diff --git a/src/machine/m_at_socket7_3v.c b/src/machine/m_at_socket7_3v.c
index c9fb65e58..3357f5918 100644
--- a/src/machine/m_at_socket7_3v.c
+++ b/src/machine/m_at_socket7_3v.c
@@ -40,9 +40,10 @@
 #include <86box/fdd.h>
 #include <86box/fdc.h>
 #include <86box/nvr.h>
+#include <86box/plat_unused.h>
 
 static void
-machine_at_thor_common_init(const machine_t *model, int mr)
+machine_at_thor_common_init(const machine_t *model, UNUSED(int mr))
 {
     machine_at_common_init_ex(model, 2);
 
diff --git a/src/machine/m_ps1_hdc.c b/src/machine/m_ps1_hdc.c
index 116acbf11..f35879458 100644
--- a/src/machine/m_ps1_hdc.c
+++ b/src/machine/m_ps1_hdc.c
@@ -649,7 +649,7 @@ do_format(hdc_t *dev, drive_t *drive, ccb_t *ccb)
         fcb = (fcb_t *)dev->data;
 #endif
             dev->state = STATE_FINIT;
-            /*FALLTHROUGH*/
+            fallthrough;
 
         case STATE_FINIT:
 do_fmt:
@@ -745,7 +745,7 @@ hdc_callback(void *priv)
     switch (ccb->cmd) {
         case CMD_READ_VERIFY:
             no_data = 1;
-            /*FALLTHROUGH*/
+            fallthrough;
 
         case CMD_READ_SECTORS:
             if (!drive->present) {
@@ -772,7 +772,7 @@ hdc_callback(void *priv)
                     dev->buf_len = (128 << dev->ssb.sect_size);
 
                     dev->state = STATE_SEND;
-                    /*FALLTHROUGH*/
+                    fallthrough;
 
                 case STATE_SEND:
                     /* Activate the status icon. */
@@ -938,7 +938,7 @@ do_send:
 
         case CMD_WRITE_VERIFY:
             no_data = 1;
-            /*FALLTHROUGH*/
+            fallthrough;
 
         case CMD_WRITE_SECTORS:
             if (!drive->present) {
@@ -965,7 +965,7 @@ do_send:
                     dev->buf_len = (128 << dev->ssb.sect_size);
 
                     dev->state = STATE_RECV;
-                    /*FALLTHROUGH*/
+                    fallthrough;
 
                 case STATE_RECV:
                     /* Activate the status icon. */
diff --git a/src/machine/m_tandy.c b/src/machine/m_tandy.c
index 6cd1afde9..1d4c3303f 100644
--- a/src/machine/m_tandy.c
+++ b/src/machine/m_tandy.c
@@ -1239,7 +1239,7 @@ static void *
 eep_init(const device_t *info)
 {
     t1keep_t *eep;
-    FILE     *f = NULL;
+    FILE     *fp = NULL;
 
     eep = (t1keep_t *) malloc(sizeof(t1keep_t));
     memset(eep, 0x00, sizeof(t1keep_t));
@@ -1257,11 +1257,11 @@ eep_init(const device_t *info)
             break;
     }
 
-    f = nvr_fopen(eep->path, "rb");
-    if (f != NULL) {
-        if (fread(eep->store, 1, 128, f) != 128)
+    fp = nvr_fopen(eep->path, "rb");
+    if (fp != NULL) {
+        if (fread(eep->store, 1, 128, fp) != 128)
             fatal("eep_init(): Error reading Tandy EEPROM\n");
-        (void) fclose(f);
+        (void) fclose(fp);
     } else
         memset(eep->store, 0x00, 128);
 
@@ -1274,12 +1274,12 @@ static void
 eep_close(void *priv)
 {
     t1keep_t *eep = (t1keep_t *) priv;
-    FILE     *f   = NULL;
+    FILE     *fp  = NULL;
 
