         ------------------------------------------
        |          READDISK, version 2.00          |
        | copyright (c) 1997, 1998 by Matthew Reed |
        |            all rights reserved           |
        |           for free distribution          |
        |                                          |
        |       last updated February 8, 1998      |
         ------------------------------------------


INTRODUCTION
------------
Most TRS-80 emulators (including my Model 1/3 and Model 4
emulators) use virtual disk files to emulate real TRS-80
disks.  In order to use those emulators effectively, you
need some way to easily create virtual disks.

READDISK is a utility program for PC compatibles that reads
real TRS-80 disks and converts them into virtual disk
files.  Obviously, READDISK requires that your PC have the
right sized disk drive; in other words, if you want to
convert 5 1/4" TRS-80 disks, your PC must have a 5 1/4"
drive installed!

Under most circumstances, READDISK will automatically
recognize the format of the TRS-80 disk and will adjust
itself to transfer the disk automatically.  (The exception
is that READDISK cannot automatically determine whether your
CP/M disks are double-sided.  If they are, you will need to
use the /2 command line option described below.)  However,
there are significant limitations to this type of transfer,
most of which are directly related to the limitations of the
PC disk controller.  Specifically:

     o  READDISK cannot be used to transfer most protected
        disks.  (PC disk controllers are less flexible than
        TRS-80 disk controllers and cannot tolerate most
        TRS-80 protection schemes.)

     o  READDISK cannot transfer single-density disks on
        most computers (because most PC disk controllers do
        not support single density operation).

     o  Disks formatted by some TRS-80 operating systems,
        most notably TRSDOS 1.3 and NEWDOS/80, may have
        some unreadable sectors.  (These operating systems
        frequently wrote sectors closer to the index hole
        than PC disk controllers will allow.)  Disks
        formatted with later versions of LDOS and LS-DOS
        should not have this problem.

Note:  READDISK will not write to or alter your TRS-80 disks
in any way, but just as a common-sense precaution, place a
write-protect tab on any TRS-80 disk before you convert it.


USAGE
-----
The simplest way to use READDISK is to use a command line
like this:

     READDISK A: DISKFILE

Replace "DISKFILE" with the name of the virtual disk file
you want to create.  (Note that the virtual disk files MUST
be created on your hard drive; floppy to floppy transfers
are not supported.)  Virtual disk files will automatically
be given a ".DSK" extension.  If the virtual disk file you
want to create already exists, you will be asked if you want
to overwrite it.

If you're using drive B to transfer TRS-80 disks, then
replace the "A:" in the command line with "B:".

READDISK will display a title message, and then it will
start converting your TRS-80 disk into a virtual disk file. 
The process will take a while, but READDISK displays an
on-screen status report at all times.  If all goes well,
READDISK will convert the disk without needing any further
intervention from you.  It will then display a success
message and return you to the DOS prompt.


ERRORS
------
If all does not go well, you will be presented with some
sort of error message.  The most common error message is
displayed when READDISK can't read a sector on the TRS-80
disk, even after repeated attempts:

     Retry or Skip (R/S)?

If you press "R", for "Retry", READDISK will try to read the
sector again.  If you press "S", for "Skip", READDISK will
mark the sector as unreadable and go on to the next one.  Be
aware that unreadable sectors can make a disk unusable, so
use the "Retry" option as many times as you can.  Remember,
you only have to successfully read the sector ONCE.

Another error occurs when READDISK can't determine the
format of your TRS-80 disk.  READDISK will then display its
help screen and suggest that you run READDISK again with the
appropriate command line options (described below).


COMMAND LINE OPTIONS
--------------------
All command line options should follow the word "READDISK"
but precede the drive letter and virtual disk file name. 
Here are the available options and a description of what
they do.  Remember, though, that these options need to be
used ONLY when READDISK can't automatically determine the
format of your TRS-80 disk, or when you are transferring a
double-sided CP/M disk.  For most TRS-80 disk transfers,
these options are completely unnecessary.

