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mkdisk(1) mkdisk(1)
NNaammee
mkdisk - Make a blank emulated floppy or hard disk for
xtrs, or add/remove an emulated write protect tab
SSyynnttaaxx
mmkkddiisskk --11 ffiilleennaammee
mmkkddiisskk [[--33]] ffiilleennaammee
mmkkddiisskk --kk [[--ss ssiiddeess]] [[--dd ddeennssiittyy]] [[--88]] [[--ii]] ffiilleennaammee
mmkkddiisskk --hh [[--cc ccyyll]] [[--ss sseecc]] [[--gg ggrraann]] ffiilleennaammee
mmkkddiisskk {{--pp||--uu}} {{--11||--33||--kk||--hh}} ffiilleennaammee
DDeessccrriippttiioonn
The mkdisk program is part of the xxttrrss(1) package. It has
two distinct functions: (1) It can make a blank (unformat
ted) emulated floppy or hard drive in a file. (2) With
the -p or -u flag, it can turn the write protect flag on
or off for an existing emulated floppy or hard drive file.
See the xtrs man page for background information.
The conventional file extensions are .dsk for emulated
floppies and .hdv for emulated hard drives, but mmkkddiisskk
does not enforce this convention; you can use any file
name. Other extensions sometimes used for emulated flop
pies are .jv1, .jv3, .8in, and .dmk.
MMaakkiinngg EEmmuullaatteedd FFllooppppiieess
With the -1 flag, mmkkddiisskk makes an unformatted emulated
floppy of type JV1. No additional flags are accepted.
With the -3 flag (which is the default and should normally
be used), mmkkddiisskk makes an unformatted emulated floppy of
type JV3. No additional flags are accepted.
With the -k flag, mmkkddiisskk makes an unformatted emulated
floppy of type DMK. With -k, the optional flags -s, -d,
-8, and -i can be used to give the emulated floppy special
properties. Specifying -s1 limits the floppy to one side;
with -s2 (the default), the floppy can be formatted as
either one- or two-sided. Specifying -d1 limits the
floppy to single density; with -d2 (the default), the
floppy can be formatted in either single or double den
sity. Specifying -8 allows the floppy to be formatted in
an emulated 8" drive; by default it will work properly
only in an emulated 5" drive. Setting -s1 or -d1 saves
space after the floppy is formatted; setting -8 consumes
additional space. Specifying -i activates a peculiar fea
ture in some TRS-80 emulators that causes each formatted
sector to appear to be both single and double density.
MMaakkiinngg EEmmuullaatteedd HHaarrdd DDrriivveess
With the -h flag, mmkkddiisskk makes an unformatted emulated
hard drive with _c_y_l cylinders, _s_e_c sectors, and _g_r_a_n gran
ules (LDOS allocation units) per cylinder. The hard drive
will have cylinder _d_i_r marked for use as its directory.
You will usually want to use the default values for all
these parameters. The default is 202 cylinders, 256 sec
tors per cylinder (that is, 8 heads and 32 sectors per
track), and 8 granules per cylinder. This is the largest
hard drive that can be used by all LDOS/LS-DOS operating
systems without partitioning the drive or patching the
FORMAT command. The details on what nondefault values are
possible vary, depending on which of xtrs's two hard drive
emulations you are using and which other emulators you
want to be compatible with, and it is probably best not to
delve into these complexities, but read on if you really
want to.
For _c_y_l, the number of cylinders on the drive, the default
value is 202, the minimum is 3, and the maximum that can
be represented in the HDV file's header is 256. You can
use 203 cylinders with LDOS and LS-DOS if you format the
drive with Model 4 LS-DOS; a minor bug in Model I/III FOR
MAT/CMD prevents more than 202 cylinders from being for
matted, but the system can use 203 thereafter. 203 cylin
ders is the absolute maximum for LDOS/LS-DOS drivers that
do not support partitioning, including the emulator-spe
cific drivers supplied with xtrs (XTRSHARD/DCT), with
Matthew Reed's emulator (HARD/CMD), and with David Keil's
emulator (EHARD/DCT).
In xtrs 4.1 and later, and in David Keil's emulator ver
sion 6.0 and later, a true emulation of Radio Shack's
WD1010-based hard disk controller is also available, which
works with the native drivers for the original hardware,
such as RSHARDx/DCT and the hard disk drivers for NEWDOS
and CP/M. In xtrs, the WD1010 emulation ignores the maxi
mum number of cylinders specified in the HDV file's header
and allows the driver to format up to 65536 cylinders.
