Run Length Limited (RLL) is a commonly used encoding technique for magnetic disks, such as SATA, SAS, PATA, and SCSI connections. The goal of this technique is to store more bits on the disk than there are actual data bits.
Earlier disk drives had to add extra bits to the data stream to create enough space between the data bits for successful data retrieval. However, as electronics advanced, less extra bits were needed, allowing for a higher proportion of recorded bits to data bits.
In RLL, the number of consecutive 0s before a 1 bit is recorded is known as the “run length.” For example, RLL 1,7 means that there will be at least one 0 and at most seven 0s between each flux change.
What are some benefits of RLL encoding for magnetic disks?
RLL encoding allows for greater storage capacity on magnetic disks and improved data retrieval accuracy.
How does RLL compare to other encoding techniques?
RLL is considered more advanced than previous encoding techniques that required more extra bits to be added to the data stream.
What types of magnetic disks use RLL encoding?
SATA, SAS, PATA, and SCSI connections are some of the disk types that commonly use RLL encoding.
In summary, RLL is an encoding technique that allows for greater storage capacity and improved data retrieval accuracy on magnetic disks. It uses a “run length” to determine the number of consecutive 0s before a 1 bit is recorded, and is commonly used for SATA, SAS, PATA, and SCSI connections.