xtrs(1) xtrs(1)
Name
xtrs - TRS-80 Model I/III/4/4P emulator for the X Window System
Syntax
xtrs [-model m] [-diskdir d] [-debug] [other options]
Description
xtrs is built on top of a Z-80 emulator, with added routines to
support keyboard and video I/O through an X interface. The hardware
emulation can operate as a TRS-80 Model I, Model III, Model 4, or
Model 4P.
xtrs supports 48K of RAM in Model I or Model III mode, 128K in Model 4
or Model 4P mode. Floppy disks and hard disks are emulated using
files to store the data; or under Linux only, real floppy drives can
be used. A printer is emulated by sending its output to standard
output. A serial port is emulated using a Unix tty device. Cassette
I/O is emulated using files to store the cassette data; real cassettes
can also be read or written (with luck), either directly through your
sound card (on Linux and other systems with OSS-compatible sound
drivers), or via .wav files. Game sound and music output are also
supported if you have an OSS-compatible sound driver; sound output
though the cassette port, through the Model 4 sound option, and
through the optional Orchestra-85/90 music synthesizer card are all
emulated. In Model I mode, the HRG1B graphics card is emulated. In
Model III and 4/4P mode, you can select whether the Radio Shack
graphics card or Micro Labs Grafyx Solution is emulated. There is
also a mouse driver for Model 4/4P mode. Several common time-of-day
clock cards are emulated on all models. The Alpha Products joystick
is emulated using the PC's numeric keypad.
Because xtrs emulates the hardware, all known TRS-80 Model I/III/4/4P
operating systems should run on it, including all flavors of TRSDOS,
LDOS/LS-DOS, NEWDOS, DOSPLUS, MultiDOS, and TRS-80 CP/M. However, the
emulator also includes some extensions to the standard hardware, and
the special drivers, utilities, and instructions needed for these are
not provided for all operating systems.
The Z-80 emulator has a debugger called zbx. You can enter the
debugger either by starting xtrs with the -debug flag or by pressing
F9 while xtrs is running. The debugger runs in the X terminal window
that you started xtrs from. Once you are in the debugger, type "help"
for more information.
Special support in the emulator allows the program to block when
waiting for information from the keyboard. This will work only for
programs that wait for keyboard input using the standard Model I/III
ROM call; the emulator decides whether to block the Z-80 program when
it tries to read from the keyboard memory by pattern-matching its
stack.
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Keys
The following keys have special meanings to xtrs:
F11 toggles onscreen help on the keyboard mappings.
LeftArrow, Backspace, or Delete is the TRS-80 left arrow key.
RightArrow or Tab is the right arrow key. UpArrow is the up arrow
key. DownArrow or Linefeed is the down arrow key. Esc or Break is
the Break key. Home, Clear, or LeftAlt is the Clear key. Control is
the Model 4 Ctrl key (address bit 7, data bit 2). RightAlt is
equivalent to the shifted down arrow key (used as a control key with
some TRS-80 software).
F1, F2, and F3 are the Model 4/4P function keys (address bit 7, data
bits 4, 5, and 6). F1 is also the Model I Electric Pencil control key
that some users added to their machines. F4 is the Model 4 Caps Lock
key (address bit 7, data bit 3). F5, Compose, or ScrollLock is
equivalent to the @ key (so that @ can be used as a modifier key). F6
is equivalent to the 0 key (so that a shifted 0 can be obtained). F7
signals a disk change in the emulated floppy drives (see below). F8
exits the program. F9 enters the debugger (zbx). F10 is the reset
button.
In Model III, 4, and 4P modes, the left and right shift keys are
distinct; in Model I mode, they are the same. The PageUp and PageDown
keys always activate the positions that correspond to the Model
III/4/4P left and right shift keys (address bit 7, data bits 0 and 1
respectively), even in Model I mode. The End key activates an unused
position in the keyboard matrix (address bit 7, data bit 7).
The keys [, \, ], ^, _, {, |, }, and ~ also activate unused positions
in the keyboard matrix (address bit 3, data bits 3-7). With many
TRS-80 keyboard drivers, these keys map to the corresponding ASCII
characters; with others, they do nothing. In some cases you may find
the shift state is reversed from what it should be; if you press [ but
{ is displayed instead (etc.), see the -shiftbracket and
-noshiftbracket options below to correct the problem. The Insert key
maps to the same position as underscore (address bit 3, data bit 7),
so that this key can be used both with and without shift pressed; with
many TRS-80 keyboard drivers one of these maps to ASCII code 0x7f.
On a German keyboard, the umlaut and "ess-tsett" keys should activate
the corresponding characters used in the GENIE, a German Model I
clone. This feature is most useful together with the "-charset genie"
command line argument.
Pressing a key on a PC numeric keypad with NumLock disengaged emulates
the Alpha Products joystick. Keys 2, 4, 6, 8 (KP_Down, KP_Left,
KP_Right, KP_Up) are the main directions; keys 1, 3, 7, and 9 (KP_End,
KP_Page_Down, KP_Home, KP_Page_Up) work as diagonal directions by
activating two main directions at once; and key 0 (KP_Insert) or 5
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(KP_Begin) is the fire button. Note that your X server may default to
sending digits for the keys on the numeric pad even if NumLock is not
pressed. If you have this problem, you can use the xmodmap program to
remap your numeric pad, and use the xev program to debug it.
Emulated cassette
To control the emulated cassette, a file called ".cassette.ctl" in the
current directory keeps track of what file is currently loaded as the
cassette tape and the current position within that file. The
cassette(1) shell script provides a way to manipulate this file. You
may use this script to load and position cassette tape files. The
operation works very much like an actual tape recorder. See the
cassette man page for more information about the cassette shell script
and the cassette file formats that are supported.
Printer
For printer support, any text sent to the TRS-80's printer (using
LPRINT or LLIST, for example) is sent to the standard output.
Emulated floppy disks
In Model I mode, xtrs emulates a Radio Shack Expansion Interface with
the Percom Doubler or Radio Shack Doubler installed. The Doubler
provides double-density disk access by allowing either the stock
WD1771 FDC chip or a WD1791 chip to be selected under program control.
At powerup the 1771 is selected, so operating systems with no Doubler
driver see a stock system. By default, the emulator pretends to be
both a Percom and Radio Shack Doubler at the same time -- it responds
to the special commands of both -- so a driver for either should work.
