What is random access?

Random Access

In computer science, random access (sometimes called direct access) is the ability to access an element at an arbitrary position in a sequence in equal time, independent of sequence size. The position is arbitrary in the sense that it is unpredictable, thus the use of the term "random" in "random access". The opposite is sequential access, where a remote element takes longer time to access. A typical illustration of this distinction is to compare an ancient scroll (sequential; all material prior to the data needed must be unrolled) and the book (random: can be immediately flipped open to any random page). A more modern example is a cassette tape (sequential—you have to fast-forward through earlier songs to get to later ones) and a CD (random access—you can skip to the track you want).

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Some articles on random access:

DDR4 SDRAM
... for double data rate (fourth generation) synchronous dynamic random-access memory, is a type of dynamic random-access memory (DRAM) with a high bandwidth interface expected to be released to the ... and is not compatible with any earlier type of random access memory (RAM) due to different signaling voltages, physical interface and other factors ...
Random Access
... In computer science, random access (sometimes called direct access) is the ability to access an element at an arbitrary position in a sequence in equal time ... The position is arbitrary in the sense that it is unpredictable, thus the use of the term "random" in "random access" ... The opposite is sequential access, where a remote element takes longer time to access ...
Java Platform, Standard Edition - General Purpose Packages - Java.io - Random Access
... The RandomAccessFile class supports random access reading and writing of files ... The class uses a file pointer that represents a byte-offset within the file for the next read or write operation ...
Professional Mobile Radio - PMR Trunking Using MPT1327
... This invitation may be explicitly addressed to a mobile or a group or it may be random access ... Random access timeslots will be used when a mobile user initiates a call, or when a mobile registers on the TSC ... is likely that two or more mobile radio units will try to transmit at the same time on the same random access timeslot ...
St AX
... document is read into memory as a tree structure for random access by the calling application event based - the application registers to receive events as entities are encountered within the source document ... Both have advantages the former (for example, DOM) allows for random access to the document, the latter (e.g ... These two access metaphors can be thought of as polar opposites ...

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