The following glossary defines terms related to the IT Industry.  
You should not reproduce this terms without permission.

RAID

Redundant Array of Independent (or Inexpensive) Disks.  Type of disk, often used on servers, where several physical disks are combined into an array for better speed and fault tolerance.

• Level 0 implements data striping where file blocks are written to separate drives.  Does not provide fault tolerance, because failure of one drive will result in data loss.
• Level 1 implements data mirroring.  Data is duplicated on two drives either through software or hardware.  Provides faster read performance than a single drive.
• Level 2 - not used in practice. Data is split at bit level at written to multiple drives.
• Level 3 - requires at least 3 drives.  Data block is striped at byte level across drives and error correction codes (parity info) is recorder on another drive.  Provides fault tolerance but slower writing performance.
• Level 4 - Similar to Level 3 but provides faster performance because it uses blocks for striping.
• Level 5 - Similar to Level 4 but improves performance but also striping parity info across multiple drives.
• Level 6 - Similar to Level 5 but also uses second parity scheme for better fault tolerance.
• Level 7 - Proprietary RAID design by Storage Computer Corporation.  Level7 is faster than other levels because it uses multiple levels of cache and asynchronous I/O transfers.

In addition multiple RAID levels can be combined to improve performance or reliability.

Raw Logs

Raw access data updated in real-time that can be downloaded and used by any statistics program.  Typically each line show the user's IP, date and time of the access, what kind of request was done, which document was requested, HTTP status code, bytes transferred, referrer, and user agent info.  If a host doesn't have statistics, you'll need access to raw logs to identify who your site's visitors are.  Analyzing raw logs can also provide more detailed look at site accesses than stats.

Reseller

Resellers are usually smaller companies that still try to build their customers base.  They don't own the server with user accounts but can perform most administrative functions.

RJ-11

A standard connector that is used to connect to the telephone line.

RJ-45

A standard connector that is used to connect to the Ethernet network.

ROFL

Rolling On the Floor Laughing

ROI

Return of Investment

Router

A network device (can be a dedicated computer) that is used to connect two or more networks together and route packets between them.

RSA

A public key cryptosystem developed by Ron Rivest, Adi Shamir, and Leonard Adleman. It can be used to encrypt session keys and to generate digital certificates.