Under LDOS, use the command "FDUBL" (newer versions of LDOS), or
"PDUBL" or "RDUBL" (older versions) to install the driver. Software
that tries to detect which doubler you have (such as Super Utility)
may be confused by the emulation of both at once, so you can choose to
emulate only one with a command line option; see below.
In Model III, 4, or 4P mode, xtrs emulates the stock floppy
controller, which uses a WD1793 chip (software-compatible with the
WD1791) to provide both single and double density.
Four 5.25-inch floppy drives are emulated, with storage in files named
diskM-U, where M is the TRS-80 model (1, 3, 4, or 4p) and U is the
drive unit number (0, 1, 2, or 3). If a file of the required name is
not found, a drive with no disk in it is emulated (but see below). If
the user does not have write permission for a floppy file, and/or the
file has an internal write protect flag set, a write-protect tab is
emulated. Use the mkdisk(1) program to turn the write protect flag on
or off. To change floppies in an emulated drive, rename the existing
file for the drive (if any), rename the new floppy file to the proper
name, and hit function key F7 in the emulator.
If you try to boot an emulated Model I, III, or 4 with no file named
diskM-0 (that is, no disk in drive 0), xtrs emulates having no floppy
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disk controller. The behavior of a real machine with a disk
controller in this case didn't seem useful to emulate faithfully: A
real Model I hangs with a screen full of garbage; a real Model III or
4 goes into a retry loop printing "Diskette?" on the screen and
rechecking whether you've inserted one. A real Model 4P always has a
floppy controller, however, so xtrs always emulates one.
Due to a limitation of the original Model I hardware, drive :3 cannot
be double-sided in Model I mode. In the original Model I, you could
not have a drive :3 at all if any drive in the system was double-
sided, but the emulator is able to be more forgiving.
Emulated floppy image files can be of any of three types: JV1,
compatible with Jeff Vavasour's popular freeware Model I emulator for
MS-DOS; JV3, a compatible extension of a format first used in
Vavasour's commercial Model III/4 emulator; or DMK, compatible with
David Keil's Model 4 emulator. All three types work in xtrs
regardless of what model it is emulating. A heuristic is used to
decide which type of image is in a drive, as none of the types has a
magic number or signature.
JV1 supports only single density, single sided, with directory on
track 17. Sectors must be 256 bytes long. Use FORMAT (DIR=17) if you
want to format JV1 disks with more (or less) than 35 tracks under
LDOS.
JV3 is much more flexible, though it still does not support everything
the real controllers could do. It is probably best to use JV3 for all
the disk images you create, since it is the most widely implemented by
other emulators, unless you have a special reason to use one of the
others. A JV3 disk can be formatted with 128, 256, 512, or 1024-byte
sectors, 1 or 2 sides, single or double density, with either FB
(normal) or F8 (deleted) data address mark on any sector. In single
density the nonstandard data address marks FA and F9 are also
available. You cannot format a sector with an incorrect track number
or head number. You can format a sector with an intentional CRC error
in the data field. xtrs supports at most 5802 total sectors on a JV3
image.
The original Vavasour JV3 format supported only 256-byte sectors, and
had a limit of 2901 total sectors. If you use sector sizes other than
256 bytes or format more than 2901 sectors on a disk image, emulators
other than xtrs may be unable to read it. Note that an 80 track,
double-sided, double-density (18 sector) 5.25-inch floppy will fit
within the original 2901 sector limit; the extension to 5802 is
primarily for emulation of 8-inch drives (discussed below).
The DMK format is the most flexible. It supports essentially
everything that the original hardware could do, including all
"protected" disk formats. However, a few protected disks still may
not work with xtrs due to limitations in xtrs's floppy disk controller
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emulation rather than limitations of the DMK format; see the
LIMITATIONS section below.
The program mkdisk(1) makes a blank emulated floppy or "bulk erases"
an existing one. By default, mkdisk makes a JV3 floppy, but with the
-1 flag it makes a JV1 floppy, or with the -k flag a DMK floppy. See
the mkdisk man page for more information.
Early Model I operating systems used an FA data address mark for the
directory on single density disks, while later ones wrote F8 but would
accept either upon reading. The change was needed because FA is a
nonstandard DAM that is fully supported only by the WD1771 floppy disk
controller used in the Model I; the controllers in the Model III and 4
cannot distinguish between FA and FB (which is used for non-directory
sectors) upon reading, and cannot write FA. To deal nicely with this
problem, xtrs implements the following kludge. On writing in single
density, an F8 data address mark is recorded as FA. On reading with
an emulated WD1771 (available in Model I mode only), FA is returned as
FA; on reading with a WD179x, FA is returned as F8. This trick makes
the different operating systems perfectly compatible with each other,
which is better than on a real Model I! You can use the -truedam flag
to turn off this kludge if you need to; in that case the original
hardware is emulated exactly.
TRS-80 programs that attempt to measure the rotational speed of their
floppy disk drives using timing loops will get the answers they
expect, even when xtrs does not emulate instructions at the same speed
as the original machines. This works because xtrs keeps a virtual
clock (technically, a T-state counter), which measures how much time
it should have taken to execute the instruction stream on a real
machine, and it ties the emulation of floppy disk index holes to this
clock, not to real time.
Emulated 8-inch floppy disks
In addition to the four standard 5.25-inch drives, xtrs also emulates
four 8-inch floppy drives. There is no widely-accepted standard
hardware interface for 8-inch floppies on the TRS-80, so xtrs emulates
a pseudo-hardware interface of its own and provides an LDOS/LS-DOS
driver for it.
Storage for the emulated 8-inch disks is in files named diskM-U, where
M is the TRS-80 model number (1, 3, 4, or 4p) and U is a unit number
(4, 5, 6, or 7). The only difference between 5.25-inch and 8-inch
emulated drives is that the emulator allows you to format more bytes
per track in the latter. A new JV3 floppy can be formatted as either
5.25-inch or 8-inch depending on whether you initially put it into a
5.25-inch or 8-inch emulated drive. A new DMK floppy, however, must
be created with the -8 flag to mkdisk in order to be large enough for
use in an 8-inch emulated drive. JV1 floppies cannot be used in 8-
inch drives. Be careful not to put an emulated floppy into a 5.25-
inch emulated drive after it has been formatted in an 8-inch emulated
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drive or vice versa; the results are likely to be confusing. Consider
using different file extensions for the two types; say, .dsk for
5.25-inch and .8in for 8-inch.
