What happens at the physical level when you 'delete' a file on a traditional hard drive and empty the Recycle Bin?

The file's entry in the directory is removed and the space is marked as available, but the actual data bits remain until new data overwrites them The magnetic particles are physically rearranged to a neutral state The data is moved to a hidden system partition for 30 days The file is immediately overwritten with random data for security

You need to permanently destroy sensitive data on an old hard drive before recycling it. Which method is most effective?

Use secure erase software to overwrite all sectors multiple times, or physically destroy the drive platters Delete all files and empty the Recycle Bin Format the drive once using the quick format option Unplug the drive from power for 24 hours — data disappears without power

What is a relational database, and what makes it 'relational'?

A database that stores data in tables and links related data across tables using shared fields (like a customer ID) A database that stores only related people — like family tree data A database where all data is stored in one giant table for simplicity A database that is related to (synchronized with) another database on a different server

What does it mean for data to be stored 'in the cloud'?

Your data is stored on remote servers in data centers owned by companies, accessed over the internet Your data is stored in satellites orbiting the Earth Your data is stored on a special chip built into your router Your data is compressed into a small packet and floats wirelessly nearby

What is 'data redundancy' in storage, and why is it valuable?

Storing multiple copies of data so that if one storage medium fails, no data is lost Removing duplicate records from a database to save space Compressing data multiple times to make it as small as possible Storing data in multiple formats so different programs can open it

An image saved as PNG vs JPEG will look the same on screen but have different file sizes. Why?

PNG uses lossless compression preserving all pixel data; JPEG uses lossy compression that discards some detail to achieve smaller files JPEG is a newer format with better technology than PNG PNG files are always larger because they store more colors than JPEG The difference is only in the filename — the actual image data is identical

A hospital needs to store millions of patient records securely for decades. Which concern is LEAST important for them?

Minimizing file sizes to save storage costs Ensuring data is encrypted and access-controlled Maintaining multiple redundant backups Preserving exact data integrity over decades

What problem does 'data deduplication' solve in large storage systems?

It identifies and stores only one copy of identical data, saving storage space when the same files are stored by many users It deletes duplicate user accounts to reduce database size It prevents users from creating two files with the same name It runs two copies of the same calculation and compares results for accuracy

When you share a photo via a messaging app and it arrives looking slightly worse quality, what likely happened?

The app re-compressed the image (applied lossy compression again) to reduce data usage during transmission The receiving phone's screen has a lower resolution than the sender's Internet transmission always randomly corrupts some pixels in photos The photo was automatically resized to match the recipient's storage limit

What is 'data integrity' and why does it matter?

Data integrity means the data is accurate, complete, and unaltered — critical because corrupted or tampered data leads to wrong decisions Data integrity means all data is public and transparent Data integrity refers to how quickly data can be accessed Data integrity means old data is deleted to keep databases current