diff --git a/src/fsmap.c b/src/fsmap.c
new file mode 100644
index 00000000..aeac9e5f
--- /dev/null
+++ b/src/fsmap.c
@@ -0,0 +1,50 @@
+#include <errno.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+int main(int argc, char **argv)
+{
+    int status;
+
+    if (argc > 1) {
+        status = 0;
+        while (--argc) {
+            const char *fn = *++argv;
+            FILE *fp = fopen(fn, "rb");
+            if (fp) {
+                unsigned char fsmap[0x200];
+                if (fread(fsmap, sizeof fsmap, 1, fp) == 1) {
+                    puts(fn);
+                    unsigned char *sptr = fsmap;
+                    unsigned char *eptr = fsmap + fsmap[0x1FE];
+                    unsigned char *lptr = fsmap + 0x100;
+                    while (sptr < eptr) {
+                        uint32_t start = *sptr++;
+                        start |= (*sptr++ << 8);
+                        start |= (*sptr++ << 16);
+                        uint32_t len = *lptr++;
+                        len |= (*lptr++ << 8);
+                        len |= (*lptr++ << 16);
+                        if (len > 0)
+                            printf("%06X %06X (%d)\n", start, len, len);
+                    }
+                }
+                else {
+                    fprintf(stderr, "fsmap: unable to read fsmap from %s: %s\n", fn, strerror(errno));
+                    status = 3;
+                }
+            }
+            else {
+                fprintf(stderr, "fsmap: unable to open %s for reading: %s\n", fn, strerror(errno));
+                status = 2;
+            }
+        }
+    }
+    else {
+        fputs("Usage: fsmap <dat-file> [ ... ]\n", stderr);
+        status = 1;
+    }
+    return status;
+}
diff --git a/src/hdresize.c b/src/hdresize.c
new file mode 100644
index 00000000..b1717be3
--- /dev/null
+++ b/src/hdresize.c
@@ -0,0 +1,157 @@
+#include <errno.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+static int parse_size(const char *size)
+{
+    int value;
+    char *end;
+
+    value = strtol(size, &end, 10);
+    switch (*end) {
+        case 'k':
+        case 'K':
+            value *= 1024;
+            break;
+        case 'm':
+        case 'M':
+            value *= 1024 * 1024;
+            break;
+        case 'g':
+        case 'G':
+            value *= 1024 * 1024 * 1024;
+            break;
+    }
+    return value;
+}
+
+static inline uint32_t read24(const unsigned char *base)
+{
+    return base[0] | (base[1] << 8) | (base[2] << 16);
+}
+
+static inline void write24(uint8_t *base, uint32_t value)
+{
+    base[0] = value & 0xff;
+    base[1] = (value >> 8) & 0xff;
+    base[2] = (value >> 16) & 0xff;
+}
+
+static uint8_t checksum(uint8_t *base)
+{
+    int i = 255, c = 0;
+    unsigned sum = 255;
+    while (--i >= 0) {
+        sum += base[i] + c;
+        c = 0;
+        if (sum >= 256) {
+            sum &= 0xff;
+            c = 1;
+        }
+    }
+    return sum;
+}
+
+int main(int argc, char **argv)
+{
+    int status;
+
+    if (argc == 3) {
+        int size = parse_size(argv[2]);
+        if (size > 0) {
+            const char *fn = argv[1];
+            size_t len = strlen(fn) + 5;
+            char *dat_fn = alloca(len);
+            snprintf(dat_fn, len, "%s.dat", fn);
+            FILE *dat_fp = fopen(dat_fn, "rb+");
+            if (dat_fp) {
+                unsigned char fsmap[512];
+                if (fread(fsmap, sizeof fsmap, 1, dat_fp) == 1) {
+                    if (fsmap[0x1FE] <= 3) {
+                        status = 0;
+                        char *dsc_fn = alloca(len);
+                        snprintf(dsc_fn, len, "%s.dsc", fn);
+                        FILE *dsc_fp = fopen(dsc_fn, "rb+");
+                        if (dsc_fp) {
+                            unsigned char geom[22];
+                            if (fread(geom, sizeof geom, 1, dsc_fp) == 1) {
+                                int new_sects = size / 256;
+                                int old_sects = read24(fsmap + 0x0FC);
+                                printf("hdresize: old sectors=%d, new_sects=%d\n", old_sects, new_sects);
+                                if (new_sects > old_sects) {
+                                    write24(fsmap + 0x0FC, new_sects);
+                                    fsmap[0x0FF] = checksum(fsmap);
+                                    unsigned char *ptr = fsmap + 0x100;
+                                    write24(ptr, read24(ptr) + (new_sects - old_sects));
+                                    fsmap[0x1ff] = checksum(ptr);
+                                    int cyl = 1 + ((new_sects - 1) / (33 * 255));
+                                    geom[13] = cyl % 256;
+                                    geom[14] = cyl / 256;
+                                    geom[15] = 255;
+                                    if (fseek(dsc_fp, 0, SEEK_SET) == 0 && fwrite(geom, sizeof geom, 1, dsc_fp) == 1) {
+                                        if (fseek(dat_fp, 0, SEEK_SET) == 0 && fwrite(fsmap, sizeof fsmap, 1, dat_fp) == 1) {
+                                            status = 0;
+                                            printf("hdresize: %s grown\n", fn);
+                                        }
+                                        else
+                                        {
+                                            fprintf(stderr, "hdresize: unable to write fsmap to %s: %s\n", dat_fn, strerror(errno));
+                                            status = 8;
+                                        }
+                                    }
+                                    else {
+                                        fprintf(stderr, "hdresize: unable to write geometry to %s: %s\n", dsc_fn, strerror(errno));
+                                        status = 7;
+                                    }
+                                }
+                                else {
+                                    fputs("hdresize: shrinking not implemented\n", stderr);
+                                    status = 6;
+                                }
+                            }
+                            else {
+                                fprintf(stderr, "hdresize: unable to read geometry from %s: %s\n", dsc_fn, strerror(errno));
+                                status = 5;
+                            }
+                        }
+                        else {
+                            fprintf(stderr, "hdresize: unable to open dsc file %s: %s\n", dsc_fn, strerror(errno));
+                            status = 2;
+                        }
+                    }
+                    else {
+                        fprintf(stderr, "hdresize: %s has more than one free entry, compact before resizing\n", fn);
+                        status = 4;
+                    }
+                }
+                else {
+                    fprintf(stderr, "hdresize: unable to read fsmap from %s: %s\n", dat_fn, strerror(errno));
+                    status = 3;
+                }
+                fclose(dat_fp);
+            }
+            else {
+                fprintf(stderr, "hdresize: unable to open data file %s: %s\n", dat_fn, strerror(errno));
+                status = 2;
+            }
+        }
+        else {
+            fprintf(stderr, "hdresize: %s is not a valid size\n", argv[2]);
+            status = 1;
+        }
+    }
+    else {
+        fputs("usage: hdresize <dat-file> <size>\n", stderr);
+        status = 1;
+    }
+    return status;
+}
+
+
+
+
+
+
+