To use the emulated 8-inch drives, you'll need a driver. Under LDOS
or LS-DOS, use the program XTRS8/DCT supplied on the emulated floppy
utility.dsk. This driver is a very simple wrapper around the native
LDOS/LS-DOS floppy driver. Here are detailed instructions.
First, make sure an appropriate version of LDOS is in emulated floppy
drive 0, and the supplied file utility.dsk is in another emulated
floppy drive. Boot LDOS. If you are using Model I LDOS, be sure
FDUBL is running.
Second, type the following commands. Here d is the LDOS drive number
you want to use for the 8-inch drive and u is the unit number you
chose when naming the file. Most likely you will choose d and u to be
equal to reduce confusion.
SYSTEM (DRIVE=d,DRIVER="XTRS8",ENABLE)
Enter unit number ([4]-7): u
You can repeat these steps with different values of d and u to have
more than one 8-inch drive. You might want to repeat four times using
4, 5, 6, and 7, or you might want to save some drive numbers for hard
drives (see below).
Finally, it's a good idea to give the SYSTEM (SYSGEN) command (Model
I/III) or SYSGEN command (Model 4/4P). This command saves the SYSTEM
settings, so the 8-inch drives will be available again the next time
you reboot or restart the emulator. If you need to access an 8-inch
drive after booting from a disk that hasn't been SYSGENed, simply use
the same SYSTEM command again.
In case you want to write your own driver for another TRS-80 operating
system, here are details on the emulated pseudo-hardware. The 8-inch
drives are accessed through the normal floppy disk controller, exactly
like 5.25-inch drives. The four 5.25-inch drives have hardware select
codes 1, 2, 4, and 8, corresponding respectively to files diskM-0, -1,
-2, and -3. The four 8-inch drives have hardware select codes 3, 5,
6, and 7, corresponding respectively to files diskM-4, -5, -6, and -7.
(See also the -sizemap option below, however.)
Real floppy disks
Under Linux only, any diskM-U file can be a symbolic link to a real
floppy disk drive, typically /dev/fd0 or /dev/fd1. Most PCs should be
able to read and write TRS-80 compatible floppies in this way. Many
PC floppy controllers cannot handle single density, however, and some
may have problems even with double density disks written on a real
TRS-80, especially disks formatted by older TRS-80 operating systems.
Use the -doublestep flag if you need to read 35-track or 40-track
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media in an 80-track drive. If you need to write 35-track or 40-track
media in an 80-track drive, bulk-erase the media first and format it
in the 80-track drive. Don't write to a disk in an 80-track drive if
it has ever been written to in a 40-track drive. The narrower head
used in an 80-track drive cannot erase the full track width written by
the head in a 40-track drive.
If you link one of the 5.25-inch floppy files (diskM-0 through diskM-
3) to a real floppy drive, TRS-80 programs will see it as a 5.25-inch
drive, but the actual drive can be either 3.5-inch or 5.25-inch. The
drive will be operated in double density (or single density), not high
density, so be sure to use the appropriate media.
If you link one of the 8-inch floppy files (diskM-4 through diskM-7)
to a real floppy drive, TRS-80 programs will see it as an 8-inch
drive. Again, you need to use the XTRS8/DCT driver described above to
enable LDOS/LS-DOS to access an 8-inch drive. The real drive can be
either 3.5-inch, 5.25-inch, or 8-inch. A 3.5-inch or 5.25-inch drive
will be operated in high-density mode, using MFM recording if the
TRS-80 is trying to do double density, FM recording if the TRS-80 is
trying to do single density. In this mode, these drives can hold as
much data as a standard 8-inch drive. In fact, a 5.25-inch HD drive
holds exactly the same number of bits per track as an 8-inch drive; a
3.5-inch HD drive can hold 20% more, but we waste that space when
using one to emulate an 8-inch drive. In both cases we also waste the
top three tracks, since an 8-inch drive has only 77 tracks, not 80.
The nonstandard FA and F9 data address marks available in single
density on a real Model I with the WD1771 controller also need special
handling. A PC-style floppy disk controller can neither read nor
write sectors with such DAMs at all. This raises three issues: (1) It
will be impossible for you to read some Model I disks on your PC even
if your PC otherwise supports single density. In particular, Model I
TRSDOS 2.3 directory tracks will be unreadable. (2) On writing in
single density, xtrs silently records a F9 or FA DAM as F8. (3) On
reading in single density with an emulated WD1771 (Model I mode only),
F8 is returned as FA. If you need more accurate behavior, the
-truedam flag will turn on error messages on attempts to write F9 or
FA DAMs and will turn off translation of F8 to FA on reading.
Hint: Be sure to set the drive type correctly in your PC's BIOS.
Linux and xtrs rely on this information to know how fast your drives
are spinning and hence what data rate to use when reading and writing.
All 3.5-inch drives spin at 300 RPM. Newer 5.25-inch high-density
capable drives ("1.2MB" drives) normally always spin at 360 RPM.
(Some can be jumpered to slow down to 300 RPM when in double-density
mode, but you should not do that when plugging one into a PC.) Older
5.25-inch drives that cannot do high density ("180KB", "360KB" or
"720KB" 5.25-inch drives) always spin at 300 RPM. All 8-inch drives
spin at 360 RPM. If you plug an 8-inch drive into a PC (this requires
a 50-pin to 34-pin adaptor cable), tell your BIOS that it is a 5.25-
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inch 1.2MB drive.
Emulated hard disks
xtrs can emulate a hard disk in a file in one of two ways: it can use
a special, xtrs-specific LDOS driver called XTRSHARD/DCT, or it can
emulate the Radio Shack hard drive controller (based on the Western
Digital WD1010) and use the native drivers for the original hardware.
Using XTRSHARD/DCT
The XTRSHARD/DCT driver has been tested and works under both LDOS
5.3.1 for Model I or III and TRSDOS/LS-DOS 6.3.1 for Model 4/4P. It
may or may not work under earlier LDOS versions. It definitely will
not work under other TRS-80 operating systems or with emulators other
than xtrs. The hard disk format was designed by Matthew Reed for his
Model I/III and Model 4 emulators; xtrs duplicates the format so that
users can exchange hard drive images across the emulators.
