File Slack Space

File slack potentially contains randomly selected bytes of data from computer memory because DOS/Windows normally writes in 512 byte blocks called sectors. Clusters are made up of blocks of sectors. However, if there is not enough data in the file to fill the last sector in a file, DOS/Windows makes up the difference by padding the remaining space with data from the memory buffers of the operating system. This randomly selected data from memory is called 'RAM Slack' because it comes from the memory of the