How Computers Safely Resume Interrupted Data Backups

A method for computers to pause a large data backup and resume exactly where they left off without restarting the entire process from scratch.

What it covers

This patent describes a system that tracks the progress of a data backup, allowing it to be interrupted by a user or a system event like a crash. When the backup resumes, the system compares timestamps on the existing backup files against the last successful backup to determine which data is already safe. It then only processes the remaining uncompleted portion of the data. This prevents the need to re-copy files that were already successfully stored before the interruption.

What it doesn't cover

• —Does not cover cloud-based synchronization services that do not use local timestamp-based file system backups.
• —Does not cover methods for data compression or deduplication during the backup process.
• —Does not cover the specific hardware interface used to store the backup data.

The clever bit

The system uses timestamp comparisons against the last completed backup to identify valid progress, essentially creating a 'checkpoint' system for file-level backups that can survive a system crash or power-off.

Why it matters

Before this, interrupting a large backup often meant losing all progress, forcing users to restart a potentially multi-hour process. This technology was essential for the reliability of consumer-grade backup software, specifically Apple's Time Machine, which allows users to disconnect their external drives or shut down their computers without worrying about backup corruption.

Real-world examples

• 1.Apple Time Machine on macOS
• 2.Local file system backup utilities