MAN page from RedHat Other xtrs-1.9-1.i386.rpm

mkdisk

Section: User Commands (1)
Index

Name

mkdisk - Make a blank emulated floppy or hard disk for xtrs

Syntax

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

Description

The mkdisk program is part of the xtrs(1) package. It makes ablank (unformatted) emulated floppy or hard drive in a file. See thextrs man page for background information.

With the -1 flag, mkdisk makes an unformatted emulated floppy oftype JV1. With the -3 flag (which is the default and should normallybe used), mkdisk makes an unformatted emulated floppy of typeJV3. The conventional file extension for both types is ".dsk", butmkdisk does not enforce this convention; you can give any filename.

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

For cyl, the default value is 202, the maximum is 202 (ModelI/III) or 203 (Model 4), and the minimum is 3. Note: Model I/III LDOScould handle 203 cylinders except for a minor bug in FORMAT/CMD thatprevents such a large drive from being formatted. You can use a203-cylinder drive with Model I/III LDOS if you format it with Model 4LDOS.

For sec, the default value is 256, the maximum is 256, and theminimum is 4. Note: if you are using version 1.1 of Matthew Reed'sModel I/III emulator and you would like to share emulated hard driveswith it, then if sec is greater than 32, it must be divisible by32. Later Reed emulators do not have this limitation.

For gran, the default value is 8, the maximum is 8, and theminimum is 1. In addition, it is necessary that sec be evenlydivisible by gran, and that sec/gran be less than or equalto 32.

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

Seeing that the absolute maximum drive size is less than 13 MB andthat the maximum granule size is only 8 KB, wasted space should not bemuch of a concern for most xtrs users. Therefore the defaultparameters have been chosen to give you the largest drive possible.

The dir parameter declares which cylinder will contain the LDOSdirectory. The default value is 1, a good choice so that the emulateddrive image can start out small, with no data written past cylinder 1by the LDOS FORMAT program. You should invoke the LDOS FORMAT programon the new image with the same dir value you used withmkdisk; for example, if you omitted the -d option and acceptedthe default value of 1, then type FORMAT (DIR=1). Note: settingthe -d dir and DIR=dir values to agree is not essentialunless you plan to share hard drive images with Matthew Reed'semulators; xtrs itself ignores the dir parameter andallows FORMAT to place the directory on any cylinder.

Authors

mkdisk was written by Timothy Mann <mannAATTpa.dec.com>, DigitalEquipment Corporation.

The floppy file formats here called JV1 and JV3 were developed by JeffVavasour for his MSDOS-based Model I and Model III/4 emulators(respectively). They have become a de facto standard in the TRS-80emulation community, and much TRS-80 software is available on theInternet in .dsk format. Thanks to Jeff for designing and documentingthe formats.

The hard drive format was developed by Matthew Reed for hisMSDOS-based Model I/III and Model 4 emulators. I have duplicated hisformat to allow users to exchange .hdv hard drive images betweenxtrs and Matthew's emulators. Thanks to Matthew for designingthe format and providing documentation.

This document was created byman2html,using the manual pages.