25 minv1.0

Storage, archives and resources

Learning objectives

Check disk and memory capacity, measure project size, create an archive, inspect it, and calculate a checksum.

1 Objective→ 2 Learn→ 3 Example→ 4 Practice→ 5 Verify→ 6 Continue

How to study this lessonUnderstand the idea first. Use the example to see the behaviour, practise where provided, then make sure you can explain the result before continuing.

Explanation

Capacity and usage

df reports free space on a mounted filesystem. du measures files below a directory. They answer different questions: a filesystem may be nearly full even when your project is small, and a user quota may block writes even when df shows free space.

Commands you will use

Command	What it does	Example
`df`	Shows filesystem capacity.	`df -h "$HOME"`
`du`	Measures directory or file usage.	`du -sh project/`
`free`	Shows memory and swap usage.	`free -h`
`lsblk`	Lists block devices and mount points.	`lsblk`
`tar`	Creates or reads an archive.	`tar -czf evidence.tgz evidence/`
`gzip` / `gunzip`	Compresses or expands one file.	`gzip report.txt`
`sha256sum`	Calculates an integrity checksum.	`sha256sum evidence.tgz`

An archive groups files. Compression reduces the archive size when the data can be compressed. Inspect archive member paths before extraction; reject unexpected absolute paths or .. entries.

Worked example

cd "$HOME/asic-linux-practice"
df -h .
du -sh .
free -h
tar -czf evidence.tgz logs source
tar -tzf evidence.tgz
sha256sum evidence.tgz > evidence.tgz.sha256
sha256sum -c evidence.tgz.sha256

Expected result: tar -t lists the archived files without extracting them, and the final checksum check reports OK.

RTL/DV use

Waveforms and regression logs can grow quickly. Check df before a large run and use du to locate project directories consuming space. Archive only the evidence required for review; avoid packaging generated data that can be recreated.

Common mistakes

Confusing filesystem free space from df with project size from du.
Extracting an unknown archive without listing it first.
Treating a checksum from an untrusted source as proof of authenticity.
Archiving huge waveform files without checking whether they are required.

Check yourself

Why can df report free space while your account still cannot create a file?

Engineering practice

Practice: Storage, archives and resources

Task→Run / reason→Check result→Explain why

Create an archive of your practice workspace, list its contents, save a SHA-256 checksum, and verify it.

Practice work is non-certified and is not stored by ASIC Campus.