diff --git a/m4/tuklib_cpucores.m4 b/m4/tuklib_cpucores.m4
index bb33c6f4..d48f2e5e 100644
--- a/m4/tuklib_cpucores.m4
+++ b/m4/tuklib_cpucores.m4
@@ -9,7 +9,7 @@
 #   This information is used by tuklib_cpucores.c.
 #
 #   Currently this supports sysctl() (BSDs, OS/2) and sysconf() (GNU/Linux,
-#   Solaris, Cygwin).
+#   Solaris, IRIX, Cygwin).
 #
 # COPYING
 #
@@ -54,7 +54,13 @@ int
 main(void)
 {
 	long i;
+#ifdef _SC_NPROCESSORS_ONLN
+	/* Many systems using sysconf() */
 	i = sysconf(_SC_NPROCESSORS_ONLN);
+#else
+	/* IRIX */
+	i = sysconf(_SC_NPROC_ONLN);
+#endif
 	return 0;
 }
 ]])], [
@@ -71,7 +77,8 @@ case $tuklib_cv_cpucores_method in
 	sysconf)
 		AC_DEFINE([TUKLIB_CPUCORES_SYSCONF], [1],
 			[Define to 1 if the number of available CPU cores
-			can be detected with sysconf(_SC_NPROCESSORS_ONLN).])
+			can be detected with sysconf(_SC_NPROCESSORS_ONLN)
+			or sysconf(_SC_NPROC_ONLN).])
 		;;
 esac
 ])dnl
diff --git a/m4/tuklib_physmem.m4 b/m4/tuklib_physmem.m4
index 59a645a4..a8c869f3 100644
--- a/m4/tuklib_physmem.m4
+++ b/m4/tuklib_physmem.m4
@@ -18,6 +18,8 @@
 #
 #     - BSDs use sysctl().
 #
+#     - IRIX has setinvent_r(), getinvent_r(), and endinvent_r().
+#
 #     - sysinfo() works on Linux/dietlibc and probably on other Linux
 #       systems whose libc may lack sysconf().
 #
@@ -78,6 +80,19 @@ main(void)
 }
 ]])], [tuklib_cv_physmem_method=sysctl], [
 
+AC_COMPILE_IFELSE([AC_LANG_SOURCE([[
+#include <invent.h>
+int
+main(void)
+{
+	inv_state_t *st = NULL;
+	setinvent_r(&st);
+	getinvent_r(st);
+	endinvent_r(st);
+	return 0;
+}
+]])], [tuklib_cv_physmem_method=getinvent_r], [
+
 # This version of sysinfo() is Linux-specific. Some non-Linux systems have
 # different sysinfo() so we must check $host_os.
 case $host_os in
@@ -101,7 +116,7 @@ main(void)
 		tuklib_cv_physmem_method=unknown
 		;;
 esac
-])])])])
+])])])])])
 case $tuklib_cv_physmem_method in
 	sysconf)
 		AC_DEFINE([TUKLIB_PHYSMEM_SYSCONF], [1],
@@ -114,6 +129,11 @@ case $tuklib_cv_physmem_method in
 			[Define to 1 if the amount of physical memory can
 			be detected with sysctl().])
 		;;
+	getinvent_r)
+		AC_DEFINE([TUKLIB_PHYSMEM_GETINVENT_R], [1],
+			[Define to 1 if the amount of physical memory
+			can be detected with getinvent_r().])
+		;;
 	sysinfo)
 		AC_DEFINE([TUKLIB_PHYSMEM_SYSINFO], [1],
 			[Define to 1 if the amount of physical memory
diff --git a/src/common/tuklib_cpucores.c b/src/common/tuklib_cpucores.c
index 0a8081ff..e35d9bc7 100644
--- a/src/common/tuklib_cpucores.c
+++ b/src/common/tuklib_cpucores.c
@@ -37,7 +37,13 @@ tuklib_cpucores(void)
 		ret = (uint32_t)cpus;
 
 #elif defined(TUKLIB_CPUCORES_SYSCONF)
+#	ifdef _SC_NPROCESSORS_ONLN
+	// Most systems
 	const long cpus = sysconf(_SC_NPROCESSORS_ONLN);
+#	else
+	// IRIX
+	const long cpus = sysconf(_SC_NPROC_ONLN);
+#	endif
 	if (cpus > 0)
 		ret = (uint32_t)cpus;
 #endif
diff --git a/src/common/tuklib_physmem.c b/src/common/tuklib_physmem.c
index b2d21283..1536e6e5 100644
--- a/src/common/tuklib_physmem.c
+++ b/src/common/tuklib_physmem.c
@@ -42,6 +42,10 @@
 #	endif
 #	include <sys/sysctl.h>
 
+// IRIX
+#elif defined(TUKLIB_PHYSMEM_GETINVENT_R)
+#	include <invent.h>
+
 // This sysinfo() is Linux-specific.
 #elif defined(TUKLIB_PHYSMEM_SYSINFO)
 #	include <sys/sysinfo.h>
@@ -136,6 +140,21 @@ tuklib_physmem(void)
 			ret = mem.u32;
 	}
 
+#elif defined(TUKLIB_PHYSMEM_GETINVENT_R)
+	inv_state_t *st = NULL;
+	if (setinvent_r(&st) != -1) {
+		inventory_t *i;
+		while ((i = getinvent_r(st)) != NULL) {
+			if (i->inv_class == INV_MEMORY
+					&& i->inv_type == INV_MAIN_MB) {
+				ret = (uint64_t)i->inv_state << 20;
+				break;
+			}
+		}
+
+		endinvent_r(st);
+	}
+
 #elif defined(TUKLIB_PHYSMEM_SYSINFO)
 	struct sysinfo si;
 	if (sysinfo(&si) == 0)