add page cache with read-ahead and dirty writeback, file-backed and anonymous mmap with CoW, VAD-based virtual memory replacing the old user region model, PFN database with eviction and reclaim, file identity for cross-open section sharing, FAT32 path cache and per-file cluster chain cache, serial.sys for COM1 keyboard input, xHCI MSI with INTx and polled fallback, PciEnableMsiAuto, waitable input queue, KeWaitForAnyEvent, per-process thread info syscall, expanded kernel stats (PFN/PTE/VAD/file-cache/disk), pool allocation tags, async I/O user buffer locking, file flush on close, add docs.md.

code/user/apps/memtop/memtop.c

@@ -0,0 +1,71 @@
+#include <stdint.h>
+#include <stddef.h>
+#include <stdbool.h>
+#include <string.h>
+#include <ntlite/syscall.h>
+
+static int u64_to_string(uint64_t n, char* buf) {
+    int i = 0;
+    if (n == 0) {
+        buf[i++] = '0';
+        buf[i] = '\0';
+        return i;
+    }
+    char rev[24];
+    int r_idx = 0;
+    while (n > 0) {
+        rev[r_idx++] = (char)('0' + (n % 10));
+        n /= 10;
+    }
+    while (r_idx > 0) {
+        buf[i++] = rev[--r_idx];
+    }
+    buf[i] = '\0';
+    return i;
+}
+
+int main(void) {
+    SYS_CONSOLE_INFO console;
+    SYS_MEMORY_STATUS mem;
+    char metricsBuf[128];
+
+    while (true) {
+        if (SysGetConsoleInfo(&console) == SYS_STATUS_SUCCESS &&
+            SysGetMemoryStatus(&mem) == SYS_STATUS_SUCCESS) {
+
+            // If the system isn't reporting columns correctly, default to a safe standard width
+            int columns = (console.Columns > 0) ? (int)console.Columns : 80;
+
+            char freeStr[24], poolStr[24], heapStr[24];
+            u64_to_string(mem.FreePhysicalBytes / 1024u, freeStr);
+            u64_to_string(mem.KernelPoolBytes / 1024u, poolStr);
+            u64_to_string(mem.UserHeapBytes / 1024u, heapStr);
+
+            metricsBuf[0] = '\0';
+            strcat(metricsBuf, "[ Free: ");
+            strcat(metricsBuf, freeStr);
+            strcat(metricsBuf, "K | Pool: ");
+            strcat(metricsBuf, poolStr);
+            strcat(metricsBuf, "K | Heap: ");
+            strcat(metricsBuf, heapStr);
+            strcat(metricsBuf, "K ]");
+
+            size_t textLen = strlen(metricsBuf);
+            int targetX = columns - (int)textLen;
+            int targetY = 0; 
+
+            if (targetX >= 0) {
+                size_t written = 0;
+                
+                // Loop through the string and use the console's dedicated text filling API
+                // This utilizes the console's native font configuration instead of drawing raw screen bits
+                for (size_t i = 0; i < textLen; i++) {
+                    SysFillConsoleCharacter(metricsBuf[i], targetX + (int)i, targetY, 1, &written);
+                }
+            }
+        }
+
+        SysSleep(500);
+    }
+    return 0;
+}