


Name
  mkdisk - Make a blank emulated floppy or hard disk for WinTRS80

Syntax
  mkdisk [-1 | -3 | -h] [-c cyl] [-s sec] [-g gran] [-d dir] filename

Description
  The mkdisk program is part of the WinTRS80 package.  It makes a blank
  (unformatted) emulated floppy or hard drive in a file.  See the WinTRS80
  manual for background information.

  With the -1 flag, mkdisk makes an unformatted emulated floppy of type JV1.
  With the -3 flag (which is the default and should normally be used), mkdisk
  makes an unformatted emulated floppy of type JV3.  The conventional file
  extension for both types is ".dsk", but mkdisk does not enforce this con-
  vention; you can give any filename.

  With the -h flag, mkdisk makes an unformatted emulated hard drive with cyl
  cylinders, sec sectors, and gran granules (LDOS allocation units) per
  cylinder.  You should format the drive with its directory on cylinder dir.
  You will usually want to use the default values for all these parameters.
  The conventional file extension for emulated hard drives is ".hdv", but
  mkdisk does not enforce this convention; you can give any filename.

  For cyl, the default value is 202, the maximum is 202 (Model I/III) or 203
  (Model 4), and the minimum is 3.  Note: Model I/III LDOS could handle 203
  cylinders except for a minor bug in FORMAT/CMD that prevents such a large
  drive from being formatted.  You can use a 203-cylinder drive with Model
  I/III LDOS if you format it with Model 4 LDOS.

  For sec, the default value is 256, the maximum is 256, and the minimum is
  4.  Note: if you are using version 1.1 of Matthew Reed's Model I/III emula-
  tor and you would like to share emulated hard drives with it, then if sec
  is greater than 32, it must be divisible by 32.  Later Reed emulators do
  not have this limitation.

  For gran, the default value is 8, the maximum is 8, and the minimum is 1.
  In addition, it is necessary that sec be evenly divisible by gran, and that
  sec/gran be less than or equal to 32.

  The maximum size of a hard drive image is controlled by cyl and sec: it can
  be at most cyl*sec 256-byte sectors.  The image file starts out small and
  grows as you write to more cylinders.  The allocation efficiency is con-
  trolled by the granule size: LDOS allocates file space in gran-sized units.
  Therefore (1) gran should always be set as large as possible and (2) reduc-
  ing sec, thereby making the granules smaller, reduces wasted space due to
  fragmentation but limits the maximum size of the drive.

  Seeing that the absolute maximum 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 WinTRS80 users.  Therefore the default parameters have been
  chosen to give you the largest drive possible.

  The dir parameter declares which cylinder will contain the LDOS directory.
  The default value is 1, a good choice so that the emulated drive image can
  start out small, with no data written past cylinder 1 by the LDOS FORMAT
  program.  You should invoke the LDOS FORMAT program on the new image with
  the same dir value you used with mkdisk; for example, if you omitted the -d
  option and accepted the default value of 1, then type FORMAT (DIR=1).
  Note: setting the -d dir and DIR=dir values to agree is not essential
  unless you plan to share hard drive images with Matthew Reed's emulators;
  WinTRS80 itself ignores the dir parameter and allows FORMAT to place the
  directory on any cylinder.

Authors
  mkdisk was written by Timothy Mann <mann@pa.dec.com>, Digital Equipment
  Corporation.

  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 (respec-
  tively).  They have become a de facto standard in the TRS-80 emulation com-
  munity, and much TRS-80 software is available on the Internet in .dsk for-
  mat.  Thanks to Jeff for designing and documenting the formats.

  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 WinTRS80 and Matthew's
  emulators.  Thanks to Matthew for designing the format and providing
  documentation.
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