Differences from btm

ntop uses bottom (btm) 0.14.9 as its reference for screens, keys, mouse controls, and CLI flags. This page covers defined entries D1, D2, D4-D9, and D11; D3 and D10 have no defined behavior.

ID	btm 0.14.9	ntop
D1	Passes sysinfo's process disk read and write values to its read/write rate columns on macOS.	Calculates process read and write rates from byte-counter deltas and actual elapsed sample time.
D2	On Linux, divides process I/O counter deltas by whole elapsed seconds; failed division yields zero.	On Linux, divides process I/O counter deltas by fractional elapsed seconds.
D4	Uses the process user ID and runtime reported by its system-information library to derive a user name and elapsed time.	On macOS, reads the effective UID and start time for processes owned by other users, so their user name and elapsed time remain available when other fields are unavailable.
D5	Formats process memory, CPU, and I/O from numeric values; only an unresolved user name displays as N/A.	Displays unavailable process values as N/A, including memory percentage when ntop cannot read it for another user's process on macOS.
D6	Gets disk usage from each physical partition and calculates used space as total minus available space.	On macOS, reports APFS used space per volume.
D7	Uses sysinfo component labels unchanged and does not deduplicate repeated sensor names.	Shows every named temperature sensor and adds numeric suffixes such as (1) and (2) to duplicate names.
D8	Discards an initial collection, waits 5 ms, then publishes the next collection.	Collects a baseline CPU sample first, then calculates the first displayed CPU usage value from the following interval.
D9	Waits for the configured update interval after each collection, so collection time adds to the cycle.	Schedules repeated collection against fixed deadlines, so a long collection does not shift later deadlines.
D11	The default build includes ZFS ARC collection; --free_arc subtracts reclaimable ARC from RAM usage.	Does not collect ZFS ARC. The --free_arc flag is accepted but does not change the display.

Unsupported behavior

The project specification excludes configuration-file handling. ntop does not read or write configuration files. Passing -C, --config, --config-location, or --config_location exits with status 2.

Argument	btm 0.14.9	ntop
-C, --config, --config-location, --config_location <path>	Accepts the path and proceeds to TUI initialization.	Exits with status 2 without reading or writing the specified file.

ntop supports macOS and Linux. It exits with status 1 on other platforms, including Windows and FreeBSD.

ntop does not include Linux Intel GPU data, per-process GPU usage on macOS, or metric export.