Computer Evidence Glossary

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LAN (Local Area Network): A group of computers at a single location (usually an office or home) that are connected by phone lines, coaxial cable or wireless transmission. See Network.

Landscape Mode: The image is represented on the page or monitor such that the width is greater than the height (Horizontal).

Laser Disc: Same as an optical CD, except 12” in diameter.

Laser Printing: A beam of light hits an electrically charged drum and causes a discharge at that point. Toner is then applied, which sticks to the non­charged areas. Paper is pressed against the drum to form the image and is then heated to dry the toner. Used in laser printers and copying machines.

Latency: The time it takes to read a disc (or jukebox), including the time to physically position the media under the read/write head, seek the correct address and transfer it.

Latent Data: Latent or ambient data are deleted files and other ESI that are inaccessible without specialized forensic tools and techniques. Until overwritten, these data reside on media such as a hard drive in unused space and other areas available for data storage.

Latent Semantic Indexing and Analysis: A statistical method for finding the underlying dimensions of correlated terms. For example, words like law, lawyer, attorney, lawsuit, etc., all share some meaning. The presence of any one of them in a document could be recognized as indicating something consistent about the topic of the document. Latent Semantic Analysis uses statistics to allow the system to exploit these correlations for concept searching and clustering.

LCD (Liquid Crystal Display): Two polarizing transparent panels with a liquid crystal surface between; application of voltage to certain areas causes the crystal to turn dark, and a light source behind the panel transmits though crystals not darkened.

Leading: The amount of space between lines of printed text.

Legacy Data, Legacy System: Legacy Data is ESI in which an organization may have invested significant resources, but has been created or stored by the use of software and/or hardware that has become obsolete or replaced (“legacy systems”). Legacy data may be costly to restore or reconstruct when required for investigation or litigation analysis or discovery.

Legal Hold: A legal hold is a communication issued as a result of current or reasonably anticipated litigation, audit, government investigation or other such matter that suspends the normal disposition or processing of records. Legal holds may encompass procedures affecting data that is accessible as well as data that is not reasonably accessible. The specific communication to business or IT organizations may also be called a “hold,” “preservation order,” “suspension order,” “freeze notice,” “hold order,” or “hold notice.” See, The Sedona Conference^® Commentary on Legal Holds, August 2007 Public Comment Version, available for download at http://www.thesedonaconference.org.

Level Coding: Used in Bibliographical coding to facilitate different treatment, such as prioritization or more thorough extraction of data, for different categories of documents, such as by type or source.

LFP: IPRO Tech’s image cross reference file; an ASCII delimited text file required for cross­reference of images to data.

Lifecycle: The records lifecycle is the life span of a record from its creation or receipt to its final disposition. It is usually described in three stages: creation, maintenance and use, and archive to final disposition.

Line Screen: The number of half­tone dots that can be printed per inch. As a general rule, newspapers print at 65 to 85 lpi.

Link: See Hyperlink.

Load file: A file that relates to a set of scanned images or electronically processed files, and indicates where individual pages or files belong together as documents, to include attachments, and where each document begins and ends. A load file may also contain data relevant to the individual documents, such as metadata, coded data, text, and the like. Load files must be obtained and provided in prearranged formats to ensure transfer of accurate and usable images and data.

Local Area Network (LAN): See Network.

Locale: A set of parameters that define language, country and any special system configurations that correspond to the language and country. For example, locale typically determines the date format (month first in the US, day first in the UK), the time format (12­hour clock in the US, 24­hour clock in some European countries), the keyboard layout, and so forth. These settings can be overridden, but the locale sets the default.

Logical File Space: The actual amount of space occupied by a file on a hard drive. The amount of logical file space differs from the physical file space because when a file is created on a computer, a sufficient number of clusters (physical file space) are assigned to contain the file. If the file (logical file space) is not large enough to completely fill the assigned clusters (physical file space) then some unused space will exist within the physical file space.

Logical Unitization: See Unitization ­Physical and Logical.

Logical Volume: An area on the hard drive that has been formatted for files storage. A hard drive may contain a single or multiple volumes.

Lossless Compression: Exact construction of image, bit­by­bit, with no loss of information.

Lossy Compression: Reduces storage size of image by reducing the resolution and color fidelity while maintaining minimum acceptable standard for general use. A lossy image is one where the image after compression is different from the original image due to lost information. The differences may or may not be noticeable, but a lossy conversion process does not retain all the original information. JPEG is an example of a lossy compression method.

Lotus Domino: An IBM server product providing enterprise­level email, collaboration capabilities, and custom application platform; began life as Lotus Notes Server, the server component of Lotus Development Corporation’s client­server messaging technology. Can be used as an application server for Lotus Notes applications and/or as a web server. Has a built­in database system in the format of .NSF.

Lotus Notes: See Lotus Domino.

Lpi (lines per inch): The number of lines in an inch, as found on screens that create halftones and four­color process images. The more lines per inch, the more detailed the image. With the growth of computer­generated imagery, the term dpi is quickly replacing the term lpi.

Lumen: Measure of brightness often associated with the amount of light output of a projector.

LTO (Linear Tape­Open): A type of backup tape that can hold as much as 800 GB of data, or 1200 CDs depending on the data file format.

LZW (Lempel­Ziv & Welch): A common, lossless compression standard for computer graphics, used for most TIFF files. Typical compression ratios are 4/1.

Glossary - Courtesy of The Sedona Conference^®