To use XTRSHARD/DCT, first run the mkdisk program under Unix to create
a blank hard drive (.hdv) file. Typical usage would be: mkdisk -h
mydisk.hdv. See the mkdisk(1) man page for other options.
Second, link the file to an appropriate name. XTRSHARD/DCT supports
up to eight hard drives, with names of the form hardM-U, where M is
the TRS-80 model (1, 3, or 4; in this case Model 4P also uses M=4) and
U is a unit number from 0 to 7. It looks for these files in the same
directory as the floppy disk files diskM-U.
Third, make sure an appropriate version of LDOS is in emulated floppy
drive 0, and the supplied file utility.dsk is in another emulated
floppy drive. Boot LDOS. If you are using Model I LDOS 5.3.1, patch
a bug in the FORMAT command by typing PATCH FORMAT/CMD.UTILITY
M1FORMAT/FIX. You need to apply this patch only once. It must not be
applied to Model III or Model 4/4P LDOS.
Fourth, type the following commands. Here d is the LDOS drive number
you want to use for the hard drive (a typical choice would be 4) and u
is the unit number you chose when naming the file (most likely 0).
SYSTEM (DRIVE=d,DRIVER="XTRSHARD",ENABLE)
Enter unit number ([0]-7): u
FORMAT d (DIR=1)
Answer the questions asked by FORMAT as you prefer. The DIR=1
parameter to FORMAT is optional; it causes the hard drive's directory
to be on track 1, making the initial size of the image smaller. You
can repeat these steps with different values of d and u to have more
than one hard drive.
Finally, it's a good idea to give the SYSTEM (SYSGEN) command (Model
I/III) or SYSGEN command (Model 4/4P). This command saves the SYSTEM
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settings, so the drive will be available again the next time you
reboot or restart the emulator. If you need to access the hard disk
file after booting from a floppy that hasn't been SYSGENed, simply use
the same SYSTEM command(s) again, but don't FORMAT. You can freely
use a different drive number or (if you renamed the hard disk file) a
different unit number.
The F7 key currently doesn't allow XTRSHARD/DCT disk changes to be
recognized, but you can change to a different hard disk file for the
same unit by renaming files as needed and rebooting LDOS.
Technical note: XTRSHARD/DCT is a small Z-80 program that implements
all the required functions of an LDOS disk driver. Instead of talking
to a real (or emulated) hard disk controller, however, it uses special
support in xtrs that allows Z-80 programs to open, close, read, and
write Unix files directly. This support is described further in the
"Data import and export" section below.
Using native hard disk drivers
Beginning in version 4.1, xtrs also emulates the Radio Shack hard disk
controller (based on the Western Digital WD1010) and will work with
the native drivers for this hardware. This emulation uses the same
hard drive (.hdv) file format that XTRSHARD/DCT does. With LDOS/LS-
DOS, the RSHARDx/DCT and TRSHD/DCT drivers are known to work. With
Montezuma CP/M 2.2, the optional Montezuma hard disk drivers are known
to work. The hard disk drivers for NEWDOS/80 and for Radio Shack CP/M
3.0 should work, but they have not yet been tested at this writing.
Any bugs should be reported.
To get started, run the mkdisk program under Unix to create a blank
hard drive (.hdv) file. Typical usage would be: mkdisk -h mydisk.hdv.
See the mkdisk(1) man page for other options.
Second, link the file to an appropriate name. The WD1010 emulation
supports up to four hard drives, with names of the form hardM-U, where
M is the TRS-80 model (1, 3, 4, or 4p) and U is a unit number from 0
to 3. It looks for these files in the same directory as the floppy
disk files diskM-U. If no such files are present, xtrs disables the
WD1010 emulation.
Note that if hard drive unit 0 is present on a Model 4P (file hard4p-
0), the Radio Shack boot ROM will always try to boot from it, even if
the operating system does not support booting from a hard drive. If
you have this problem, either hold down F2 while booting to force the
ROM to boot from floppy, or simply avoid using unit number 0. Stock
TRSDOS/LS-DOS 6 systems do not support booting from a hard drive;
M.A.D. Software's HBUILD6 add-on to LS-DOS for hard drive booting
should work, but is untested. Montezuma CP/M 2.2 does boot from the
emulated hard drive.
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Finally, obtain the correct driver for the operating system you will
be using, read its documentation, configure the driver, and format the
drive. Detailed instructions are beyond the scope of this manual
page.
Data import and export
Several Z-80 programs for data import and export from various TRS-80
operating systems are included with xtrs on two emulated floppy
images. These programs use special support in the emulator to read
and write external Unix files, discussed further at the end of this
section.
The emulated floppy utility.dsk contains some programs for
transferring data between the emulator and ordinary Unix files.
IMPORT/CMD, EXPORT/CMD, and SETTIME/CMD run on the emulator under
Model I/III TRSDOS, Model I/III LDOS, Model I/III Newdos/80, and Model
4/4P TRSDOS/LS-DOS 6; they may also work under other TRS-80 operating
systems. Model III TRSDOS users will have to use TRSDOS's CONVERT
command to read utility.dsk.
IMPORT/CMD imports a Unix file and writes it to an emulated disk.
Usage: IMPORT [-lne] unixfile [trsfile]. The -n flag converts Unix
newlines (\n) to TRS-80 newlines (\r). The -l flag converts the Unix
filename to lower case, to compensate for TRS-80 operating systems
such as Newdos/80 that convert all command line arguments to upper
case. When using the -l flag, you can put a [ or up-arrow in front of
a character to keep it in upper case. Give the -e flag if your TRS-80
operating system uses the Newdos/80 convention for representing the
ending record number in an open file control block. This should be
detected automatically for Newdos/80 itself and for TRSDOS 1.3, but
you'll need to give the flag for DOSPLUS and possibly other non-LDOS
operating systems. If you need the flag but don't give it (or vice
versa), imported files will come out the wrong length. If the
destination file is omitted, IMPORT uses the last component of the
Unix pathname, but with any "." changed to "/" to match TRS-80 DOS
file extension syntax.
