Glossary
page 54
LaCie SAFE Mobile Hard Drive with encryption
User’s Manual
and adopted as a national standard in US in 1977. DES encrypts and decrypts data in 64-bit blocks, using a 64-bit key.
DES takes a 64-bit block of plain text as input and outputs a 64-bit block of cipher text. Since it always operates on blocks of
equal size and it uses both permutations and substitutions in the algorithm, DES is both a block cipher and a product cipher.
Although the input key for DES is 64 bits long, the actual key used by DES is only 56 bits in length. The least significant bit
in each byte is a parity bit, and should be set so that there are always an odd number in every byte. These parity bits are
ignored, so only the seven most significant bits of each byte are used, resulting in a key length of 56 bits.
Digital –
Discrete information that can be broken down to zero or one bits.
Driver (peripheral manager) –
A software component that enables the computer system to communicate with a peripheral.
Most peripherals will not operate correctly – if at all – if the appropriate drivers are not installed on the system.
File System –
Links the physical map of a disc to its logical structure. Thanks to the file system, users and computers can easily
display path, directories and files recorded onto the disc.
Fingerprint –
An impression on a surface of the curves formed by the ridges on a fingertip, especially such an impression
made in ink and used as a means of identification.
Firmware –
Permanent or semi-permanent instructions and data programmed directly into the circuitry of a programmable
read-only memory or an electronically-erasable, programmable read-only memory chip. Used for controlling the operation of
the computer or tape drive. Distinct from the software, which is stored in random access memory and can be altered.
Folder –
A list created on a disk to store files. Creating folders and sub-folders enables you to organize the storage of your
files in a logical, hierarchical manner so that you can find and manage them more easily.
Format, -ting, -ted –
This is a process where a device is prepared to record data. In this process, the hard disk writes special
information onto its own recording surfaces into areas (blocks) that are ready to accept user data. Since this operation causes
all current user data stored on the hard disk to be lost, this is an infrequent operation that usually only happens at the factory
that created the hard disk. It is unusual for something to happen to a hard disk that requires the end-user to initially perform
this operation.
Gigabit –
Unit of measure, commonly used to express the amount of data in one second between two points. E.g. in the term
Gigabit Ethernet
–
1 gigabit per second (1 Gbps) equals 1 billion bits per second and is equivalent to 1000Mb/s.
GB (GigaByte) –
This value is normally associated with data storage capacity. Basically, it means a thousand million or a
billion bytes. In fact, it equals 1,073,741,824 bytes (or 1,024 x 1,024 x 1,024).
Hardware –
Physical components of a computer system, including the computer itself and peripherals such as printers,
modems, mice, etc.
