diff --git a/src/main/java/org/truffleruby/core/support/IONodes.java b/src/main/java/org/truffleruby/core/support/IONodes.java
index ec425502a6fa..6c497bee0c89 100644
--- a/src/main/java/org/truffleruby/core/support/IONodes.java
+++ b/src/main/java/org/truffleruby/core/support/IONodes.java
@@ -87,7 +87,6 @@
 import org.truffleruby.language.control.RaiseException;
 import org.truffleruby.language.library.RubyStringLibrary;
 import org.truffleruby.language.objects.AllocationTracing;
-import org.truffleruby.platform.Platform;
 
 import com.oracle.truffle.api.CompilerDirectives;
 import com.oracle.truffle.api.CompilerDirectives.TruffleBoundary;
@@ -153,9 +152,6 @@ boolean fnmatch(Object pattern, Object path, int flags,
                     flags) != FNM_NOMATCH;
         }
 
-
-        private static final boolean DOSISH = Platform.IS_WINDOWS;
-
         private static final int FNM_NOESCAPE = 0x01;
         private static final int FNM_PATHNAME = 0x02;
         private static final int FNM_DOTMATCH = 0x04;
@@ -164,7 +160,7 @@ boolean fnmatch(Object pattern, Object path, int flags,
         public static final int FNM_NOMATCH = 1;
 
         private static boolean isdirsep(char c) {
-            return c == '/' || DOSISH && c == '\\';
+            return c == '/';
         }
 
         private static boolean isdirsep(byte c) {
@@ -259,19 +255,15 @@ private static int fnmatch_helper(byte[] bytes, int pstart, int pend, byte[] str
                         if (s >= send) {
                             return FNM_NOMATCH;
                         }
-                        if (DOSISH && (pathname && isdirsep(c) && isdirsep(string[s]))) {
-                        } else {
-                            if (nocase) {
-                                if (Character.toLowerCase(c) != Character.toLowerCase((char) string[s])) {
-                                    return FNM_NOMATCH;
-                                }
-
-                            } else {
-                                if (c != (char) (string[s] & 0xFF)) {
-                                    return FNM_NOMATCH;
-                                }
+                        if (nocase) {
+                            if (Character.toLowerCase(c) != Character.toLowerCase((char) string[s])) {
+                                return FNM_NOMATCH;
                             }
 
+                        } else {
+                            if (c != (char) (string[s] & 0xFF)) {
+                                return FNM_NOMATCH;
+                            }
                         }
                         s++;
                         break;
diff --git a/src/main/java/org/truffleruby/platform/Platform.java b/src/main/java/org/truffleruby/platform/Platform.java
index cbf1836ce059..8104889ef5b9 100644
--- a/src/main/java/org/truffleruby/platform/Platform.java
+++ b/src/main/java/org/truffleruby/platform/Platform.java
@@ -35,12 +35,8 @@ public abstract class Platform extends BasicPlatform {
     public static final String LIB_SUFFIX = determineLibSuffix();
     public static final String CEXT_SUFFIX = OS == OS_TYPE.DARWIN ? ".bundle" : LIB_SUFFIX;
 
-    public static final boolean IS_WINDOWS = OS == OS_TYPE.WINDOWS;
-
     private static String determineLibSuffix() {
         switch (OS) {
-            case WINDOWS:
-                return ".dll";
             case DARWIN:
                 return ".dylib";
             default:
diff --git a/src/shared/java/org/truffleruby/shared/BasicPlatform.java b/src/shared/java/org/truffleruby/shared/BasicPlatform.java
index af281e425fa5..a3e0ec35d7ca 100644
--- a/src/shared/java/org/truffleruby/shared/BasicPlatform.java
+++ b/src/shared/java/org/truffleruby/shared/BasicPlatform.java
@@ -41,9 +41,7 @@ public abstract class BasicPlatform {
 
     public enum OS_TYPE {
         LINUX("linux"),
-        DARWIN("darwin"),
-        SOLARIS("solaris"),
-        WINDOWS("mswin32");
+        DARWIN("darwin");
 
         private final String rubyName;
 
@@ -54,8 +52,7 @@ public enum OS_TYPE {
 
     public enum ARCH {
         AMD64("x86_64"),
-        AARCH64("aarch64"),
-        UNKNOWN("unknown");
+        AARCH64("aarch64");
 
         private final String rubyName;
 
@@ -79,14 +76,9 @@ public static OS_TYPE determineOS() {
         final String osName = System.getProperty("os.name");
 
         final String lowerOSName = osName.toLowerCase(Locale.ENGLISH);
-        if (lowerOSName.contains("windows")) {
-            return OS_TYPE.WINDOWS;
-        }
 
         if (lowerOSName.startsWith("mac") || lowerOSName.startsWith("darwin")) {
             return OS_TYPE.DARWIN;
-        } else if (lowerOSName.startsWith("sunos") || lowerOSName.startsWith("solaris")) {
-            return OS_TYPE.SOLARIS;
         }
 
         final String upperOSName = osName.toUpperCase(Locale.ENGLISH);
@@ -96,7 +88,7 @@ public static OS_TYPE determineOS() {
             }
         }
 
-        throw new UnsupportedOperationException("Unknown platform: " + osName);
+        throw new UnsupportedOperationException("Unsupported operating system: " + osName);
     }
 
     private static ARCH determineArchitecture() {
@@ -110,7 +102,7 @@ private static ARCH determineArchitecture() {
             case "arm64":
                 return ARCH.AARCH64;
             default:
-                return ARCH.UNKNOWN;
+                throw new UnsupportedOperationException("Unsupported CPU architecture: " + architecture);
         }
     }