-    f = nvr_fopen(eep->path, "wb");
-    if (f != NULL) {
-        (void) fwrite(eep->store, 128, 1, f);
-        (void) fclose(f);
+    fp = nvr_fopen(eep->path, "wb");
+    if (fp != NULL) {
+        (void) fwrite(eep->store, 128, 1, fp);
+        (void) fclose(fp);
     }
 
     free(eep);
diff --git a/src/machine/m_xt_philips.c b/src/machine/m_xt_philips.c
index 4caff1431..1fc284a46 100644
--- a/src/machine/m_xt_philips.c
+++ b/src/machine/m_xt_philips.c
@@ -91,8 +91,8 @@ philips_write(uint16_t port, uint8_t val, void *priv)
 static uint8_t
 philips_read(uint16_t port, void *priv)
 {
-    philips_t *dev = (philips_t *) priv;
-    uint8_t    ret = 0xff;
+    const philips_t *dev = (philips_t *) priv;
+    uint8_t          ret = 0xff;
 
     switch (port) {
         /* port 0xc0
diff --git a/src/machine/m_xt_t1000.c b/src/machine/m_xt_t1000.c
index 1b7cdab91..a12fa4e96 100644
--- a/src/machine/m_xt_t1000.c
+++ b/src/machine/m_xt_t1000.c
@@ -833,7 +833,7 @@ t1000_read_roml(uint32_t addr, void *priv)
 int
 machine_xt_t1000_init(const machine_t *model)
 {
-    FILE *f;
+    FILE *fp;
     int ret;
 
     ret = bios_load_linear("roms/machines/t1000/t1000.rom",
@@ -856,15 +856,15 @@ machine_xt_t1000_init(const machine_t *model)
      * If the file is missing, continue to boot; the BIOS will
      * complain 'No ROM drive' but boot normally from floppy.
      */
-    f = rom_fopen("roms/machines/t1000/t1000dos.rom", "rb");
-    if (f != NULL) {
+    fp = rom_fopen("roms/machines/t1000/t1000dos.rom", "rb");
+    if (fp != NULL) {
         t1000.romdrive = malloc(T1000_ROMSIZE);
         if (t1000.romdrive) {
             memset(t1000.romdrive, 0xff, T1000_ROMSIZE);
-            if (fread(t1000.romdrive, 1, T1000_ROMSIZE, f) != T1000_ROMSIZE)
+            if (fread(t1000.romdrive, 1, T1000_ROMSIZE, fp) != T1000_ROMSIZE)
                 fatal("machine_xt_t1000_init(): Error reading DOS ROM data\n");
         }
-        fclose(f);
+        fclose(fp);
     }
     mem_mapping_add(&t1000.rom_mapping, 0xa0000, 0x10000,
                     t1000_read_rom, t1000_read_romw, t1000_read_roml,
@@ -986,62 +986,62 @@ t1000_syskey(uint8_t andmask, uint8_t ormask, uint8_t xormask)
 static void
 t1000_configsys_load(void)
 {
-    FILE *f;
+    FILE *fp;
     int   size;
 
     memset(t1000.t1000_nvram, 0x1a, sizeof(t1000.t1000_nvram));
-    f = plat_fopen(nvr_path("t1000_config.nvr"), "rb");
-    if (f != NULL) {
+    fp = plat_fopen(nvr_path("t1000_config.nvr"), "rb");
+    if (fp != NULL) {
         size = sizeof(t1000.t1000_nvram);
-        if (fread(t1000.t1000_nvram, 1, size, f) != size)
+        if (fread(t1000.t1000_nvram, 1, size, fp) != size)
             fatal("t1000_configsys_load(): Error reading data\n");
-        fclose(f);
+        fclose(fp);
     }
 }
 
 static void
 t1000_configsys_save(void)
 {
-    FILE *f;
+    FILE *fp;
     int   size;
 
-    f = plat_fopen(nvr_path("t1000_config.nvr"), "wb");
-    if (f != NULL) {
+    fp = plat_fopen(nvr_path("t1000_config.nvr"), "wb");
+    if (fp != NULL) {
         size = sizeof(t1000.t1000_nvram);
-        if (fwrite(t1000.t1000_nvram, 1, size, f) != size)
+        if (fwrite(t1000.t1000_nvram, 1, size, fp) != size)
             fatal("t1000_configsys_save(): Error writing data\n");
-        fclose(f);
+        fclose(fp);
     }
 }
 
 static void
 t1200_state_load(void)
 {
-    FILE *f;
+    FILE *fp;
     int   size;
 
     memset(t1000.t1200_nvram, 0, sizeof(t1000.t1200_nvram));
-    f = plat_fopen(nvr_path("t1200_state.nvr"), "rb");
-    if (f != NULL) {
+    fp = plat_fopen(nvr_path("t1200_state.nvr"), "rb");
+    if (fp != NULL) {
         size = sizeof(t1000.t1200_nvram);
-        if (fread(t1000.t1200_nvram, 1, size, f) != size)
+        if (fread(t1000.t1200_nvram, 1, size, fp) != size)
             fatal("t1200_state_load(): Error reading data\n");
-        fclose(f);
+        fclose(fp);
     }
 }
 
 static void
 t1200_state_save(void)
 {
-    FILE *f;
+    FILE *fp;
     int   size;
 
