Hardware and disk organization

Understanding of underlying mechanisms of data storage, organization and data recovery.

This section provide a comprehensive overview of how hard disk drives physically store data and logically organize it for computer systems to access and boot from.

This section contains information about:

Physical Storage Layer:

Hard disks contain spinning platters with data stored in concentric tracks, divided into 512-byte sectors (the smallest storage units). Tracks at the same position across multiple platters form cylinders. File systems group sectors into clusters for efficient allocation, though this can lead to fragmentation when contiguous space is unavailable.

Boot Process Layer:

The Master Boot Record (MBR), located at the very first sector of every disk, contains executable code and the Partition Table. During startup, the MBR identifies the system partition, loads its boot sector, and transfers control to continue booting the operating system. This critical location is vulnerable to viruses that can prevent system startup.

Partition Organization Layer:

The Partition Table (within the MBR sector) defines up to four partitions per disk, specifying each partition's file system type, bootability, starting/ending locations, and size. Due to field size constraints, it can address disks up to approximately 7.8 GB directly. For more than four partitions, extended partitions create a linked chain of logical drives, each with its own partition table.

Practical Implications

Understanding these layers is essential for disk management, troubleshooting boot failures, performing data recovery, and comprehending capacity limitations in legacy systems. The architecture balances backward compatibility with MS-DOS/Windows 95 while supporting modern file systems like NTFS.