update go-fs

resolves #2421

vendor/github.com/mitchellh/go-fs/fat/directory_cluster.go

@@ -7,9 +7,9 @@ import (
 	"fmt"
 	"github.com/mitchellh/go-fs"
 	"math"
+	"strings"
 	"time"
 	"unicode/utf16"
-	"strings"
 )
 
 type DirectoryAttr uint8
@@ -160,8 +160,8 @@ func NewFat16RootDirectoryCluster(bs *BootSectorCommon, label string) (*Director
 
 	// Create the volume ID entry
 	result.entries[0] = &DirectoryClusterEntry{
-		attr: AttrVolumeId,
-		name: label,
+		attr:    AttrVolumeId,
+		name:    label,
 		cluster: 0,
 	}
 

vendor/github.com/mitchellh/go-fs/fat/super_floppy.go

@@ -72,15 +72,25 @@ func (f *superFloppyFormatter) format() error {
 			label = "FAT16   "
 		}
 
-		// Determine the number of root directory entries
-		if f.device.Len() > 512*5*32 {
-			bsCommon.RootEntryCount = 512
+		// For 1.44MB Floppy, for other floppy formats see https://support.microsoft.com/en-us/kb/75131.
+		// We make an exception for this most common usecase as the calculations don't create a working image for older operating systems
+		if f.config.FATType == FAT12 && f.device.Len() == 1474560 {
+			bsCommon.RootEntryCount = 224
+			bsCommon.SectorsPerFat = 9
+			bsCommon.SectorsPerTrack = 18
+			bsCommon.Media = 240
+			bsCommon.NumHeads = 2
 		} else {
-			bsCommon.RootEntryCount = uint16(f.device.Len() / (5 * 32))
+			// Determine the number of root directory entries
+			if f.device.Len() > 512*5*32 {
+				bsCommon.RootEntryCount = 512
+			} else {
+				bsCommon.RootEntryCount = uint16(f.device.Len() / (5 * 32))
+			}
+
+			bsCommon.SectorsPerFat = f.sectorsPerFat(bsCommon.RootEntryCount, sectorsPerCluster)
 		}
 
-		bsCommon.SectorsPerFat = f.sectorsPerFat(bsCommon.RootEntryCount, sectorsPerCluster)
-
 		bs := &BootSectorFat16{
 			BootSectorCommon:    bsCommon,
 			FileSystemTypeLabel: label,

vendor/vendor.json

@@ -461,13 +461,14 @@
 		{
 			"checksumSHA1": "mVqDwKcibat0IKAdzAhfGIHPwI8=",
 			"path": "github.com/mitchellh/go-fs",
-			"revision": "4f9d2cb031e44bef60d0c00ccb3f31f68867e85e",
-			"revisionTime": "2016-09-29T19:58:49Z"
+			"revision": "7bae45d9a684750e82b97ff320c82556614e621b",
+			"revisionTime": "2016-11-08T19:11:23Z"
 		},
 		{
-			"checksumSHA1": "Z28nPI+n3iAnsqVSLCt5LZh/Zhg=",
+			"checksumSHA1": "B5dy+Lg6jFPgHYhozztz88z3b4A=",
 			"path": "github.com/mitchellh/go-fs/fat",
-			"revision": "4f9d2cb031e44bef60d0c00ccb3f31f68867e85e"
+			"revision": "7bae45d9a684750e82b97ff320c82556614e621b",
+			"revisionTime": "2016-11-08T19:11:23Z"
 		},
 		{
 			"checksumSHA1": "z235fRXw4+SW4xWgLTYc8SwkM2M=",