EXPORT/CMD reads a file from an emulated disk and exports it to a Unix
file. Usage: EXPORT [-lne] trsfile [unixfile]. The -n flag converts
TRS-80 newlines (\r) to Unix newlines (\n). The -l flag converts the
Unix filename to lower case. When using the -l flag, you can put a [
or up-arrow in front of a character to keep it in upper case. Give
the -e flag if your TRS-80 operating system uses the Newdos/80
convention for representing the ending record number in an open file
control block. This should be detected automatically for Newdos/80
itself and for TRSDOS 1.3, but you'll need to give the flag for
DOSPLUS and possibly other non-LDOS operating systems. If you need
the flag but don't give it (or vice versa), exported files will come
out the wrong length. If the destination file is omitted, EXPORT uses
the TRS-80 filename, but with any "/" changed to "." to match Unix
file extension syntax.
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SETTIME/CMD reads the date and time from Unix and sets the TRS-80
DOS's date and time accordingly.
The next several programs were written in Misosys C and exist in two
versions on utility.dsk. The one whose name ends in "6" runs on Model
4 TRSDOS/LS-DOS 6.x; the other runs on LDOS 5.x and most other Model
I/III operating systems.
CD/CMD (or CD6/CMD) changes xtrs's Unix working directory. Usage: CD
[-l] unixdir. The -l flag converts the Unix directory name to lower
case. When using the -l flag, you can put a [ or up-arrow in front of
a character to keep it in upper case. Running CD/CMD will change the
interpretation of any relative pathnames given to IMPORT or EXPORT.
It will also change the interpretation of disk names at the next disk
change, unless you specified an absolute pathname for xtrs's -diskdir
parameter.
PWD/CMD (or PWD6/CMD) prints xtrs's Unix working directory.
UNIX/CMD (or UNIX6/CMD) runs a Unix shell command. Usage: UNIX [-l]
unix command line. The -l flag converts the Unix command line to
lower case. When using the -l flag, you can put a [ or up-arrow in
front of a character to keep it in upper case. Standard I/O for the
command uses the xtrs program's standard I/O descriptors; it does not
go to the TRS-80 screen or come from the TRS-80 keyboard.
MOUNT/CMD (or MOUNT6/CMD) is a convenience program that switches
emulated floppy disks in the drives. Usage: MOUNT [-l] filename U.
The -l flag converts the Unix filename to lower case. When using the
-l flag, you can put a [ or up-arrow in front of a character to keep
it in upper case. The filename is any Unix filename; U is a single
digit, 0 through 7. The command deletes the file diskM-U (where M is
the TRS-80 model) from the disk directory (see -diskdir option),
replaces it with a symbolic link to the given filename, and signals a
disk change (as if F7 had been pressed).
UMOUNT/CMD (or UMOUNT6/CMD) is a convenience program that removes an
emulated floppy disk from a drive. Usage: UMOUNT U. U is a single
digit, 0 through 7. The command deletes the file diskM-U (where M is
the TRS-80 model) from the disk directory (see -diskdir option) and
signals a disk change (as if F7 had been pressed).
The emulated floppy cpmutil.dsk contains import and export programs
for Montezuma CP/M, written by Roland Gerlach. It was formatted as a
"Montezuma Micro Standard DATA disk (40T, SS, DD, 200K)," with 512-
byte sectors. Be careful to configure your CP/M to the proper disk
format and drive parameters (40 track, not 80), or you will have
confusing problems reading this disk. Documentation is included in
the file cpmutil.html and source code in the file cpmutil.tgz (a
gzipped tar archive). See
http://members.optusnet.com.au/~rgerlach/trs-80/cpmutil.html where you
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will sometimes find a newer version of the utilities than is included
with xtrs.
The emulator implements a set of pseudo-instructions (emulator traps)
that give TRS-80 programs access to Unix files. The programs listed
above use them. If you would like to write your own such programs,
the traps are documented in the file trs_imp_exp.h. Assembler source
code for the existing programs is supplied in xtrshard.z, import.z,
export.z, and settime.z. You can also write programs that use the
traps in Misosys C, using the files xtrsemt.h and xtrsemt.ccc as an
interface; a simple example is in settime.ccc.
Interrupts
The emulator supports only interrupt mode 1. It will complain if your
program enables interrupts after powerup without executing an IM 1
instruction first. All Model I/III/4/4P software does this, as the
built-in peripherals in these machines support only IM 1.
The Model I has a 40 Hz heartbeat clock interrupt, while the Model III
uses 30 Hz, and the Model 4/4P can run at either 30 Hz or 60 Hz. The
emulator approximates this rather well even on a system where clock
ticks come at some frequency that isn't divisible by the emulated
frequency (e.g., 100 Hz on Intel Linux), as long as the true frequency
is not slower than the emulated frequency. The emulator has a notion
of the absolute time at which each tick is supposed to occur, and it
asks the host system to wake it up at each of those times. The net
result is that some ticks may be late, but there are always the proper
number of ticks per second. For example, running in Model I mode on
Intel Linux you'd see this pattern: (tick, 30ms, tick, 20ms,...)
instead of seeing ticks every 25ms.
Processor speed selection
A standard Model 4 has a software-controlled switch to select
operation at either 4.05504 MHz (with heartbeat clock at 60 Hz) or
2.02752 MHz (with heartbeat clock at 30 Hz). xtrs emulates this
feature.
Model I's were often modified to operate at higher speeds than the
standard 1.77408 MHz. With one common modification, writing a 1 to
port 0xFE would double the speed to 3.54816 MHz, while writing a 0
would set the speed back to normal. The heartbeat clock runs at 40 Hz
in either case. xtrs emulates this feature as well.
Sound
Sound support uses the Open Sound System /dev/dsp device, standard on
Linux and available on many other Unix versions as well. This support
is compiled in automatically on Linux; if you have OSS on another
version of Unix, you'll need to define the symbol HAVE_OSS in your
Makefile or in trs_cassette.c. Any time TRS-80 software tries to
write non-zero values to the cassette port (or the Model 4/4P optional
sound port) with the cassette motor off, it is assumed to be trying to
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make sounds and xtrs opens /dev/dsp. It automatically closes the
device again after a few seconds of silence.
