case "linux":
			// Copied from golang.org/x/sys/unix/dev_linux.go.
			major := uint32((dev & 0x00000000000fff00) >> 8)
			major |= uint32((dev & 0xfffff00000000000) >> 32)
			minor := uint32((dev & 0x00000000000000ff) >> 0)
			minor |= uint32((dev & 0x00000ffffff00000) >> 12)
			h.Devmajor, h.Devminor = int64(major), int64(minor)
		case "darwin", "ios":
			// Copied from golang.org/x/sys/unix/dev_darwin.go.
			major := uint32((dev >> 24) & 0xff)

// license that can be found in the LICENSE file.

package tar

import "strings"

// Format represents the tar archive format.
//
// The original tar format was introduced in Unix V7.
// Since then, there have been multiple competing formats attempting to
// standardize or extend the V7 format to overcome its limitations.
// The most common formats are the USTAR, PAX, and GNU formats,

				epoch := time.Date(1601, time.January, 1, 0, 0, 0, 0, time.UTC)
				modified = time.Unix(epoch.Unix()+secs, nsecs)
			}
		case unixExtraID, infoZipUnixExtraID:
			if len(fieldBuf) < 8 {
				continue parseExtras
			}
			fieldBuf.uint32()              // AcTime (ignored)
			ts := int64(fieldBuf.uint32()) // ModTime since Unix epoch
			modified = time.Unix(ts, 0)
		case extTimeExtraID:
			if len(fieldBuf) < 5 || fieldBuf.uint8()&1 == 0 {

	zip64ExtraID       = 0x0001 // Zip64 extended information
	ntfsExtraID        = 0x000a // NTFS
	unixExtraID        = 0x000d // UNIX
	extTimeExtraID     = 0x5455 // Extended timestamp
	infoZipUnixExtraID = 0x5855 // Info-ZIP Unix extension
)

// FileHeader describes a file within a ZIP file.
// See the [ZIP specification] for details.
//

	var spb []byte
	blk := tw.templateV7Plus(hdr, f.formatString, f.formatNumeric)
	if !hdr.AccessTime.IsZero() {
		f.formatNumeric(blk.toGNU().accessTime(), hdr.AccessTime.Unix())
	}
	if !hdr.ChangeTime.IsZero() {
		f.formatNumeric(blk.toGNU().changeTime(), hdr.ChangeTime.Unix())
	}
	// TODO(dsnet): Re-enable this when adding sparse support.
	// See https://golang.org/issue/22735
	/*
		if hdr.Typeflag == TypeGNUSparse {

	if len(ss) > 0 && ss[0] == '-' {
		return time.Unix(secs, -1*nsecs), nil // Negative correction
	}
	return time.Unix(secs, nsecs), nil
}

// formatPAXTime converts ts into a time of the form %d.%d as described in the
// PAX specification. This function is capable of negative timestamps.
func formatPAXTime(ts time.Time) (s string) {
	secs, nsecs := ts.Unix(), ts.Nanosecond()
	if nsecs == 0 {

		header:  &Header{ModTime: time.Unix(1, 500)},
		paxHdrs: map[string]string{paxMtime: "1.0000005"},
		formats: FormatUSTAR | FormatPAX | FormatGNU,
	}, {
		header:  &Header{ModTime: time.Unix(1, 0)},
		formats: FormatUSTAR | FormatPAX | FormatGNU,
	}, {
		header:  &Header{ModTime: time.Unix(1, 0), Format: FormatPAX},
		formats: FormatUSTAR | FormatPAX,
	}, {
		header:  &Header{ModTime: time.Unix(1, 500), Format: FormatUSTAR},

		if ts.IsZero() {
			return // Always okay
		}
		if !fitsInBase256(size, ts.Unix()) {
			whyNoGNU = fmt.Sprintf("GNU cannot encode %s=%v", name, ts)
			format.mustNotBe(FormatGNU)
		}
		isMtime := paxKey == paxMtime
		fitsOctal := fitsInOctal(size, ts.Unix())
		if (isMtime && !fitsOctal) || !isMtime {
			whyNoUSTAR = fmt.Sprintf("USTAR cannot encode %s=%v", name, ts)

				Uname:    "dsymonds",
				Gname:    "eng",
				ModTime:  time.Unix(1246508266, 0),
			}, nil},
			testWrite{"Kilts", 5, nil},

			testHeader{Header{
				Typeflag: TypeReg,
				Name:     "small2.txt",
				Size:     11,
				Mode:     0640,
				Uid:      73025,
				Uname:    "dsymonds",
				Gname:    "eng",
				Gid:      5000,
				ModTime:  time.Unix(1245217492, 0),
			}, nil},

				Content:  []byte("important \r\n"),
				Modified: time.Date(2011, 12, 8, 10, 6, 8, 0, time.UTC),
				Mode:     0444,
			},
		},
	},
	{
		// created by Zip 3.0 under Linux
		Name: "unix.zip",
		File: []ZipTestFile{
			{
				Name:     "hello",
				Content:  []byte("world \r\n"),
				Modified: time.Date(2011, 12, 8, 10, 4, 24, 0, timeZone(0)),
				Mode:     0666,
			},
			{