A buffer underrun error, also known as a buffer underflow, is a type of error that occurs in the buffer system that communicates between two processes or devices. With a buffer underrun, the buffer is empty and one device or process needs to stop while the other attempts to feed more data into the buffer. This error may cause no problems aside from slowing down the computer, or it may cause serious functional issues in processes such as with compact-disc (CD) burning. The underrun error is usually fixed by changing the buffer size or speed and ensuring the computer has adequate resources.
In computers, a buffer acts as a chamber, or holding area, for memory. The buffer is usually in the random access memory (RAM), and allows the central processing unit (CPU) to manipulate data before sending them to another device. One side of the buffer fills the chamber while the other side takes data from the chamber. This is most often seen in read and write processes, such as CD burning.
The buffer underrun error occurs when the buffer empties. This means the device feeding the data has no data available to feed the buffer, and the device taking data cannot write anymore data, because the buffer is not supplying anything to write. There are many reasons for this error, such as minor slowdowns stopping the information flow, a fragmented hard drive, or using a computer that has weak hardware or low resources from running other processes.
Ramifications for a buffer underrun can be slight or serious. With processes occurring inside the computer and without a physical medium, this normally just causes a slowdown that makes the user wait for the buffer to refill. If burning a disc, the disc may stop burning and lock whatever data it wrote to the disc before the underrun happened. Programs with poor coding that can cause a buffer underflow can be exploited and hacked to ensure the computer continuously encounters the underflow error.
Fixing a buffer underrun is usually simple and can normally be done without purchasing anything new for the computer. Defragmenting the hard drive will lessen the chance of a buffer underflow, as will closing all programs to free up resources. Setting the buffer size higher or slowing down the writing speed should fix this error. Restarting the computer also should be effective in freeing up resources and stopping this error. If the computer has weak hardware, such as low RAM, the user should purchase and install better hardware if the other methods do not stop the error.