-    f = plat_fopen(nvr_path("t1200_state.nvr"), "wb");
-    if (f != NULL) {
+    fp = plat_fopen(nvr_path("t1200_state.nvr"), "wb");
+    if (fp != NULL) {
         size = sizeof(t1000.t1200_nvram);
-        if (fwrite(t1000.t1200_nvram, 1, size, f) != size)
+        if (fwrite(t1000.t1200_nvram, 1, size, fp) != size)
             fatal("t1200_state_save(): Error writing data\n");
-        fclose(f);
+        fclose(fp);
     }
 }
 
@@ -1049,13 +1049,13 @@ t1200_state_save(void)
 static void
 t1000_emsboard_load(void)
 {
-    FILE *f;
+    FILE *fp;
 
     if (mem_size > 512) {
-        f = plat_fopen(nvr_path("t1000_ems.nvr"), "rb");
-        if (f != NULL) {
-            (void) !fread(&ram[512 * 1024], 1024, (mem_size - 512), f);
-            fclose(f);
+        fp = plat_fopen(nvr_path("t1000_ems.nvr"), "rb");
+        if (fp != NULL) {
+            (void) !fread(&ram[512 * 1024], 1024, (mem_size - 512), fp);
+            fclose(fp);
         }
     }
 }
@@ -1063,13 +1063,13 @@ t1000_emsboard_load(void)
 static void
 t1000_emsboard_save(void)
 {
-    FILE *f;
+    FILE *fp;
 
     if (mem_size > 512) {
-        f = plat_fopen(nvr_path("t1000_ems.nvr"), "wb");
-        if (f != NULL) {
-            fwrite(&ram[512 * 1024], 1024, (mem_size - 512), f);
-            fclose(f);
+        fp = plat_fopen(nvr_path("t1000_ems.nvr"), "wb");
+        if (fp != NULL) {
+            fwrite(&ram[512 * 1024], 1024, (mem_size - 512), fp);
+            fclose(fp);
         }
     }
 }
diff --git a/src/machine/m_xt_zenith.c b/src/machine/m_xt_zenith.c
index 5525b36ce..0e0f9b9b0 100644
--- a/src/machine/m_xt_zenith.c
+++ b/src/machine/m_xt_zenith.c
@@ -56,7 +56,8 @@ typedef struct {
 static uint8_t
 zenith_scratchpad_read(uint32_t addr, void *priv)
 {
-    zenith_t *dev = (zenith_t *) priv;
+    const zenith_t *dev = (zenith_t *) priv;
+
     return dev->scratchpad_ram[addr & 0x3fff];
 }
 
diff --git a/src/machine/machine_table.c b/src/machine/machine_table.c
index 7a0b3efdb..5ce4b0795 100644
--- a/src/machine/machine_table.c
+++ b/src/machine/machine_table.c
@@ -12981,16 +12981,16 @@ machine_count(void)
     return ((sizeof(machines) / sizeof(machine_t)) - 1);
 }
 
-char *
+const char *
 machine_getname(void)
 {
-    return ((char *) machines[machine].name);
+    return (machines[machine].name);
 }
 
-char *
+const char *
 machine_getname_ex(int m)
 {
-    return ((char *) machines[m].name);
+    return (machines[m].name);
 }
 
 const device_t *
@@ -13056,16 +13056,16 @@ machine_get_net_device(int m)
     return (NULL);
 }
 
-char *
+const char *
 machine_get_internal_name(void)
 {
-    return ((char *) machines[machine].internal_name);
+    return (machines[machine].internal_name);
 }
 
-char *
+const char *
 machine_get_internal_name_ex(int m)
 {
-    return ((char *) machines[m].internal_name);
+    return (machines[m].internal_name);
 }
 
 int
@@ -13121,12 +13121,12 @@ machine_get_type(int m)
 }
 
 int
-machine_get_machine_from_internal_name(char *s)
+machine_get_machine_from_internal_name(const char *s)
 {
     int c = 0;
 
     while (machines[c].init != NULL) {
-        if (!strcmp(machines[c].internal_name, (const char *) s))
+        if (!strcmp(machines[c].internal_name, s))
             return c;
         c++;
     }