This may be useful if your drivers support partitioning
(but why would anyone want to partition an emulated hard
drive instead of just making two smaller ones?), or if
your operating system supports more than 203 cylinders per
partition. Note that although RSHARDx/DCT allows up to
406 cylinders per partition, if you use more than 203, the
maximum number of sectors per cylinder is limited to 128,
so you gain nothing; the maximum size of a partition is
still the same.
For _s_e_c, the number of sectors per cylinder, the default
value is 256, the maximum is 256, and the minimum is 4.
There are some restrictions on the values that will work.
For the greatest portability, choose a value that is
divisible by 32. With xtrs's XTRSHARD/DCT and David
Keil's EHARD/DCT, any value is allowed that can be evenly
divided into granules; see the next paragraph. With
Matthew Reed's HARD/CMD, if _s_e_c is greater than 32, it
must be divisible by 32. With the emulation of a real
WD1010 in newer versions of xtrs (and probably David
Keil's emulator too), _s_e_c must always be divisible by 32,
because we always emulate a drive with 32 sectors per
track and from 1 to 8 heads (tracks per cylinder). The
RSHARDx/DCT driver assumes that there are always 32 sec
tors per track.
For _g_r_a_n, the default value is 8, the maximum is 8, and
the minimum is 1. In addition, it is necessary that _s_e_c
be evenly divisible by _g_r_a_n, and that _s_e_c_/_g_r_a_n be less
than or equal to 32. This value is used only with the
emulator-specific drivers listed above; it is ignored when
xtrs is using native hardware drivers such as RSHARDx/DCT.
The maximum size of a hard drive image is controlled by
_c_y_l and _s_e_c: it can be at most _c_y_l_*_s_e_c 256-byte sectors.
The image file starts out small and grows as you write to
more cylinders. The allocation efficiency is controlled
by the granule size: LDOS allocates file space in gran
ules. Therefore (1) _g_r_a_n should always be set as large as
possible and (2) reducing _s_e_c, thereby making the granules
smaller, reduces wasted space due to fragmentation but
limits the maximum size of the drive.
Seeing that the maximum unpartitioned drive size is less
than 13 MB and that the maximum granule size is only 8 KB,
wasted space should not be much of a concern for most xxttrrss
users. Therefore the default parameters have been chosen
to give you the largest drive possible without partition
ing.
WWrriittee PPrrootteeccttiioonn
With the -p flag, mmkkddiisskk turns on write protection for an
existing emulated floppy or hard drive. It turns off all
Unix write permission bits on the file, and (except for
JV1 floppies) also sets a write-protected flag inside the
file.
With the -u flag, mmkkddiisskk turns off write protection for an
existing emulated floppy or hard drive. It turns on Unix
write permissions to the file, masked by your current
umask and the file's current read permissions. It also
clears a write-protected flag inside the file (except on
JV1 floppies, which don't have such a flag).
mmkkddiisskk currently does not have code to auto-recognize file
formats, so the -p or -u flag must be accompanied by
either -1 (JV1), -3 (JV3), -k (DMK), or -h (hard disk) to
identify the file format. There is also no checking for
the correct file format, so if you give the wrong flag,
the wrong byte inside your file will be changed.
TTeecchhnniiccaall ddaattaa
The JV1 format is just an array of 256-byte sectors, in
the order (track 0 sector 0, track 0 sector 1, ... track 0
sector 9, track 1 sector 0, ...). It can represent only
single-sided, single-density floppies. The directory is
assumed to be track 17.
The original JV3 format is documented in the printed man
ual for Jeff Vavasour's commercial Model III/4 emulator.
The xtrs implementation includes some extensions.
Full documentation for both JV1 and JV3 can be found at
http://www.tim-mann.org/trs80/dskspec.html. A copy of
this html file is also included in the xxttrrss distribution.
The DMK format is documented in a file on David Keil's web
site, http://discover-net.net/~dmkeil/trsdoc.htm#Techni
cal-disks; this file is also included with his emulator.
