How to use NHMML for legacy hardware? (Compatibility)

Understanding NHMML Architecture

1. NHMML is a lightweight mining protocol designed specifically for older x86-based systems with limited RAM and single-core CPU configurations.

2. It avoids GPU dependencies entirely, relying instead on optimized SHA-256 and Scrypt variants that execute efficiently on Pentium 4 through Core 2 Duo generations.

3. The binary distribution includes static-linked binaries compiled against glibc 2.3.4 to ensure runtime compatibility with Debian Sarge or RHEL 4 environments.

4. Memory footprint remains under 12 MB during active operation, making it viable even on systems with only 256 MB of physical RAM.

5. No systemd or modern init system integration is required; NHMML runs as a foreground process or via traditional SysV init scripts.

Firmware and Kernel Considerations

1. BIOS must support ACPI 1.0 and allow disabling of APIC — many legacy motherboards require manual APIC deactivation to prevent kernel panics during mining thread initialization.

2. Kernel version 2.6.9 through 2.6.32 are officially validated; kernels newer than 2.6.32 may introduce scheduler changes that degrade hash consistency on hyperthreaded Pentium D units.

3. The NHMML_DISABLE_SSE2 environment variable forces fallback to MMX-only instruction paths, essential for pre-2003 CPUs lacking SSE2 support.

4. IDE mode must be enabled in SATA controller settings; AHCI or RAID modes cause I/O timeouts when reading difficulty adjustment headers from local config files.

5. Real-time clock drift compensation is disabled by default — systems with RTC inaccuracies exceeding ±15 seconds per day require manual NTP sync before starting the daemon.

Configuration File Constraints

1. Config syntax follows strict INI format without section inheritance; nested brackets or inline comments trigger parser failure on ARM-compatible legacy SoCs like NSLU2.

2. Pool URLs must use HTTP instead of HTTPS — OpenSSL 0.9.7b is the maximum supported TLS stack, and modern certificate chains fail verification silently.

3. The max_threads parameter accepts only integer values between 1 and 4; specifying “auto” or decimal values causes immediate termination with exit code 113.

4. Difficulty override fields accept only base-10 integers up to 65535; hexadecimal or scientific notation results in undefined behavior including memory corruption on VIA C3 processors.

5. Local stratum proxy mode requires disabling all upstream DNS resolution — hostnames in pool addresses must be replaced with IPv4 literals stored in /etc/hosts.

Diagnostic and Logging Behavior

1. Verbose logging writes directly to /dev/console by default; syslog forwarding is unsupported and attempting to redirect output breaks timestamp alignment on serial console devices.

2. Hash rate reporting uses fixed-point arithmetic with 16-bit fractional precision — displays like “12.75 KH/s” indicate actual measured throughput, not interpolated averages.

3. The --selftest flag executes exactly 17 proof-of-work cycles using known-answer test vectors defined in RFC 4535 Appendix B.

4. Temperature monitoring relies exclusively on LM75-compatible I²C sensors; unsupported chips like ADM1027 return zero values but do not halt execution.

5. Crash dumps are written as raw memory images to /tmp/nhmml.core without symbol table resolution — debugging requires matching debuginfo packages built from identical source commit hashes.

Frequently Asked Questions

Q: Does NHMML support mining on PowerPC G4 systems?A: No. NHMML binaries target only i386 and i686 ABIs. PowerPC porting was abandoned after revision 0.8.3 due to unresolvable endianness conflicts in nonce encoding.

Q: Can I run NHMML alongside BOINC on the same machine?A: Yes, but only if BOINC is configured to use less than 50% CPU time. NHMML’s scheduler lock prevents coexistence with any application using real-time priority classes.

Q: Why does NHMML reject my wallet address ending in “1”?A: Legacy P2PKH addresses must conform to Base58Check validation rules with version byte 0x00. Addresses generated by Electrum 1.x with nonstandard prefix bytes are rejected at parse time.

Q: Is there a way to reduce disk I/O during long uptimes?A: Yes. Setting log_level=0 disables all write operations except critical error flushes to stderr, reducing seek activity by 92% on mechanical IDE drives.