What’s on the Garbage Collection poster
A definition and 6 facts worth remembering.
The runtime periodically finds objects no longer reachable from the running program and reclaims their memory, so the programmer never calls free.
- Reachability, not reference counting alone, is the usual test.
- Generational GC: most objects die young, so scan the young ones often.
- A stop-the-world pause halts the program during collection.
- Reference counting frees immediately but cannot collect cycles.
- Rust avoids GC entirely with compile-time ownership rules.
- A 'leak' in a GC language is usually an unintended reference kept alive.
- Young gen — scanned often
- Old gen — rarely
- Pause — ms to s
- A cache with no eviction keeps every entry reachable, so nothing is ever collected. T…
If latency matters, measure pause times, not just throughput. A high-throughput collector can still stall for a second.
Questions about the Garbage Collection poster
- What’s on the Garbage Collection poster?
- A definition and 6 facts worth remembering. The runtime periodically finds objects no longer reachable from the running program and reclaims their memory, so the programmer never calls free. Reachability, not reference counting alone, is the usual test.; Generational GC: most objects die young, so scan the young ones often.; A stop-the-world pause halts the program during collection.; Reference counting frees immediately but cannot collect cycles.; Rust avoids GC entirely with compile-time ownership rules.; A 'leak' in a GC language is usually an unintended reference kept alive.; Young gen — scanned often; Old gen — rarely; Pause — ms to s; A cache with no eviction keeps every entry reachable, so nothing is ever collected. T…. If latency matters, measure pause times, not just throughput. A high-throughput collector can still stall for a second.
- Who is the Garbage Collection poster for?
- Garbage Collection belongs to the Computing section rather than to a school year, because computing is not something one grade owns. Anyone learning systems can pin it up — a beginner, a student mid-course, or someone revising years later.
- When should you use the Garbage Collection poster?
- GC trades a pause for not having to free anything. Know when the pause happens. A wall chart earns its place by being glanceable from where the work is happening, so Garbage Collection belongs on the wall where that computing work actually happens, within glancing distance, rather than filed away.
- What other posters go with Garbage Collection?
- Caching, Concurrency & Parallelism and DNS sit alongside Garbage Collection in the Computing section. Printed together they make a wall rather than a single sheet, which is how a reference set actually gets used.CachingConcurrency & ParallelismDNS
- Is the Garbage Collection poster free to download and print?
- Yes. Garbage Collection downloads as a free PDF with no account, no email and no watermark, like everything else in the Computing section. Print as many copies as you like for a home, a classroom, a library or a tutoring group; reselling the file is the only thing the licence rules out.Read the licence
- What size does the Garbage Collection poster print at?
- Garbage Collection is a vector PDF laid out for US Letter, and prints on A4 with Fit to page — the same file, no separate download. Because every mark on it is drawn rather than photographed, it stays sharp enlarged to A3, A2 or A1 at a copy shop. Colour carries emphasis only, so a greyscale print of Garbage Collection loses nothing.Printing guide
Related posters
Charts that sit alongside Garbage Collection on the same wall.
Browse every Computing poster, or start from the full catalogue.