If you are playing a game with sound, you'll want to use the
-autodelay flag to slow down instruction emulation to approximately
the speed of a real TRS-80. If you don't do this, sound will still
play correctly, but the gameplay may be way too fast and get ahead of
the sound.
On the other hand, if your machine is a bit too slow, you'll hear gaps
and pops in the sound when the TRS-80 program lags behind the demand
of the sound card for more samples. The -autodelay feature includes a
small speed boost whenever a sound starts to play to try to prevent
this, but if the boost is too much or too little, you might either
find that the game runs too fast when a lot of sound is playing, or
that the sound has gaps in it anyway. If your sound has gaps, you can
try reducing the sample rate with the -samplerate flag.
The Orchestra-85 music synthesis software will run under xtrs's Model
I emulation, and the Orchestra-90 software will run with Model III
operating systems under xtrs's Model III, 4, or 4P emulation. For
best results, use Orchestra-90 and the Model 4 emulation, as this lets
the software run at the highest emulated clock rate (4 MHz) and thus
generate the best sound. If you want to run Orchestra-85 instead, you
can tell it that you have a 3.5 MHz clock speedup with enable sequence
3E01D3FE and disable sequence 3E00D3FE; this will let the software run
twice as fast as on an unmodified Model I and generate better sound.
There is no need to use xtrs's -autodelay flag when running
Orchestra-85/90, but you might want to specify a small fixed delay to
keep from getting excessive key repeat.
Mouse
A few Model 4 programs could use a mouse, such as the shareware hi-res
drawing program MDRAW-II. The program XTRSMOUS/CMD on the utility disk
(utility.dsk) is a mouse driver for Model 4/4P mode that should work
with most such programs. xtrs does not emulate the actual mouse
hardware (a serial mouse plugged into the Model 4 RS-232 port), so the
original mouse drivers will not work under xtrs. Instead, XTRSMOUS
accesses the X mouse pointer using an emulator trap. XTRSMOUS
implements the same TRSDOS/LS-DOS 6 SVC interface as the David Goben
and Matthew Reed mouse drivers. (It does not implement the interface
of the older Scott McBurney mouse driver, which may be required by
some programs.)
By default XTRSMOUS installs itself in high memory. This is done
because MDRAW-II tests for the presence of a mouse by looking to see
whether the mouse SVC is vectored to high memory. If the driver is
installed in low memory, MDRAW thinks it is not there at all. If you
use mouse-aware programs that don't have this bug, or if you edit the
first line of MDRAW to remove the test, you can install XTRSMOUS in
low memory using the syntax "XTRSMOUS (LOW)".
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Time of day clock
Several battery-backed time of day clocks were sold for the various
TRS-80 models, including the TimeDate80, TChron1, TRSWatch, and T-
Timer. They are essentially all the same hardware, but reside at a
few different port ranges. xtrs currently emulates them at port
ranges 0x70-0x7C and 0xB0-0xBC. The T-Timer port range at 0xC0-0xCC
conflicts with the Radio Shack hard drive controller and is not
emulated.
These clocks return only a 2-digit year, and it is unknown what their
driver software will do in the year 2000 and beyond. If you have
software that works with one of them, please send email to report what
happens when it is used with xtrs.
Also see SETTIME/CMD in the "Data import and export" section above for
another way to get the correct time into a Z-80 operating system
running under xtrs.
Finally, you might notice that LDOS/LS-DOS always magically knows the
correct date when you boot it (but not the time). When you first
power up the emulated TRS-80, xtrs dumps the date into the places in
memory where LDOS and LS-DOS normally save it across reboots, so it
looks to the operating system as if you rebooted after setting the
date.
Joystick
Pressing a key on a PC numeric keypad with NumLock disengaged emulates
the Alpha Products joystick. See the Keys section above for details.
The emulated joystick is mapped only at port 0, to avoid conflicts
with other devices. The joystick emulation could be made to work with
real joysticks using the X input extension, but this is not
implemented yet.
Running games
Some games run rather well under xtrs now, provided that your machine
is fast enough to run the emulation in real time and that you choose
the right command line options. "Galaxy Invaders Plus" by Big 5
Software is particularly good. You will usually want to turn on
autodelay, and if your machine is slow you may need to reduce the
sound sample rate. Running your X server in 8-bit/pixel mode also
seems to help in some cases. Example command lines:
startx -- -bpp 8
xtrs -autodelay
If you have a slow machine and the sound breaks up, it is possible
that your machine is not fast enough to generate samples at the
default rate of 44,100 Hz. If you think this may be happening, try
"-samplerate 11025" or even "-samplerate 8000".
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Options
Defaults for all options can be specified using the standard X
resource mechanism, and the class name for xtrs is "Xtrs".
-display display
Set your X display to display. The default is to use the DISPLAY
environment variable.
-iconic
Start with the xtrs window iconified.
-background color
-bg color
Specifies the background color of the xtrs window.
-foreground color
-fg color
Specifies the foreground color of the xtrs window.
-title titletext
Use titletext in the window title bar instead of the program
name.
-borderwidth width
Put a border of width pixels around the TRS-80 display. The
default is 2.
-scale xfac[,yfac]
Multiply the horizontal and vertical window size by xfac and
yfac, respectively. Possible values are integers in the range
[1,4] for xfac and [1,8] for yfac. Defaults are xfac=1 and
yfac=2*xfac.
-resize
In Model III or 4/4P mode, resize the X window whenever the
emulated display mode changes between 64x16 text (or 512x192
graphics) and 80x24 text (or 640x240 graphics). This is the
default in Model III mode, since 80x24 text is not available and
the 640x240 graphics add-on card is seldom used.
-noresize
In Model III or 4/4P mode, always keep the X window large enough
for 80x24 text or 640x240 graphics, putting a blank margin around
the outside when the emulated display mode is 64x16 text or
512x192 graphics. This is the default in Model 4/4P mode, since
otherwise there is an annoying size switch during every reboot.
-charset name
Select among several sets of built-in character bitmaps.
