Disk DBMS have large data storage capacities without size restrictions unlike memory DBMS, making them suitable for historical and data warehouse data. However, disk I/O causes performance limitations as the disk must be accessed for indexing even when data is buffered in memory. Disk DBMS separate data storage on disk from memory processing for large data capacities at the cost of reduced performance due to disk access times.

1. Disk DBMS Features
 Large capacity of data processing
• Unlike Memory DBMS, there is no size restriction of storing data
• Suitable for history type of data and DW
 Limitation of processing performance
• Performance reduced by Disk I/O
• Index is created from the disk even though the data is loaded into buffer
MEMORY LAYER
DISK STORAGE LAYER
DATABASE ENGINE
DISK
Tablespace
Memory
Buffer