Generate realistic Linux boot logs including dmesg output, kernel initialization, and systemd startup sequences. Perfect for system administration training and log parser testing.
Press Ctrl + C to exit. Output is simulated for demo purposes only.
This module simulates kernel init, driver load, and system services log events with realistic pacing.
It is designed for demos, log pipeline testing, and documentation where the real stack is unavailable.
All output is generated locally in the browser and is safe to run.
PMAP: PCID enabled TSC Deadline Timer supported and enabled ACPI: System State [S0 S3 S4 S5] (S3) PCI configuration changed (bridge=16 device=4 cardbus=0) com.Example.FSCompressionTypeZlib load succeeded
No. It is a simulator that prints log text only.
Yes. The CLI supports speed and repeat options, and the web page can be refreshed.
No. It does not install, update, or modify anything.
Boot logs are produced by the Linux kernel and early userspace during system startup. They include driver loading, ACPI, PCI, and service messages.
This module mimics typical dmesg and boot log lines so you can test log aggregation, monitoring, or training materials without a real boot.
Popular questions and answers from Stack Overflow related to boot log.
Use dmesg command to view kernel ring buffer messages, or journalctl -b to see boot logs from systemd. You can also check /var/log/boot.log on some systems.
ACPI System State indicates power states supported: S0 (working), S1-S3 (sleep levels), S4 (hibernate), S5 (soft off). The value in parentheses shows the deepest supported sleep state.
Use journalctl --list-boots to see available boots. Then journalctl -b -1 for previous boot, -b -2 for two boots ago. Requires persistent journal storage in /etc/systemd/journald.conf.
This indicates BIOS/UEFI did not allocate enough memory for PCI devices. Try updating BIOS, enabling "Above 4G Decoding" in BIOS, or adding pci=realloc kernel parameter.
Use systemd-analyze blame to find slow services. Disable unnecessary services with systemctl disable. Use systemd-analyze critical-chain for dependency analysis. Consider using systemd socket activation.
TSC (Time Stamp Counter) Deadline Timer is a precision timing feature in modern CPUs. When enabled, it allows more efficient timer interrupts. It is used by the kernel for high-resolution timers.
This is informational, not an error. CPU microcode updates are applied early in boot for security/stability. Ensure linux-firmware package is up to date. Messages are normal and expected.
PCID (Process Context ID) is a CPU feature that reduces TLB flush overhead during context switches. "PCID enabled" message means the kernel is using this optimization. Improves performance especially with Meltdown mitigations.
Use rsyslog or syslog-ng to log kernel messages to a file. Or configure systemd-journald for persistent storage. Set Storage=persistent in /etc/systemd/journald.conf and create /var/log/journal directory.
ACPI BIOS errors indicate issues with system firmware ACPI tables. Often caused by buggy BIOS. Usually non-fatal. Try updating BIOS or using acpi=off kernel parameter as workaround (may disable some features).
Popular video tutorials to learn more about boot log.
Chris Titus Tech
Detailed walkthrough of the Linux boot sequence from BIOS/UEFI to login prompt. Covers bootloader, kernel initialization, and systemd startup.
Watch on YouTubeLinux Crash Course
Learn how to read and analyze Linux system logs including dmesg, journalctl, and /var/log files for troubleshooting boot issues.
Watch on YouTube
