Sekvenssiläpikäynti

Sekvenssiläpikäynti, often translated as sequential access or sequential processing, refers to a method of data access and processing where data elements are accessed or processed in a linear order, one after another. This is in contrast to random access, where any data element can be accessed directly without regard to its position. In sequential access, to reach a particular element, all the preceding elements must be read or passed over.

This method is common in older storage technologies like magnetic tape. When a specific piece of data is required from a tape, the tape must be physically wound or rewound to the correct position, reading through all the data before the desired location. In modern computing, sequential access is often employed for processing large files, especially when the entire file needs to be examined or modified in order. For example, reading a text file line by line is a form of sequential access. Similarly, processing data streams or logs typically involves sequential access, as the data arrives and is handled in the order it is generated.

The efficiency of sequential access depends heavily on the task. For tasks that require processing data in order, it can be very efficient. However, for tasks that require frequent access to scattered pieces of data, it can be significantly slower than random access. The underlying data structure and the storage medium play a crucial role in determining the performance characteristics of sequential access.