     /L          Forces an LDOS/DOSPLUS/MULTIDOS transfer
     /T          Forces a TRSDOS 1.3 transfer
     /C          Forces a CP/M transfer (also use the /2
                   option if your CP/M  disks are double-
                   sided)
     /1          Forces a single-sided transfer
     /2          Forces a double-sided transfer
     /D:track    Specifies the directory track
     /N:tracks   Specifies the number of tracks to transfer
     /8          Read 80 track disks in a 1.2Mb drive

As an example, if you are using READDISK to transfer a
single-sided, 40-track LDOS disk with the directory on track
20, AND if READDISK can't determine the format of this disk
automatically, you would use a command line like this:

     READDISK /1 /N:40 /L /D:20 A: DISKNAME

If you are transferring a double-sided CP/M disk, the
appropriate command line would be something like this:

     READDISK /2 /C A: DISKNAME

If you are transferring an 80-track DOSPLUS disk, the
command line would look something like this (NOTE: you MUST
be using a 1.2Mb drive for an 80-track transfer to be
successful):

     READDISK /N:80 /L /8 A: DISKNAME


POSSIBLE TRANSFER PROBLEMS
--------------------------
On some computers, transferring TRS-80 disks with READDISK
may be impossible, no matter how many command line options
you use.  The problem is not READDISK, but the PC disk
controller itself.  As strange as it may seem, the disk
controllers used in TRS-80 computers were more capable and
more flexible than the disk controllers used in today's
PC's.

When READDISK tries to read a TRS-80 disk, it must
manipulate the PC disk controller at a very low level,
making requests that would never be made by MS-DOS or
Microsoft Windows.  Some PC disk controllers are just not
capable of fulfilling these requests; others fulfill them,
but not reliably.  A good case in point is the sector placed
too close to the index hole by TRSDOS 1.3 and NEWDOS/80. 
TRS-80 disk controllers had no problem with this practice,
but PC disk controllers just can't handle it.

Consider also that many TRS-80 disks (particularly early
TRS-80 disks) were written using drives whose heads had
drifted out of alignment, or whose rotational speed had
drifted outside the tolerance range.  Old TRS-80 magazines
and newsletters are filled with questions from people who
were creating disks in drive zero that could not be read in
drive one, or whose drives could not read the factory-
perfect master disks from companies such as Logical
Systems, MISOSYS, Anitek, or Powersoft.  If so many early
TRS-80 disks could not be read reliably from system to
system (or even between drives in the same system), then it
is no surprise that READDISK on a PC can't read them either.

Since these facts are no comfort to someone whose TRS-80
disks refuse to convert, here are some conversion
suggestions:

     o  Try using READDISK on as many computers as you can. 
        Try older computers, if possible.  (The Tandy 1000
        and BSR series of computers seem to work well.)
        Retry and retry and retry.  Remember, you only need
        to convert each disk ONCE.  After conversion, the
        resulting virtual disk file can be copied and moved
        just like any other MS-DOS file.

     o  If the READDISK transfer just doesn't work, and you
        still have access to a TRS-80, use it to make fresh
        copies of your TRS-80 disks.  Make the copies in
        the newest, best-conditioned, most-perfectly-aligned
        TRS-80 drive you have.  If possible, use the latest
        versions of LDOS or LS-DOS to make the copies.
        Then go back and try the READDISK transfers again.

     o  If the full disk transfers don't work and you have
        the registered version of my Model 1/3 or Model 4
        emulators, try using them to read the TRS-80 disk.
        (The necessary instructions are in the document
        files included with the emulators.)  If that
        doesn't work, try using the TRSREAD program to
        extract individual files from the TRS-80 disks. 
        Then use TRSWRITE to transfer the individual files
        into virtual disk files.

     o  As a last resort, if you still have your TRS-80, try
        buying or constructing a null modem cable and
        transferring files from your TRS-80 to your PC with
        communications programs.  (Directions on how to
        make this transfer can be found on many web pages
        and Usenet newsgroups.)  Then use TRSWRITE to
        transfer individual files into virtual disk files.


NOTE
----
READDISK is freeware.  Free distribution of READDISK is
encouraged, or distribution for a small handling fee,
PROVIDED THAT THE ORIGINAL .ZIP FILE REMAINS INTACT. 
Remember, however, that READDISK is NOT public domain
software.  All copyrights connected with the program and its
accompanying document files remain with me (Matthew Reed).


------------
Matthew Reed
mkr@poboxes.com
http://www.arrowweb.com/mkr