Some updates to the 4.00 version of the document: (1) If
neither the single density nor ignore density option is
set and single density data is recorded, each single den
sity byte is written twice (i.e., the four bytes 12345678
would be written as 1212343456567878). This ensures that
when single and double density sectors are mixed, each
type occupies the correct relative amount of space in the
track. This update will be effective in version 4.3 of
David's emulator; it is incompatible with previous ver
sions. (2) Bit 15 of an IDAM offset is 1 if the sector is
double-density, 0 if single density. Bit 14 is reserved;
it currently must be 0. The actual offset is in bits
13-0. These offsets are relative to the start of the
track header, they must be in ascending order (I hope!!),
and an offset of 0 or 0xffff terminates the list.
An HDV (hard disk) image has the following format. This
information is based on email from Matthew Reed. There is
an initial 256-byte header block, followed by an array of
sectors. The geometry of the drive is defined in the
header block, which looks like this (from mkdisk.c):
typedef unsigned char Uchar;
typedef struct {
Uchar id1; /* 0: Identifier #1: 56H */
Uchar id2; /* 1: Identifier #2: CBH */
Uchar ver; /* 2: Version of format: 10H = version 1.0 */
Uchar cksum; /* 3: Simple checksum:
To calculate, add together bytes 0 to 31 of header
(excepting byte 3), then XOR result with 4CH */
Uchar blks; /* 4: Number of 256 byte blocks in header: should be 1 */
Uchar mb4; /* 5: Not used, currently set to 4 */
Uchar media; /* 6: Media type: 0 for hard disk */
Uchar flag1; /* 7: Flags #1:
bit 7: Write protected: 0 for no, 1 for yes
[warning: xtrs currently ignores this flag]
bit 6: Must be 0
bit 5 - 0: reserved */
Uchar flag2; /* 8: Flags #2: reserved */
Uchar flag3; /* 9: Flags #3: reserved */
Uchar crtr; /* 10: Created by:
14H = HDFORMAT
42H = xtrs mkdisk
80H = Cervasio xtrshard port to Vavasour M4 emulator */
Uchar dfmt; /* 11: Disk format: 0 = LDOS/LS-DOS */
Uchar mm; /* 12: Creation month: mm */
Uchar dd; /* 13: Creation day: dd */
Uchar yy; /* 14: Creation year: yy (offset from 1900) */
Uchar res1[12]; /* 15 - 26: reserved */
Uchar dparm; /* 27: Disk parameters: (unused with hard drives)
bit 7: Density: 0 = double, 1 = single
bit 6: Sides: 0 = one side, 1 = 2 sides
bit 5: First sector: 0 if sector 0, 1 if sector 1
bit 4: DAM convention: 0 if normal (LDOS),
1 if reversed (TRSDOS 1.3)
bit 3 - 0: reserved */
Uchar cyl; /* 28: Number of cylinders per disk */
Uchar sec; /* 29: Number of sectors per track (floppy); cyl (hard) */
Uchar gran; /* 30: Number of granules per track (floppy); cyl (hard)*/
Uchar dcyl; /* 31: Directory cylinder [mkdisk sets to 1; xtrs
ignores, but value must be correct if image is
to be used with Reed emulators.] */
char label[32]; /* 32: Volume label: 31 bytes terminated by 0 */
char filename[8];/* 64 - 71: 8 characters of filename (without extension)
[Cervasio addition. xtrs actually doesn't limit this
to 8 chars or strip the extension] */
Uchar res2[184]; /* 72 - 255: reserved */
} ReedHardHeader;
SSeeee aallssoo
xxttrrss(1)
http://www.tim-mann.org/trs80/dskspec.html
AAuutthhoorrss
mmkkddiisskk was written by Timothy Mann <tim@tim-mann.org>.
The floppy file formats here called JV1 and JV3 were
developed by Jeff Vavasour for his MSDOS-based Model I and
Model III/4 emulators (respectively). They have become a
de facto standard in the TRS-80 emulation community, and
much TRS-80 software is available on the Internet in .dsk
format. Thanks to Jeff for designing and documenting the
formats.
The format here called DMK was developed by David Keil for
his MSDOS-based Model 4 emulator. This format has the
advantage that it can represent essentially everything the
original TRS-80 floppy disk controllers can write, includ
ing all forms of copy protected disk. Thanks to David for
designing and documenting this format.
The hard drive format was developed by Matthew Reed for
his MSDOS-based Model I/III and Model 4 emulators. I have
duplicated his format to allow users to exchange .hdv hard
drive images between xxttrrss and Matthew's emulators. Thanks
to Matthew for designing the format and providing documen
tation.
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