In Model I mode, five sets are available. The default, wider, is
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a modified Model III set with characters 8 pixels wide; it looks
better on a modern computer screen with square pixels than the
real Model I fonts, which were 6 pixels wide. lcmod is the
character set in the replacement character generator that was
supplied with the Radio Shack lower case modification. (It was
reconstructed partly from memory and may have some minor bit
errors.) stock is the character set in the stock character
generator supplied with most upper case only machines. Since xtrs
currently always emulates the extra bit of display memory needed
to support lower case, this character set gives you the
authentic, unpleasant effect that real Model I users saw when
they tried to do homebrew lower case modifications without
replacing the character generator: lower case letters appear at
an inconsistent height, and if you are using the Level II BASIC
ROM display driver, upper case letters are replaced by
meaningless symbols. early is the same as stock, but with the
standard ASCII characters [, \, ], and ^ in the positions where
most Model I's had directional arrows. This was the default
programming in the Motorola character generator ROM that Radio
Shack used, and a few early machines were actually shipped with
this ROM. Finally, german or genie gives an approximate
emulation of the GENIE, a German Model I clone. Characters are 8
pixels wide, and double width is supported even though later
GENIE models did not include it.
In Model III, 4, and 4P modes, three sets are available: katakana
(the default for Model III) is the original Model III set with
Japanese Katakana characters in the alternate character
positions. This set was also used in early Model 4's.
international (the default for Model 4 and 4P) is a later Model 4
set with accented Roman letters in the alternate positions. bold
is a bold set from a character generator ROM found in one Model
III, origin uncertain.
-usefont
Use X fonts instead of the built-in character bitmaps.
-nofont
Use the built-in character bitmaps, not a X font. This is the
default.
-font fontname
If -usefont is also given, use the specified X font for normal
width characters. The default uses a common X fixed-width font:
"-misc-fixed-medium-r-normal--20-200-75-75-*-100-iso8859-1".
-widefont fontname
If -usefont is also given, use the specified X font for double
width characters. The default uses a common X fixed-width font,
scaled to double width: "-misc-fixed-medium-r-normal--20-200-
75-75-*-200-iso8859-1".
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-nomicrolabs
In Model I mode, emulate the HRG1B 384x192 hi-res graphics card.
In Model III mode or Model 4/4P mode, emulate the Radio Shack
hi-res card. This is now the default.
-microlabs
In Model III or 4/4P mode, emulate the Micro Labs Grafyx Solution
hi-res graphics card. Note that the Model III and Model 4/4P
cards from Micro Labs are very different from one another.
-debug
Enter zbx, the z80 debugger.
-romfile filename
-romfile3 filename3
-romfile4p filename4p
Use the romfile specified by filename in Model I mode, the
romfile specified by filename3 in Model III and Model 4 mode, or
the romfile specified by filename4p in Model 4P mode, A romfile
can be either a raw binary dump, Intel hex format, or TRS-80 cmd
format (for example, a MODELA/III file). If you do not set this
option or the corresponding X resource, a default established at
compile time is used (if any); see Makefile.local for
instructions on compiling in default romfiles or default romfile
names.
-model m
Specifies which TRS-80 model to emulate. Values accepted are 1
or I (Model I), 3 or III (Model III), 4 or IV (Model 4), and 4P
or IVP (Model 4P). Model I is the default.
-delay d
A crude speed control. After each Z-80 instruction, xtrs busy-
waits for d iterations around an empty loop. A really smart C
optimizer might delete this loop entirely, so it's possible that
this option won't work if you compile xtrs with too high an
optimization level. The default delay is 0.
-autodelay
Dynamically adjusts the value of -delay to run instructions at
roughly the same rate as a real machine. The tracking is only
approximate, but it can be useful for running games.
-noautodelay
Turn off -autodelay. This is the default.
-keystretch cycles
Fine-tune the keyboard behavior. To prevent keystrokes from
being lost, xtrs "stretches" the intervals between key
transitions, so that the Z-80 program has time to see each
transition before the next one occurs. Whenever the Z-80 program
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reads the keyboard matrix and sees an emulated key go up or down,
xtrs waits cycles Z-80 clock cycles (T-states) before it allows
the program to see another key transition. Key transitions that
are received during the waiting period or when the Z-80 program
is not reading the keyboard are held in a queue. The default
stretch value is 4000 cycles; it should seldom if ever be
necessary to change it.
-shiftbracket
Emulate [, \, ], ^, and _ as shifted keys, and {, |, }, and ~ as
unshifted. This is the default in Model 4 and 4P modes, and it
works well with the keyboard driver in Model 4 TRSDOS/LS-DOS 6.
-noshiftbracket
Emulate [, \, ], ^, and _ as unshifted keys, and {, |, }, and ~
as shifted. This is the default in Model I and III modes, and it
works well with many TRS-80 keyboard drivers. With some keyboard
drivers these keys do not work at all, however.
-diskdir dir
Specify the directory containing floppy and hard disk images. If
the value starts with "~/" (or is just "~"), it is relative to
your home directory. The default value is ".".
-doubler type
Specify what type of double density adaptor to emulate (Model I
mode only). The type may be percom, radioshack (or tandy), both,
or none. The type may be abbreviated to one character. The
default is both, which causes the double density adaptor
emulation to respond to the special commands of both the Percom
and Radio Shack cards.
-doublestep
Make all real floppy drives double-step, allowing access to 35-
track or 40-track media in an 80-track drive. Linux only. See
the Floppy Disks section for limitations.
-nodoublestep
Turn off double-step mode for all real floppy drives. Linux
only. This is the default.
-stepmap s0,s1,s2,s3,s4,s5,s6,s7
Selectively set double-step mode for individual real floppy
drives. If sU is 2 and diskM-U is a real drive, the drive will
be double-stepped; if sU is 1, it will be single-stepped. You
can omit values from the end of the list; those drives will get
the default value set by -doublestep or -nodoublestep.
-sizemap z0,z1,z2,z3,z4,z5,z6,z7
Selectively set whether drives are emulated as 5-inch or 8-inch;
see the section "Emulated 8-inch floppy disks" above. If zU is
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5, the drive will appear to Z-80 software as 5-inch; if 8, as 8-
inch. The default setting (as reflected in the documentation
above) is 5,5,5,5,8,8,8,8. You can omit values from the end of
the list; those drives will get the default values. Setting one
or more of the first four drives to 8-inch may be useful for CP/M
software that supports 8-inch drives. You can also use XTRS8/DCT
with 8-inch drives in the first four positions; even though the
prompt suggests the unit number must be 4-7, numbers 0-3 are
accepted. XTRS8 does not check whether the unit you've selected
is really being emulated as an 8-inch drive, however; you'll
simply get errors during FORMAT if you get this wrong.
