and capacity. RAID levels greater than RAID 0 provide protection against unrecoverable (sector) read errors, as well as whole disk failure.

19) CD-ROM , DVD, HVD, Blue-Ray

1)CD-ROM - 700 MB (0.7 GB), single layer, red laser, cheap, outdated. For delivering music, software, storing data.

2) DVD+-R/RW (Digital Vesatile Disk), 4.7 GB (DVD-5) (single-layer), 8.5 GB (DVD-9) (dual-layer), 9.4 GB (double-sided disk), red laser, current, cheap. For software, movies, data.

3) Blu-Ray, 25 GB (single layer), 50 GB (double-layer), may support up to 6-8 layers in the future, blue laser, quite expensive. For high-definition movies, HDTV, data.

4) HVD (Holographic Vesatile Disk) - 3.9 TB, 2 lasers, very expensive, emerging

22) Type of scanners

Flatbed scanners - used to input photos, sketches, slides, book pages, and other relatively flat documents into the computer

Portable scanner – used to capture small amount of text, the text is typically transferred to computer at a later time.

Integrated scanners – built into other devices , such as into ATM machine that captures images of deposit checks.

23) Types of printers

- laser printers (use toner powder)

- ink-jet printers (use liquid ink)

- special purposes printers (photoprinter, 3D printer)

24) Types of monitors:

CRT monitors

Flat-panel displays: - liquid crystal displays (LCD)

- plasma displays

Organic light emmiting diode (OLED) displays

2. TCP/IP

The Internet protocol suite is the set of communications protocols used for the Internet and similar networks, and generally the most popular protocol stack for wide area networks. It is commonly known as TCP/IP, because of its most important protocols: Transmission Control Protocol (TCP) and Internet Protocol (IP), which were the first networking protocols defined in this standard.

TCP/IP provides end-to-end connectivity specifying how data should be formatted, addressed, transmitted, routed and received at the destination. It has four abstraction layers which are used to sort all Internet protocols according to the scope of networking involved.[1][2]

4. Web server

Web server can refer to either the hardware (the computer) or the software (the computer application) that helps to deliver web content that can be accessed through the Internet.The most common use of web servers is to host websites, but there are other uses such as gaming, data storage or running enterprise

4. HTTP

HTTP defines how messages are formatted and transmitted, and what actions Web servers and browsers should take in response to various commands. For example, when you enter a URL in your browser, this actually sends an HTTP command to the Web server directing it to fetch and transmit the requested Web page

7. URL

Definition: URL stands for Uniform Resource Locator. A URL is a formatted text string used by Web browsers, email clients and other software to identify a network resource on the Internet. Network resources are files that can be plain Web pages, other text documents, graphics, or programs.

7. Top-level domains

The top-level domains such as .com and .net and .org are the highest level of domain names of the Internet. A top-level domain is also called a TLD. Top-level domains form the DNS root zone of the hierarchical Domain Name System. Every domain name ends in a top-level or first-level domain label.

Second-level and lower level domains

Below the top-level domains in the domain name hierarchy are the second-level domain (SLD) names. These are the names directly to the left of .com, .net, and the other top-level domains. As an example, in the domain example.co.uk, co is the second-level domain.