diff --git a/include/gdt.h b/include/gdt.h
new file mode 100644
index 0000000..f66d62d
--- /dev/null
+++ b/include/gdt.h
@@ -0,0 +1,23 @@
+#ifndef _GDT_H
+#define _GDT_H
+
+#include <stdint.h>
+
+struct gdt_entry {
+    uint16_t limit_low;     /* Lower 16 bits of limit */
+    uint16_t base_low;      /* Lower 16 bits of base */
+    uint8_t  base_middle;   /* Next 8 bits of base */
+    uint8_t  access;        /* Access flags */
+    uint8_t  granularity;   /* Granularity + high 4 bits of limit */
+    uint8_t  base_high;     /* Last 8 bits of base */
+} __attribute__((packed));
+
+struct gdt_ptr {
+    uint16_t limit;   /* Size of GDT - 1 */
+    uint32_t base;    /* Base address of GDT */
+} __attribute__((packed));
+
+void gdt_install();
+void gdt_set_entry(int num, uint32_t base, uint32_t limit, uint8_t access, uint8_t gran);
+
+#endif
diff --git a/include/idt.h b/include/idt.h
new file mode 100644
index 0000000..364255f
--- /dev/null
+++ b/include/idt.h
@@ -0,0 +1,24 @@
+#ifndef _IDT_H
+#define _IDT_H
+
+#include <stdint.h>
+
+struct idt_entry {
+  uint16_t base_low;
+  uint16_t sel;       /* Kernel segment selector */
+  uint8_t  always0;   /* Always 0 */
+  uint8_t  flags;     /* Type and attributes */
+  uint16_t base_high;
+} __attribute__((packed));
+
+struct idt_ptr {
+  uint16_t limit;
+  uint32_t base;
+} __attribute__((packed));
+
+void idt_install(void);
+void idt_install_isrs(void);
+void idt_install_syscall(void);
+void idt_set_entry(int num, uint32_t base, uint16_t sel, uint8_t flags);
+
+#endif
diff --git a/include/io.h b/include/io.h
new file mode 100644
index 0000000..2cfa726
--- /dev/null
+++ b/include/io.h
@@ -0,0 +1,16 @@
+/* Defines a abstract base for I/O in the Espresso kernel. */
+
+#ifndef ESPRESSO_IO_H
+#define ESPRESSO_IO_H
+
+#include <stdint.h>
+#include <text_display.h>
+
+void print(const char* str);
+
+char* input(uint8_t dev=0);
+
+void writefile(uint8_t mode, char* file, char* data);
+char* readfile(char* file);
+
+#endif
\ No newline at end of file
diff --git a/include/isr.h b/include/isr.h
new file mode 100644
index 0000000..bd4734c
--- /dev/null
+++ b/include/isr.h
@@ -0,0 +1,15 @@
+#ifndef _ISR_H
+#define _ISR_H
+
+#include <stdint.h>
+
+typedef struct {
+    uint32_t ds, edi, esi, ebp, esp, ebx, edx, ecx, eax;
+    uint32_t int_no, err_code;
+    uint32_t eip, cs, eflags, useresp, ss;
+} regs_t;
+
+void isr_handler(regs_t *r);
+void syscall_handler(regs_t *r);
+
+#endif