-truedam
Turn off the single density data address mark remapping kludges
described in the "Emulated floppy disks" and "Real floppy disks"
sections above. With this option given, the distinction between
F8 and FA data address marks is strictly observed on both writing
and reading. This option is probably not useful unless you need
to deal with Model I disks that use the distinction as part of a
copy-protection scheme. See also "Common File Formats for
Emulated TRS-80 Floppy Disks", available at http://www.tim-
mann.org/trs80/dskspec.html.
-notruedam
The opposite of -truedam. This setting is the default.
-samplerate rate
Set the sample rate for new cassette wav files, direct cassette
I/O to the sound card, and game sound output to the sound card.
Existing wav files will be read or modified using their original
sample rate regardless of this flag. The default is 44,100 Hz.
See also the cassette(1) man page.
-serial ttyname
Set the tty device to be used for I/O to the TRS-80's serial
port. The default is /dev/ttyS0 on Linux, /dev/tty00 on other
versions of Unix. Setting the name to be empty (-serial "")
emulates having no serial port.
-switches value
Set the sense switches on the Model I serial port card. This
option is meaningful only in Model I mode, and only when the
-serial option is not set to "". The default value is 0x6f,
which Radio Shack software conventionally interprets as 9600 bps,
8 bits/word, no parity, 1 stop bit.
-emtsafe
Disable emulator traps (see "Data import and export") that could
write to host files other than disk images in the original
diskdir.
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-noemtsafe
The opposite of -emtsafe. This setting is the default.
Additional resources
There are many other TRS-80 resources available on the Web, including
shareware and freeware emulators that run under MSDOS and other
operating systems, software for converting TRS-80 physical media to
the emulator's disk file format, ROM images, and TRS-80 software that
has already been converted. For pointers, see http://www.tim-
mann.org/trs80.html.
Bugs and limitations
The emulated serial port's modem status and control signals are not
tied to the signals on the real serial port, because the real signals
are not available to software through the Unix tty device interface.
The ability to check for parity, framing, and overrun errors and
receive an interrupt when one occurs is not emulated. Unix does not
support 2000, 3600, or 7200 baud, so these TRS-80 data rates are
remapped to 38400, 57600, and 115200 baud respectively.
A better signal processing algorithm might help read real cassettes
more reliably, especially at 1500bps.
Some features of the floppy disk controller are not currently
emulated: Force Interrupt with condition bits 0x01, 0x02, or 0x04 is
not implemented. Read Track is implemented only for DMK emulated
floppies. The multiple-sector flags in Read and Write are not
implemented. The timing of returned sectors is emulated only for the
Read Address command, and not very accurately for JV1 or JV3. If a
disk has more than one sector with the same number on a track, xtrs
will always see the first (counting from the index hole) when reading
or writing; a real machine would see the next one to come under the
head depending on the current rotational position of the disk.
Partially reformatting a track (which TRS-80 programs like HyperZap
and Model I Super Utility do to achieve mixed density) is supported
for DMK but not JV3; however, switching densities while formatting
(which Model III and 4 Super Utility do) works on both DMK and JV3.
Real physical floppy disks are supported only under Linux, because
Unix does not define a portable interface to the low-level floppy
controller functionality that xtrs needs. There are some limitations
even under Linux: Index holes are faked, not detected on the real
disk, and the timing of returned sectors is not emulated at all. Due
to the limitations of PC-style floppy disk controllers, when
formatting a physical floppy under xtrs, you cannot mix sectors of
different sizes on the same track, switch densities in the middle of a
track, or reformat only part of a track. However, xtrs can read and
write to physical floppies that have already been formatted in these
ways (perhaps by a real TRS-80).
The extended JV3 limit of 5802 sectors is somewhat arbitrary. It
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could be raised by generalizing the code to permit more than two
blocks of 2901, but this does not seem too useful. 5802 sectors is
already enough for a 3.5-inch HD (1.44MB) floppy, which the TRS-80
didn't support anyway. If you need more space, use emulated hard
drives instead of emulated floppies with huge numbers of tracks.
XTRSHARD/DCT ignores the internal write-protected flag in hard drive
images, but a hard drive image can still be effectively write
protected by turning off its Unix write permission bits.
The emulator uses a heuristic to decide what format a ROM file is in.
If a raw binary ROM image starts with 0x01, 0x05, or 0x22, it can be
misidentified as being in a different format. This is rather unlikely
to occur, as ROMs typically begin with 0xF3, the DI instruction.
The joystick emulation could be made to work with real joysticks using
the X input extension, but this is not implemented yet.
If you discover other bugs, write fixes for any of these, or make any
other enhancements, please let us know so that we can incorporate the
changes into future releases.
Authors and acknowledgements
xtrs 1.0 was written by David Gingold and Alec Wolman. The current
version was revised and much extended by Timothy Mann (see
http://tim-mann.org/). See README and README.tpm for additional notes
from the authors.
We also thank the following people for their help. The JV1 and JV3
floppy disk file formats were designed by Jeff Vavasour, originally
for his MSDOS-based TRS-80 emulators. The DMK format was designed by
David Keil for his MSDOS-based TRS-80 emulator. The hard disk file
format was designed by Matthew Reed for his MSDOS-based TRS-80
emulators. Al Petrofsky and Todd P. Cromwell III supplied font data.
Roland Gerlach contributed the CP/M import and export programs as well
as several bug reports and fixes for the emulator itself. Ulrich
Mueller added the -borderwidth option, improved the -scale option and
the bitmap font scaling, ported the import, export, and settime
utilities to Newdos/80, and contributed the HRG1B emulation. Branden
Robinson supplied the first version of the cassette man page, fixed
Makefile bugs, translated cassette to the Bourne shell, and
implemented watchpoints in zbx. Mark McDougall provided documentation
for the Micro Labs Grafyx Solution card. Jenz Guenther added the
-title option and contributed code to emulate the GENIE (German Model
I clone). Joe Peterson contributed code to emulate the TimeDate80 and
the -emtsafe feature. Denis Leconte contributed part of the -scale
implementation.
$Id: xtrs.man,v 1.69 2009/06/15 23:44:43 mann Exp $
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